Header Dyno Testing

I talk about the importance of headers. I also show results of Dyno test with a different set of headers.
Website www.wengines.com
Email: [e-mail]

[@Finding_K_Factor]

I bought and have used Pipemax for my header data and more importantly for figuring out my cam data. Been very happy with what Pipemax suggested for both. My headers are older Hooker super comps for a second Gen Camaro 2” inch primary 3 1/2” collectors. Pipemax suggested adding collector extensions which I did make and have used since the engine has been back together. Pipemax also helped nail down my lifts and durations for the cam. The centerline came from David Vizard’s Big Chevy books. Comp Cams ground my custom cam, intake is a REV lobe 0.832” lift with 1.8 rocker, exhaust is a High Torque 420 lobe 0.726” lift with 1.73 rockers. Durations @ 0.050” 278 intake 283 exhaust and 111 centerline. I have no idea what the horsepower is since I havent dynoed the engine but car has gone 9.997/134 with 1.29 60 at 3600 lbs with GM 781 heads. Thank you for the header theory!

[@kevinjennische8209]

David vizard is the man! Been reading his books for 40 years. Never let me down.......

[@Finding_K_Factor]

@@kevinjennische8209 I can honestly say what I learned and applied from his two Big Chevy books and his Porting book really helped with my 468 781 head combo. I ended up doing my own valve job on my old Bridgeport using the guidelines David put in the Porting book. I had to make a bunch of tooling to do the valve job but I believe that work did pay off in the performance of my Camaro.

[@edsmachine93]

Great subject Eric. Reminds me of the changes that happen from the engine dyno to to chassis dyno and finally to the track. Testing is important. 👍 Have a great day.

[@user-zd9ex2bn7q]

I can assure you the super comp guy's are paying attention to their headers.

[@WeingartnerRacing]

I’m sure most do but I went to an event and many just had regular headers on.

[@yarrdayarrdayarrda]

Competition Eliminator/Pro Stock most certainly, Super Comp not so much as that is an index class rather than a heads up class.

[@user-zd9ex2bn7q]

@@WeingartnerRacing my bad Eric was thinking that was a heads-up class.not a index class

[@zAvAvAz]

Great work Eric, your work is so valuable and enlightening for anyone interested in this and racing. Thanks tons.

[@philzellmer6073]

The 128 formula is where you START!...it doesn't mean you don't take other things into consideration....the end result comes from all factors involved....

[@wayneskelly4297]

Danny at Predator cams explained to me awhile back that as the heads get better and better the LSA can be spread out. Not as much need for the overlap with a more efficient port. It seemed to knock down the peak numbers a little but we are usually 1800-2000rpm peak to peak now with a flat torque curve. 110-112 LSA makes for a happy 383-421 Powerglide bracket basher. That "other" formula makes some really shift sensitive rides....just my 2 cents

[@hankclingingsmith8707]

Because the peak torque might be lower

[@lamarw9901]

Thank you for the long explanation. I have done a fair amount of reading and watching videos on this and always looking to learn more even if my options are limited. That dyno is a heckuva a street car. My builds are stick shift street cars and road curse lapping days builds. Lenghts, size,step or not, tri-y, merge colector, x pipe are all discussed amongst the top 4 brands of headers. Also given my goals I like seenig the broader torque. You are 100% correct on torque curve range for drag racing. Down stream exhaust turn down or full exhaust and sizing comes into play.

[@magnusdanielsson2749]

One can get sizing on the headers from burns stainless. They have a form to fill out from wich theyll design the headers. On the speed talk forums one can read posts made by Calvin Elston. Fascinating stuff. Uses the name exhausted there.

[@chevyrc3623]

Nice that's awesome information I couldn't understand all of it but when you showed Dyno results I go wow huge difference. So I am surprised the step headers didn't do good but at the same time you mentioned everything else on the headers is different to so dang but oh well great testing

[@Giftied]

so when you calculate tube diameter, are you calculating inside diameter or outside diameter. like if the sum of your calculations tell you to use an 1 7/8 header, are you using a off the shelf header that is 1 7/8 outside diameter, which depending on wall thickness is really a 1 3/4 or do you use a 2 in primary that would be 1 7/8 depending on wall thickness. tube is measured in outside diameter and tube is inside diameter if i recall?

[@hankclingingsmith8707]

Excellent..so perhaps the 128 formula is as close as you can get without adding headers into the equation give. That a lot of people have little knowledge of cam choosing..there is a lot of info you add into the 128 formula..

[@mikewillett5076]

I looked at pics of a lot of headers. Hardly any went through the trouble of makkg the #5 a little short and #7 a little long. In fact they make the #5 unnecessarily longer than it should be. There could be fitment issues of course, but don't want those 2 pulses hitting the collector at the same time or way too close.

[@YouCantSawSawdust]

Tri-Y's fix that issue.

[@mikewillett5076]

@@YouCantSawSawdust . I was thinking Tri-Ys but always think they'll hurt top end power. What's your experience been? But even so, back to 4 into 1 does anyone have input on the question.

