Turbo, Carbs, Throttle Bodies, Boost???

[quikydan]

Originally Posted by dannygti

John, please could you give me your input on what sort of spec you would use if YOU were building a turbo 16v with reasonable budget as a track car?

good question

[blackie_2k5]

Originally Posted by axsaxoman

no I wssn,t aware what type of engine it was, until andy posted --but same would hold true for any make ,its the shape thats is funny for a turbo,but I am not suprise it cannot hold 15psi knowing what turbo it is + power its making

the turbo has play so im basically helping it on its way out(then its getting hybi rebuild, from all counts and alot of reading that turbo is capable of running 18psi safely IF its fitted with a 360 degree thrust bearing, many run it on 15 psi without for a very long time with no issues

its very odd, as the gauge is T'd off the inlet manifold to give true manifold pressure... but it shows is holding full boost via gauge... however it also did this when i had the BIG hole...but didnt make as good power, once fixed it was a totally different animal

this is what i was wondering about the graph, as the s13's i managed to find graphs for running same pressure had similar lines.....

this is the old graph, on 10psi with small leak i didnt know about then, and fuel and exhaust isues, this was after first map, just to give me an idea of what i was working with, the lines are alot better...

[axsaxoman]

without showing boost pressure at same time on the graph it always going to be guessing games -
I could be wrong but if you look at the swift graph on page 10 you will see the boost line how it climbed then is a straight line when it was fully spooled,which shows the wastegate is working correctly ,if the engine eats all the boost ,ie turbo too small or not well matched,overspeeding you will see the boost drop .
it would also show how what ever boost control system you are running is working .
surely this and AFR are as important as bhp + torque on a turbo power run ,then you have some info to decide your next move and can see problems without stressing the engine too much with repeated runs. If you can add inlet temp + ambient as well then you have all you ever need

[blackie_2k5]

ai, well cheers for your input john, ill just have to tie up the bits and pieces and get a tweak to sort the richness out, and see where that lands me untill it gets a decent map with the turbo cam & electronic controller etc

edit- so your saying that more info is needed for the actual dyno data?

i think the first plan of action is to sort the issues i do know about, this alone will probs have a massive affect of the graph alone, the leak is causing a pretty irratic idle. so its going to be quite bad on positive pressure

[axsaxoman]

Originally Posted by dannygti

John, please could you give me your input on what sort of spec you would use if YOU were building a turbo 16v with reasonable budget as a track car?

not that I am going to tell you alot ,bearing mind the postings you have been making ,
I,ll do what you suggested and shut up
but how could i answer such a vague question anyway
whats a reasonable budget?,,,what bhp and at what rpm do you want this target bhp , what will be the internal spec of engine
all those things will effect how you should approach the whole build and must be set in stone before starting to do anything

[axsaxoman]

you cannot have too much data ==
dyno run should take no less than 15secs.(longer is better if your cooling can stand it) to allow things to stabalise and give best chance of accurate data

[dannygti]

Originally Posted by axsaxoman

not that I am going to tell you alot ,bearing mind the postings you have been making ,
I,ll do what you suggested and shut up
but how could i answer such a vague question anyway
whats a reasonable budget?,,,what bhp and at what rpm do you want this target bhp , what will be the internal spec of engine
all those things will effect how you should approach the whole build and must be set in stone before starting to do anything

John theres a lot of "you" in your statement.. Im not telling you what I want I'm asking what YOU would want

What do YOU think is a reasonable budget
What bhp would YOU want
What rpm YOU would want it at
How YOU would approach the build

Don't think I'm going to jump down your throat at this, I'm genuinely interested and would appreciate it.

[dannygti]

And John I stand by all my comments, sometimes its comical how you try and make turbocharging look so inefficient and insignificant. I don't think you have said one positive thing about this method of tuning.

Not to say I'm against other methods. Quite the opposite. I just think even with your own opinion it doesnt take much effort to praise/recognise advantages other ways of doing things even if you wouldn't do them yourself.

I LOVE Alex's engine
I LOVE adz engine
And would recommend these ways to other people. But I always ask what people want from their car first.

