single turbo turbine a/r selection

[--hoff]

Right now I have single turbo setup on my car. The turbo that i am using right now is T04S turbine a.r .63 and the compressor turbin a.r .70. The engine is boosting around 3500-3800rpm (the engine is start boosting around 2500-2800rpm and you will start feel the car pulling around 3500-3800rpm) all the way to 7000rpm.

I was thinking of making the car boost below the 3500rpm mark. So the idea is using smaller turbine housing. After checking the garret turbo T series journal bearing catalog, there are two turbine a.r that I am interested on the .48 or .58 still using T04S turbo with .70 compressor housing.

If I am using a.r .48, I am sure it will boost faster. I predicted the boost should come up around below 3000. And i think its going to be a fun car to drive cause the boost comes up early. But i am worry the power band will be limited and it will short of power before it reach the 7000 and also I am worry that the exhaust temp will go high.

The other option is going a.r 58, this option the boost will come right around 3000rpm-3500 ( just rough estimate). The power will still comes up early compare to .63, the power band will still go up to 7000rpm and the exhaust temp should be a problem.

For now the best option is using turbine housing a.r .58...but i am still open to other opinion....if guys have any other thought about the turbine selection just throw it on this thread.

Please stick with the subject discussion and do not ruin with comparing to twin turbo setup.....

[bradc]

Why not go with a more modern GT series turbo with ball bearings?

[--hoff]

Why not go with a more modern GT series turbo with ball bearings?

the budget for the turbo is under 1000 usd...the gt series line up are all above 1000 usd mark...

All my friend are using the t series journal bearing with good results as long as you r using the coorect turbo size...

[Madhav]

You could find a gt30r for around $1k, it would be second hand, however they are sold frequently on various forums. Check here for example in the turbo section:

http://www.boostcruising.com/forums/index.php?act=Search&CODE=show&searchid=b2add17471d9b09b355c04723df215f2&search_in=titles&result_type=topics&highlite=%2BGT30%2A

I Think that one would suit you perfectly. These turbos frequently come up on that forum, along with the 450hp disco potato GT28r and the like. I have seen them sell for under $1k.

http://www.boostcruising.com/forums/index.php?act=Search&CODE=show&searchid=92c865480081fce1dc41fcf499daecf3&search_in=titles&result_type=topics&highlite=%2BGT28%2A

[ILLEGAL]

if you can get the A/R.70 to boost before 4000RPM id say your doing well, and leave it at that, you could end up choking the turbo (compressor surge, the real kind) if you go too small a turbine housing and turbine ..personally im going too be happy if my TD06 25G with A/R .70 housing can boost at 4500RPM once hooked up. my TD05HR big 16G boosted 23psi @ 3800RPM and im only a 2.0L (6a12)

[scientist]

if you can get the A/R.70 to boost before 4000RPM id say your doing well, and leave it at that, you could end up choking the turbo (compressor surge, the real kind) if you go too small a turbine housing and turbine ..personally im going too be happy if my TD06 25G with A/R .70 housing can boost at 4500RPM once hooked up. my TD05HR big 16G boosted 23psi @ 3800RPM and im only a 2.0L (6a12)

Going smaller will most likely choke that turbo and make the spool up even worse. It would definitely kill top end and prevent you from hitting higher boost levels.

What is your current boost level?

[ILLEGAL]

Going smaller will most likely choke that turbo and make the spool up even worse. It would definitely kill top end and prevent you from hitting higher boost levels.

What is your current boost level?

thats just what i meant. i was referring too Hoff's plan.. if he gets a smaller turbine and housing, he will choke his engine.

on my 2.0L 7G, i WAS running (upto a few weeks ago) a Evo4 TD05HR @ 15-25psi.. 18psi being the sweet spot. 230ish Kw ATW.

i am in the process of mounting (downgrading performance for visual gain) a new single 25G TD06, A/R.70 compressor housing with a 25G wheel, on a TD06 cartrage with what looks like a 8cm turbine?? not 100% sure on that turbine spec.

this is what info i could find about the turbo

compressor
INLET 60.3MM
OUTLET 78MM
TRIM 60
AR/0.7 INCH

turbine
INLET 67MM
OUTLET 58.8
TRIM 64
AR/0.5 INCH

i plan to run 15-25 psi again.. but need new cam to take advantage of the new flow.. happy to get same Kw @ less boost. with full boost around 4500rpm?

ps: this is a drag car on a budget.. spent under NZ$6000 to date, including initial purchase of the car ($2K), and run 12.6-12.8 consistant :P

HOFF: what are the specs of your current turbo?

other suggestions:
#1 cut down a gear?... pump the clutch?... try limiter launch? sorry had to be said!
## i WOULD NOT go any smaller than the .58 on your 2.5L if at all!
## what would happen if you down sized the diameter of the runner going too the current turbo?
## perhaps a TD05 20G with a back cut turbine wheel? this will spool real quick on your 2.5L and should still have plenty of flow at the top end?
## Garrett TA3410? similar to the T04 but with upgraded technology in it.
## ofcause there is NOS and/or antilag for this issue when running massive turbos on little capacity engines.

Question# why do you want boost by 3000rpm? i find fuel economy better when boost threshold is higher (closer too 4000rpm) IMO.

[--hoff]

illegal, I had the same thought as you once. Why would anybody wants to boost @ 3000rpm. I started to feel the boost kick in around 3800 rpm. On the drag race or highway is not a problem. But once you enter city traffic or country roadside, your car become so lazy to move.

So in a real cruel world, I use to drive more on city traffic and country roadside more often than drag strip. Now its becoming a big issue.

I am torn apart between 2 turbo right now:
- brand new T3/T4e
- second hand GT2871R turbine a/r .63 ( for the spec you check on www.atpturbo.com)

I have seen the second hand GT2871R in person. But if its still in good condition and got a good bargain might go with the GT.

Illegal, you can try the T3/T4e trim 50 setup if are on a budget is around 600 USD brand new for that turbo. You can pick your own turbin A/R that suit your application. And its good for 400hp.

If I had the money to spent I would spend on GT3076 here is the dyno on volvo engine 2.5ltr:
http://atpturbo.com/root/releases/images/release060908/c30_dyno1.gif
sweet graph, the torque is spreading all across the rpm range....and the peak torque right below 4000rpm...compare to my setup which about 5000rpm...

The GT2871R is a good option too. here is the dyno graph on GOLF TSI 2.0T:
http://atpturbo.com/root/releases/images/release090110/ATP-VVW-256_DYNO.gif

well all the dyno above is not an apple to apple comparison. But at least we can estimate the rough output on our 2.5 ltr engine.

[ILLEGAL]

Hoff i see you problem.. damn traffic lights! so i see your need from more low down power.

i already have my TD06 25G, steam pipe and wastegate so i cant change my mind now.. will just have to put it to the test and do abit of development around it eg. cams and tuning. lucky for me this is my drag racing car so lag isnt a issue for me. i had a TD05HR which has been proven to 400hp and comes on real strong, it just didnt look the part next to the v6. thanks for the info though. hope something works out for you.. also im interest to see the new power curve versus the old one once you settle on a turbo.