Primary Size?

[K4fxd]

Angrey;

I was building headers with Ed Hennamen (sp) back in the day. He was laughed at by all the magazines and manufacturers. Every set we built and put on a car went faster. Physics and gas dynamics have not changed since the 60's and 70's.

He was against stepped headers said if sized correctly a single size will make more power. Never got around to testing this.

What Greg said is true, unless you build your own you are stuck with what can be bought.

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[GregO]

All you have to do is move the center studs and the GT350 flanges fit the 5.0.

As far as I know only the 5.2 VooDoo heads are drilled and tapped with (4) stud locations on the center two exhaust ports.
5.0 Coyote heads only have (2) stud locations per each exhaust port.

 

[K4fxd]

5.0 Coyote heads only have (2) stud locations per each exhaust port.

You are correct, I was thinking the other way around. I'll edit my post.

 

[K4fxd]

A Formula One car that revs to 20k rpms is going to want very LONG tubes and the diameter depending on how it's geared (again, bigger = higher rpm for peak torque, smaller = lower rpm for peak torque).

This high revving Cosworth F1 engine has very short headers.
https://collectingcars.com/for-sale/cosworth-ca-formula-1-engine-and-headers

 

[Angrey]

This high revving Cosworth F1 engine has very short headers.
https://collectingcars.com/for-sale/cosworth-ca-formula-1-engine-and-headers

Yeah, i questioned that after I wrote it. I did say depends on the gearing. F1 engines make a lot of power but have little torque due to their low volume, so ostensibly they're trying to shore up the below peak torque. I'm unfamiliar with the gear boxes for F1 or Indy cars.

Point is, primary tube length adjusts the curve, diameter moves the peak.

 

[K4fxd]

diameter moves the peak.

Not what I have found on real engines.

Too big diameter kills torque, too small kills HP, the TQ peak RPM stays the same unless you change the cam timing or other things.

I'll let you have the last word.........

One other thing I'll point out is the collector on that Cosworth is only slightly larger in diameter than the primary tube size. It also has a stepped design so ED was probably wrong on his disdain for stepped tubes. Like I said I never tested this. If I get the chance I will.

 

[GregO]

Some bed time stories.
https://www.speed-talk.com/forum/viewtopic.php?f=1&t=51295&sid=d94786a97dd6a5ac9ff9b3be445ed050

 

[GregO]

One other thing I'll point out is the collector on that Cosworth is only slightly larger in diameter than the primary tube size. It also has a stepped design

Stepped 4-2-1’s and collector Choke design.
Calvin Elston is a Wizard.

 

[K4fxd]

Some bed time stories.

I read a couple pages and what Elston says follows what I have learned over the years. One reason there isn't much when adding headers to the coyote is the stock 4 into 2 into 1 design. The engineers got 90% of what they wanted in the stock header.

 

[GregO]

I read a couple pages and what Elston says follows what I have learned over the years. One reason there isn't much when adding headers to the coyote is the stock 4 into 2 into 1 design. The engineers got 90% of what they wanted in the stock header.

Absolutely they did.
And Calvin Elston is the man that helped make NASCAR Super Speedway restrictor plate racing fast again.

 

[K4fxd]

This helps enplane why the coyote can use tubes that are 2 sizes too big and not lose any power.


"There is another factor you run into here is 4 valve engines and there are a lot more of them in 4cyl than 8cyl. They breath like crazy and do not need anywhere near the cam timing to run the same rpm as a 2 valve engine. As a result they do not run into reversion problems as soon. This allows the engine builders to bigger headers and rely solely on wave tuning to tune upstairs or not even bother "tuning" at all and still make power...
Basically there is less need to develop a exhaust system that can reduce reversion, so they don't."

Calvin Elston
Elston Exhaust

 

[Cory S]

My bud just went 9.7 @ 141 on a bone stock 2019 exhaust on gasoline/meth. 1 7/8” full lengths are fine to 1300ish all day. We made 1560 through 1 7/8” at 33psi as well.

 

[GregO]

My bud just went 9.7 @ 141 on a bone stock 2019 exhaust on gasoline/meth. 1 7/8” full lengths are fine to 1300ish all day. We made 1560 through 1 7/8” at 33psi as well.

Catted or Catless on the 9.7 et ?

 

[Cory S]

Catted or Catless on the 9.7 et ?

Bone stock exhaust. . The ENTIRE length.

 

[K4fxd]

Bone stock exhaust. . The ENTIRE length.

I wonder how much he would pick up getting rid of the 2 1/4 inch choke point?

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