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Saxo Engine/Performance If you're interested in tuning Saxo engines, or if you need to know something which is engine related... this is the place for you.

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Old 8th January 2011, 18:25   #1
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Default Engine/Performance mods explained....

Guide to getting started in Modding.

This is just a basic guide. Everyone has there own idea on modifying and where to start. If your starting out. This quide covers the basics.

The easiest and most cost effective mod you can make to your car engine wise is replace the standard filter. Dead bugs and other muck clogs up the filter and restricts airflow into the inlet manifold which, in turn, means the car compensates by sending less fuel to the engine to stop it running rich. Think of trying to run a marathon with a blocked nose and you will understand. Simply replacing the standard airfilter with a performance one which is better design will make it run better.

Panel Filters

As the name suggests, a panel filter is a flat square or oblong foam or paper filter designed to sit in the cars airbox. Its the first and only line of defence for the engine, and it should be cleaned or replaced fairly regular to keep the car in tip-top condition. They are boring to look at but are effective. Some cars benifit from a performance pannel filter in the standard box with a larger diameter cold air feed than they do any other type of filter. Manufactuers spend millions developing there engines for standand tune and longevity. Some compnays such as honda get it spot on and fitting a performance filter can loose you power. Its best to go with what others reccomend.

Box and Pancake filters

Box and pancake filters tend to sit ontop of the engine. Think of top fed carb engines like the VW polo etc. People with these type of engines really benifit from performance filters 99% of the time.

Cone Filter

Panel filters are all very well, but some are mounted low in the engine bay, and should you hit a huge puddle, can scoop water into the engine. Cone filters are more compact. And can be placed virtualy anywhere your car permits. Its best to place them towards front of the car behind the grille if possible so they get a good flow of air, if this is not possible a good diameter cold air feed will do the trick. They also look good. One down side is they can suck hot air from the engine bay in loosing power. You can fit a metal heat sheild to lessen this.

Enclosed Kits

Enclosed kits are abit like the standard system. But will in most cases give you more performance and better looks under the bonnet.
U have a section which atatches to the inlet. Then you will have an enclosed cylinder or such like container which houses your filter. Then a cold air feed which has to be run to the front of the car. These are better as they stop the filter sucking in Hot air loosing you power.

MAF sensor

The Mass Air Flow sensor is a little widget in the induction system that tells the ECU how much air the car is getting. The ECU then works out how much fuel the car needs.


The material the filter is made from is important. Paper filters are cheap and are fine for standard engines. They are how ever not re-useable. Most performance filters can be washed out when needed. Cloth filters are thought to be more efficient they filter well and allow high airflow.

Induction kits.

There is a common belief that inductions kits = bolt on power. This is not always the case. As mentioned some cars work better on there standard systems with decent pannel filters than they do cones etc
Cold air feeds
These are usefull for directing cold air to open cone filters and standard boxes, they are very versatile so can be put just about anywhere you wish. They look good and do a decent job, may be worth noting that if they run over hot parts of the engine the air flowing throught will warm up and defeat the object slightly so may be worth thinkign about the route it will take


The other end of the engine is the exhaust. Just as important as induction and modding one without the other is pointless if your sucking more air in and making more gasses you need to get rid of them somehow.A good exhaust will also help draw air into the engine as there is a point when both valves are open so the gasses going out suck more in.

Turbos and Exhausts

Big IS clever when it comes to exhausts on turbo cars. Any back pressure in the exhaust will feed back along the system to the turbo housing and place stress on the turbo, slowing it down and reducing pressure.

Most OE manifolds are cast iron, these are then bolted to the downpipe and sectioned exhaust system that vents to the rear of the car.
Tubular manifolds are a good investment. They are expensive because of the design and manufactur process that goes into them.
Each will be designed for each model specificaly and for maximum power gains.

Mild V Stainless

Simply comes down to budget. Mild steel is cheaper but doesnt last as long. Stainless costs more and lasts longer. A stainless steel system is always the best to go for if you have the cash. If you can not afford a system then a backbox will be fine. Just dont expect power gains from it.

The catalytic converter is a device that sits in the front part of the exhaust system and helps to reduce pollution. Its creates interuption in the flow of exhaust gasses so many favor to take them off and fit a de-cat pipe for that extra bit of power. You will need it for the MOT tho so its best to get a slot out section.

ECU Mapping

Modern cars now use ECU's. Remapping is simply a blackart of improving performance of the engine by tweaking the fueling and ignition settings. Any given engine has an Ideal air/fuel ratio setting and ignition setting at every given rev. Its the job of the re-mapper to dial these figure into the ECU to give you that extra power. Its best to do it after fitted mods like cams etc to get the best from them. Mappers will almost certainly map it to a safe level. As there is a limit to what can be done safetly.

ECU upgrade

Upgraded ECU's can give you more room for improvment when it comes to changing the settings. also switchable modes I.e Road/Track etc so you can adjust it to suit.

ECU Locking

Some ECU's will lock you out after a certain number of re-flashes. Some will acept loads. But eventualy they lock. They can be either unlocked or replaced.

