Exhaust Myths vs Reality

[WarBaby]

Welcome to the board and congrats for your new Busa!  

You may get more replies by posting this as a standalone thread in the "Engine & Performance Mods" section. Since no one has responded here, I will.

Yes, I am "big" on BDE for its excellent spread of features (performance foremost among them), but I have used and appreciate other systems also. It's just a matter of your preference. The HMF Dual system is excellent and should make about as much power (when properly mapped) as the other leading systems. If you like the HMF, go for it. It's not like you'll be down 5 HP from the others. Dual systems are heavier but it's just a few pounds difference. Muzzy, Ak, Yosh, TiForce, HMF--all are capable of very good results. The tuning that accompanies any of these systems is as important as the hardware.

Good luck!

 

[natedogg3321]

ok i have a ? i have a hmf big bird system puts out large amounts of air and sounds good, but i'm looking for better short times on the track would it be better to go with a sindwinder or just keep what i got

 

[WarBaby]

Without more info about your bike, I can only say...unless you already have an otherwise well-refined race bike, keep the Big Bird and find lower short times in other mods such as fine tuning, tire compounds/pressures, weight reduction, gearing, clutch, etc.

 

[Genek08]

Greetings all!
I've read this entire thread and have learned enough to know I don't know enough. So I'm asking for your help.

I have a 'Busa powered sand car and need to have headers made for the engine. Right now the engine is at HeadsUp getting the following mods: 1397, cams, springs, adjustable cam sprocket, billet shaft set, undercut gears, larger diameter billet output shaft, decked head and a windage tray, Power Commander, etc.

The engine sits in the car rotated 90* from stock and it is coupled to a differential. I looked at Dwarf car left exit headers but they would require serious modification.

My goal is overall torque. I've read about stepped down pipes, gentle curves, merge collectors. etc. S&S makes a point of 180* firing cycle for scavenging and 26" as header length for a 4 cylinder engine at 10,000 RPM.

Please comment on S&S. Is there any information I can provide my header builder (no motorcycle engine experience) so that he makes a great set of 4-1 pipes for my car?
Thanks!

 

[pitman3321]

VERY GOOD POST THANK YOU

 

[WarBaby]

Greetings all!
I've read this entire thread and have learned enough to know I don't know enough. So I'm asking for your help.

I have a 'Busa powered sand car and need to have headers made for the engine. Right now the engine is at HeadsUp getting the following mods: 1397, cams, springs, adjustable cam sprocket, billet shaft set, undercut gears, larger diameter billet output shaft, decked head and a windage tray, Power Commander, etc.

The engine sits in the car rotated 90* from stock and it is coupled to a differential. I looked at Dwarf car left exit headers but they would require serious modification.

My goal is overall torque. I've read about stepped down pipes, gentle curves, merge collectors. etc. S&S makes a point of 180* firing cycle for scavenging and 26" as header length for a 4 cylinder engine at 10,000 RPM.

Please comment on S&S. Is there any information I can provide my header builder (no motorcycle engine experience) so that he makes a great set of 4-1 pipes for my car?
Thanks!

You sound serious about getting the design that's right for you. With that said, I suggest that you explore this link Exhaust Design.

 

[OB_WRIST~ROCKET]

Item # 1 - Note the "stepped header" tubes, a trick developed by drag racers. The first few inches of header tubes are welded to slightly larger diameter tubes for the journey to the merge collectors. This maintains high gas velocity at the head's exhaust port and allows for high gas volume as the gases cool and expand in the headpipes. Also, notice the smooth mandrel bends in the BDE tubes which allow the inertial gas colume to change directions with less effort than sharper bends for reduced pumping losses. [/QUOTE]

Gas does not expand as it cools...it becomes more dense.

 

[WarBaby]

Item # 1 - Note the "stepped header" tubes, a trick developed by drag racers. The first few inches of header tubes are welded to slightly larger diameter tubes for the journey to the merge collectors. This maintains high gas velocity at the head's exhaust port and allows for high gas volume as the gases cool and expand in the headpipes. Also, notice the smooth mandrel bends in the BDE tubes which allow the inertial gas colume to change directions with less effort than sharper bends for reduced pumping losses.

Gas does not expand as it cools...it becomes more dense.[/QUOTE]
Thanks for your observation. I did not intend to convey that gases were expanding because they were cooling. Perhaps the term "as the gases cool and fill the headpipes" would be less ambiguous.

 

[06BUSA]

Micron's innovative manufacturing technique is a pioneering event that makes excellent performance sense... theoretically. I don't have Micron's header tube cross-sectional area data (the "flattened" or hydro-formed area) and therefore can't offer a quantitative response. However, if the cross-sectional area reduction is correctry sized with respect to the head's exhaust port, it could very well have superior flow velocity at lower RPM and, because of it's "tapered" cross-sectional design (as opposed to the "sudden" area change with stepped tubes), could sustain that higher velocity across a wider portion of the powerband. I have only read of one Busa that dynoed with the Serpent system, mapped, and a small box mod. He scored a respectable 169 HP with a fat low-RPM power curve. Not too shabby for a "crushed" pipe, eh?  

