More cam questions... again
#21
Sorry, I keep forgetting that some people know less than nothing about their bike and only want to stick with BRAND name parts. After all of the research and review reading I have done, the combination I mentioned is and will out perform any other similar combo. If you take the time to call either of these two and honestly seek advice on your riding style, they will refer you to the product that is going to get the job done.
#22
Dave Mackie and RBRacing would have their feeling hurt if they knew that they weren't considered BRAND names.
#23
Would the peak numbers with the 204 be a little higher than the 255 ?
#24
Man, you just jumped from the frying pan into the fire. That's a pretty bold statement and will require some backup. It's going to take more than your "research and reading" to convince; post the dyno sheets.
Dave Mackie and RBRacing would have their feeling hurt if
they knew that they weren't considered BRAND names.
Dave Mackie and RBRacing would have their feeling hurt if
they knew that they weren't considered BRAND names.
#25
Sorry, I keep forgetting that some people know less than nothing about their bike and only want to stick with BRAND name parts. After all of the research and review reading I have done, the combination I mentioned is and will out perform any other similar combo. If you take the time to call either of these two and honestly seek advice on your riding style, they will refer you to the product that is going to get the job done.
To quote their website
“LSR 2-1 Pro Stock
Pure Race Systems! No Baffles!”
The Pro Stocks come in two primary pipe configurations and neither achieves ideal exhaust gas velocity in the right RPM range for the OPs 103 Road Glide, I’m actually surprised that someone with your research expertise wouldn’t already know that; 1 3/4" which is too small for the 103", and 2" which is too large for the 103" unless you constantly run at 6500 RPMs. RBR are racers first, their performance parts hobby finances their racing business. I have spoken with them and they are pompous airbags, they rubbed me the wrong way and I wouldn’t give them a plug nickel for one of their dirty shop rags. They don’t care if they ***** you off because they don’t need your business, and they will tell that flat out. Their competitive smart-*** racer attitude bleeds over into the consumer side of their operation, and they assume everyone who calls is a complete idiot, kinda like you did with me in this thread. If you like the flavor of the RB Racing kool-aid, thats great, and you can keep it.
#27
(Piston speed / 60) X ( bore X bore / pipe ID X pipe ID)= gas velocity
(stroke X 2 / 12) X (RPM) = piston speed
I made an excel table with the formula in 500 RPM increments, so I can just plug in different values for a quick reference. There's probably a calculator on somebodys website but I never looked for one.
Basically too little velocity will be sluggish/non respononsive just like an oversized intake, and too much velocity will cause friction and start increasing backpressure. The other formula for primary tube length suggests that a stock cam would benefit from an exhaust system with 58-60" primaries. This winter I plan on building a 2:1 system actually matched to a 95" with Andrews 26 cams. Makes you wonder why primary length isn't a published specification for all exhaust systems, sure would make it eaiser to eventually figure out what "really" works, wouldn't it.
#28
I don't think I've heard this complaint before. What kind of heat issues, radiated heat or oil temp? If the latter, what kind of temps were you seeing?
Haven't heard this one either, but I did see a 103/204 chart once with a dip, and IIRC it also had a 2-into-1. You might give Jamie at Fuel Moto a call for advice on this. He sells Wood cams at discount prices.
Haven't heard this one either, but I did see a 103/204 chart once with a dip, and IIRC it also had a 2-into-1. You might give Jamie at Fuel Moto a call for advice on this. He sells Wood cams at discount prices.
When the temps got up, the bike also got sluggish as you would expect from any hot engine... When it was cool, very nice throttle response and great acceleration.
Last edited by 1931jamesw; 10-25-2011 at 10:20 PM.
#29
I didn't come up with the formulas, but Ideal exhaust gas velocity is about 290 FPS at the midpoint of your cams' powerband.
(Piston speed / 60) X ( bore X bore / pipe ID X pipe ID)= gas velocity
(stroke X 2 / 12) X (RPM) = piston speed
I made an excel table with the formula in 500 RPM increments, so I can just plug in different values for a quick reference. There's probably a calculator on somebodys website but I never looked for one.
Basically too little velocity will be sluggish/non respononsive just like an oversized intake, and too much velocity will cause friction and start increasing backpressure. The other formula for primary tube length suggests that a stock cam would benefit from an exhaust system with 58-60" primaries. This winter I plan on building a 2:1 system actually matched to a 95" with Andrews 26 cams. Makes you wonder why primary length isn't a published specification for all exhaust systems, sure would make it eaiser to eventually figure out what "really" works, wouldn't it.
(Piston speed / 60) X ( bore X bore / pipe ID X pipe ID)= gas velocity
(stroke X 2 / 12) X (RPM) = piston speed
I made an excel table with the formula in 500 RPM increments, so I can just plug in different values for a quick reference. There's probably a calculator on somebodys website but I never looked for one.
Basically too little velocity will be sluggish/non respononsive just like an oversized intake, and too much velocity will cause friction and start increasing backpressure. The other formula for primary tube length suggests that a stock cam would benefit from an exhaust system with 58-60" primaries. This winter I plan on building a 2:1 system actually matched to a 95" with Andrews 26 cams. Makes you wonder why primary length isn't a published specification for all exhaust systems, sure would make it eaiser to eventually figure out what "really" works, wouldn't it.
#30
It certainly would. Thanks for the great response! Everyone says "this cam or this exhaust might be worth a look" and i get that but you can look at something and approve of it until the cows come home but theres no way to know its going to perform until you try it or someone else does and you copy them. I cant afford to just buy different exhausts and cams until I find what works best but at the same time, I dont want to do what everyone else is doing. Know what I mean?