Ready to pull the trigger on the turbos for my build. JZ over at forceinductions recommended two s300 61s with a .91 ar. Im hesitant due to the high a/r number, but he assured me that the twin scroll housing will help spool fast. What do you guys think?


Lq9, stock bottom. Brian tooley custom cam, possibly e85(not 100% sure). It will be mainly street driven, occasional track. My goal is to run 9s. Car is under 3000 lbs, true 4 link rear, 4l80e. I want good street performance.

Thanks again.

 

you will be just fine with stalled Auto

 

Unless you have full twin scroll manifolds, then it makes no sense to use a divided housing.

Twin scroll only helps spool when the manifolds are actually working in conjunction with the turbine housing. And on a V8, true twin scroll as per a 4 cylinder is never actually possible anyway due to firing orders.

 

A good stall converter is going in for sure. I just don't want to have a huge lag on the street.

 

Those s300's come in three turbine sizes. 68mm, 71mm, and 73mm. If your looking for quicker spool do the 68mm turbine. Still a descent size turbine for twins on that motor. With your weight 9's should be a cakewalk

 

+100
You could use the worst turbo ever and go 9's on accident with that weight.

 

So .91 ar on a 68mm housing would be a good street/strip option? Am I understanding correct? Thank guys.

 

Imo, you're not way off with .91. It's probably the correct starting point, if it isn't right on.

 

You guys think full boost ( im thinking around 16 psi) would come around 4000-4500rpm with this twin setup?

Thanks

 

Well what engine size are you intending to use ?

the bigger the engine the more chance you have of it spooling earlier

 

I wrote it on the initial post. Its an lq9. Stock bottom end. Brian tooley twin turbo cam.

Thanks

 

If a pair of 361's then I'd say yes certainly by 4500rpm, and more than likely by 4000rpm.

Check out the AGP Turbo kits they offer for the 2010 Camaro's. They offer a good range of turbos, one of which is a BW based S261.
61mm compressor in a smaller housing with a T3 based turbine for faster spool.

http://www.agpturbo.com/camaro-5-ss-agp-twin-turbo-kit/

It would be no bad thing to give them a call and see what they can suggest, and their units are physically much smaller than the 300's

 

Thanks for your input Stevie.

Im just concerned about how much lag its going to have. I dont want to spend $1400on the wrong turbos.

I see a lot of setups making well over 1000 horses with smaller A/Rs and mm housings.

 

those should light off very fast.

 

There do seem to be a few cars over on the Camaro5 forum with very good results from the AGP stuff, with what seem to be very small turbochargers

With such a light car I dont see running 9's as being any problem whatsover though, with almost any twins.

 

You will have no problem running running 9's in that light of a car with twins. I ran 9's with my too small 7875 Turbonetics in my 3400+ lb. Fbody.

 

No problemo. Thanks for all the recommendations. I have more confidence going forward with the purchase.