What's the smallest, or more important, fastest spooling turbo, that can hold it's breath and provide power up to 8500 rpm before it starts losing efficiency, and therefore, power?

 

The hot side of the turbo is whats important for your spool friend.. Most any turbo will work.
Stealth

 

I'd think a GT30 with a smaller hotside would work well. My GT35R hits hard at 3300 rpm and make 340 rwhp at 10 lbs boost. At 18 lbs it makes 459 rwhp ;-) For road racing I run the 10 psi as I want it to last for the two hour enduro races.

-Trent

 

you are asking for the perfect turbo there
i dont believe there is a turbo whos efficiency range is all of a rx7's rev range
i think a GT30 with a smaller hotside might choke at higher rpms and thus might be a better autox turbo.
in my opinion the GT35 with .96 or .8x is a good turbo for both road and drag race if set up properly, on stock ports. if you are looking for a turbo for autox dont worry about not making power up high and focus on the low rpm.
if you are looking for a road race turbo i think the GT35 would acutally do quite well as like TrentO said it does pull at 3300 and you should be able to keep the rpm above that while road racing, i think?

 

Anyone make a 25 or 28 turbo with a large hotside? (like......1.0x?) =P

 

just to add, it'll be on an aggressive street port engine, looking to boost very small amount (4-8 psi)

 

No such thing.

You're looking for small, but small implies loosing steam at high RPM's.
Hell, the turbo 13B never did redline up at 8,500RPM!

This is the delicate balance most of us are looking for.
Decent spool up times with power all the way up to redline...


-Ted

 

damn....I was afraid of that.

I guess the GT30 is the best compromise in order to match a quick spooling turbo to the higher redline of the race engine?

 

I think the GT30 is too small.
It'll definitely choke at 8,500RPM.
Personally, I'd use a GT35R with a 0.8x turbine A/R if you're really worried about spool-up.


-Ted

 

the t3 35r chokes up top. but a lot depends on what your actual hp goal is. before the turbo topic is even addressed, you need to state that.

 

i'm thinking from a strict boost perspective, 4-8 psi and held all the way to 8.5k?

In terms of a power curve, i'd like it ideally flat around +100 hp over the motor itself.

 

I liked the Apexi RX6 turbo. It did die down, but it was worth having a fast spooling turbo

 

you're not gonna pull to 8500 on a turbo motor, unless it's a bridgeport with a big hot side, or you build a manifold to peak that high, but that will kill your low end.

 

obviously the motor will have the necessary mods to run that high, redline will be set at 9000, with peak power around 8500. This isn't exactly a street car, hence why I put it in Race Car Tech.

 

I run a GT35R with .8x hotside. It spools pretty quick (15psi by 3700rpm with my short gears) and will maintain decent power to redline. At first I had a stock ported motor and it fell off big time at high rpm, but with a decent sized street port it pulls well to redline (9000). I posted my stock port dyno sheet awhile back.

-Andy

 

I have an RX-6 and I track my car and love it. It is very quick spooling and comes on very strong. At the track I just run 10-11 psi and it pulls very hard and even up to redline.

 

What about the GReddy TD06-20G?

 

Too slow to spool compared to other similar sized turbos.
Also needs a lot of boost to hit it's top efficiency plateau...


-Ted

 

Toss the turbo and go NA, espically for race purposes. I just wish Id follow my own advice

 

Does anyone have an air consumption chart for a 13b? I would like to see a streetported chart, but I am doubtful anyone will have that.

 

If you are racing you don't really need that fast spooling of a turbo. At the track with my GT35R with a 1.05 hotside I'm always above 4500 RPM. I usually shift at 8000 rpm, but I have legged it to 8500 on occasion. I've got the blow off valve set fairly soft, so it doesn't kill my spool when I drop the throttle. When I pick the throttle back up early or mid corner I sometimes have to ease a bit out with the throttle to keep the car smooth. Without easing out the turbo spools, I get 10 lbs very quick and the back end steps out. I'm running a 13B streetport with hardened stationary gears, 3 mm steel apex seals and the racing beat Tilton lightweight flywheel 7.25" twin disk clutch setup. So the motor can rev if required, but since my torque peak is right around 5000 rpm it doesn't make sense to push above 8000. Even with the long drop on the 2-3 shift I'm still close to 5000.
Buy a GT35R with a good manifold and wastegate. My setup is from A-spec. It's run about 12 hours in anger so far without even a hiccup. I pull hard on most cars, including a few 911's

-Trent