600HP - Is 3" exhaust worth $700 additional cost over 2.5"

[Chad-1stGen]

General consensus is that over 500hp it makes sense to run 3" exhaust. I currently have a 2.5" kit and 3" kit (both flowmaster) to see what I can fit under my car with the TCI torque arm. Either kit will require modifying the tail pipes but between the extra cost of the 3" kit ($220+) and the extra labor to get it to fit (maybe another $300-400 I'm just not sure if it's worth it.

When I think about spending over $700 for maybe 10-15 horse power it seems like a waste. Now if this would cost me 30-40 hp then it might be worth it.

I don't care about loosing a few horses on the street but care about it when on the road course.

What do you guys think?

[TraviZ28]

If money is the issue then stick with 2.5" and enjoy the car and your wallet. You can always rebuild the exhaust later when you have the money to dump into it.

[Flash68]

Chad, if you can piece it together, I'd consider going 3" to the mufflers, then 2.5" from the muffler to the back.... I have seen that recommendation hundreds of times for both packaging benefit and noise help.... the power loss there vs a full 3" has been proven in most scenarios to be minimal.... esp if that's where the packaging issue is.... plus it will keep the noise down a bit vs the 3".... if you care about that. :)

[chuckd71]

Could you keep the 2.5s and just get cutouts for when racing?

[Chad-1stGen]

If money is the issue then stick with 2.5" and enjoy the car and your wallet. You can always rebuild the exhaust later when you have the money to dump into it.

Well its not a matter of having money now vs later. I can fund the additoinal cost. It's a matter of cost/benefit in the first place. The last thing I want to do is spend $5-600+ putting in a 2.5 in system in order to spend $1,200+ a couple of years later. I'd rather do it right the first time. I'm just of the mind set that just because the money is in my bank account doesn't mean I should spend it.


Chad, if you can piece it together, I'd consider going 3" to the mufflers, then 2.5" from the muffler to the back.... I have seen that recommendation hundreds of times for both packaging benefit and noise help.... the power loss there vs a full 3" has been proven in most scenarios to be minimal.... esp if that's where the packaging issue is.... plus it will keep the noise down a bit vs the 3".... if you care about that. :)

Yeah I've thought about that. Tails and mufflers are pretty cheap to buy. But Flowmaster doesn't sell the H pipe section separately.


Could you keep the 2.5s and just get cutouts for when racing?

I've been thinking about this one also :p

[6D9 Matt]

Yeah with the minimal gains, Id probably just stick with the 2.5" and then add some cutouts.

[TraviZ28]

From what you have said Chad, Don't do it unless you personally think the extra 700 dollars is worth another 2-3% horsepower. Me? at 500+hp, hell no, Another 10hp would not be worth it.

[dontlifttoshift]

Why buy a kit then? Kits do not fit to your headers and you will need to modify the tailpipes....there certainly must be a decent exhaust shop in southern california that can bend a 3" system front to back for under $800. Pick any mufler you want and get the 3" you likely need......


These guys turned up in a search http://bromuffler.com/ and http://www.autoexcellenceonline.com/ Give em a call and see what they think.


Exhaust kits are great for stock or near stock cars, I have never taken one out of the box and just put it on.

[Flash68]

Yeah I've thought about that. Tails and mufflers are pretty cheap to buy. But Flowmaster doesn't sell the H pipe section separately.






Why buy a kit then? Kits do not fit to your headers and you will need to modify the tailpipes....there certainly must be a decent exhaust shop in southern california that can bend a 3" system front to back for under $800. Pick any mufler you want and get the 3" you likely need......


These guys turned up in a search http://bromuffler.com/ and http://www.autoexcellenceonline.com/ Give em a call and see what they think.


Exhaust kits are great for stock or near stock cars, I have never taken one out of the box and just put it on.

Good call right there.

[Chad-1stGen]

Good point on the kit vs custom. Basically a kit gets you 50-75% of the way there and allows Fab53 to finish the exhaust at his shop. A full custom solution wouldn't be as feasible since he doesn't have a mandrel bender next to the car. I'll figure something out.

[dontlifttoshift]

I don't have a bender either. We fab our exhaust from a pile of 90s.... cut, fit, and weld. It's time consuming but I can put exhaust in places where no one with a bender can.

[camaroinct]

Cut outs are a good option as mentioned by chuckd71, The advantage is, you can keep your 2.5" exhaust, the cut offs are installed before the muffler. The neat thing about the cut offs is you can open them electrically to any degree you choose, providing the amount of flow and / or horse power gains you are after with the uncorked exhaust. Of course don't forget about the desired degree of sound you might enjoy also. I personally have Race Readies on my camaro, have had them on the car for about 3 years, very happy with them.