Read Me Before you start a new thread!* Looking for more Power? Read in here, all you need to know. - Saxperience

-Dan- · 8th June 2009, 19:43

I'm fed up with seeing people asking the same question(s) over and over again about how to get '-Insert figure here- bhp' extra from their '1.1, Westcoast, Furio, VTR, VTS etc etc' Saxo, so I thought, despite there being a fair bit of information around, I'd summarise it into an easy to read and understand format, with all models of the Saxo range catered for.

Right...

The first step when looking for more power, is not an ebay 'Electronic Supercharger' or an '-Insert figure here- BHP Chip'. These are rubbish, and while occasionally the 'chip' is quite effective on some engine types, the power claims are bollocks. The general rule is you pay for what you get, for more info - see Ryans thread in the stickies on Ebay Superchargers and Chips.

Acceleration isn't all about power, its about a great bit list of things, the most notable are power to weight, and traction. So a lightweight car like the S1 Lotus Elise that only has a 1.8 118bhp engine, yet only weighs 750kg will nearly always out-accelerate something with a huge engine but weighs far more like a BMW 540i with it's 4.4 V8 and 286bhp.

You simply don't need high litre, high bhp engines for a Saxo, the weight of it would make it counter productive, and you can guarentee you will hit every single problem possible at some point during the project, and odds on say it would be an absolutely MASSIVE achievement if you even got it running, let alone moving, and handling even slightly well.

If you don't fancy the work/costs/drawbacks involved with boosting, you could go down the N/A route. There are numerous examples of very highly tuned N/A Saxos/106s on here, which I can only imagine goes like stink, and I think it's fair to say this is massively more than your average person would be able to handle, and certainly overkill If the car is intended for road use (as I guess most people want their cars for).

So don't let power and massive bhp figures go to your head, in the real world figures are basically just a guideline, and anyone that knows anything about cars will tell you to take power figures etc with a pinch of salt unless the entire car (suspension, chassis, brakes, tyres etc) are to a similar standard.

On to the improvements

If you want my advice, the engine, albeit arguably the most important part of a car isn't the ONLY part. Don't neglect things like the suspension, brakes etc.
The rule of thumb when it comes to performance upgrades, is do things evenly. You see a prime example in the Muscle vs Jap Car feud.

You have huge amounts of power in the muscle cars, which great, down the drag strip is all well and good, but as soon as you include corners, or places where they have to brake, the well-rounded (but less powerful) jap cars dick on them.

In the same way (although not quite as extreme) spending £1,000s of pounds on your engine, and keeping the standard suspension is the same sort of thing. I think most of the regular track go-ers will back me up in saying that a well-balanced saxo with a decent suspension setup running about 150bhp, will beat any 200bhp Turbo'd Saxo running standard shocks and springs, standard brakes etc around a track every day of the week. Especially if the less powerful car is properly setup and much lighter.

Further to what I said above about an overall package being better than just spunking money into the engine, I thought I'd lay out a couple of guideline setups for people looking for a well-rounded package.

Road-Setup

Based on a standard setup - with the following modifications.

Power and Transmission
- Panel Filter and Cold-Air Feed or Enclosed Induction Kit - choice is yours.
- Decat Pipe (For a MK1 or a VTS) or an aftermarket Manifold on the 8v MK2s to replace the Mani-Cat
- Choice of exhaust system - for a road-car a double-silenced system will help stop droning.

Suspension
- Bilstein B4 Dampers Front and Rear or the OE Citroen ones if they're still in good condition.
- Eibach Pro-Kit (35mm) or Eibach Sportline (50mm) springs - choice is yours.

This setup will have a good combination of noise, performance and looks without compromising the car on the sh*tty UK roads.

Fast-Road-Setup

Based on a standard setup - with the following modifications.

Power and Transmission
- Panel Filter and Cold-Air Feed or Enclosed Induction Kit - choice is yours.
- Decat Pipe (For a MK1 or a VTS) or an aftermarket Manifold on the 8v MK2s to replace the Mani-Cat
- Choice of exhaust system - for a road-car a double-silenced system will help stop droning.
- Uprated Gear linkages (firms up the gearchange)
- Quickshift

Suspension/Control
- Bilstein B8 Dampers Front and Rear
- Faulkner 155lb springs, lowering roughly 35mm
- Powerflex/Polyrace uprated bushes all-round
- Some nice grippy sports tyres - See the Tyres thread in the stickies for good choices.
- Kamracing 'Fast-Road' brake package - Mintex M1144 Pads all round and Maxtorq Group N Discs.

Interior
- Bucket Seats and Harnesses
- Decent Wheel (OMP or a replica)

This is a more driver focussed setup and it's all about hitting the twisties and letting the Bilstein and Faulkner setup work it's magic.

Light Track-Work and Fast-Road Setup

The next stage after that is where it gets complicated and much more 'personal' to the individual. But personally for Light Track and Heavy Fast-Road usage I'd get everything done that I listed in the Fast-Road setup then, I'd look into getting a wilder cam profile going on, and a decent remap. Match this to the AST Coilover unit with the 170lb Springs coupled again with some Bilstein B8s on the rear and you'd have a nice setup going on. I'd also definately looking into getting some high-performance discs and pads resistant to fade and warping. Then of course arguably the most important two things - I'd lose all the un-necessary weight from the car, and get some lightweight wheels wrapped in some decent tyres.