[Gareth_R]

Someone hurry up and drop a flag

[Sophia_Bush]

Lets say for argument sake 200bhp atw on either 8v or 16v how would you do it so it's going to be reliable usable daily and have scope for upgrade in future. I think thats a reasonable figure that a majority of people want from the off

[mangojace]

Also why did bmw mini change from supercharging to turbo?

Because they were more reliable, more fuel efficient and faster

[Ryanp]

Originally Posted by mangojace

Also why did bmw mini change from supercharging to turbo?

Because they were more reliable, more fuel efficient and faster

Just because a company have changed something it doesn't mean it changed to a better unit.

Often on cars the changes have alot to do with reducing the costs/more importantly emissions.

[mangojace]

Originally Posted by Ryan

Just because a company have changed something it doesn't mean it changed to a better unit.

Often on cars the changes have alot to do with reducing the costs/more importantly emissions.

Yes! Cheaper, Better on fuel, More Reliable and faster. John knows alot about supercharging , i give you that. But he seams very narrow minded when it comes to turbo's.

[axsaxoman]

the first point is bmw picked a very old fashioned type of s/c unit in the eaton which is very thirsty on power to drive it and it didn,t give good results --ran 14psi and only made 160bhp? -- now i would be ashamed if I couldn,r do a the same bhp with half that boost with a rotrex ,and I am not saying its the perfect s/c ,but at presnt its the best about --more on that later,
it was an obvious choice for them to go to turbo as so much development on turbo,s has taken place in the last few years with emission control and of curse there are alot of vested interests in keeping tubo,s on cars --the people who make then and with the numbers they make the pricing was always going to be better at this point in time ,
that said, in a couple of years you will see something different from rotrex --for the OE market --not after market at present and that is a fully variable speed torodial gearbox type of charger --ecu controlled which will get rid of the limitations it has at this time and will beat the turbo on emission control as well as response .
imagine a very high comp n/a but with a totally electronic control s/c so it can deliver exactly the boost you want at any engine rpm with no lag ,better emissions (mainly due to time it takes to warm up the turbo housing etc ,which is a draw back to turbo,s for emmissions on start + warm up
have you noticed how small the oil capacity and water rad sizes are --its all about getting the combustion temp up quick so the cat can work quicker.
we already have engines that need no throttle butterfly which is replaced by varying the inlet vlave lift from nothjing to wide to regulate the power while the fly by wire throttle is fully open .well add fully controllable boost so you can run even leaner and you get better fuel consumption + emmissions . smaller engines --boosted to give same power as larger n/a engines .but with all the benefits of a small unit
turbo,s can never give as good emmisions as a s/c ,run the ex gas too hot and it melts turbine blades --,so there are limitations and thats what the new generation of VNT turbo,s are trying to do,get ex gas too hot and you create NOX-you can control this without need for EGR systems with s/c-
for smallr cars and engines turbo days are numbered ==exactly when it will happen ,its a few years is my guess

[axsaxoman]

Originally Posted by dannygti

John theres a lot of "you" in your statement.. Im not telling you what I want I'm asking what YOU would want

What do YOU think is a reasonable budget
What bhp would YOU want
What rpm YOU would want it at
How YOU would approach the build

Don't think I'm going to jump down your throat at this, I'm genuinely interested and would appreciate it.