[@Project-gr6zy]

The manifold i made for my 300 ford 6 improves my tq from 1300 to 4300 then dies off This is with a 2inch cleveland valve 1.6 exhaust Ported and polished promaxx cnc head flowing 231cfm The header i made is a 6 into 3 4 ft long runners that are 1 5/8 matching the exhaust port Cyl 1 and 6 merge Cyl 2 and 5 Cyl 3 and 4 This improved my tq by 16.5 lbs over the hooker header off of summit for 299 But the summit header made better top end power Both headers were tested the same day so the same conditons were met The hooker header started to make 7lbs more tq on avg up to 5800 rpm where i stopped the pull at

[@yarrdayarrdayarrda]

I have a set of Doug's Headers SBC 1 7/8/3.5 second gen Camaro headers from my bracket car that's worth power on the dyno over the 1 3/4 dyno headers, but they're only better above 5800 RPM. Bolt them on a 427 that's only turning 5500 and the smaller dyno headers are better everywhere. On my personal 406 they're worth about 12 HP over the smaller dyno headers. (7500+)

[@musclebone7875]

How much hp and torque did your engine make?

[@zorpit]

Really great video Eric. Always learning something.

[@gregsidel3557]

Thank you so much. You're very informative and I appreciate that you explain everything. Thank you

[@garyhosier4765]

Using 128 cam theory choose a cam then try both headers and see what you get vs the runs you just explained. Then take the worst and see if you can make it better than the best run. Without changing headers. Does that make sense. I know it’s infeasible due to expense but it’s be fun to see.

[@WeingartnerRacing]

I wouldn’t mind testing that but right now it’s too expensive.

[@bradytallred]

How is this affected by forced induction? Does reversion still take place?

[@timothybayliss6680]

Ya...a 406 with cast heads and a dual plane making 600hp is actually kind of nuts.

[@rickyfulks889]

Good stuff Eric, thanx for ur hard work

[@timrayburn2461]

Thanks for the video and your effort

[@chevyrc3623]

So ny question is if both headers were just like the 1 3/4 where the collector was 3 1/2 and same length and longer length length header. Let's say if they were both the same in that aspect would the step header work better than just the 1 3/4

[@freelancerider100]

So long as they tubes clear the spark plugs! I am happy

[@user-si4sn1ub9h]

This is awesome information. What about zoomies on a dragster. Na

[@markbogle8062]

I use that program to design my headers and I fought with the header guys

[@musclebone7875]

Do some big block chevy dyno header testing!

[@WeingartnerRacing]

I would need more headers.

[@musclebone7875]

​@@WeingartnerRacing I have some 1 3/4 headers for big block chevy that I can send you to test.

[@freelancerider100]

Scavage! Its the best

[@FORCFED]

Think it would change with using header gaskets like as in an intake manifold port matching and type of gasket??? Instead of silicone

[@WeingartnerRacing]

Not enough to matter

[@user-ye3ty9zd2l]

Is a Channel Member the same as a Subscriber? I want to get the PDF files for a friend in Austin that ports Chevy heads. I'm a Mopar guy and have cast iron heads (LOL!).

[@WeingartnerRacing]

No. You have to pay for the membership.

[@grahamh2758]

What do you think about anti-reversion chambers?

[@WeingartnerRacing]

I would have to see what you are referring too.

[@davidreed6070]

Is the reversion happening at the end up the overlap period or at the end of the intake stroke?

[@cedricwilson2055]

Most at low rpm when the charge is moving slow

[@davidreed6070]

@@cedricwilson2055 absolutely

[@lcxu1051]

DV 128 is 99% accurate for any given engine in a street application. DV also explains that 99% of headers are wrong and gives a darn good guideline for the correct length headers for a v8.

[@WeingartnerRacing]

Have you tested to see if that is true? Of all the engines I have tested at best he might be 80% but nowhere near 99%

[@lcxu1051]

DV will produce any dyno information you want. So you might want to talk to him before you run him down. He has 10s of thousands of dyno results to back up what he says.

[@WeingartnerRacing]

@@lcxu1051he really doesn’t. What he has is other people dyno tests that he uses to try to confirm his theories. It’s conformational bias. I use to believe all what he said until I got my own flowbench and started dyno testing. If you ever do that you will see the flaws too.

[@jeffwooton7138]

DV's 128 formula is for a certain engine, under certain build conditions. He consistently states this. It is for a 355 CI, at 10.5/1 CR. There are adjustments that need to be made, for engine size, valve size, compression ratio, etc. So no, 128 is not a fit all. But, it is a kick off point, and should be used accordingly. Biggest example is a ProStock, at 17:1CR. It uses a wider LCA than his 132 BigBlock formula would suggest. There are boundaries for everything, and testing should be done. He's done a ton, but, one should do their own testing as well, using his info as a kick-off point

[@patrickwendling6759]

Thank you for your knowledge and video's USA 🇺🇸 USA 🇺🇸

[@timleonard86]

What about 30" zoomies