Onwards we go...

-Dan- · 8th June 2009, 19:43

The Basics

No matter which model in the range you have, the first steps to freeing up some extra horses is to get the breathing mods done, and most importantly - done correctly.

By this you should be looking at:

Enclosed Induction kit - Most people claim these to be the best form of Induction for your Saxo, as it's a completely enclosed filter being fed through a Cold Air Feed - direct piping from the front of the car (where the air rushes in) into the filter, which in turn filters all the crap out of the air.

A well known problem is when sitting stationary or not moving these kinds of filters may lack in drawing in the necessary cold air.

These are the most expensive type of filter available, and along with the panel filter, the only type of filter you should consider if looking for decent gains. They can cost anywhere upwards of £90, some going all the way up to £300+

The Panel Filter

A panel filter is a direct replacement for the cars standard filter element and offers superior airflow and better quality materials used. Generally these cost anywhere around £30-40 depending on make, but obviously you can get them more expensive or perhaps cheaper, depending on you budget.

Something worth considering when upgrading to a panel filter, is to get an aftermarket cold air feed, to replace the more restrictive factory piping (especially on the 8v models) and attach to where the 1st jubilee clip clamps onto where the filter is located.

Which you choose out of these two forms of upgraded induction is up to you, and the difference is largely debated. If you are trying to get power on a smallish budget, then the panel filter should be your choice, or If money is no object, then It may be worth considering the likes of the BMC CDA.

The Exhaust System

The Exhaust in Saxos are generally broken down into 3 Separate Sections

The Exhaust Manifold - This is connected to the head and is the first system of exhaust gas exit after the engine. If you open up your engine bay, it is the 4 metal pipes that come out of the head and dissapear off down under the car.

Centre Section - This links the Manifold to the Back Box, and is basically a long straight pipe. It may have a Silencer in, or not, depending on what model the car is etc. (The Silencer will be a box that is in the middle of all the piping)

Back Box - This is the final part of the exhaust system the bit that people see with the tailpipe. It is also known as a Siliencer. It reduces the noise levels, and the exhaust gases flow out of here and out into the air through the tailpipe.

Also

The Catalytic converter - This is a new addition to a exhausts system all cars after 1994 have had to have a cat to pass an emission test at a MoT, it is a box with special materials to filter out harmful elements in the exhaust gases.

It depends on what model and year of car you have, as to where this will be located.

General rule -

All MK1's will have the Cat in the Centre Section (IIRC Y Reg was the first year not to have it here)

All the 8v MK2's (Y Reg onwards IIRC) Will have it in the manifold, and will have either a Straight through centre section (base models) or a pipe with a Silencer in (Furio and VTR)

All VTS's have the Cat in the Centre Section similar to the MK1, even the MK2 VTS's.

So now you know that, your thinking ok, but how do I improve things?

The Basics

The first step to see big Improvements (in terms of breathing mods) will be to De-Cat the car. Depending on what model this will either mean buying an aftermarket Manifold, or an Aftermarket Centre Section. This will give a big improvement on the overall responsiveness of the car.

The Backbox alone won't make barely any difference in terms of power gains, but determines the note of the exhaust tone, and should be a matching bore size to the rest of the exhaust so's to not lose back-pressure.

* - Credit for the following sections go to VTS_16v_Boy - Taken from the 'Exhaust thread'.

*The Centre Pipe - This is basically what it says it is, a centre section with the siliencer removed. This will do two things, greatly improve gasflow and increase noise levels. This is totally legal, as older cars may have only had a single siliencer but as laws and MoTs have changed over the years cars have had to be quiter, so most cars will come with at least one siliencer as well as the back box which is a siliencer. These can cost anywhere between £50-£100 depending on brand and material

*The Manifold - As well as the Cat this is the most restrictive part of a cars exhaust system, some more than others its worth pointing out! By changing the way the gases exit the head and entre the exhaust its possible to change the way the car performs. Most cars have a two peice cast item from new which is heavy and restrive, by changing it to a Mild Steel or Stainless Steel item you can improve a cars performance. These are call 4 Branch as they have 1 pipe per cyclinder so on a inline 4 engine you have 4 branchs or pipes.

*There are two tpes available a 4-2-1 which is 4 pipes that go into 2 pipes that go into 1 pipe which then connects to the exhaust system or Cat, there is also a 4-1 whcih is again 4 pipes but this time all 4 pipes go into 1 pipe which connects to the exhaust system or Cat. The two have a different effect on the way it improves the performance of the car whcih I will explain later. There are manifolds with Sports Cats in them for certain VTR's but these are very expensive with most people choicing to avoid these simply because of high costs.

*Back pressure is created in a exhaust system and the amounts of pressure effect performance. Bigger is not always better, too larger bore in a exhaust system and the gases in the system will lose pressure and the performance of your car will suffer, the same goes for if the bore is too small the gases will be restricted and again performance will suffer. Most aftermarket 'off the shelf' exhausts are the same size bore as the factory item so when buying a sports exhaust of anykind you shouldnt have to worry, but with Custom Exhausts becoming more and more common its improtant to get it right.

Right so If you've now followed me this far - and have upgraded all the components mentioned - your basic breathing mods are done.

