BIGGEST POSSIBLE HEADERS ON ROCKET 2500CC

vsteel · Nov 11, 2024

Jagster said:
Nice work, Sunny.

My understanding is that Richard isn't currently focussing too much time on headers, but that doesn't mean that he won't do. ....He's a busy man.
My understanding is that Paul Bryant is developing some big bore headers and matching tail end......Anyone wanting bigger headers, I suggest it might be worth asking how far down the road he's got with it.

Just pinged him so I will let everyone know when I hear back. That way he doesn't have to reply to 20 emails.

vsteel · Nov 12, 2024

Here is what I got in my mailbox today:

my apologies for the delay getting back to you, I've been out riding for a week.

We're looking at about a Month out to have this current pipe sorted.
The heat shield is taking shape, making the heat shield itself is one thing, but it's all the making of the mould and plug etc to be able produce the item that has taken the time.

I've always been a little concerned as to what a heat shield would look like styling wise, but this one is actually enhancing the over all look/style.

I'll get some photos today and will send them through.

Regards,
Paul.

No photos yet but when I get them I will post them here.
(above is a direct quote and all grammar and spelling belongs to Paul)

1olbull · Nov 12, 2024

sunny said:
yes, I can fiddle around a lot more now, I can make 2.5inch straight pipe but I dont know long it should be,

Can anyone provide inputs from their experience, if I were to put at 2.5inch straight pipe how long it should be?

Exhaust formulas are your friend.

vsteel · Nov 13, 2024

1olbull said:
Exhaust formulas are your friend.

Could use the old drag racing trick of running a long pipe and then cutting it off 6 inches past where it turns color/burns the paint off.

Mongler07 · Nov 13, 2024

vsteel said:
Could use the old drag racing trick of running a long pipe and then cutting it off 6 inches past where it turns color/burns the paint off.

Yea it's works mostly on 2 stroke. Done that a few times. You end up chasing your tail a bit because it's a constant retune on most cuts on non 2 stroke engines.
That is to say it's easier to build a high end exhaust and then tune the fuel map for it.

sunny · Nov 16, 2024

Dyno numbers - 2.5inch Headers vs Stock headers

Dyno runs charts are 2 years apart. Both Dyno are from Different Businesses. Not the same Dyno machine. Dyno1 was ran during Summer July, Dyno2 was run today in Nov. Dyno run 1 is with Werkes Exhaust + Penner Tune + Stock Headers Dyno run 2 is with Open Exhaust + Penner Tune + 2.5inch...

www.r3owners.net

DesertRat · Mar 30, 2025

sunny said:
yes, I can fiddle around a lot more now, I can make 2.5inch straight pipe but I dont know long it should be,

Can anyone provide inputs from their experience, if I were to put at 2.5inch straight pipe how long it should be?

Sunny,

The R3 will be my first Motorcycle Study but Physics are usually an almost constant in Mechanical Engineering.

There is a lot more to Performance Exhaust Design than just Primary Tube Size and Length.

One of the most neglected factors that an Owner fails to analyze is the Engine's Camshaft Profile and Cylinder Head/Valve Profiles.

I have yet to obtain the Camshaft Profile for an R3, so I really cannot render an opinion Exhaust Design YET, (give me a few moths)

There's a really good Book about Race Exhaust Science named;

Scientific Design of Exhaust and Intake Systems (Engineering and Performance)

Author PhilLIP Hubert Smith

Here's a Formula that, (the Formula Looks to be Valid, YET HAVE NOT VALIDATED on a Dyno),

IMHO this Formula/Design Calculations will give you an idea of what mechanical values are needed to design an Exhaust System for maximum performance.

In the

Primary Header Tube Length and Diameter Calculator

Calculate Header Tube Length and Diameter - by Wallace Racing Home of Pontiac Powered Firebirds,Trans Ams,Pontiac Powered Dragsters,Pontiac Power Rules!

www.wallaceracing.com

You're on the right track!

J

DesertRat · Mar 30, 2025

In the meantime you might want to experiment with a Ceramic Exhaust Wrap and do an A to B Comparison on the Track.

The Exhaust Wrap will increase the Exhaust Velocity which will show a slight increase in top-end HP., (but again until I study the OEM Camshaft Profile I can't be certain)

You might gain at least 1/10th off your 1/4 mile times.

DesertRat · Mar 30, 2025

Sunny,

While waiting for the Book;

You might want to call and speak to these Guys;

Burns Stainless: Performance Exhaust, Collectors, Race Mufflers

High Performance Stainless Steel Exhaust Parts. Burns Stainless offers exhaust parts, tubing, collectors, headers, race mufflers and accessories. 304 Stainless Steel, 321 Stainless Steel, Iconel, Aluminum, Tubing and pipe, bends and straights, v-band, turbo collectors, flanges, bungs, plugs, and...

burnsstainless.com

I've seen some good work coming out of their Custom Race Exhaust Shop.

BIGGEST POSSIBLE HEADERS ON ROCKET 2500CC

vsteel

.060 Over

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1olbull

Riding Motor Since 1950

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Mongler07

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DesertRat

.020 Over

Scientific Design of Exhaust and Intake Systems (Engineering and Performance)

Author PhilLIP Hubert Smith

Primary Header Tube Length and Diameter Calculator

DesertRat

.020 Over

DesertRat

.020 Over

Burns Stainless: Performance Exhaust, Collectors, Race Mufflers

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