Thread: Turbo size help

I have a 69 bluebird with an SR20det (currently fucked). I have a replacement bottom end with eagle rods, CP pistons,main and head studs. Probably going to stick my 52F head back on it (off the old motor).

Requirements are:
- 91pump friendly (MAYBE meth injection to help)
- I'm aiming for around 450+500 WHP, maybe a little less if I can net at least mid 11s at over 120MPH.
- Road race friendly (no turbo longevity issues) IE probably water cooled turbo
- Want to spool in the 3500-4k RPM range, maybe a little higher if I get some cams

With that said, I've been told a GT3076R is what I want.... I'm a little concerned it might be too small for my goals. Also... not sure what exhaust housing I want, probably not the stock T2 setup (which is what's on it now). It's smog exempt so I see no reason not to go with a t3 or t4 setup and maybe externally gated.

Opinions/experience wanted

30r would be pushing it. A good sized cheap turbo for that power range is a Garrett 60 trim T3 w/ .82 turbine housing. It uses a 59mm inducer compressor wheel. With the .82 housing its good for 550whp max. So basicly perfect sizing for what your looking for. It will spool where your looking for it to spool. It will really kick in right about 4-4200 rpm. My 8.5:1 86.5mm CP piston, eagle rod VE block with DE head w/S4 cams made 401whp on pump gas at 19psi, after the intake manifold roughly around 440-450 on 19psi, 24psi before the manifold made 461whp, I later went to 30psi with the aftermarket manifold and was roughly at about 530-550whp.

I have ran up to 24psi on pump gas as well with the aftermarket manifold so probably around 490-500whp, 91 octane, without a problem. Its a great turbo that can be had for about $300-400 in pefect condition. Easily rebuildable if the journal bearing or thrust bearing wears out.

In all honesty a bb turbo is a waste for a street car, your really only gonna see 200-300rpm better spool time with a bb turbo but if the seals or anything ever go, your screwed. On a journal bearing turbo 75 dollar kmaak rebuild kit and your good to go.

My 60 trim turbo setup was a great street setup, not too laggy and made power all the way to 8k. Even on stock cams it should do really well but you will see a huge gain from some S4's.

You dont need a water cooled turbo for longevity either. Just make sure you dont shut the car off just after getting on it without letting it idle for a bit first.

With 450whp you will be in the 11's for sure once you get some seat time and practice on slicks. Mid 120 traps easy. Plenty good enough turbo for road racing but Ill say this that much power is way too much for road racing with our cars. Keep the boost down to about 12-14psi and you should be in the 325-350whp range and is a good power level for it.

In a bluebird/510 chassis you can do 11s with less then 400 based on weight
Dont look at it from a # perspective. A good all around turbo for your car that will yield a fat torque curve to use on the road course would be a GT2876 with a .82 housing
It can support 400 and give spool quick down low.
Another cheap option is a evo 16g turbo.

Road racing on a turbo making that kind of power on 91-pump is never going to be right. You're right you'll need something larger than the GT3076R and that's going to be quite a bit of delayed boost onset to deal with.
I would build the car around the GT3076R and think more about a reliable 400WHP instead. With water/meth injection you could maybe reach 450WHP and still be reliable on that turbo.

Like Ashton said, water jacketed turbos have nothing to do with reliability in a racing scene. Talk to the Porsche guys about oil-only turbo reliability. =]

Also I would suggest e85 as engine temps will be a lot lower

Hell most semi trucks use oil cooled only turbos and have been for years and turbos last a million miles or more. Just take proper steps.

Yeah exactly, a 2871 or 2876 will never make 400whp on pump gas, not for long anyways. lol. You need a larger frame t3 turbo something that is really efficient when it comes to the turbine and exhaust flow to keep backpressures down. A 60 trim size turbo is a good choice if you want that kind of power. Again it will lag a bit for road racing unless you become really good at quick shifting to keep it in the power band and good at keeping the rpm up at say 5k all the time. 5k rpm on my 60 trim was instant boost, just as instant as a t25 or t28 is at 3000 rpm. Just a matter of keeping the rpm up.

Here in this vid of my 60 trim, i was partial throttling it up until 4800-5k then punched it, you can see how instant it is, lol Its all about keeping where your powerband is.



All ill say is the higher your powerband is the more stressful on the motor in road racing. Other than that its no different than having a t2 turbo as far as response goes.

I know of several 2876 making that power on pump.
It's all in how efficient the set up as a whole is

Efficient setup and GT2876 do not mix. Inefficient turbo is inefficient.

Dyno


I'm not saying it a larger turbo isn't what he wants but it's just another option for him