road race turbo. 6262, or 6266?
 

guys i'm about to buy a turbo for my FD (mainly doing HPDE track days with the car)

i have a nice Turblown divided T4 manifold, pineapple streetported (intake and exhaust) REW, fuel, PFC, yadda yadda.

i'm only going for ~350whp, but i want to keep the boost low at about 10psi, i may turn it up just on the dyno to see what power it will make on 15psi.

i'm basically wondering if the 6262 turbine wheel is going to be too restrictive with the .84 divided housing (i havent competely decided on the .84, but i'm pretty sure about it) for extended full boost full throttle pulls, or if i need to go with the 6266... i came across ludwig's thread about carter's FD (https://www.rx7club.com/single-turbo...d-dyno-956766/) and i'm really thinking 6262 .84...


anyone with any experience in this?

i would run the 6266 with an .84 housing. It will help keep the EGTs down on track days. The smaller turbine will spool a little quicker but is gonna drive your EGTs up top. This is okay for autocross but not ideal for road racing.

86v8rx7, i'm aware of the backpressure concept, but i'm wondering how much of a problem it will actually be.
the 6262 turbine wheel is still bigger than a 35R turbine wheel, and people road race with those, and others make over 400whp easily with them.

i'm planning to run ~10-12psi and make under 400whp. i wouldn't think the backpressure would be an issue at low boost with a medium/small hot side. carter's FD in ludwig's dyno thread had a .63 t3/35 hotside on it...

yes as stated above me in the last 2 posts autox needs a hell of a lot more response into the boost threshold. which is why carters car is a tiny turbo on race gas with high teens of boost and a massive exhaust.

for a road course you are unwinding the wheel as you are leaning on the gas, giving you a few lbs into boost before rolling back to full throttle. and depending on track/ your gearing/ redline you wont see under 3k rpm/

i did some street tuning on the 6262 .84 today and it is very responsive.

full boost in 4th gear at about 3500 rpms.