bi-turbo gt v6 (z7u)

its good, we agree an the 0.55 bsfc, although this is a very theoretical discussion, related to engine efficiency.

@tony

i think this is correct, the restriction is not so much what is before the turbine, but the turbine itself and whats downstream.

if i may volunteer my opinion on turbo manifold disign:

idealy you want the pulse from every cylinder to reach the impeller undisturbed to fully transfer its kinetic energy. (this is the most eficient way to drive a turbo.) to achieve this, you have to keep the tubing diameter unchanged all the way to the turbine. actually this means the secondaries will be the size of the primaries. now of couse, if the turbine inlet area is bigger then the primaries you make a compromise and increase the secondaries by say one size.

to anybody really wants to take on the hassle of fabricating his own exhauts headers: if aming a something like 300 hp, do youself a favour and make them pipes smaller then the originals.

question: why would anybody want the primaries to be equal lenghth on a turbo system? is it for shifting a couple of Nm up or down the range to loose them somewhere else?

nice GTA Roman...if i owned a hat, i'd be tipping it

@david

sorry, opening time of couse is 1.0 ms, otherwise the engine couldnt be run at all.

@david

thanks for the links, have saved them and will look at them when i find the time.

maybe im mistaken, but on first sight it seems there is a duty cycle of 80 % everywhere. maybe this makes the difference. im talking about fully open injectors. these calculating aids are only a rough approximation, as they dont seem to be taking the opening time into account. this used to be around 10 ms on these "ancient" units i believe. so if you loose this twice per engine cycle and add the loss to the 25 % (20/80 = 0.25) increase due to the dutycycle goin to 100% you wind up with an increase in flow or probably 30 % over what the tables tell you. Dont really feel like calculating this now.

yes i used to run 300 cc injectors with the standart ecu, reprogramed for them of course.

Roman, if you leave it at 0.8 then the injectors are definately not big enough! I put the settings (the RCeng is a good calculator) as 370bhp, 0.55 BSFC, 6 cylinders, 100% duty, and 65psi fuel pressure.

300cc/injectors are not big enough. Loose the sums, and use the calculators designed for it, it prevents errors...

There is an old rule of thumb, you can look it up, that to get the max power of an injector, divide the CC of the injector by 5 and them multiply by the number of cylinders...

300cc = 360bhp on a 6 pot.

@tony

i think this is correct, the restriction is not so much what is before the turbine, but the turbine itself and whats downstream.

if i may volunteer my opinion on turbo manifold disign:

idealy you want the pulse from every cylinder to reach the impeller undisturbed to fully transfer its kinetic energy. (this is the most eficient way to drive a turbo.) to achieve this, you have to keep the tubing diameter unchanged all the way to the turbine. actually this means the secondaries will be the size of the primaries. now of couse, if the turbine inlet area is bigger then the primaries you make a compromise and increase the secondaries by say one size.

to anybody really wants to take on the hassle of fabricating his own exhauts headers: if aming a something like 300 hp, do youself a favour and make them pipes smaller then the originals.

question: why would anybody want the primaries to be equal lenghth on a turbo system? is it for shifting a couple of Nm up or down the range to loose them somewhere else?

Roman, you are disagreeing with the most basic proven stuff here on any car, and contradicting yourself. You say you want each pulse to hit the turbine undistubed from each cylinder, then at the same time 'why would you want it equal length'

Forget the design of engine, or how many cylinders it has. Treat each cylinder as seperate. You want each of the 6 individual cylinders to work exactly the same as the next. No compromises. Everything equal, why give away power...

You never, ever, hear of anyone reducing the the size of the manifold volume from standard, unless it could be badly designed in the first place. By doing this you have just reduced the volumetric efficiency of your engine. You wouldnt make your standard exhaust smaller on a normally aspirated car, so why would you want to do it with the added back pressure and heat of forced induction?

Look at every high performance aftermarket manifold and it will try to be as close to equal length as possible, with even primaries.

Youve said in the past over 300bhp is 'easy' on a standard system, even though a pattern is there that 300bhp is the extreme upper limit even with all the right components (barring the manifolds etc) and then that your car made 'well over 400bhp AT THE WHEELS' in a previous post, which you have told us is now 370, and flywheel power/

Can we see a dyno plot please.

sorry, i dont even know where to look for the dyno sheet, i have been abroad for a couple of years, and my stuff is in several places now.

however i dont understand why you make such a fuss about 450 hp from 2.5 liters. we have seen 600 hp 1.6 litre hondas for over 10 years now (only for the drags though), the tour de corse engine is being discussed in this forum and 600 hp prv engines are a fact (venturi). im not claiming any raicing reliability, the car cant handle this power thermically. a friend of mine had 400 hp on his 1.6 litre golf, 85 it was , i believe, easily spinning the tires in third gear. dont forget the A4 with 400 hp as well.

what power levels do you intend to achieve with your bi-turbo? if you do it right, 500 is within reach with todays technology, although as i say, what good will that do if you cannot brake the car, the drivetrain cannot handle it and you cannot race it.

axel resss engines are making 360 hp through the restrictive intercooler, you can go and watch them at hockenheim on eastern. the golin brothers are not slower, by the way.

however i dont understand why you make such a fuss about 450 hp from 2.5 liters. we have seen 600 hp 1.6 litre hondas for over 10 years now (only for the drags though), the tour de corse engine is being discussed in this forum and 600 hp prv engines are a fact (venturi). im not claiming any raicing reliability, the car cant handle this power thermically. a friend of mine had 400 hp on his 1.6 litre golf, 85 it was , i believe, easily spinning the tires in third gear. dont forget the A4 with 400 hp as well.

.

Thankyou, there is my answer.....

Another dream ruined!

i have bee waiting for somebody to ask me, but now i have to ask the question myself:

@david

how do you plan to cool the liquid in your intercooler on the bi-turbo?

roman, have a wee look at this........

http://www.renaultalpineownersclub.com/ ... rge+cooler

love what you have done with your GTA, well done that man

i have bee waiting for somebody to ask me, but now i have to ask the question myself:

@david

how do you plan to cool the liquid in your intercooler on the bi-turbo?

Can't speak for Dave but the major advantage of a chargecooler is thermal mass. You don't need a massive pre-rad unless you're planning on driving at full pelt for extended periods, which is unlikely. Put the pre-rad wherever you like, and maybe stick a fan on it.

[Alpineandy]

http://www.chargecooler.co.uk/

@simon

that looks good. what is the hose going to the roof?

@simon

that looks good. what is the hose going to the roof?

Filler pipe, to fill the system. Just blocked off at the moment.