I know you won't care about all this and you just want to know how much power your now running?

General rule is If all are done well on a good system you can make UP TO 15bhp, but by no means is this a guarentee.

Of course power gains won't be as high on models such as the 1.1 because the engine is smaller and has less potential.
So your:

1.1 - will have gone from 60bhp to possibly around 70bhp

Furio/Westie - Can get anywhere between 80 and 90 bhp

VTR -
MK1 Models - May see around 100-105bhp
MK2 Models - May see around 105-115 bhp

VTS - Could see potentially up to 135 bhp - but generally breathing is already quite good on the VTS, so gains aren't generally as good as you'd see on a VTR.

Note: These figures are a rough guideline - I'm by no means saying you WILL get this figure - there are far too many variables to consider, but just giving people some sort of ballpark figures to look for.

-Dan- · 8th June 2009, 19:43

So now what you ask?

Well this is where big power gains are to be had, and where big money is starting to be spent.

Uprated Camshafts * Credit goes to Balance Motorsport

Camshafts probably change the character of an engine more than any other component. The aggressive profiles available for race engines by people such as CatCams and Newmans do for sure.

By controlling the timing of the inlet and exhaust valve opening this simple component can change an engine from a low revving, economical and docile specification to a high revving race engine. The biggest issue for the driver looking for more speed in todays world is catalysts.

If your vehicle will be still for road use and is equipped with a cat it will affect cam choice. All out race cams are designed to operate well at high RPM and often run poorly at low rpm.

That said with modern engine management and vernier cam pulleys you can get even very highly tuned engines through an MOT and then optimise for maximum performance on the track.

Honda's VTEC range of engines utilise 2 distinct cam profiles, one of which is akin to a race specification cam. This engages when the revs are above say 5500 rpm. Anyone who has driven one of these will know what you can expect from the top end of the rev range by fitting an uprated camshaft.

The key to successful cam selection for your engine is matching it to the engines intended use. Many cams suggest the intended application in their name. Race for instance generally means race use only.

Bear in mind though that cam choice is influenced by the ratio volume of the cylinder to the valve area. In a nutshell a bigger engine with the same valves will be more flexible at lower revs and probably not rev as high with the same cam as a smaller engine. e.g fit the same cam in a 1.6 and 2.0 engine that have the same head design and the 1.6 engine will be much more inflexible in its power delivery.

If you fit a hot cam with a largely standard head the engine will be more tractable than with a big valve head. The big valve head will get into it's stride higher in the rev range and make more power though.

These are all important considerations if you are opting for a capacity increase or if you are fitting a cam into an an engine with 2 valves per cylinder (such as the VTS). 2 valve heads usually flow less air but can often stand a hotter cam and remain flexible at low revs.

Due to the costs involved, most people don't tend to Cam Saxos lower in the range than the VTR. This is simply because the gains aren't proportionate to the costs involved.

Rough cost of Cams can range upwards of 210+Vat (for a VTR) up to £1000s depending on model, make etc. Factor into this the cost of a remap and your looking at about £1000 to get the cams set up, timed and having the whole lot remapped to use the best power.

* (following credit goes to WilliamsVTS)

*When choosing a cam you want to leave about 1.5mm valve to piston clearance, you never know what could happen.

*lift on standard cam is 8.49mm and has valve clearance of 3.01mm, so you can work it out from there (although this would need to be worked out from lift at TDC). if you were wanting cams with more lift you would either need your pistons rebated or some forged pistons. you would also need to consider throttle bodies as cams with that much lift would be being restricted by the standard inlet.

So to simplify things - you can buy:

Mild Cams - These aren't a huge amount different than standard, and once mapped will give nice smooth idle. Power gains Once mapped would probably see about 15 bhp on a VTS. An Example would be the Newmans PH1.

Mild Fast Road/Track Cams - These are the ones that most people go for, and offer a good compromise of everyday useability with good power gains. Once mapped on a VTS would see probably pushing 20-25bhp. An Example would be the Newmans PH3

Full Race/Rally Spec Cam - Only realisticly usable in a track car, will give even better gains due to the wildness of the cam, but not recommended for use in a road car. An example would be the Newmans PH5.

-Dan- · 8th June 2009, 19:43

Headwork - *Section Taken from Import Tuner

An internal combustion engine is like a big air pump, and the more air you can get it to pump, the more torque and horsepower it will make. Things like bigger camshafts, aftermarket intakes and exhausts can help increase airflow to a certain point, but ultimately, to get the most out of your high-tech air pump, you've got to make the cylinder head more efficient.

The goal of modding any cylinder head is to increase its volumetric efficiency (VE). The VE is a measurement of how efficiently an engine can pump air relative to how much it displaces. For example, if an engine has a displacement of 1000cc and moves 700cc of air with every stroke, it has a VE of 70 percent. If it moved 1000cc with each stroke, the VE would be 100 percent.

Cleaning up any imperfections where the valve meets the head, will help the intake charge flow into the head with the least amount of resistance possible.

Most modern multi-valve engines have a peak volumetric efficiency of around 80 percent; which leaves plenty of room for improvement. All things equal, bringing the VE up by 10 percent should yield an additional 10 percent increase in power and torque-in theory at least. There are different ways to increase the VE of a 4-stroke cylinder head, and the key to getting the highest VE is to make sure all the methods and parts used are compatible.

