| Author | Message | ||
     Xband |
I'm struggling to digest the theory (theories) as to what makes good primary header / collector design. I think a little data about what others have done in practice would be great about now. Has anyone found data (length, diameter, maybe taper) on an aftermarket or the stock system? | ||
| Slaughter |
Go to Burns and check out their pipe design checklist. MUCH more than you'd think in designing a pipe. Worth a look-see: http://www.burnsstainless.com/RESF.pdf If you fill in the form, Burns can cut and package the whole kit and ship to you for welding. | ||
| Bob_thompson |
I do not think you could beat, very easily, the Buell race pipe design and they have used a 2 1/4" or 2 1/2" collector to a free flowing muffler. I used a 2 1/4" in my own design and a fiberglass straight through muffler and am well pleased with the results along with an Erik Buell Racing race ECM. Bob | ||
| 1_mike |
Header design is all over the net...just need to look..! There...IS NO perfect header that fits all circumstances. You build a header for - 1. what the intended engine use is. 2. for what the engine combination is. 3. for what the RPM range will be. If it were a car...you'd add manual or automatic transmission. This is the short list. Take the three items above...and expand each of them to its fullest. Headers...just like intakes...(and many other things) are a compromise for the intended final use. The street..being one of the most compromising of them all. Mike | ||
| Slaughter |
From Burns Stainless Exhaust design checklist: Vehicle and type of racing Engine manufacturer Useable RPM range Maximum RPM Peak horsepower Peak torque Displacement Bore Stroke Compression ratio Racing class or category Configuration / # cylinders Kind of gain you want If you are able to send a copy of a current dyno sheet, flow data, or information abstract, please do so. Additional comments: Cylinder head manufacturer # of camshafts & location Valves / cylinder Intake valve head diameter Exhaust valve head dia. Cam manufacturer & model # Intake lift at valve Int. duration @ .050 lift degrees * * if duration @ .050 is unknown, specify lift at which it is measured Intake opens @ degrees BTDC Exhaust lift at valve Exh. duration @ .050 lift degrees * * if duration @ .050 is unknown, specify lift at which it is measured Exhaust opens @ degrees BBDC Primary length Secondary length Collector outlet diameter Collector type Cylinder head model Type of fuel system Carburetor or throttle size Intake port dimensions Exhaust port dimensions Lifter type (roller, flat, hyd.) Intake rocker arm ratio Intake lobe centerline Intake closes @ degrees ABDC Exhaust rocker arm ratio Exhaust lobe centerline Checklist from Burns Stainless: Exhaust closes @ degrees ATDC Primary OD (or step diameters) Step lengths Secondary OD Step lengths Tailpipe diameter Header Configuration ( 4-1, tri-y, etc ) 32 | ||
| D_adams |
That was part of the formula I used a while back. Realistically, getting much over 140-145 hp on a dynojet with the stock headers will in all likelyhood be very, very difficult to do. Stepping the headers will help some, but keeping the exhaust tucked under the bike makes it tougher to accomplish. | ||
| Xband |
Holy crap! And I haven't even gotten to the calculus yet. |
