Youre right. I guess ill succumb to the fantasy, strap some 2" primary headers on, and top it off with a 55 gallon drum intake manifold to make power.

 

now you've got it! Trapping 92mph with a 6 speed cammed car with 14 degrees of overlap I'd say you need to listen to more advice here. You could probably strap on some 1-7/8 headers and pick up some mph there too.

I'm still waiting for you to tell me how plenum volume can get you to 101kpa at 75% throttle in that thread btw.

 

No, I'm not. I was assuming since you believe 1 7/8 is too much primary that you most likely think too little back pressure vs too much is terrible.

Might as well start arguing about scavenging.

You stick with 1 3/4 and keep running 7.7s or whatever the hell your Sig says.. we will stick to 2" and deep 5s.
Hell idc either way... I'm personally running stock manifolds.

 

I'm glad I'm not the only one that laughed when he didn't understand what I did there.

This is simple to break down...
One person is arguing about stuff he reads..... Theory.
The other person is arguing about real world data and what happens on every motor .. even with the junk cams we run. Lol!

 

Has anyone tried a stepped header? I thought I read a thread that American Racing makes them... Not a pro on exhaust just throwing this out there hoping you guys can shed some light.

 

lemons.good to have you back.

 

We are all aware Factory LS heads flow light years a head of like the old sbc **** etc. not a shocker bigger headers make more power. 2 inch header will be going on mine. Nitrous loves big exhaust. Think my mph says I was making power maybe I would have went faster with 1 3/4 haha

 

Stepped headers are best, the problem is they're just so expensive compared to the gains you get. A 1-3/4 to 1-7/8 header will usually make more power than just a straight 1-7/8 header. The reason as lemons touched on earlier is velocity. The 1.75 part on the very top of the header speeds up the exhaust pulse as it exits the head port then as it opens up into 1.875 the venturi effect takes hold and almost sucks the exhaust straight out of the smaller section creating much better scavenging with the more free flowing pipe. There are a couple threads over on camaro5 about it. Not many people buy them because,

A. theyre clueless and anything 1-7/8 is just voodoo.
B. they're just too expensive

btw that also blows dckmn or whatever the names' theory about all exhaust gains being done at the collector out of the water. anytime you can gain flow with velocity you will make more power the motor doesnt care where it is.
He's been coming and going lol I wish he'd stick around because his advice is always good lol

 

Very true, also I'll add a couple things to that....
The merge collector like on ARH / Kooks headers also plays a huge role in better exhaust scavenging. A lot of "old school" LS headers like SLP's, hookers, pacesetters etc. did not have them. The research and development of LS headers has come a long ways since the late 90's early 2000's. I gained 5whp alone going from an SLP 1 3/4 LTs to ARH 1 7/8 on a bolt on car lol that's just changing headers and doing nothing else.

 

How expensive we talking on the stepped header?

 

Hell, the new TFS LS3 and LS7 stuff is built around a 2" primary header. You can't even run a 1-7/8" on those.

But whatever.

Those guys don't know what their ports are doing.

In related news, header design comes down to four things in this order:

1) Exhaust valve size
2) Collector length and diameter
3) Primary length
4) Primary diameter

I recommend you buy Larry Meaux's PipeMax. It'll tell you the optimal header and exhaust design based on cam timing, head flow, exhaust valve size, and RPM.

 

like 1200 for an fbody header lol when a normal kooks or arh 1-7/8 is 850. i dont even wann know what vette stuff would be. however if I owned a vetter i would seriously give the lg super comp 1-3/4 a look HINT HINT mainly for reason number 3 posted by jake

 

There was a thread on the corvette forums I think where ARH were talking about their stepped headers. I think they said they are best as an open header. When you put all the pipe out to the back of the car they lose their effectiveness . I'll look for the thread.

 

ARH has 2" headers on their website now. It looks updated! Nice posts guys

 

Well, I purchased my ARH stepped thru Tick Performance and received 10% off. Martin did say, the design was the best for my ls6 and performance goals. They are rather expensive and I elected to also go with their catted y-pipe. I did get free shipping woohoo and the total came to $1782 bucks. They are bloody expensive indeed.

 

Good call Mark! What kind of numbers are you putting down?

 

I am not sure being that it's a 02 camaro A4. It's currently sitting untuned as I have a newly spec'd smog cam, AFR's and a Mamofied FAST 102 waiting to be installed. The cam is 223-227 619/597 on 116+3 for my A4 trans.

 

I went with ARH mainly for a few reason. The first is that they have a unique design all their own. Kooks, tsp, pacesetter, speed egn, etc all have the same primary design more or less modeled after the early grot headers. ARH is a fresh slate design. They seem to make a touch more power than other ls stuff but that's debatable but they do have a long primary length by a little. Their design hugs the block VERY tightly my 1-7/8 aren't even in the same hemisphere with my steering shaft, aka tons of room whereas my buddies kooks hit the steering shaft right out of the box. They also slide in very easily because of this reason, no removing the steering shaft or oil filter or whatever mine just slide right in. The collector on the ARH was unique up until kooks redid theirs a few months ago. The collector necks down and then opens up to help scavenging.

Finally though all my friends had kooks and I wanted to be different lol. Plus if you ever need anything Nick is a super nice guy who is very accommodating, I asked for a wideband bung and he did it for me at no charge. Even when I thought I might have an issue with my msd starter he offered to modify the headers to fit. Btw ARH will not work with aftermarket starters like the msd or power master the headers hug the block too close

 

I went Kooks stepped LTs to full Kooks TDs and no CATs. Still sorting out me custom grind cam install so no numbers yet, but I will post them up once the car hits the dyno - no promises on when, life is a little busy these days (3 performance vehicles + building a garage LOL).

 

I run the Edelbrock stepped headers with 3.5" collectors that were on close out for ~$310 a few years back. Unfortunately they don't have high velocity merge collectors like the kooks/ARH, but the car still seems to make decent power with them.