Aftermarket cams can increase airflow by keeping the valves open for a longer period of time (more duration), or by just pushing the valve farther into the combustion chamber (more lift). Be warned, if you just install bigger cams without making any changes to the head, you're not getting all the power the cams can offer. Because OEM heads often have many manufacturing imperfections in the ports and combustion chamber that inhibit flow, often times opening the valves up more or longer won't increase airflow much over stock.

Even without changing the camshafts, mild headwork can increase an engine's VE substantially, and gains of around 10 percent or more are common if the job was done well. If that's not enough and you decide to toss some cams on too, consider this: Camshafts and heads are designed to work as a single unit. In order to get the best results, have the same shop that does the headwork grind you a set of custom camshafts to match the head.

One way they increase effieciency is with a machine used to force an abrasive putty-like substance through things like intake manifolds and cylinder head ports to remove casting imperfections and increase airflow.
Most people that know anything about headwork will tell you that 50 percent of the gains of a full port and polish could be had by simply performing a quality valve job. This is good news for budget racers, considering the cost of a quality port and polish.

The reason behind this phenomenon is a simple one. All of the air that flows into the engine must flow directly past the valve, making the aerodynamic profile of the valve very important. If the valve has sharp angles and casting imperfections, it will create turbulence and decrease the amount of air that can move past it. Making the valve as aerodynamic as possible can pay in dividends.

Multi-angle valve jobs are the most common way to make a valve more aerodynamic and make the head more efficient. A multi-angle valve job puts extra cuts on the valve near where it mates with the cylinder head, streamlining it and helping to move air past its surfaces with the minimum resistance and turbulence possible. OEM valve jobs are usually one or two-angle valve jobs. This is done to keep costs low, and even if they want more airflow, OEMs will often just switch to a larger valve instead of using multi-angle valve jobs because it's cheaper than performing the extra machining of a multi-angle job. However, for the average enthusiast, the opposite typically holds true because oversized valves can be very costly.

The more angles a valve job employs, the better it will generally flow. The most common multi-angle valve jobs are 3-angle, 5-angle and radius valve jobs. A radius valve job is basically a 5-angle job where the transitions between the 5 angles are smoothed out. The downside is that the more cuts, the higher the cost. For this reason, 3-angle jobs are the most common and offer a good balance between cost and performance. Don't underestimate the importance of a quality valve job.

We've all heard the term "ported and polished," and it's likely we've all got idea what it means. To the average enthusiast, this means enlarging, and possibly reshaping the intake and exhaust ports and polishing the combustion chamber. Sounds simple enough, right?

Wrong. Cylinder head porting is an art. While some of the common methods and techniques can be explained, because of the advanced physics involved, porting is something best left to the professionals. In fact, without expensive and complex equipment, there is no way to even measure any changes.

Contrary to popular belief, a good port job doesn't simply include making all the ports as big as possible, as this will often result in a soggy engine that has lousy throttle response. Things like air velocity must be taken into consideration, which sometimes requires making the ports smaller than stock to increase the velocity. That's the thing about porting-sometimes the results are counter-intuitive; which means unless you are willing to destroy a few heads through trial and error, make sure your head shop knows what they are doing. The only real way to test if the changes that were made helped is with the use of a flow bench or a dyno... and do you have either of those?

What the car will be used for will generally dictate how much porting will actually be done. Proper porting takes into consideration things like engine size, RPM range, horsepower, etc and must be done to match the other mods. For a street car, this usually means only cleaning up casting imperfections, a mild un-shrouding of the valves and smoothing everything out. For a full-race motor, a port job might include enlarging the intake and exhaust ports as well as reshaping and polishing the combustion chamber. It all depends on the goals. Any reputable head builder should be able to tell you what is best for your car.

-Dan- · 8th June 2009, 19:44

Boost (Turbo/Supercharger) Setup - * Entire Section taken from GMC Motorsport

*For those contemplating fitting a supercharger as a means of performance enhancement, whose knowledge of its operation is small, this is how it works. Put simply, the supercharger is an air pump that forces air into the engine. As the power of an engine is dependent upon the volume of air that can be fuelled and burnt in the cylinders, this is a vastly superior method of induction than allowing the engine to suck its fill of air, as even with the most efficient engine it will not suck enough to fill the cylinders. A supercharger is similar to turbocharger insofar as it acts as an air pump; the crucial difference being a supercharger is a mechanically driven pump whereas the turbocharger uses the power of hot exhaust gases to power the pump.

Why a supercharger rather than a turbocharger? Turbochargers are inherently more difficult to control due to the tremendously high temperatures they generate and the way they produce a dramatic rise in air pressure, resulting in instantaneous large horsepower increases. Although this may sound ideal it usually results in uncontrollable wheel spin and loss of handling to the point of making driving dangerous, forcing the driver to back off and losing the benefits of all this power, always assuming he's still on the road. All these problems of a turbocharger can be tamed to a certain extent but it involves much extra technology and cost.

Apart from this driveability problem the other downside is that this sudden rise in pressure, means very careful engine management adjustments to set the fuelling and ignition correctly to avoid engine blow ups.

