Most responsive turbo around 450fwhp.

Hello.

I have to put my N/A-T conversion off for a few months but i want to do some homework properly.

Now as a personal preference i prefer faster response and lower top speed. So i'm looking for a turbo with the least lag [broadest torque curve] i can get and still get 450hp at crank.

Sounds like the ball bearing turbos from Garrett are a great piece of art as they are supposed to spool up hundreds/thousands of RPMs quicker.

I can't decide between two turbo's [GT3076R versus GT3582R] and i want to know what you guys all think.

I have a feeling that the GT3076R is slightly too small for my goal and a GT3582R will yield better results overall ... but ... everybody knows the famous video with the Amuse Supra (GT30, 450fwhp) and the Mines Skyline... http://www.youtube.com/watch?v=tDiTWaIhLNw

It looks like the only manifold flanges available [from what i can find] for the GT30R are T3 flanges and the NA-T manifolds are all made with a T4 flange.

GT35R can be so many different turbos depending on how they are spec'd up with regards to compressor wheel size and trim and different exhaust A/R ratios. I'm confused.

Am i making sense, and do you have some turbo suggestions?

Thanks for listening.

Tomasz

Xs power sell flanges to convert from a T3 - T4 or vise versa mate. They are about £80 IIRC.

Have you lowered the cars compression, or is it still stock NA? This will make a big difference to the spool time.

/here ya go mate:

http://cgi.ebay.co.uk/T3-TO-T4-TURBO-FLANGE-ADAPTER_W0QQitemZ250146526595QQihZ015QQcategoryZ38786QQrdZ1QQcmdZViewItem

It does raise the height of the turbo slightly which could be a bonus even to clear the distributor.

Also the thickness of the intercooler piping can have an effect on the lag i have heard??

Also the thickness of the intercooler piping can have an effect on the lag i have heard??

The diameter?

Only by milliseconds. You'd never notice the difference.

Have you lowered the cars compression, or is it still stock NA? This will make a big difference to the spool time.

I bought Boostlogic 2.5mm head gasket. This will reduce compression to 8.5:1 [same as a tt]. I know that the proper way to do it is with new pistons, but all the US guys change only the gasket to reduce the compression and they haven't any problems.

/here ya go mate:

http://cgi.ebay.co.uk/T3-TO-T4-TURBO-FLANGE-ADAPTER_W0QQitemZ250146526595QQihZ015QQcategoryZ38786QQrdZ1QQcmdZViewItem

It does raise the height of the turbo slightly which could be a bonus even to clear the distributor.

Thanks mate.

Ok that's cool. Anyway IMHO a GT35R or T61 is a small as you want to go in a street supra. I think with a smaller turbo it would produce it's torque so low down it come be a nightmare to drive.

Ok that's cool. Anyway IMHO a GT35R or T61 is a small as you want to go in a street supra. I think with a smaller turbo it would produce it's torque so low down it come be a nightmare to drive.

I think that it will be a great fun

Thanks mate.

No problem mate. Yeah jake sorry i mean diameter. It was just something i heard

you could get a TT up to 450bhp with hybrids, BPU, some 550's and a remap. seems a small goal to achieve for the money to go single. i know your NA but surely just getting a TT would be better for what your after. then you have the lower down grunt at well

you could get a TT up to 450bhp with hybrids, BPU, some 550's and a remap. seems a small goal to achieve for the money to go single. i know your NA but surely just getting a TT would be better for what your after. then you have the lower down grunt at well

Yes, you are right, but i love my car and can't buy 2002 TT.

What's your opinion? First and last bump.

N/A-T, rev limiter 6800rpm, peak boost 1.2 bar from 2750rpm (prediction)

Pressure ratio.

1.2bar+1.0=2.2

Air flow rate.

air flow rate=(L x RPM x VE x Pr) / 5660

L -> engine capacity in litres

VE -> volumetric efficiency -> stock engine 4 valves/cylinder = 90

Pr -> pressure ratio

6800rpm:

(3x6800x90x2,20)/5660=714cfm

714/14,27=50lb/min

2750rpm

(3x2750x90x2,20)/5660=20.2lb/min

Surge line.

