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

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

Good post Jerry.This would be about my luck.LOL

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

For those interested, Jere still has all of those news letters, they're available for free on his web site. Jere is still extremely active, and one of the sharpest people I know, and not just about headers, but cam design, data acquisition, dyno operation, and racing in general. He's a lot like Bill Jenkins and Warren Johnson, he's a contrary old codger, but if you can talk sense and knowledge to him, there's a ton of information he has to offer. But he is completely intolerant of B.S. or people that waste his time.

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

I have read that equal length primaries (assuming proper diameter) will deliver the most power but in a narrow RPM band, Running different length primaries will lower the peak HP but broaden the HP curve delivering higher average HP over a larger RPM band.

It seems to me that higher average HP should be the goal for a drag motor.

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

If the primary length varies enough that some primaries are off enough to lower the amount of HP produced by those cylinders, they'll just lower the overall average HP, in the vast majority of cases.

The reason is that you have an approximately 3" "window" for tuned length. After that, the length of the primary is far enough from the correct harmonic length that it hurts HP over the entire range. That happens because you lose way more off the peak than you ever gain everywhere else.

The "tuned" in the term tuned equal length header refers to the length of the primaries and the collector being tuned to one of the natural harmonics created by the rest of the combination, cam timing, port size, bore, stroke, rod length, etc. If the primary and the collector do not match one of those harmonic lengths, you are not operating in a "tuned" state, and therefor the header is not working with the engine, it is working against it, by disrupting those harmonic tuning lengths. That's a crude layman's way of explaining it, used here for the sake of brevity and clarity.

Obviously, given the constraints imposed by the stock engine location, mostly stock chassis, and ground clearance on a Stock or Super Stock car, it is next to impossible to build absolutely perfectly tuned headers. In some cases, it can be impossible to even get within the 3" "window", at least on the primary tubes, no matter what you do. Also, in some cases, even if you add extra bends to move a tube to get close to the window, between the extra bends and the inch or two that end up from perfect, you're better off to just use fewer and/or less severe bends and live with the incorrect length.

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

There are a couple of things I have observed over the years about headers on my car that may or may not be true for others. #1 Is that a dyno is not the place to test headers. Mike Keown told me years ago a bigger header will make more power on the dyno but won't go down the race track like it shows on the dyno and that has been my experience. #2 is what I heard from a really good header builder and that was that the first 8 inches of the primary tubes were the most important part of a header and the size of the first step should match the port size. These are just my experiences on my car and probably aren't relevant for every one else.

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

I experienced what Greg mentioned about big headers on the dyno. I quit drag racing in 1980 and went dirt track racing. I had a 358" methanol burning, Hilborn injected engine on Carroll Caudle's dyno, and tried a set of his 2" dyno headers just for grins. My thinking was if my 292" C/SM Camaro liked 2" headers (It did. Thanks Garly), so this 358" should. On the dyno it did, it was up everywhere, as much as 40 ft lbs. Bought a set for the car. It was just plain lazy. My driver said it felt like he was towing something. Finally listened to him and put the smaller ones back on it and it stepped right back up.

Guess we don't race dynos, right? :D

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

I think allot of that is PROBALLY due to the acceleration rate of the engine being different on the dyno vs. the track. If I remember correctly, on our truck engine design of a 440, the engine will accelerate at 2,000 rpm/second in first gear after the converter locks up. I don't think a dyno can simulate that very well.

What does a superflow test at, 300 rpm/sec correct? I think that is still slower than the accel rate in high gear, but it's been a long time since I've looked at that.

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

Chris, that acceleration rate is selectable. Too many years ago, so I don't remember what Carroll was using that day. Most guys use what is closest to their car pulls in high gear. With that dirt car, I have no idea what that would be. No data logger. We had no minimum weight, so if you tossed it up and it came back down, if we could get by without it we didn't use it. :D

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

Has anyone done any testing with extentions on merge collectors, also adding to primary tubes ? thanks, in advance.........

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

had a set of hookers 1 7/8 primarys with 3 1/2 collectors ,,added extensions and picked up 2-3 hundreths ,,then i built a set of steps with a smaller collector size,merg collector and picked up about 3 hundreths ,,now this is track results and over many runs and conditions this was the average gmonde

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

Because there is an array of differences between engine designs and components used, especially camshaft designs, establishing the correct header size for any engine can be complicated and many times considered a mystery.

As others have said, headers that work in the dyno may not work at the track. For many years, the old belief was the larger the header, the more power the engine will make. (The old “Bigger the Better” Theory) The reality is many are running engines with headers that are too big in size for its application.

I have examined data from both dyno and track date were a Comp Eliminator engine gained a lot of power by switching from a 2-Step header to a 3-step design with smaller primaries and merged collectors. Very interesting to see how the change affected both the BSFC and EGT also eliminating a reversion issue that the engine was experiencing.

In the early days and prior to the advent of computers when we had to use a slide rule, paper and pencil, I recommended the use the guide lines as shown in the book titled; “Scientific Design of Exhaust & Intake Systems (Engineering and Performance) by Philip H. Smith and John C. Morrison. Another good book is Practical Gas Flow by John Dalton.

To have an idea on what it takes to design the proper header for your car, the elements and factors to be considered, just go to the Burns Stainless or Kromer Kraft Headers website and look at the “Race/Engine Specification Forms” and you will have an understanding of all the parameters they take in consideration when designing a header.

In fact, Calvin Elston asks potential customers to fill the form from Burns Stainless and when they get the results, he will discuss the recommendations and add his input based on his prior experiences.

Mark at Performance Welding Headers has a lot of knowledge and experience he gained throughout the years while working at Ak Miller Turbo. Ak Miller was the pioneer of race and street turbocharging and much of today’s turbo technology started at Ak’s shop. Much of the power of turbocharged engines is dependent on proper exhaust design. I believe this is one of the many reasons why his headers work so well and because he has taken the time to read and study many of the published SAE treatises and publications on exhaust science.

This is not taking away from other great header builders such as Stahl and Gebbler.

If you are serious about the performance of your car and have the budget, stay away from other brands that just bend tubes to build headers to fit a specific chassis and do not take in consideration how the will perform.

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

gmonde,

Did you have the extentions on when you put the step headers on ?
Also, how long were they ? Thanks, for your input .....

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

We run Mark's Merged collectors on all our stockers! On our low torque/HP cars they make a very nice improvement(.03 to 04) in our 60 ft times. If we could afford them we would have his headers on our cars...just not in our current budget. We run a production Hooker or TTI header....13/4 on small block mopar and 17/8 on big block ...usually buy different used one's from swap meet to try. These collectors were best money we have spent on our cars in terms of improvement per $$.

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

Dave, go to Larry Meaux's site www.maxracesoftware.com and get his PipeMax software. While you're at it, get on the list for his ET software. The PipeMax software is some of the best header software there is, it has some pretty good dyno simulation software built in, and it is affordable. The software comes with tech support and a membership to his tech support forum.

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

when first done i just had a short collector(cone) car sounded very responsive but didnt seam to have torque (60 foot wasnt there) removed the short cone and installed a longer tapered 10 " cone that opened to three inch and used the short cone removed and installed on the end coned back to 2 5/8 ,,,the car had its best 60' at the divisional in july,with not the best air conditions
but that is my combo,,i do a lot of asking of racers what they are running and there are so many different senarios for the same cubic inch ,,,gmonde

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

Thanks ; Alan, gmonde & GTX JOHN for the input ... Looks like I will have to some more reading & testing ....