Several Saxo turbo's that we have heard of produced reasonable power but destroyed themselves and the installer then rebuilt them with lower boost to preserve the engine. This did cure the reliability but then power was way down. Another example of this was a turbo conversion on a Ford Fiesta done by a well know company, the result was only 30% increase in power, in our opinion not worth the bother or expense. Another downside of turbo's due to the very rapid increase in power, is the effect on the transmission components, all turbo's wear out clutches and gearboxes more quickly. These components like gradual torque increases not sudden violent increases.

There are several types of supercharger, most compress the air with the use of vanes screws or rotors, these types of units are called positive displacement superchargers, meaning that that they suck in a set volume of air and compress it into a smaller higher pressure volume. This method means you have to have a large unit in comparison to the volume it compresses and because of it’s size, plus the physical effort of compressing the air, it takes a lot of power to drive it. This creates several problems, one being that due to the high power needed to drive them, they need a large heavy-duty drive train, usually consisting of a wide toothed belt driven off the engine crank shaft by means of a custom made pulley.

The other main problem is the power it takes to drive. It is not uncommon to take 45 or more horsepower to drive them even for a relatively small unit. While these two problems can possibly be accepted these units are only really suitable for vehicles with large engine compartments due to their physical size, also, due to the complex engineering needed to build them, they are expensive. Another downside of all displacement superchargers is that they produce maximum boost at about 3000 engine rpm and then slowly tail off, this may seem great to get such high boost quickly.

The reality is that it is bad from a driving situation, especially if you want maximum acceleration from a standing start. As you know any car will spin its wheels when driven away fast in first gear, the last thing you want is near max power at 3000 rpm, this just aggravates the problem, nor do you want power reducing the higher up the rev range you go, this is just the opposite of what you need. What you need is the ROTREX type charger that is centrifugal and is basically a gear driven turbo charger. The benefit of this type of charger is it takes little power to drive and the pressure builds up gradually from 1000 rpm at a linear rate, making driving a lot easier and the power more useable.

PLUS AND MINUS TURBO'S V SUPERCHARGERS

TURBO PLUS

Only one, where max boost/max power is required in full race, track application, where other considerations can be rejected, e.g. cost to build and develop, life expectancy etc.

TURBO MINUS

Much higher boost pressure needed for the same bhp due to pressurised air being much hotter, due to conduction from red hot exhaust manifold.
Much more complex management needed to control fuelling and ignition due instantaneous rise of boost pressure.
Higher pressures and temperatures encouraging detonation, the big engine destroyer.
More intercooling needed to cool inlet air.
Much higher under bonnet temperature making everything hotter and so reducing power.
High under bonnet temperature reducing life of things like wiring looms and hoses.
Much higher incidents of fire due to red hot turbo and manifold.
Compromise exhaust manifold and system function due to restriction of turbo not letting the gas flow freely.
Extra shock loadings on transmission due to sudden increase in power

SUPERCHARGER PLUS

Basically all the things the turbo is bad at the supercharger is good at.

SUPERCHARGER MINUS

No dump valve to make a nice noise

The ROTREX chargers are made in several sizes depending on engine capacity.

For those building their own kit I would recommend always going to a charger 1 size above what the engine capacity suggests, as the price for the next size higher is quite small and if necessary put a restrictor in to reduce the boost. The reason I say this is that most people start off with quite modest expectations but as soon as they have it fitted they want MORE and if the charger they have already fitted is running at max capacity, they have to discard it and buy a complete new unit. This problem of running out of charger capacity is especially a problem if the engine is 1) High revving e.g. over 7000 rpm. 2) 16 valve unit, as they eat air quicker than 8 valves. 3) The compression is lowered.

-Dan- · 8th June 2009, 19:44

Engine Conversion - * Entire Section taken from GMC Motorsport

*For those wanting to increase the power of their car one of the best and easiest ways is to change up to a bigger capacity unit. For those with a 1.0, 1.1 or 1.4 engine lots of tuning mods can be done to improve performance, in fact the same ones and at the same price as on the 1.6, so why not get a 1.6 engine to start with. If you were to tune a 1.0 or 1.1 to the limit it would cost far more than a mildly tuned 1.6 and would still not have the power and to a lesser degree this holds good for the 1.4.

The great advantage of putting a 1.6 VTR engine into a smaller engine model (this can also be done on AX’s) is that as it is the same series of engine, the TU, it just goes straight in with no modifications. I know some people; especially those with 1.4’s will say that the VTR engine is only 90 hp and so very little more than the 1.4. Whilst this is true the VTR has been deliberately restricted by Citroen to make it less powerful than the 16v VTS otherwise no one would buy a VTS. They achieve this by putting on an exhaust system that reduces in size in the middle section so if you fit a good sports system like the Scorpion or Piper, the power rises instantly. One more thing that most people don’t consider is the torque of engine, they only look at horsepower. Torque is far more important, torque gives acceleration, and horsepower gives top speed. The 1.6 VTR engine has substantially more torque than the 1.4 so even if you do not tune the engine it will be far superior.

Another point worth noting is that the engine looks the same as the one it replaces so that if you do not wish to disclose the change to your insurance company it is very unlikely in the event of an accident that they will ever know.

