Alright, I'm looking to dip in to the 10's at a race I'm going to at the end of the month. So far I've went an 11.15@120 with a DA of 2685.

I'm running a stock '03 LQ4 short block, solid valve 243's milled .030" (10.87:1 CR) an 03 zo6 cam with patriot gold springs, an ls1 intake, and ported stock throttle body.

My question is this, will I ultimately benefit from a fast 90 with my setup?
I have one sitting at home that I traded a stock k member and $25 for. The 60ft is what is going to make or break the car on the track, and I can't afford to be down on power on the bottom end if the intake is going to kill power down low.

 

Should be able to get you in the 10s if you get it all dyno tuned afterwards...you will need an ls2 90mm to match if you wanna do it cheap, if money isn't an issue get a nick Williams 90mm throttle body bc there is no sense putting on a fast 90mm intake if you have to run a reducer right before it...

 

^^^ Agreed, If you get it tuned afterwards it shouldn't be an issue at all!

 

Tuning is already set up. He's just waiting on me to do the intake swap.
I'll see If I can swing the cash for a 90mm tb before then.
My mentality in this was, a fast 90 with a stock TB should breathe similar to an ls6 intake with a stock tb. Only thing is, I have a FAST intake, but no ls6 at the moment.

 

I would get a used ls2 90mm tb to match should be able to find one for $100 or under on here or ebay

 

Not really what I would call a bolt on motor, but it should help you a little. You say that you don't want to loose bottom end but you've either got a decent size stall or a manual to cut the 60s that you are cutting. Either way the very low end should bother you too much.

With a FAST 90 on my bolt on car (stock 01 LS1 with lid, pulley, catback, tune, EWP and PT4000) I only lost .02 on my 60' over my LS6 intake. I made a thread about it if your interested.


And am I missing something? A stock TB won't fit a FAST 90 and an LS2 TB is DBW.

 

True, it's not a "bolt on" ls1, but it's basically An iron block ls2, with a slightly better camshaft. I'm running an Edge "3400rpm", 2.6 STR converter. So yeah, "low end" is a relative term I know, but for every bit of power I lose down low, it's going to tighten up the converter a little.

I'm not really sure on the stock TB to fast 90 compatibility, my intake has the 4 bolt style flange, with a 5th bolt hole on top like a stock 75mm tb has, so I just assumed either one would work.
DBW isn't something I really wanna mess with on this car either, lol.

 

Stock LS1 intake is killing you. 90 Fast would be nice with the gears and converter you have any power you might lose down low will not be a factor.