What is the max recommended horsepower using a 3" high flow cat and 3" cat-back with 2 chamber flowmaster? I will be looking at around 500hp and don't want to choke it up. Would 4" be better? Does anyone make a 3" inlet 4" outlet cat?

 

I would like to know the same thing. I am a little lower at 400hp. But I was thinking of 3.5", or just dual 2.5". As far as the cat, if the inlet is 3", and the outlet is 4", it will still only be as good as a 3" exhaust.

 

Well, not necessarily....airflow can be cramped up into a little less diameter and not lose much velocity unless the smaller tube is quite long (I think I remember this from physics somewhere). I would think if the only section 3" in diameter is the beginning of the cat, the velocity and flow should still be pretty high due to the short length of the restriction.
Someone help me out if this is false logic

 

I would definately like to know the same thing. I want to run around 400hp but don't want to lose ground clearance with duals (dropping the 82 with Eibach Pro-kit)

Dragula,
Love your set up. I was wondering if your SLP 1 3/4" headers and y-pipe hit your Jegster SFC's? Did you notch the sfc's? I have the Jegster SFC's and was gonna buy the SLP's but was worried about them hitting the frame connectors.
Also, I see your running 190 AFR's. Did these bolt up nicely with the SLPs? No Modifications and are you running straight or angled plug? Sorry for the questions but I'm in awe of your set up and was thinking of building it up the same way. Thanks

 

500 Hp? I would go with a 4" system. I believe 3" is good up to around 350 HP or so. There was a post a while back about the HP ratings and the size exhaust needed.

 

Hey Sals....the whole project is still in progress.....Haven't got the engine in yet or the sub frame connectors. The SLP's fit nice against the straight plug AFR's. The Jegs SFC's are supposed to work but we all know what that means. The car is TOTALLY torn apart and getting put back together slowly. Pretty much everything is new....fuel tank, lines, pump, engine,suspension, tranny.....its been a 4-year project of accumulating parts and I finally have everything!!! I'll let y'all know soon how it turned out and provide some times.