Spark plugs
Uprating the plugs wont exactly give you better performance but will help the engine run smoother. Gapping them to the Spec in the handbook for your car is a great start as it will keep the engine at its optimum power and help it burn fuel. Plugs also have heat ranges. If the plugs get to hot you get pre-ignition and in extreme cases the plug melts. So always follow what the Manufacturer says.
Multi-tip plugs give better sparking and longer life span. This makes the plug more efficient.


Replacement leads not only look good but give you a better connection. Most producers of performance leads make them vehicle specific so they are not hard to get hold of or pick. Just remember to re-place the leads one at a time so you get the firing order correct. Leads themselves also wont give you power gains as such. Just a more reliable ignition system

A turbo is basicaly a compressor. It has a turbine that sucks air in and forces it into the engine. This makes the engine alot more powerfull. Cooler air forced in by the turbo is mighty dense, so more fuel can be used thus more power. Only draw back is the turbo unit generates alot of heat as the compressors spin and very high speed. To overcome this a intercooler is fitted to cool the inlet charge. The exhaust gases are sent throught the intercooler then back to the turbo.Most intercoolers are air to air types.Efficiency is key,as any pressure drop means the turbo will be laggy, but forcing to much air into the cooler means it wont cool down properly. So choose carefully.


Superchargers are belt driven from the crank. It means power delivery is linear and inline with the increasing engine speed. Power delivery is smoother and earlier than a turbo system but it does the same job as a turbo by forcing air into the engine.

Boost pressure and Dumpvalves

Boost is a measure of pressure over atmospheric pressure excerted on the inlet manifold. It can be linked to a gauge inside the carand standard turbos are mapped to produce 0.5-1.4bar but highly modified engines produce way more. Boost pressure is limited by the wastegate that opens when turbo pressure builds up inside the exhaust side of the turbo.
Turbos work very well when you have your foot on the power. When your not on it, the pressure builds up and has no where to go. So it will either force its way past the butterfly, split hoses on the system or build up back pressure and slow the turbine. This means it takes longer to spool back up. So a valve is fitted in the inlet called a dump valve this dumps this pressure making the turbo run better.

Turbo Timers
With turbos running at over 100,000rpm it takes a while for the compressor to stop spinning. Early turbos were lubricated with a oil feed which stopped when the engine was switched off which meant the turbos internals where un-lubricated. So turbo timers where brought in so keep the car running for a few minutes after u leave it to allow the turbo to slow down.

Camshafts & Pulleys

Hi-lift camshafts are a good power mod, as they open the valve more and for longer to allow more air/fuel in and gasses out. This increases the amount of mixture the engine can burn and how fast it can do it. They normaly come as a kit with things such as valves springs etc. Some kits on High performance cars require alot more work. vernier pulleys are adjustable pulleys to adjust cam timing. They can give power gains when set correct.

Diesel Tuning
There are many alterations you can do to a diesel engine to increase power. Diesel engines run lean to reduce smoke. Adding more fuel will give you more power till the point where it increases the smoke and heat and no increase in power. Uprating the turbo is one of the best ways to get more fuel/air into the engine, itsnot as simple as turning the boost up tho. Has to be done carefully to stop dreaded black smoke and emmisions. Mechanical injections pumps found on older engines where easy to tune, most where screw type adjustment again just turning them up until smoke appears. Remaps and Tuning boxes are by far the most common way of getting more power from a Ci engine. They are mapped to suit the individual car just like on a petrol and give a very noticeable return in power and torque
The OE suspension on a car is designed for passenger comfort. So most people "lower" there cars to get better handling and road stance.
Lowering springs are the simplist form of getting better handling out the car. Matched with OE dampers they will drop the car by up to 60mm dependant on design. Damper and Spring kits are exactly that. Dampers designed to work with the springs, they will give better overall handling over just lowering the car and better peice of mind for some people. Coil-overs are the best option. They can be adjusted so you can set the stiffness ride height etc.

Anti-roll bars.

Almost every car is fitted with an anti roll bar. The ARB is a torsioning spring and connects the left and right wheels together through a drop link either side of the car. Its designed to reduce body roll in corners. A stiffer ARB will promote understeer while a stiffer rear ARB will promote oversteer.

Poly Bushes

If ultimate suspension response and feel are important to you then a set of polyurthane bushes will transform the feel of your car. They are alot siffer than OE bushes and offer greater feel and vehicle handling.

Brake Upgrades

If your finding the pedal response isnt what you wanted a cheap upgrade is some DOT5 Fluid, its the best you can get and you will feel a big difference in the pedal. But make sure you system can handle it before you put it in. Also braided brake hoses will give you better feel as it reduces buldging under heavy braking. Pads are the next cheapest option in upgrading. A decent set of pads will improve brakes alot. The new materials designed for performance pads is alot better than OE pads. Dont go for track pads, as they dont work well from cold so a tootle round town wont get them hot enough to operate correct. harder pads will wear standard discs alot quicker so its best to upgrade these to. OE discs do the job on most cars, but performance discs work alot better at disipating heat, they reduce stopping distances and also look very good. Bedding in, its important as you dont want to shell out £300 on a set of brakes to warp them by not bedding them in correct. its no good sticking them on, booting it slamming them on as they wont work. A few hundred miles of gentle driving will get rid of any surface grease/film on the pads and dics. And reduces the risk of warping them.

