Headers necessary for the KB?

[stangin]

Originally posted by sambandit
Check the sig, I haven't seemed to have lost tq.

But you dont really know, you did not do a before and after with just the header install. You just have a good overall number, maybe it would have been higher.. maybe lower?? Hard to say. This is my point, no hard evidence.. prior to the KB I put out as much or very close on the dyno as most people with the same major mods with LT's and I even have the stock cat back.

With my mods prior to the KB:

rwhp / rwtq
444 / 469 Eaton 2.8, CAI, Diablo, UPR O/R X, stock cat back

These were my only mods, even the stock cat back, if I added a
6 lb lower as you have I will bet my numbers would either be the same or very close to yours maybe even higher.. even though you have more goodies.. and LT's. Nice #'s by the way.

Now I am at: 520 / 570 CAI, KB 21lbs, KB Chip, UPR O/R X, stock cat back, belt slip.. and shooting for:

630 / 670 CAI, KB 21lbs, Diablo re-tuned, 55lb inj, UPR O/R X, stk CB, belt slip fixed.. all without headers or a good cat back. I am just saying I wish there was hard proof and I would probably go with the LT's if there was enough of a gain in it.

 

[stangin]

Originally posted by wicked03snake
like philly said. the engine is an air pump and the more it flows the more power. you can lose torque at the low end but make more on the top end along with more power if all that air goes in and doesnt come out you will make good boost and lots of low end torque, but as soon as you free it up you lose boost and torque but gain massive power up top. although i dont know if i want to do it yet because if you can get that low end torque to hook, that is what gets the car moving for good 60' times, however if you launch at higher rpms you should still be able get roughly the same torque. the main place you will notice the loss of tq is on the street so i guess it depends how often you street drive and how important the 1/4 times are.

Yes, I agree with the air pump statement.. exactly right and yes you can loose torque at the low end and gain it back up top, but why? I like the power being down low, this is the seat of the pants fun torque, down low and I like not pushing the engine so hard to get it back in the upper rpms and there is no garantee that you will get it back at all. That is why I like this thread, maybe someone will pull a dyno before and after and convince me to go LT's if the gain is good enough. I also agree with the torque being down low, a getting a good 60' time and not having to burn the clutch doing a higher rpm launch, not to mention how hard higher rpm launches are on the irs. A good debate.. thanks!

 

[stangin]

Originally posted by JSHTROD
People loose torque when they go to a too large header, or too open exhaust system.

It seems complete 3" systems loose torque. So do catless systems.

The vast majority of headers are great. Just don't do 1 7/8's tubes.

:coolman:

I would not even do 1 3/4", lots of lost torque for sure.. I am only talking about loosing torque even with the 1 5/8", which is the norm.

 

[wicked03snake]

well it like i said before, it depends whether you street drive a lot or drag race more. on the street, imo, and just an opinion, no proof, i would stick with cast manifold, off road x pipe, and good cat back if going to a kb. someone on here yesterday posted a dyno graph before and after kb. the first one was identical to my mods and made almost exactly the same numbers. he had, 2.8,cai, off road x, magnaflow catback, idlers. he made 446/462 tq. with only a kb and good tune added he made 555.7/501.8tq. thats with stock manifolds. I know the torque didnt gain much peak, but you should see the curve, it is a lot flatter and stays up many more rpm, and the hp just kept climbing. convinced me on the kb

 

[stangin]

Originally posted by wicked03snake
someone on here yesterday posted a dyno graph before and after kb. the first one was identical to my mods and made almost exactly the same numbers. he had, 2.8,cai, off road x, magnaflow catback, idlers. he made 446/462 tq.

Ok, here is an interesting note: I made 444/469 with the exact same mods with my Eaton, but here is the kicker.. I had and still have the stock cat back which everyone says is restrictive.. vs the magnaflow cat back so the numbers should be higher than mine, I produce slightly more torque.. granted dyno's vary and conditions etc.. I just find this interesting and I really feel that there should be some back pressure. Headers with a free flowing cat back system.. maybe loose some torque, hmmmm. I wonder if headers would benifit me more than most with no loss of torque with my o/r x and stock cat back giving some back pressure, I never thought of this, it scavenges the air out of the engine via header and o/r x.. has lots o room for the expanding exhaust gasses coming out, before the mufflers and as the exhaust gas cools a little (it cools by the time it gets to the stock mufflers somewhat) and being cooler needs less room to expand so would actually draw the exhaust gasses out through the mufflers and cat back. An interesting thought..

 

[wicked03snake]

that is a good thought. id say youre probably right i thought about shorty headers because ill get a 2 1/2 inch mac catback o/r x and with shorty headers i might gain some midrange torque and keep my low end torque. possibly gain high end horsepower too. but as far as i know no one makes shorties for the 03, the 01 will fit, but the exhaust port is smaller, probably not making any difference than the stock manifolds