Running high HP without headers

v8killr

Registered User
I wanted to see how many of you high HP guys are running headers,or when you where doing your build up's at what point did you go to headers.

I know some of you guys are running 340 rwhp with stock manifolds but how much porting can you actually do to these.I'm trying to get an idea as to what parts i want to buy and what order i need to buy them.It's going to be a long project so it really don't matter i guess what order i buy them in.

Btw-- I'm trying to get around 350rwhp and go from there,but my goal is 350 .... I know about all the bolt on's,i'm just curious about how important the headers are..
Thanks David
 
I know that Bill McNeil is runnin somethin like 360 with his ported stock manifolds, Maybe get in touch with him he is VERY knowledgable and a nice guy to chat with. But about the header ? i am interested also when they are needed.

Jay
 
After comparing the headers to the manifolds, I'll never go back. The manifolds collectors alone are somethin like 1 7/8 in. at best compared to the 2.5 in on the mid lengths. If you got a pulley and a lot of inlet items, get headers!!!!!!
 
WOW....When I first came here in 99-2000????? I tried to talk about headers and was told I was crazy and did'nt know what I was talking about, nice to see some guy's arent in denial about the subject. Hmmmmm.........I just may offer to sell the headers I make after all.......second thought maybe not. My feelings are still hurt by it all.
 
Its hard to beleive no one has done any dyno tests,of before & after
header installation.Surely someone like kooks has done this.

Randy
 
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mike38

Hey i never hurt your feeling's,lol.
I'd be interested in checking your headers out,do you have any for sale?What kind are you making...ie,long tube,shorties..
Thanks David
 
Mike....I feel the same way..Only in teh SC world will you hear headers arnt worth crap haha..It still boggles my mind....But noone has done say day same car dyno testing on with and without headers..at $600 it wouldnt be my first mod on an SC however if I was doing heads and cam....Ohh yeahhh..Wait..It was one of my first mods done to my SC...ehh Anyway...
 
That is not exactly true. Testing has been done but most people prefer to dismiss the results.

Fact.

Bill has the highest HP 5spd SC and he doesn't have all the "best" parts even. No headers, no FMIC, no alum flywheel, no welded heads, no radical cam, no race fuel, etc etc. Sure his car isn't that quickest 5spd, but at 110mph and full weight, it's no slouch.

Gary's 5spd makes 350rwhp and has run 109-110 also but he has headers, bigger cam, welded heads, fmic, alum flywheel AND driveshaft.

Fact. Coy Miller did testing. Of course it is also next to impossible to get info our of him but at one point is was stated that longtubes were worth about 5hp over the shorties but only at certain rpms.

Fact. Brian at Apten has tested many 03 Cobras with stock manifolds vrs longtube headers and has not observed any appreciable gain.

In most cases, people simply install headers at the very start of things and almost always combine header installs with exhaust and other upgrades making the true effects impossible to really determine.

Plus our manifolds are NOT that bad of a design. In fact, if you know anything about header design, you will realize that in most cases where a 3" collector is used (or even a 2.5" for that matter) is TOO big for a 3.8L V6 anyhow. I think that my Kooks longtube header design might actually be hurting things at certain rpms. They do look cool though. :)

How much more evidence is really necessary?
 
And I thought buying the most expensive kooks headers would be worth
more horse.Than buy a cheap set of MACs .
More money faster you go.:rolleyes:

For 600.00 bucks plus coatings & shipping for kooks.You can just buy a cheap
mig welder and build your own.And then be able to fab up other mods.

RANDY
 
Randy or Mike,

You know anyone within a couple hundred miles that can build a top quality custom turbo system (including headers and FMIC) for my 347 SC project ?

David
 
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Good one Dave N!

I still hold my ground that the EVEN PORTED COLLECTOR size on the stock SC manifolds is what kills performance. I think on a roots type blown engine long tubes arnt important..And perhaps a 3 inch collector is too much. But when compared to the stock manifolds collector I'll take the headers any day..


Why Bills car runs what it does yet makes the power it does can be attributed to many things. One of which can be the dyno used...I know that weve been through this discussion before however different dynos do indeed give different results. Temperature humitity elevation all play a role as well. Bill had a stock or double IC as well??..Not very good for having consistent results due to heat soak at the track

Last year we had done dyno comparison of different headers and exhaust setups on an Aprilia Mille. Same bike same day same cooldown period...There seemed to be arguments over whos products were superior so someone stepped up and said Ill do it. Untill someone does this...There really isnt any good comparison in my opinion..Too many variables
 
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Good one Dave N!

Damon, I'm serious.



There really isnt any good comparison in my opinion..Too many variables

I agree, and I think the only pracital way to do the type of comparison your talking about is on an engine dyno in a controlled enviornment.

But your still going to have several varibles...for example if Coy Miller did the test, the results would only be meaningfull if you had the same engine and supporting mods that his dyno does.

I installed the headers on my car along with the rest of the SCP exhaust system before doing any other mods except gears. I was dissapointed in the results and couldn't feel any differince. How good would it run now with ported stock manifolds instead of the mid length headers ? Beats me...might even be the same. The cats look more restrictive to me than the stock manifolds.

David
 
David N. I could machine you some flanges up for the turbo for you.
You can buy the turbo & header flanges, or I could do that to.And maybe any
brackets needed.

Are you going to build the header from steel or stainless?

I have a friend here in Effingham, That has built turbo systems
for Bonnieville racers.He does nice work.I don't know if he would
be interrested in the job or not.He work's on some fast Studebaker's.
He has used a turbo blowing into a centrifical supercharger,twin, &
single turbo systems.

He is an electrician by trade.

Just e-mail me and I will give you his business ph.# .RANDY
 
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Dave I know you were serious..I just liked the plug...

On a stock SC the exhaust itself is whats restrictive..More so then the manifolds..Id say 600 headers are overkill...I had them on my stock SC and was disapointed as well..Had the same exact exhaust as you..However I still dont like the collectors on the Kooks shorties..The full lenghts however have a real collector so to speak..Well to each his own...The manifolds on the 03 cobra are MUCH nicer then the SC ones BTW...Outlet wise definately!
 
However I still dont like the collectors on the Kooks shorties.

I don't like them either, but more because of the ball socket connection than the size. I wish they came with the nice flat 3 bolt flange like the longtubes.

David
 
Thats exactly what Im talking about Dave...There are good ball socket desighns and that isnt one of them. Currently Im working on welding 2 1/2 inch steel exhaust donuts to the bottom on my Kooks midlenghts to get a good seal and a true 2 1/2 inch outlet..Was thinking of throwing them on my new SC instead of selling them dirt cheap
 
Damon,

I looked for some of the steel donuts and couldn't find any. If you locate some I'd like to buy a couple from you.

David
 
I'm just reading this now.

I'm adding several other mods this year, and keeping the ported stock manifolds. I'm really curious to see how far they can take me. For $600 USD, I can buy the NX wet kit that David has, so that is a total waste of money from a performance standpoint.

I plan to run well into the 12s this season, and hopefully gain another 20-30 RWHP with the mods I'm adding this spring. I'm confident that my manifolds will not be a restriction in getting their considering I've already made it to 360.

As for dyno variables, I agree this is certainly a factor. Luckily, I've been to more than one dyno, and have found my results consistent with the addition of modifications over the past 2 years. I went from 310 to 322 to 336 to 360, and have about a dozen sheets with numbers in between. I think they are accurate within about 10 HP, if I had to guess.

If I had my choice, I'd hit 400 this year with my current plans. ;)
 
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