50lb/min*20%=10lb/min

http://img374.imageshack.us/img374/3402/gt3076r3cu4.gif[/b]

What do you think about this graph?

Which turbine i should choose? A/R 1.06? A/R 0.82? or A/R 0.63?

http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT30/GT3076R_700382_12.htm

Thanks in advance.

Nice write up, can a mod seperate this post and make it a sticky

Ok that's cool. Anyway IMHO a GT35R or T61 is a small as you want to go in a street supra. I think with a smaller turbo it would produce it's torque so low down it come be a nightmare to drive.

Tomasz, you already have your answer here, Terry is one of, if not the most knowledgeable guy on here when it comes to turbos. I would listen to what he says, ie. the GT3076R is too small.

Don't get too obsessed with responsiveness, the GT3076 may spool up quickly, but you'll just end up spinning the wheels up initially, then the turbo will run out of puff higher up the rpms.

GT3582R is very responsive and the smallest you'd want IMO.

Tomasz, you already have your answer here, Terry is one of, if not the most knowledgeable guy on here when it comes to turbos. I would listen to what he says, ie. the GT3076R is too small.

 

Don't get too obsessed with responsiveness, the GT3076 may spool up quickly, but you'll just end up spinning the wheels up initially, then the turbo will run out of puff higher up the rpms.

 

GT3582R is very responsive and the smallest you'd want IMO.

Hi Nic.

What A/R can you recommend? GT3582R A/R 0.63 or 0.82?

BTW Can you answer to my PM please.

Graph of GT3582R, peak boost 0.9 bar from 3000rpm.

http://img177.imageshack.us/img177/1306/gt3582r1tu2.gif

Hi Nic.

 

What A/R can you recommend? GT3582R A/R 0.63 or 0.82?

BTW Can you answer to my PM please.

 

 

Graph of GT3582R, peak boost 0.9 bar from 3000rpm.

 

http://img177.imageshack.us/img177/1306/gt3582r1tu2.gif

Mine is 0.82 AR, I think Terry use to have a 0.63 on his old car. The 0.63 will give slightly less lag (probably only around 100rpm), at the sacrifice of some top end power.

As a guide mine makes positive boost at around 2K rpm, peak boost of 1.3bar at around 3K rpm.

Mine is 0.82 AR, I think Terry use to have a 0.63 on his old car. The 0.63 will give slightly less lag (probably only around 100rpm), at the sacrifice of some top end power.

 

As a guide mine makes positive boost at around 2K rpm, peak boost of 1.3bar at around 3K rpm.

Thank you for info.

GT3582R A/R 0.63 vs GT3076R A/R 0.82 - I'm going to read technical book about turbochargers during the weekend then i will make a decision.

Graph of 450bhp Supra, Garrett GT3076R.

http://img508.imageshack.us/img508/6973/gt3076rnowe2mj4.gif

All needed formulas you can find there:

http://www.turbobygarrett.com/turbobygarrett/tech_center/turbo_tech103.html

All comments are welcome.

I have Terry's GT3582R sat on my bench here; I just fitted a GT4088R. I'll probably sell the 35 shortly.

It is a very responsive turbo, with a precision '68ar turbine housing. It's very early spooling and responsive.. as well as being as quick as you would ever need for normal driving / track driving. Also your engine would run cooler with a slightly bigger turbo than a small one wound up to the max.

I have Terry's GT3582R sat on my bench here; I just fitted a GT4088R. I'll probably sell the 35 shortly.

 

It is a very responsive turbo, with a precision '68ar turbine housing. It's very early spooling and responsive.. as well as being as quick as you would ever need for normal driving / track driving. Also your engine would run cooler with a slightly bigger turbo than a small one wound up to the max.

Thanks for information.