Any one doing a 1600 engine change to a vehicle registered pre 1992 also needs the latest type of gearbox as the fixing bolts are in different positions. The later gearbox is far superior in internal specification and it is likely that the gearbox on a pre 92 vehicle is in need of attention so it is probably a good thing to replace the gearbox anyway.

Please Note: The best Engine to use for a Conversion for power gains will quite simply be a VTS Engine. GMC don't mention it as an option and focus only on the VTR, but be under no illusions, the 16v Engine WILL be better to use.

spaghettifufanu · 8th June 2009, 19:44

Sticky , I think .

-Dan- · 8th June 2009, 19:44

Stand-Alone Management * Entire Section taken from GMC Motorsport

*For those not familiar with the term management systems, this section relates to the control of fuelling and ignition systems on modern vehicles. Management systems made their debut in the late 60s when a few vehicles had their fuelling controlled by electronic fuel injection and some year’s later crude electronic ignition systems found their way on to production vehicles. From the late 80s onwards most vehicles had partial or full modern management systems. Prior to any sort of management systems, and engines fuelling was controlled by carburetor and the ignition by distributor and contact breaker points. Both these systems were prone to the 2 problems of reliability and constant maintenance to keep performance and fuel consumption to optimum levels.

The advantage of modern management systems, for which you can read computer-controlled, means that the fuelling and ignition settings are constant for all time and cannot go out of adjustment, the system either works perfectly or does not work at all. For the majority of motorists this system is ideal as there is no maintenance or adjustments, for those who wish to improve the performance of their engine however, the lack of adjustment factor is this is the worst possible scenario. To improve the performance of any vehicle you have to make modifications,(read adjustments), so by the nature of modern vehicles with management systems, you are in conflict with their purpose.

Many tuning firms quote dramatic increases in power by various means but without altering the ECU, anyone who says they can increase the power of an engine by much more than 20% without altering the management system is either very optimistic, economical with the truth, never tested any results on a dyno or the standard management system specification was very poor.

By all means have your head ported and a better specification camshaft than standard fitted but remember the horsepower limitation will be the management system not the quality of the camshaft or cylinder head, so there is no point in fitting a race specification head and cam as you will be wasting your money. Another point worth mentioning is if you fit equipment to your car that needs more fuel than your management system can deliver, the engine will run weak causing overheating and a possible melt down. From our experience the maximum that a normal management system can handle in the way of engine modifications is a head job and 270degree, and maybe a 285degree cam; and even then you’ will probably find that the tick over and low speed running has been detrimentally affected.

So how you get large horsepower increases on an engine controlled with an ECU system? There are only two ways, one you the throw way your complete management system including the fuelling and ignition components and replace it with one of Weber’s competition kits, which reverts the system back to using carburetors along with a new electronic ignition system,(see kits in price list), or you get a programmable management system which broadly consist of two types. A unit like the DASTEK, which works in conjunction with your present system and allows, with the aid of a laptop computer, to change the fuelling and ignition parameters of your standard system but only within certain boundaries. The best unit, although more expensive, is OMEX unit, which allows all functions controlled by the ECU to be altered Which type you need depends on how far up the tuning scale you are going and also what the budget is.

These units allow the fuelling and ignition to be reprogrammed and are very good for high performance road cars when full benefits of a cam change and head job are required but no good for full competition due to limitations of what is re programmable. The main limitation to these units being that most standard management systems have a maximum revs cut out, to prevent over revving the standard engine, this function cannot be altered. There for, there is no point carrying out a conversion, particularly in respect to camshaft choice, where maximum power is going to occur at an rpm above that at which the cut out will operate. From experience, most systems with an RPM cut-out will operate very successfully up to a 285 cam. Using a DASTEK in conjunction with a head job and a 285 cam change can increase power between 20 and 40%.

Fitting a DASTEK to a the standard engine can also be of great benefit. How come I here you say? This seems to go against everything I have already said. The reason is that manufacturers designing the specification of the ECU have to take into consideration the variations between engines supposedly built to exactly the same specification. If you are building a million engines the differences between the best and the worst will be relatively wide and as you are only building one ECU to fit them all, its parameters will be less precise, than if each ECU was programmed for each engine individually, obviously no manufacturer could afford such time delays on the production line. There is one main area of the programming that has to be set well way from the ideal, this being at large throttle openings, where in order to prevent the engine running weak and possibly overheating or even worse engine destruction, they deliberately make the mixture far too rich. With any engine there are several mixture settings that can be done, relatively weak for best economy, a bit richer for maximum power, over rich for close to maximum power with some safety margin, so it is never too weak and then far too rich at which point power drops off dramatically. Naturally manufacturers not wanting any possible engine failures tend to err on the side of safety and run over rich, which obviously reduces power at the top end.

These are the reasons why is possible to find 2 totally identical cars which perform quite differently, one has all its specification in tune with ECU's parameters and the other doesn't. By fitting a DASTEK you can re-calibrate the engines fuelling and ignition parameters to exactly suit the engines and so get the most out of it that is possible. Therefore fitting a DASTEK unit should be considered as one of your first performance fitments and not one of the last as some people might think. The performance increase on a standard vehicle with the DASTEK fitted will vary as every vehicle is different, but from dyno tests most modern cars can benefit between 7 and 15% just by having the standard parameters adjusted to the engine. We have fitted many DASTEK units and everyone has given an increase after adjustment, this is not judgment, but by figures returned on our Rolling Road dyno. We are so confident that we guarantee to increase your horsepower or we do not charge you anything, but before we fit it, we do a full power test on your vehicle so that a comparison can be made after fitment. Lets assume we fit the unit and there is no power increase we will just remove the unit and you are free to go, so even assuming this situation, you will had a free power test and graph to prove it, so why not give it a try.