Further upgrades include alloy wheels, steering wheels, gearknobs, handbrake handles, gaiters, lights, gauges, seats, front and rear lights etc which dont need explaining and are down to personal choice

Last edited by Matt-T; 4th November 2011 at 11:43.
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Old 9th January 2011, 13:13   #2
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i know this isnt a guide yet but just thought you should give re-circ dumpvalves into consideration somepeople prefer to run re-circs as apposed to atmospheric!
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Old 9th January 2011, 14:02   #3
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Yeah, ill add them in when i gt chance....
will update as and when.

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Old 5th February 2011, 00:13   #4
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R1 carbs on vts possile?
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Old 21st March 2011, 13:13   #5
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Great read
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Old 26th March 2011, 21:12   #6
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Car(s): citroen saxo 1.4 8v Saxo vts 140+ bhp Mk4 golf 1

im thinking about turboing my saxo 1.4 8v does anyone no what a safe psi i could run it at without blowing the engine and not doing any engine moods atm. thanks
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Old 4th April 2011, 21:14   #7
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Originally Posted by jarvis112 View Post
im thinking about turboing my saxo 1.4 8v does anyone no what a safe psi i could run it at without blowing the engine and not doing any engine moods atm. thanks
Safely 4 psi
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Old 17th October 2011, 19:53   #8
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turbo,s run at 45000 rpm ???--
try over 100,000rpm
our s/c units run up to 120,000

MAF sensor --your description is incorrect and 106/saxo,s do not have one fitted
they have an MAP sensor
Mass Air Flow sensor is a device that consists of either a flap which is deflected by the flow of air over it (pug 205) and movesa contact across a carbon strip (like tps sensor ) which shows a variable voltage to the ecu , very old fashioned not used for 10-15years on cars in uk .
or the later types of MAF meters consist of a foil plate or coil of wire in the airstream which is cooled as the air passes it --this causes a change in the resistance in the wire ,by lowering the temperature of the wire (which alters the voltage passed through that wire --the ecu then interprets this as a Mass volume of air --quite often they will also have an inlet air tmep sensor built in them so what the ecu sees is actually RAD Relative Air Density .

MAP== Manifold Absolute Pressure sensor --this is a distortable membrane which measures the air pressure ,so a 1bar MAP sensor reads from full vacumn (0millibars)up to atmospheric pressure (1000millibars ) wide open throttle on an N/a engine

for boosted cars you will have a MAP sensor which will measure from 0 millibars to ,say 3000 millibars =2bar of boost
you will also have an inlet air temp sensor when you have a MAP sensor
some MAP sensors also have a combined air temp sensor EG .silver top 8v engine cars
when the flag drops the bulshit stops.
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Last edited by axsaxoman; 17th October 2011 at 20:11.
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Old 17th October 2011, 20:13   #9
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Originally Posted by Tweenyvts View Post
R1 carbs on vts possile?
yes but not a sensible choice --will never pass an mot and will never be as good as t/bodies
when the flag drops the bulshit stops.
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Old 2nd November 2011, 23:25   #10
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hey guys i dont come on here much but ive gots stuckwith my saxo - maby some of you can help....... i have a 1.4 furio mk2 and just baught kent sport injection cams, the car starts ok but the tappets are loose as f*ck

main problem is that a TDC the tappets have now play but when the piston is at the bottom there loose any suggestions

(sounds like a diesle) .... does any one know if i need new rockers, tappets, injectors and fuel lines, if this is the case what fits and were can i get them from

i kno its only 1.4 and people keep saying get a vts lump but ive gone to far to go back ... if ya can get back to me that ould be great x
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Old 4th November 2011, 11:42   #11
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Post your problem up as a new thread mate, you will get alot more answers doing it that way
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Old 5th December 2011, 13:53   #12
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great advice ive got a vtr its got an induction kit and straight through stainless steel exhaust where would my next move be to get even more power? please help!
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Old 13th January 2012, 10:49   #13
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Thanks,great overview for the noobs!
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Old 14th February 2012, 08:44   #14
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Loads of great info
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Old 16th March 2012, 23:42   #15
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turbo cars need back pressure!
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Old 19th April 2012, 21:18   #16
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good info especially for the noobs with lexus lights and big bores yo!
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Old 7th June 2012, 18:02   #17
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Great read, just what i was looking for
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Old 3rd July 2012, 14:45   #18
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Nice write up, a lot of good information there.
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Old 23rd July 2012, 01:00   #19
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does anyone know any sites apart from ebay ,could get a cheap SS mani from ?
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Old 23rd July 2012, 01:12   #20
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Originally Posted by azzad91 View Post
does anyone know any sites apart from ebay ,could get a cheap SS mani from ?

How cheap..?
Originally Posted by jeffchiz View Post
lol because you are a brand fag
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