what I want from a race car is to apply power and know eaxactly what is going to happen at any given rpm and any throttle angle all the time ,by able to back off the throttle completley and come back on and have no lag--just like an n/a engine and the smaller the engine for a given output the harder it is to achieve with a turbo
add front wheel drive to this and it gets harder to do.
I see people putting light weight fly wheels on turbo cars ,which will make the problem of uncontrollable rpm increase even worse,
drive on is another nice turbo effect on partial closing of throttle
you start to shut off and it keeps going ,cos of the inertia in a big turbo is still making boost even though the engine rpm is dropping .
have you noticed how small the vnt type units are now ,with suitable control it can stop this -but not simple type units.
s/c boost goes up and down with engine rpm instantly
you will not see any turbo car being able to control understeer with power like you can with n/a or s/c ,not if you are looking at big numbers.
not unless you can keep it well above the spool point all the time and then they are hard work to drive fast other than in a straight line, the 8v engine is far nicer in this respect very underrated if you are looking at an all round everyday car aswell,it already has a much more usable power curve
having said that its probably alot easier to do this if you use a lower revving engine + higher gearing and it spools from say 2.k upwards to 6.5k ,as you should be able to drive within that no problem ,but if you are wanting big numbers then you just will not get an off the shelf turbo to do that and with a small engine you will need to use a bigger rpm ,plus you willl need a very good control system -4port actuator + vacumn or pressure tank and a well written boost map tobe able to have exactly the boost you want at any rpm --no sudden rise.
name me any car that trebles the bhp by boost that is made for the road--ther isn,t one because even the car makers cannot get the nice drivable power delivery they want using that sort of boost--they just drop in a bigger cc engine and then boost it less and then fit esp and all sorts of power + traction limiting devices
this is where the reasonable price bit comes in --I don,t think you would consider the parts i have suggested very reasonable .
If you trying to make a driving machine and not just a straight line big kick in the pants car it is not going to be as easy as it looks at first glance.
a bigger cc n/a engine would be the best choice ,but you are limited in what you can fit in a saxo and keep the handling ,due to weight +space limitations .
as to power level ,if you can get good civilised delivery you can get a much better lap time so for I will alwys go for larger engines or s/c .
240 @wheels with a turbo using normal type turbo,s _ correct gearing would be my maximum suggestion for a track car ,
if yuo cannot get to revlimter or max rpm or within few hundred rpm of it by the end of longest straight you are over geared --.that much is absolute fact
you only have to watch videos of more powerful ones on the the track and how they piussyfoot around the corners and only nail the throttle once the car is very straight to see what i mean.
if you can carry more speed in the corner then you are that much quicker down the whole length of the next straight ,so being able to maximise corner speeds by basically power sliding from the apex onwards with a progressive + predictable application of throttle is going to make big lap time differences

[RDKells]

Originally Posted by adzvtr

hows about we stop arguing about which is better and learn from this

NISSAN SKYLINE R35GT-R TWIN TURBO & TWIN SUPERCHARGED - YouTube

They make some valid points...


This thread is getting abit serious.. Pass the dooby.


I have a question... Can you super charge and turbo an engine?!

[hard_corejoeboy]

Yes! The Seat Ibiza has one that S and T'd

You can even Supercharge, turbocharge and tb i believe

[RDKells]

But I can't find anything on it!

Would be cool, throttle response then a massive boost from the turbo.

I want a supra. Like: Ever since I watched that, like 3 years ago, i've wanted one.

[dannygti]

John you quoted me and I was expecting some kind of answer from it. As usual you go on about how great the s/c is than the turbo, And not actually answering the question. If you don't want to because of losing face that's cool.


I remember watching a vid on YouTube of chris in his 106 turbo and george in his (more powerful) s/c car and not being as fast especially on the exit if the corners.... Wander if the turbo car was worried about perfect throttle response OR the s/c was wishing he had that kind of mid range torque to pull him out of the corners.


I stand by my statement that the only real lag you experience is the start of 1st gear and the rest of the time it can be Driven around on a well thought out setup.

What is the fastest production fwd car around the ring?? Oh, it's a hatch with turbocharger. and the second fastest etc
I wander if Renault thought about using a rotrex for ultimate throttle control or linear power delivery?


One of the main reasons I believe a turbo motor to be a big advantage is it will make superb power-torque the second the turbo spools, not like with rotrex as you have to wait for revs to rise and come on 'cam' so to speak.

[hard_corejoeboy]

TFSI are the Super and turbo'd engines i think?

True the record is turbo car but what if that car was 265bhp N/A?
The second fastest FWD car round the ring is the same engine as the first most powerful car

I think its sad the turbo trend is all due to emmissions regs blah blah bullshit CTR has been killed but then again even the turbo focus RS which IS turbo has been killed.