Best turbo for 550hp I5

[Bambi]

My turbo blew so now I can get a new one. I gasflowed the head, fitted 7A exhaust cam and SPM conrods. I use the car as a daily driver, but I am building for track use. I've heard the GT3071RS is a good turbo with relatively low lag, I'm not sure it has enough HP to chase 500HP BMW's on the track. How bout GT3076RS? and what's the difference to a GT28. I don't know turbo codes or how they differ. Any help would be greatly appreciated! Also where to buy....

[Acidburn]

check out 034 motorsports website as they have details of each turbo and what it can do.

The 3071r afaik won't do what your after so will have to be bigger.

[UrS4boy]

check out 034 motorsports website as they have details of each turbo and what it can do. The 3071r afaik won't do what your after so will have to be bigger.

And the GT28 is smaller than a GT30 so Bambi probably looking at a GT35(ish) answer.

[Acidburn]

http://www.034motorsport.com/product_info.php?cPath=21_100&products_id=298

probably something like this, bit more power than you said but if you didn't mind the lag trade off it should do what you want.

[Bambi]

I see they have KKK/3071rs and kkk/3076rs combos. Are these straight bolt on? (i think so) draw backs? Why does the KKK/3071 spool faster (3000rpm) than the garret GT3071rs (3500)rpm?

what does the AR ratio do?

[Faheemo]

I See SAV's turbo Beemers gave you a hard time at Kayalami hey ?

ok 3071 vs 3076 -
3071 has smaller compressor wheel 71mm and the shaft size is also smaller than a 3076. therfore good spoolup !
A/R ratio effects the top end of the rev range and is generally better for big hp in upper revs - trade off is that it causes some lag.

if you use 3071 and are chasing big hp numbers use the biggest AR possible.
for good response use a smaller A/R.

for 550hp on a track car i would do a 2.5ltr with GT35R.
2.2ltr go with 3076.

Take a look at the projects section for Aronmatic and Alberts track cars, thers some dyno 's ther as well.

Image is a comparison of the spoolup difference with my old 3071 .63AR and my new GT3076 with .86 AR.
Both wher done on 2.2ltr with 7a ex cam.
3076 wasnt fully tuned and had some issues therfore the no big HP numbers.

[Puglife]

Faheemo noticed your vehicle weight is set at 1752kg, is it really that heavy????

[Bambi]

"some problems" yes.......

So now for track suspension, which - I still have to figure out, turbo and semis - I totally destroyed my dunlop7000D's

What about 3071 with big AR - I like the responce from the 3071. Are you running 102, 98 or 95?

[Faheemo]

Faheemo noticed your vehicle weight is set at 1752kg, is it really that heavy????

G tech Uses Nett weight.
IIRC Audi state dry weight of car.
So
ABY Licensed weight 1550kg + plus my ICE (now removed)+- 20kg, laptop+Inverter 7kg, + my weight + diff 18" Mags + small tool box + + + +

[Faheemo]

"some problems" yes.......

So now for track suspension, which - I still have to figure out, turbo and semis - I totally destroyed my dunlop7000D's

What about 3071 with big AR - I like the responce from the 3071. Are you running 102, 98 or 95?

I suggest u must Do a big AR on the 3071, i had a .63 Ar and the boost comes on very hard,3000rpm no boost 3600 full boost - on a couple auto crosses i did i was smoking the tyres out the bends and fighting the torsen system.

0.86 or 1.02 if u want top end grunt.

[Bambi]

which would be the better route:

3076 small AR

or

3071 big AR

[A80Avant]

3076+BIG A.R to reach 500+,otherwise you will get as much as 470hp crank.Aronmatic had 466hp with GT30R,SQmanifold and 2.0 bar boost

[S2central.net]

Agreed on this - 3076 or bigger for such a high target... But any turbo with a large A/R is going to carry more lag with it and that can be significant on the track.

If the tracks and events you do, simply don't have straights long enough where you can build to full boost on a laggy turbo, then you are going to be quicker with a less powerful turbo that is more responsive in the mid range.

IMO - the approach taken by Albert around 450bhp is very solid for a track car... In gut feel terms I think a 550bhp machine the weight of an S2 is only going to deliver to full potential on the drag strip. Only caveat to that is maybe with some exotic anti-lag system or superquick bearing technology that gives you good spool times from low revs.

Just my 2 cents on this.

[repo]

I would use CompTurbo ct357 or 58, even with journal bearing You'll get spoolup before 3500rpm.

Even 55 will give almost 550hp, and spools to pull at around 3000, if tuned right.

Cheaper than Garrett as well...

[Albert]

If I would do it, I would go for 2.5 Liter with 95.5mm crank + 82mm pistons + GT35R 0.86 a/r turbo.

This setup would be ok for 550HP with normal V-Power fuel.

If you want to do it on 2.2L engine I would still go for GT35R but the car would be more laggy, my with 0.86a/r had full boost at around 4200 rpm.