Help me pick a 400rwhp roadrace turbo for NASA ST1
 

I am re-building my formerly 20B powered racecar to participate in NASA ST1 class - I decided Super Unlimited was way too expensive as it is an open class with no restrictions at all, including whether the car is production, tube frame, etc. I recently acquired a bridgeported 13B-RE which will be going in pretty soon to replace the 3rotor.

The class rules are that the weight:power ratio can be no less than 5.5:1 - with the 20B and 15 gallons of gas my car weighed 2450lbs, so I anticipate with the 2 rotor engine it should be around 2200-2250lbs, which means at most I would be looking to make 409rwhp - there are additional penalties for being so light, so realistically the target power is 350-410rwhp. I can always run ballast if needed to bring the weight up.

Manifold is HKS cast - given the bridgeport, what are any suggestions for the right turbo setup to use here? I am thinking maybe a T60-1 with a big AR (1.15 or maybe more?) - I have no experience with bridgeports at all, so all input is appreciated.

Thanks in advance

first mod is ditch the manifold. even though it is reliable and has been proven to make power, it sucks for spool and boost control. Ask me how I know. I don't understand how you could afford a 20B but you are now using that manifold. There are some FD manifolds that should work with that RE.

I can afford alot of things, but reliability is probably the key thing for me having cracked pretty much every tubular manifold I have ever used in the past, on a variety of engines. If the HKS sucks, I can replace it, but I want to give it a shot for now (I do appreciate the feedback though and will bear it in mind going forward).

Now which turbo? :)

I know this game well, and have been working with aspec on some turbo setups to maximize the power-weight we have to run in nasa st1.

anyway, ur car is very light, so your top end is not really important sine you can not run much power. just guessign by ur weight, you are in the 350rwhpo range and I suggest a smaller turbo like the aspec 35r setup that has worked very well on Andys car (gooroo). call up aspec and ask them about a 35r on a bridge port.

you could buy my 35r that was bought from a-spec. its a T4 1.06 turbine(the biggest) pm me if interested.

Will probably take it, I sent you a PM.

at least use the divided HKS manifold for the FD and get a turbo with a divided hotside... really, the undivided FC log manifold sucks for spool.

I am using the FD version (HKS doesn't even make the FC one anymore)...had to do some grinding to the engine mount to clear the wastegate piping, but otherwise seems to fit well.

I'm surprised the 13B-RE turbo will be 200 lbs lighter than a 20B. I think my 13B-RE turbo added a substantial amount of weight over my NA 13B.

hey welcome to the RE family!! btw did you pick up the cosmo from reboot??:suspect: man i was solely going to sell my raceport RE just to buy his BP RE......:lol:


you should pu that 350-400hp real easy with tat 35r....

We weighed the 20B with the turbo, manifolds, and wastegate attached (basically fully dressed) and it was around 410lbs. I'll weigh the 13B-RE and find out how much it weighs, I could be slightly off on that estimate.

You want a GT35R turbo and the A-spec manifold. I run that setup in a road race FC. At 14 lbs I'm right around 400 rwhp. On the dyno I've pulled 340 rwhp at 8 lbs boost and 459 rwhp at 18 lbs boost. The GT 35R comes on early and spools pretty smooth. At 14lbs it pulls hard as it gets into the rpm. In the Edmonton Indy I was pulling stock cars all day and passed a few top notch GT2 cars. With more weight reduction and better gearing I think I could be faster yet.

cheers,
-Trent

Cool, thanks. I am going to pickup the GT35R with the 1.06 exhaust side. I'll give the HKS cast manifold a shot seeing as I already have it, but might upgrade to the a-spec long runner manifold next season.

update??