Exhaust size and choice questions.

[PMac18]

I've been doing a lot of research on what exhaust to buy for my goals. In the near future I want to be between 500-550 hp, so when I'm buying all of the pieces along the way, I want to do it right the first time so I don't have to spend money multiple times. I watched a few videos and it sounds like a full 3 inch exhaust is perfect for this hp range. Anyone agree or disagree?

With that in mind, I have been looking at the ARH Longtube Headers with 1 7/8 primaries and 3 in collectors. Anyone have these headers and how do you feel about them?

Also, I really like the sound of the Borla ATAK but they only come in 2.5 in, so I was looking to fabricate something using Borla's XR-1 mufflers. Has anyone used these and like or dislike them?

Any feedback is great. Thanks in advance.

Patrick

 

[SVTDom]

2.5" exhaust flow great and will work fine for your hp range you listed. Go with a Stinger or ATAK catback with an o/r x and you will be set.

 

[PMac18]

I am definitely going to go with the o/r x-pipe no matter which way I go on exhaust. The ARH headers come with full 3 in collectors with 3 in x-pipe. I was also looking at Kooks or BBK if I decided to do 2.5 inch.

 

[GodStang]

I feel that 1-7/8" may be a bit too big for your setup but not sure if you will see adverse side effects from it other than room. I had to do a MM K-member to fit 1-7/8" headers. 2.5" is good to 650rwhp so 3" is a bit too much for your said goals but again doubt you will loose much going that big other than clearance problems and less choices on systems. Just my opinion from what systems I have run in the past.

 

[PMac18]

2.5 is good to 650rwhp? watched a video on summit racing talking about true dual exhaust around from 500-600rwhp should be at 3" exhaust?

 

[masterjr33]

2.5 is good to 650rwhp? watched a video on summit racing talking about true dual exhaust around from 500-600rwhp should be at 3" exhaust?

^^

 

[masterjr33]

This is what i dont understand about terminator exhausts.
always pushing a 2.5 .


Lets see im builing a 400HP supercharged 302 fox body. what exhaust? 3 inch

Im building a 500HP 396 chevelle. what exhaust?? get a 3 inch.

I am putting LS6 heads and in my SS to make about 450 HP . what exhaust do i get?? 3 inch

I will be making around 500HP in m nissan GTR. what exhaust do i get ??? 3 inch

my brother is getting an exhaust on his 2500 with the 6.0 engine. makes about 400 HP. what exhaust did he get?? 3 inch


and you have a super charged duel over head came V8 with 20 PSI of boost making 700HP to the wheels.. what exhaust should you run?
around here 2.5 inch is just plenty. anything else is over kill really . and will hurt torque.


If a 350HP 302 engine will benifit from going up to 3 from 2.5 how the hell can you justify making over 5 to the wheels and not going three.

these cars cannot break phyisics. they are no different than any other car.. and over 400HP i could not imagine a scenario that you would not benifit from putting 3 inch exhaust behind a supercharged engine.

 

[SVTDom]

This is what i dont understand about terminator exhausts.
always pushing a 2.5 .


Lets see im builing a 400HP supercharged 302 fox body. what exhaust? 3 inch

Im building a 500HP 396 chevelle. what exhaust?? get a 3 inch.

I am putting LS6 heads and in my SS to make about 450 HP . what exhaust do i get?? 3 inch

I will be making around 500HP in m nissan GTR. what exhaust do i get ??? 3 inch

my brother is getting an exhaust on his 2500 with the 6.0 engine. makes about 400 HP. what exhaust did he get?? 3 inch


and you have a super charged duel over head came V8 with 20 PSI of boost making 700HP to the wheels.. what exhaust should you run?
around here 2.5 inch is just plenty. anything else is over kill really . and will hurt torque.


If a 350HP 302 engine will benifit from going up to 3 from 2.5 how the hell can you justify making over 5 to the wheels and not going three.

these cars cannot break phyisics. they are no different than any other car.. and over 400HP i could not imagine a scenario that you would not benifit from putting 3 inch exhaust behind a supercharged engine.

Its because of the way these motors are built. They flow really really well from the factory. Adding a 2.5'' exhaust only helps it breath even more then it already does. 3'' like stated above will really only need to be used on high high HP applications in these motors.

You cannot compare a 302 to a DOHC 4.6 S/C. A stock 302 is absolute garbage on flow tests. Even with heads, cam, upper and lower intake and more they still flow mediocre. Im not even going to get into the other motors you listed because 2.5" would work just fine on all of them besides the GTR because its turboed.

