RajDatta

And I am running a true Garrett GT series as well .
Dave, I live in Princeton Junction (West Windsor), we should get together sometime.
Regards.
Raj

special tool

Dude - PETROL????

Please just say "gasoline" so we do't start thinking of you as one of those funny-looking Brits....

SoloRacer

Friends of mine have GT35's on thier RX7's and they spool quickly. However, they also run out of steam early too.

Tms951

A Lindsey Racing super 75 is close it has a 67mm wheel, how ever the response would not be like what your friends supra is like.

All rember the 951 8v head sucks, you are working with four intake valves and wide pistons, the supra i would guess is a four valve design, and having six cylinders the combustion happens in a smaller space.

so other than just the turbo the supra has the benafit of 2 more cylinders, 8 more intake valves, and 20% more displacement.

For ultimate power the 951 is not the greatest starting piont. But on a track vs. a supra the 951 handling would dominate.

If you want a high hp straight line car get a supra the 951 is the wrong machine.

Also I don't think the GT series are a great match for these engines, no question they are great turbos, but because the head sucks so much on these cars the high boost capabilities of these turbos is lost on these engines and is better suited to a newer more advanced engine like a supra, or evo, or audi 1.8t. On the audi 1.8t it makes 375hp on 93 oct gas at like 23psi with a gt28rs, how does it make more than 200hp per litre on pump gas, it is all about the 5v head. These kits are also making full boost at like 3500rpm.

Porschefile

The fact that Gt35r's even survive on a rotary is testament alone. Those put out the EGT's of a thermonuclear reactor! j/k There was an older lineup of DBB turbos from Garrett, the GTN series I believe (not sure on the name). Those older ones were apparently a little more troublesome, though the new stuff is very nice. They are designed to be run with both coolant and oil, however when not running coolant I've heard that it's a good idea to run oil in the coolant ports as well otherwise it could lead to a shortened lifespan.

Also, don't confuse the dual ball bearing GT series with Turbonetic's single ball bearing bastardization. The T-netics single BB design apparently has not withstood the tests of time very well, and I've heard of countless issues with these.

Duke

ahahahaha

95ONE

3 liters with a 4 valve head Does well with the Turbo. Seeing how people are also revving the engines past 9K rpm and still making power shows that even if it reached full boost at 5500rpm (Often the case) There's plenty of room left to use the power. It gives an illusion of quick boost, but compare that to our cars and you've just about run out of revs before you have to shift. (Once again displaying the in-efficiency of our head design.) -- sort-of- So.... Even still, An "R" or ball bearing turbo spins free-er and more efficiently. To any Similarly sized non Gt - R series turbo. (GT being fin design and the "R" being ball bearing.) Proven over and over again on the Dyno. -

By the way. K-series Honda motor made over 650hp (663) TO THE WHEELS on a Gt35R. "S" compressor housing. Running a REALISTIC 12% drivetrain loss..... I give you your crank hp number of ... 750. Definately NOT a bad turbo.

Porschefile

The Greddy T78 typically reaches full boost about 4.5k on Supras. That's not that laggy IMO. All you have to do is row the gearbox a little more.

Rogue_Ant

Definately not that bad... considering most the single turbo Supra guys rev to ~8k.


Rogue

Fishey

Its funny so many people complain about the 8v heads sucking (They do suck) but almost no one runs a 16v head.

333pg333

So Porschefile what in your opinion is the most efficient turbo to run on a stock 2.5 951? Efficient in this case means the best compromise of power and early spoolup.

tedesco

I think this is starting to repeat what has been discussed in an earlier thread about pro and cons of the GT35r against the GT30r. If you only go with the compressor maps the GT30R is surely the better choice for the 2.5l with stock rpm limit. if you go any bigger in displacement or increse the rpm limit significantly above the stock 6500 or so, the GT35r will become better but the GT30r will certainly not run out of steam. For a stock 2.5l the GT35 will be too big and you will run below the max eff area.

Currently I am rebuilding my track day 951 engine and in the process of doing that I will change to a GT30R with a strocked 2.8L engine and stand alone ECU. I also thought about the GT35r but response and more useable power band is more important for the target purpose of the car. With a GT35r the charge air might be a bit colder at max rpm but that would be all in my eyes. it would be not worth optimising the turbo for max rpm because at max rpm you shift and in my eyes the 2.8l is the change over point from GT30r to GT35r.

With anything like the T78 or even bigger you would hardly start to build any boost until rev limit on a 951. The reason is not the compressor but the hugh turbine and the housing. As far as I remember the turbines start from 74mm and you will not find anything like a 0.8 housing for it. I have the data at home and can check if that was right later.

JET951

hijack sorry, what about a Trust T67-25g? these come in either an 8cm exhaust housing or a 10cm.

toddk911

T3/T67

Duke

I reason the exact opposite way as you do.

Yes the 8v heads suck, but in what way? They are not very detonation friendly... so what do you need to do in order to extract lots of power with a head like that? Address every part that can reduce the risk of knock.
And to do that an efficient high boost turbo is one of the key parts.

You need as cool intake charge air and as low turbine backpressure as possible. You also need a lot of other stuff as well, but IMHO it's important as ever to choose an efficient turbo on a 951 when comparing to better head designs.