can a good 3" single mandrel bent exhaust with dual hi-flow cats, high flowing muffler and 1 3/4" headers efficiently support 450hp or more with minimal losses? what kind of gains could be expected for going to 3.5"?

 

Based on your previous post about headers, I'd suggest you cut to the chase and go long tubes (1-5/8" would be fine for that power level in LT's, but 1-3/4" would do the trick, too), Mufflex Y, and 3.5" or 4" on back. Or, 2-1/2" duals all the way back.

If this is a regular street warrior, then you'll have to choose between ground clearance and peak power.

 

yup, its for street but obviously im looking to maximize peak power here and keep it all legal. so longtubes are out, so is dual exhaust.

im just curious as to why traxion was able to have such obviously ridiculous hp with a single 3" exhaust. thats the main point here i guess. that, and i understand a slightly narrower pipe will maximize scavenging and keep the gasses hotter and flowing faster, as well as keeping the noise level down somewhat, which are also goals. i realize im juggling here but its all about compromise anyway. i just want to choose the best options.

im not going for 500hp obviously, im running a superram, not a miniram. but if i can get damn close to 450hp with this setup, and i believe thats doable, then i want to do just that.

 

I'm running 500hp on the 85. I have a 3" system with shorties and no cats, 80 series flowmaster (for now). The 3" will certainly support 450hp. Goin 3 1/2" may cause clearance problems. I wanted 4" because I am putting in another motor with much more hp but my exhaust guy said 4" will be too low. Looking under my car with 3" I would agree he is right.

 

interesting. what head/cam package are you running in the 406? which shorties/y-pipe did you choose and have you had it dynoed or tested for backpressure? what trap speed are you running?

 

Hooker super comp shorties w/ypipe, no backpressure and no trap times yet.

 

no backpressure at 500hp? how did you determine this?