These systems can achieve all performance advantages of the DASTEK but is not limited in the parameters that can be changed, as it is a complete new management system to enable anything and everything to be changed. Why not add another 4 injectors or have them set sequential or not, up rev limit to 10000 RPM or perhaps decide when you sell the car to take it off and fit it to your next vehicle, as they are not model sensitive. You can fit it to any engine 2,3,4,5,6,8 or 12 cylinder. This system is so good that is the most widely used in competition motor sport today because it not only enables the engine tuner to adjust everything necessary, it is also ultra reliable.

Is not possible to quote figures for the costs of fitting either of these units other than the basics, as it depends how which you need, as there are special wiring looms, ignition triggers, relays, throttle switches, multiple throttle bodies, large injectors, ram trumpets, filters etc. so you can pick and choose the parts you to require.

CHIPS

I bet I can guess what you have been saying to yourself while reading most of this. This guy has forgotten about “CHIPS”. No I have not!

Although chips are the latest buzzword you have to appreciate what they actually are. All ECU's have a memory chip in them which records the parameters, by changing your standard chip for “performance chip” all you are doing is changing one chip with set parameters for another chip with set parameters. Knowing how even a small alteration to engine specification such as removing an air filter and replacing it with air trumpets can need quite significant changes to a program, it is impossible for anyone to write a chip in isolation and say this will give 10% more power or whatever, exactly for the reasons I mentioned earlier, that even 2 cars with supposedly the same specification will perform differently. The only time a chip could be worth even contemplating is on a set performance kit, fitted in its entirety with no deviation from the spec it was set up for. Generally this is only the case for turbo and supercharger engines where the chip is mainly altering boost pressures, not the general parameters.

There have been quite a few rolling road tests done comparing standard chips against performance chips, the results don’t make good reading, most only gained the odd horsepower which could be judged as testing error, some were even worse than standard, with the odd one showing quite a worthwhile gain. The fact that ABC company did the best chip on the test does not mean that their chip for another model would be just as good, its more likely to be down to dumb luck.

Most chips cost between £180 and £280 plus fitting or sending away your ECU for fitment at another £50, so do you think it is a chance worth taking?. Your only positive benefit might be to be able to brag in the pub that your car is chipped. Remember this when someone says his or her car has been chipped especially if you are buying it. If you are serious about more power cheaply with a guaranteed gain, get a DASTEK.

MF2 FUEL DRIVER

This unit is for adjusting the fuelling on any ECU controlled engine and all the adjustments are made by screwdriver, no lap tops or specialized equipment are needed, although highly recommended to be set on a rolling road with a gas analyzer. The problems for a lot of people, especially those living in countries where sophisticated test equipment , programmable management systems or fitting agents are not available, they are severely restricted in what modifications they can make, as no matter what specialist head,cams etc they have fitted, unless they can alter the fuelling, at the very least, the conversion is never going to work. The only downside with this unit is that it needs to operate on extra injectors fitted and cannot be used on the standard ones connected to the standard ECU. This also has a plus side in so far as your standard fuelling is not interfered with and this unit only comes in for additional fuelling requirements, most commonly it is used on supercharged and turbo charged conversions, this being the unit GMC use on all their supercharger conversions.

-Dan- · 8th June 2009, 19:44

Throttle-Body Setup *Section taken from GMC Motorsport*

Instead of going down the boost route, you could also go down the N/A route and still get pretty big power. This will come in the form of throttle-bodies.

Why fit multiple throttle bodies?

The purpose is to allow unrestricted flow of air to the cylinders, which is often a problem with standard inlet manifolds, plenum chambers when searching for maximum bhp. Having said this too many people jump to the conclusion that this what is holding their car back and want a throttle body kit. There is no point fiting throttle bodies on standard engine or on one that is only mildly tuned, as unless you have a high lift cam, head work, performance manifold and exhaust system, etc your engine will not be able to use the extra capacity of air you are throwing at it.

Sure it will go better but the money for a throttle body kit would give more power if you used it for the above mentioned parts, the only big benefit would be the fantastic sound that only throttle bodies give. It must be remebered when going for throttle bodies, the vast amount of other parts needed to fit them, the parts usually needed besides the throttle bodies themselfs are, inlet manifold, fuel rail, adaptors for trumpets, trumpets, air box, filter, throttle switch, linkage etc. For a rough guide most throttle body kits cost over £1000 plus fitting, plus you will need some form of programable management and the cost of programing time on the dyno.

Most relativley highly tuned engines do need throttle bodies, an example is the British Touring Car Championship, they are forced to use 1 single 64 mm throttle body and they still get over 280 bhp. I am noy trying to put anyone off the idea of multiple throttle bodies, just trying to make you aware that this is not be all and end all of serious tuning.

