High velocity header collectors, are they worth it?
 

Hey guys. I'm in the market for some new header collectors and was wondering if those high velocity units are really worth any e.t. on a stocker. I know the price on these over the traditional collectors is quite a bit higher. Just wondering if any of you guys that have tried them have picked up any mph or e.t. Thanks.

Re: High velocity header collectors, are they worth it?
 

What your combination requires will determine whether or not you see a gain. If you have a set of 4 into 1 headers that are the correct primary diameter and length, and your previous collector was the correct size and length, you may not gain much at all, and you may need to do some tuning to gain anything at all. If your headers are not the right size and/or length, then a good merge collector may offer a decent gain. But it still may require some tuning before you realize a gain.

Re: High velocity header collectors, are they worth it?
 

There was a good thread started by Wahl recently that had some savvy tech comments by SSDiv6 and others that led me to order Performance Welding's merge collector. Think we run similar combos even (360 Volare??) so I can give you input as soon as I get the car back out. Suppose to be worth 4 or 5 Hun. Suggest you call Mark and discuss with him and read the articles on his website.

Alan is correct as well; I've only got a 3" collector and step primaries that are all over the place so I don't expect full gains until I get some true equal length tubes as well.

Re: High velocity header collectors, are they worth it?
 

Jacob, do not buy anything until you talk to Mark @ Performance Welding. Trust me, he will get your header and collector program in order!

Wade O

Re: High velocity header collectors, are they worth it?
 

Awesome! Thanks for the info guys. I'll give him a call and pick his brain a little.

Re: High velocity header collectors, are they worth it?
 

I had some custom headers built by REF who is recognized as a pretty good builder. Based on my dyno inputs, he selected a merge collector with a big venturi and big outlet. Car felt lazy but it was pretty close in ET to the headers I had previously (Headers by Ed).
I called REF and of course he said my engine didn't make the power I claimed and he sent me a smaller venturi, smaller outlet. It immediately had a fuel starvation problem off the line (bowl running empty) but still had the best 60' ever. I installed a larger needle and seat which I had been wanting to try (but never seemed to have a problem) and immediately picked up .200 over my previous best ET with the best incremental's I had ever experienced.
So the point is, the collectors can make a HUGE difference, more so if something was not quite right previously.
And I have seen Marks work and he does great work and his performance is exceptional. He incorporates large sweeping bends with as much of a straight shot off the heads as possible, even if it means not being a "true" exact length primary tube design. To me, thats the way to make a header.

Re: High velocity header collectors, are they worth it?
 

Is equal length headers really all that important, especially on a stocker with a dual plane intake?

Reason being is on the stocker with dual plane, the intake runner length is all over the place and I thought the exhaust AND intake runner lenght need to mesh to get the full tunning effect.

Re: High velocity header collectors, are they worth it?
 

Absolutely equal length is not nearly so important as the correct size, correct length (there's a tuned length range), and smooth bends, with no unnecessary bends.

Yes, the tuned and equal lengths are very important, even though in Stock you often have a dual plane intake that does not have equal length runners.

In other words, there's a correct tuned length for the primaries and the collectors. If the correct length for the primaries is 32", you need to be within 1"-2" either way, the closer the better. But you should not add several bends, especially sharp bends, to get there.

If you stray too far from the correct length, for either the primaries or collectors, you can kill a significant amount of HP and torque. A lot of collectors are way off in length, and really hurt HP. If you need a 14" collector, and you have an 8" collector, it can make a serious difference.

The correct diameter is very important as well, although not quite as important as length. If the primaries are too big, you can often crutch them with a good merge collector that has the right length and has the right venturi size and shape to make up for the problem with the primaries.

Re: High velocity header collectors, are they worth it?
 

Years ago, in the '80's, Jere Stahl used to send out a monthly newsletter to customers with alot of good technical information. Much of it was related to his recent Dyno Testing with headers of all types. We have to remember that Jere was the originator of the Stahl "total tuned headers" and was considered to be the guru of that time with regard to headers.

I remember in one of the tech articles that he mentioned making over 2200 dyno pulls with various engine/header combinations. So he had it all figured out, and all his previous success was well-founded -- right? Not in his words! This isn't an exact quote I'm sure, but it's pretty close; "After 2200 dyno pulls, I found out that neither I nor anyone else knows a damned thing about headers".

Now with computer technology and simulations, people can get better predictions for the correct header, but I know of $3,500 headers, done with computer models, that are hanging on the garage wall, and the old Hooker Supercomp headers with homemade primary extensions and collectors are on the car and FASTER. Now it may be that you'd luck into a problem/solution like Jeff Lee did that would make the $3,500 headers faster, but if the luck didn't occur, you might go through alot of A-B-A testing and without multiple changes (which is usually a no-no), you would never find the sweet spot. I think that was Jere's suggestion. Tune around what you have, and it won't be that far off.

Need proof? How many of you have changed cams, intakes, head flow, converters, or whatever, and have picked up a bunch of ET and never touched the header? Was it right for ALL of those possible combinations? Probably not, and who knows why! Some people have actually gained hugh amounts of HP on the dyno with headers, and SLOWED DOWN on the track. So I guess that you, your car, and the ET slips are the experts on what header is best. Got a ton of money? Try all the headers you want. If you don't, tune around what you have.

Jerry

Re: High velocity header collectors, are they worth it?
 

here is something to think about ,,,in perfect world headers would be the same lenght ,but in a stocker there are many obsticals for header routing,,, equal lenghts vs bends ,if all bends where flowing with each port (like a dragster) that would be ideal but not the case
i have a customer that i altered his headers from something that was a almost a nascar set up,real nice set ,craftmanship second to none but almost didnt seam like they would be big enoungh we changed to a convetional 4 into one, results will be determainded ,i have done a few sets for my car to where i thought big was better ,,but down sized collector and stepped the header and picked up 3-4 hundreths (not alot but actual ) there is power to be had,when dyno testing bring a few sets of headers or collector sets ,,,,www.gmondeperformance.com