Micron told me the did not make the serpent system for the Hayabusa just last month. That system must have been custom from some where.

 

[WarBaby]

I stand corrected. Thanks! I assumed it was Micron because it had hydroformed headpipes. It may have been Akrapovic or another brand. Sorry if my "assumption" misled anyone. My point was that the hydroforming technology is a superior method of controlling the shape/form of the all-important headpipes, allowing designers to achieve powerband characteristics that were previously impossible (or extremely difficult/impractical) with conventional metal fabrication techniques. Happy trails...

 

[Genek08]

War Baby,
Thanks for responding to my query. I read the referenced article and completed and submitted the data sheet to Burns with some assistance from Heads Up. They left a message for me today asking for cam information. I'm using the stock intake cam for both intake and exhaust. I pasted the data sheet cam section here to see if a forum member knows the answers to the following:
Lifter type (roller, flat, hyd.)
Intake lift at valve
Intake rocker arm ratio
Int. duration @ .050†lift *     degrees
Intake lobe centerline
Intake opens @       ºBTDC
Intake closes @       ºABDC
Exhaust lift at valve
Exhaust rocker arm ratio
Exh. Duration @ .050†lift *     degrees
Exhaust lobe centerline
Exhaust opens @       ºBBDC
Exhaust closes @      ºATDC

I am serious about a system that works for me. Thank you for your help!
Gene

 

[runeight]

Boy! Am I confused now! Can somebody just tell me what the "best" can for the street would be?

oh. Just a simple and short answer would suffice.

Can't do that much reading until tomorrow!

hogger...

 

[WarBaby]

It can be a confusing subject and it depends on what you mean by "best" which is what the original post in this thread was intended to demonstrate. If you will take the time to define what you want from an exhaust, I'm sure you will get experienced answers.

 

[Genek08]

Well, it took some doing but I got the information needed by Burns Stainless to design custom headers for my 1397 'Busa powered rail. They did not need all the information missing on the form and did what they needed with lift and duration. Even my Suzuki dealer drew a blank as did Brocks and others. Total length: 17.5 before merge. Each section1.5 x 8.75 and 1.625 x 8.75. Merge transitions to 2.25. This is for stock intake on both sides, stock porting, heavier springs and 1397. Thanks for the suggestion.

 

[WarBaby]

You're welcome. Very interesting specs! Please let us know how your project dyno testing/tuning goes.

 

[hydrabusa]

Is anybody can tell me, how make my header louder? or anysuggestions? (I have a yoshi carbon) It is too quiet, if I pass 60 mph? I can't hear nothing...



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[Busa Bill]

HOLY Crap !!! now I am really confused on which pipes to get ,BDE or ARKO,EVO. or MUZZY or YOUSH or TI FORCE or..........................etc. I just want the best pipe out there for all around riding Twisties mainly and some all out skin peeling back hyper warp speed . I dont race . just street riding and of course WORK

 

[WarBaby]

HOLY Crap !!! now I am really confused on which pipes to get ,BDE or ARKO,EVO. or MUZZY or YOUSH or TI FORCE or..........................etc. I just want the best pipe out there for all around riding Twisties mainly and some all out skin peeling back hyper warp speed . I dont race . just street riding and of course WORK

This thread was not intended to be The Best Exhaust topic. If you ask which is best, you will get different answers from different folks, many of whom, "own the best". It's subjective and relative to "your" best. This thread was intended to arm you with tech info so that you could better decide for yourself.



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[mountainmotor]

Gene ,

If your looking for midrange power with the addition of HP  I suggest a different set of cams  .

I think your cheating yourself out of 15 or more HP .

You can have 115 torque at as low as 4500 rpm with the small WebCams and 1397 phased properly and 190 HP at 9600 . You could also use the 395/378's that don't have the duration spread . Just set the LCA's down a bit .

Simply saying you need more of a duration spread between the intake and exhaust for max midrange . The better the head and exhaust , the better they run that way .

Stock engines have a 20 degree spread . 14 is a small a spread as I would go unless building a drag bike .

Even AutoGrass cars powered with the Busa engine are using 20 degree spread with the Kent cams  . Those cams are huge at .040 lift though .

Look in you PM box . I am sending a phone number for a guy located in California . I spoke with him just yesterday and he has a Busa car coming in for a custom header . Maybe he can pop another off for you if the chassis's are similar . This guy knows what he's doing and is a buddy of Darryl Bassani .



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[mountainmotor]

HOLY Crap !!! now I am really confused on which pipes to get ,BDE or ARKO,EVO. or MUZZY or YOUSH or TI FORCE or..........................etc. I just want the best pipe out there for all around riding Twisties mainly and some all out skin peeling back hyper warp speed . I dont race . just street riding and of course WORK

There's a world of pipes for the otherwise stock Busa . The tune-up can make or break all of them though .

Scott at SK Racing likes the Yoshimura TRS for std bore and even cammed bikes with std bore . He's been at it for awhile too .

Next guy might think they suck .

The one that makes the best peak power may not be the one your looking for on a twisties bike . The one that makes say 2 less peak but more average during time to distance is . Thats difficult though , different dyno's and operaters , air conditions ect ect .