Stepped Headers

[WhipLash96]

I think that we all agree that a stepped header is a superior choice over a non stepped header. However, is this true in all applications? When does a stepped header become detrimental?  

[Hossamania]

Big horsepower motors used for drag racing that are wot full time?

[turboprop]

The laws of physics are global regardless of engine size.

[Ohio HD]

Agree. Smaller motors may just use a smaller primary header and subsequent steps. Size the system for the motor size.

[98s1lightning]

I got a stepped 2 into 1 on my bike now and a very similar pipe to swap out for testing stepped-vs-non stepped

I haven't got a chance to weld up the piece I need in order to run it

Reason I'm testing is to see if mid range reversion cleans up with nonstepped pipe

My bike runs really good down low and really good once its on the cam but from 1/8 throttle till the cam hits it could run better.

252 duration cam and blows 145psi. Setup is not ideal but its one of the stronger running "stock" bikes I've had. Its an Evo80 with a cam, pipe, carb. The pipe on it now is too large I figured cuz 80ci should be 1 3/4" primary; well I got that but plus 2 more steps after it! I doubt that's what the little 80 really wants.

[BigT]

I run a stepped headed on my 131" M8. Steps up to 2". Works extremely well. I would think low end torque would suffer if it was bolted onto a stock 107"

[Ohio HD]

Some exhaust manufacturers make smaller diameter primaries and the steps are smaller. The D&D Fatcat on my 96" Twin Cam is sized as 1 5/8", 1 3/4", 1 7/8". No loss in low end at all.

The Burns System I have for the new 124" in my other bike is sized as 1-7/8", 2", 2-1/8". They also have for higher output Twin Cam and M8 motors a 2", 2-1/8", 2-1/4".

[FXDBI]

I have a FM E-pipe its a tapered/stepped primary on my Dyna. 15 Discs and closed end cap thats been proven to support 150 HP. Passes the noise test has well. The Harley engine seems to like the stepped long primary but the muffler on the end will make or break any header. Has always it the combination of parts working together for best results.   Bob

[Ohio HD]

Being able to adjust flow at the muffler exit definitely has it's advantages with some applications.

[kd]

Here's an article from our newest HTT site supporting Vendor - Burns Stainless. It will help to understand the stepped header principle as compared to regular tube.  Not mentioned in detail is the steps can also assist on reducing the sound wave that travels back up the head pipe and interferes with scavenging flow from the exhaust valve as it opens.  This can cause pulses that reverb back into the intake manifold and is known to be the culprit responsible for carb standoff. There are also patented devices that fit near the head to do the same thing but stepped headers are permanent and part of the design.

https://www.performanceracing.com/magazine/columns/03-01-2023/pri-tech-stepped-pipes-vs-straight-pipes

[WhipLash96]

I run a stepped headed on my 131" M8. Steps up to 2". Works extremely well. I would think low end torque would suffer if it was bolted onto a stock 107"

Which pipe did you go with? I'm looking at the Khrome Werks Outlaw as a possible replacement for my D&D.

[BigT]

I run a stepped headed on my 131" M8. Steps up to 2". Works extremely well. I would think low end torque would suffer if it was bolted onto a stock 107"

Which pipe did you go with? I'm looking at the Khrome Werks Outlaw as a possible replacement for my D&D.

I'm using a 2-1-2 with. Fuel Moto xxx head pipe and Khrome Werk mufflers.

[60Gunner]

I run a stepped headed on my 131" M8. Steps up to 2". Works extremely well. I would think low end torque would suffer if it was bolted onto a stock 107"

Which pipe did you go with? I'm looking at the Khrome Werks Outlaw as a possible replacement for my D&D.

I'm using a 2-1-2 with. Fuel Moto xxx head pipe and Khrome Werk mufflers.

A proven top performance exhaust that rivals any 2in1 out there. It's going on a 128/TTS 250 build I'm doing.