Another example is the full race Saxo VTS engine GMC Motorsport built for a racing series in Taiwan, this engine made 150 bhp at the wheels, OK a lot of money was spent to get this and would have been a lot cheaper to get this power by not doing certian things and using mulitple throttle bodies. The reason I mention this is that many people are worried about insurance and the fact the insurance engineer will be able to see the engine has been mwage tuned if he sees throttle bodies on it, whereas you can stiil have an enigne that looks reasonalbly standard from the outside and give good power on the standard throttle body.

So what is a throttle body set up worth over the standard single unit. Assuming the engine has been well sorted first, 15 bhp is usually the extra gained, on a basically standard engine, probably about 5 to 7 bhp. These comments are based on saxo engines, some engines have terrible inlet manifolds and plenum chambers, the Vauxhall Corsa 16 valve being one where far more could be expected.

Asuming you have decided to go for a mulitple throttle body set up, which throttle body do you specify. The best we have seen are the weber and Jenvey units and recently we have been favouring Jenvey more, as they do a far greater range of sizes and fitting applications, particularly short bodied units, which are a must when fitting to a front wheel drive car that has the induction system pointing to the bulkhead.

The reason I mention this is that just fitting a throttle body kit on any car, is only going to work well if certain rules are followed. The three main things you must achieve are an inlet length (from cylinder head to the end of the trumpets) of at least 15 inches, as if this is not achieved, all the power will be at very high revs and a reduction in low speed power.

Secondly, it is no good having a system that makes the trumpets nearer than 2 inches away from the bulkhead as this will restrict air flow and finally it is no good sucking hot air from the back of the engine. So unless you can fit an unrestricted air box that draws air from the front of the car you are wasting your time. If you were to fit a throttle body kit that does not achieve all these functions it is doubtful it will be of much if any advantage over the single one it replaces.

-Dan- · 8th June 2009, 19:45

Other Changes: Stripping/Suspension Setup * Some Information here taken from JDMEngineSamurai

Lighter is better…right? Yes and no. Yes, meaning if weight is removed properly from the vehicle then you’ll gain bonuses in speed, handling and acceleration, not to mention saving on petrol and part wear.
However, randomly removing parts for the sake of reducing weight can cost you in the handling and speed departments, which is something to keep in mind if you’re serious about using the car for competition. The key is to remember why you’re making the modifications and to keep track of the weight that you remove so if you discover your car is suddenly handling improperly or has lost horsepower, you can evaluate what you’ve done.

Keep Your Car Balanced

One thing to keep in mind is that your car is a balanced vehicle. Weight is transferred from front to back when accelerating, and removing the wrong weight from the wrong area can cause a variety of hazards. For example, if you remove weight from the wrong part of the car, you can upset the balance of the car, making it handle improperly. You must remove weight from front and back equally to maintain good balance. For example, if you remove 300 lbs. from the back of the car and don’t remove an equal weight off the front of the car, you’ll have increased the front weight percentage of the car drastically and you’ll have handling problems.

Use Scales to Track Your Weight Loss

To avoid balance issues, obtain a set of wheel scales and weigh the car with the driver in the seat. Wheel scales are available at a good motorfactors or online and will give you an idea of how much weight is distributed over each wheel. For example, if your vehicle carries a bigger percentage of weight in the back, you’ll want to try to keep that same percentage in mind when removing weight. Re-weighing the vehicle will help to track what the percentages are to keep everything balanced and avoid upsetting the overall weight distribution of the vehicle by removing too much from one area.

Improve Handling By Relocating Weight

Removing weight and relocating weight are two ways to help balance a vehicle. Removing weight as high as possible will give you the best cornering performance. For example, you can remove weight from the bonnet or boot lid by replacing it with a lighter carbon fiber model.

Remove Rotating Weight to Improve Handling and Pick Up Speed

There are two types of weight to remove in a car: static and moving. Static weight refers to things that don’t move, such as the bonnet, bootlid, spare tire, seats and battery. Moving weight refers to anything that moves or rotates, such as wheels, drive shafts and flywheels. Moving weight is more important to reduce because the car will accelerate faster without it. Removing a pound of rotating mass is like removing two pounds of static mass because rotating mass needs to be accelerated both in rotation and in linear motion. In short, the car must first move the part then move itself when dealing with rotating weight.

Please Note: Full Credit is listed wherever the work above is not mine, and in no way, shape or form am I trying to take credit for any work that isn't my own, I'm simply condensing it all into one big place for people to read at their leisure.

JamesR^m · 8th June 2009, 20:01

WOW. I am stuck for words, that epic.

-Dan- · 8th June 2009, 20:05

Cheers mate, no problems.

DieHardGunner · 8th June 2009, 20:12

Brilliant, thank you very much!

Ryan^p · 8th June 2009, 20:14

made sticky for you. Will help out at somepoint dude.

should pm simo about content contributors

Might need to check with John about copying his work though as it could land in trouble even though stating its his

AlexB^p · 8th June 2009, 20:15

very good thread
shame half the people wont read it

-Dan- · 8th June 2009, 20:17

Quote:

Originally Posted by Ryan

made sticky for you. Will help out at somepoint dude.

should pm simo about content contributors

Might need to check with John about copying his work though as it could land in trouble even though stating its his

I did wonder about it, so I've sent an email to GMC just to double check - along with the link showing what I've taken and that's it's all credited to them, so it hopefully won't be an Issue.