I got the truck back with the GT67 and .96 housing.

There is WAY more lag with this setup than the GT35 I had on there. Main difference is it takes almost 1000rpm before you really start to build enough boost to get moving fast. Once at full boost it pulls and pulls but getting there takes too long.

On my GT35 boost was almost instant but seemed like it kinda felt flat in the upper rpm range.

So now I am gonna try the GT67 with an .81 housing. This should be a nice happy medium with not too much lag but still have a nice top end pull.

I'm gonna run it tomorrow night to see what it will do on 10psi but i don't expect anything great. I am now running less boost and 1 point of compression less. So don't slam me if I can't break into the 12s LOL

 

SPARY IT! Lag fixed. LOL

 

Well, that's usually the catch 22 with going to a bigger turbo. More peak power and more power in the upper RPM, but more lag.

That .81 sounds like a nice compramise though. I'm still not sure as to how STS sizes their turbos, because the rear mount this is Greek to me. You know, I don't know if they still make them, but STS should get into this: Have you heard of the VATN turbos? That's what you and all the STS guys should have! Variable Area Turbine Nozzle...damn that would be sweet. Self contained and virtually NO lag!

Good luck at the track though, I'm curious what you'll run!

 

or go to a bigger stall

 

a little juice should fix it. come on down to the twelves. it;s nice down hwere.

 

I really don't wanna have to install the nitrous kit (sitting in the garage) until I am maxed out on boost and know I can't get any further without it.

The exhaust housing is a simple change. Dave at STS is sending me out the .81 housing on Monday and I'll install it sometime next week. If that doesn't fix the problem then I still have the GT35 at Ricks shop so no matter what I have a cure one way or another.

I'm also going to reorder the FMIC since I gave mine to Rick to install on his car this weekend. I plan on having the IC on in the next 2 weks also so I can turn up the boost. I think on meth and the IC 15psi should be NP. Plus I wont have to deal with tuning on the mthanol as much which is hard then I thought.

When I droppped my compression to 8.5:1 it will take 15psi to reach the same effective compression I had at 9.5:1 and 13psi.

 

haha, shouldnt you have got it to run first with what you had before you bothered going bigger... ? Have some extra pistons or head gaskets lyin around ?

 

We had it running fine with the old setup before the fire. It was pretty damn fast on the bottom to mid range but kinda fell on it's face on the top so everyone agreed that it was either the turbo or the heads choking it down.

The bigger turbo was on it's way evern before the fire. I was just gonna try it out and see how it worked. Kind of an R&D thing.

At this point we still feel the GT35 will be too small so I'm gonna try the current turbo but with the smaller housing to correct some of this lag and get my bottom end back.

It'll all work out in the end. Just sucks when you don't make the right choice and don't run the "magic" #s the first time out. LOL

Guess I should have listened to Rick Hahaha

 

I have a feeling that I may have to swap things out a time or two also, but we'll see. Wife may end up hating this setup if I'm under the truck a lot. Still a little ways down the road though. Motor is only 30% broke in.

How long is it taking you to change out?

 

the housing is quick to change. I would say an easy 20-45 minutes at max. Of course that doesnt include letting it cool down. But its easy.

You have the t-70 on yours also? I put that same turbo on my Firehawk.

Rick