3" MAC exhaust for a Tork Tech 2v ...too much?

[JustinG60]

So I am building an 04 comp orange 2v Terminator / Tork Tech and I started considering exhausts. I bought the car as a 1 owner stock GT aside from Flowmaster mufflers welded in, a Trick Flow intake elbow, and some larger TB (stock intake manifold was leaking so they replaced it and did the inlet at the same time).

So I've read everywhere that you shouldn't do a 3" until 400hp and well, I expect to make around that and exceed that when I get a short block built/bought ...so is 3" way too much for a Tork Tech running a stock Terminator pulley @ 7psi? I know a lot of people say they're going to build and never do but I already have more in parts for this car than I paid for it, I don't see it taking longer than the year to build a short block.

Thoughts?

...bit or random info, pleasd don't recommend me a Flowmaster setup unless you know some someone custom bending one with Super 40's. Haha

Thanks for your time!

 

[StrayBullitt]

3" Single exhaust maybe. Unless maybe you are only talking about Cat back, I see 3" dual as overkill.

 

[StrayBullitt]

http://www.exhaustvideos.com/faq/ho...ing_wp_cron=1477590055.6373739242553710937500

From the website above^ First column is pipe dia. 5th is max recommended HP.

1 1/2	1.48	171	78	155
1 5/8	1.77	203	92	185
1 3/4	2.07	239	108	217
2	2.76	318	144	289
2 1/4	3.55	408	185	371
2 1/2	4.43	509	232	463
2 3/4	5.41	622	283	566
3	6.49	747	339	679
3 1/4	7.67	882	401	802
3 1/2	8.95	1029	468	935

NOTE: These numbers are just estimates. All pipes are assumed to be 16 gauge steel.
The table above is probably over-estimating pipe size, but you can see that a 400 hp vehicle with a dual exhaust system only needs 2 1/4 – 2 1/2 inch pipes. Anything larger is overkill.

 

[JustinG60]

Yeah, I have seen that chart on a bunch of different sites and it never specifies if that's 400 crank or 400 wheel ...which are substantially different. Using an old "rule of thumb" of about 15% loss through the drive train, that equates to approx 460 at the crank. 460 by that chart then maxes out the 2.5" exhaust and that's not even mentioning I'll be going with a fully forged bottom end. Even then I only want to break 500 at the wheels. My goal is to make more power than I did with bolt ons on my 03 Cobra (465 or 488 when the lower was done and a bigger upper, same boost, less belt slip)

I figured 2.5 was about just didn't want to leave power in the table later. I'd rather lose power on the stock bottom end to have it when I have everything the built bottom.

Thanks for the responses!

 

[StrayBullitt]

For sure. The 2.5" might eventually be a little bit of a bottle neck up there in power where you want to be.

You might find this video interesting. Obviously not a boosted application, but similar power level at the crank if you were at 500 whp. They did one on header size too, interesting stuff.

https://www.youtube.com/watch?v=_PVXvHkr-Vs&index=6&list=PLGvTvFzdMg_O2T3UdUEt5dIHutSOu7srE

 

[JustinG60]

That's kind of what I was thinking but I've never run a 3" exhaust ...probably should have one some builds I've done in the past after watching that video haha!

Thanks again for everyone's responses! ...it definitely made my exhaust decision easier, now I'm gonna have to get some long tubes and a 3" mid section too