 

[PMac18]

So will running a 3 in exhaust hurt performance or are you guys saying its just not worth the extra effort because 2.5" is plenty?

 

[SVTDom]

So will running a 3 in exhaust hurt performance or are you guys saying its just not worth the extra effort because 2.5" is plenty?

3" wont hurt you in my eyes. A 2.5'' exhaust will flow perfect for 500-550hp.

I ran a 2.5" exhaust on my Kenne bell cobra for 2 years and that car made just under 650hp....

 

[PMac18]

I feel that 1-7/8" may be a bit too big for your setup but not sure if you will see adverse side effects from it other than room. I had to do a MM K-member to fit 1-7/8" headers. 2.5" is good to 650rwhp so 3" is a bit too much for your said goals but again doubt you will loose much going that big other than clearance problems and less choices on systems. Just my opinion from what systems I have run in the past.

About how much does the upgraded K-member cost?

 

[PMac18]

3" wont hurt you in my eyes. A 2.5'' exhaust will flow perfect for 500-550hp.

I ran a 2.5" exhaust on my Kenne bell cobra for 2 years and that car made just under 650hp....

Alright, that sounds good. You running longtubes?

 

[SVTDom]

Alright, that sounds good. You running longtubes?

On my KB car I still even had the stock exhaust manifolds. And it still flowed very well, granted I should have bought longtubes, but it made great power and I never got around to it.

 

[c6zhombre]

On my KB car I still even had the stock exhaust manifolds. And it still flowed very well, granted I should have bought longtubes, but it made great power and I never got around to it.

+1

The stock logs on these cars are simply mind boggling considering their appearance... it really defies conventional hotrod wisdom. My car has an extremely simple setup and still makes eye popping low n mid range TQ and big upper end HP. Factory manifolds, 2.5" catted magnaflow xpipe, standard borla stinger. The blower is the "tiny" 2.3 whipple that supposedly makes "no low end...". Ya right lol. Stock caged crank pulley too!

 

[cj428mach]

I assume there are 2 reasons people push the 2.5".

1.Its proven it can make a lot of power.....C6zhombre's car is a great example.

2. The ground clearance on these cars isn't great with the exhaust running under the IRS as it is. Adding a bigger pipe will only make it worse.

The Magnaflow catback thats on my car came off my old SB car that was stock ride height and it had a large scrape on the bottom of the pipe from dragging.

 

[BlksvtCobra01]

+1

The stock logs on these cars are simply mind boggling considering their appearance... it really defies conventional hotrod wisdom. My car has an extremely simple setup and still makes eye popping low n mid range TQ and big upper end HP. Factory manifolds, 2.5" catted magnaflow xpipe, standard borla stinger. The blower is the "tiny" 2.3 whipple that supposedly makes "no low end...". Ya right lol. Stock caged crank pulley too!

Damn impressive numbers

 

[PMac18]

I assume there are 2 reasons people push the 2.5".

1.Its proven it can make a lot of power.....C6zhombre's car is a great example.

2. The ground clearance on these cars isn't great with the exhaust running under the IRS as it is. Adding a bigger pipe will only make it worse.

The Magnaflow catback thats on my car came off my old SB car that was stock ride height and it had a large scrape on the bottom of the pipe from dragging.

I've thought about that too especially if I want to go lowered in the future. Ground clearance with 3" exhaust might be a challenge. Don't really want to scrape the exhaust on everything.

 

[SVTDom]

+1

The stock logs on these cars are simply mind boggling considering their appearance... it really defies conventional hotrod wisdom. My car has an extremely simple setup and still makes eye popping low n mid range TQ and big upper end HP. Factory manifolds, 2.5" catted magnaflow xpipe, standard borla stinger. The blower is the "tiny" 2.3 whipple that supposedly makes "no low end...". Ya right lol. Stock caged crank pulley too!

WOW!!! awesome numbers. Thanks for adding that in.

 

[Quick Strike]

I am making almost 750 HP to the wheels with a 2.5" catback here. I think the key in higher HP cars is having larger exhaust where the pulses are fully expanded and smaller where they contract to help scavenge and keep them moving lively. I have stepped headers to 3" collectors to a 3" catted X-pipe to a 2.5" FR 500 catback. I made sure to have it all 3" to the X where pulses are traded and aligned.

 

[GodStang]

About how much does the upgraded K-member cost?

Anywhere for $300 used to I think my setup was around $2K depending on your setup.