WebCam cams for FJ/XJR

[TexasDave]

 
[/quote]
Most modern bikes run shorter duration cams on the exhaust than intake.   Then again,  a budget upgrade for Busa's are to install a stock intake cam on the exhaust side... [/quote] Running a shorter duration cam on the exhaust side on modern bikes is done for one main reason. Emissions control. This not only hurts engine performance but makes it run hotter. the EPA wants that exhaust valve closed before the new mixture has a chance to escape out of the exhaust. Heaven forbid if even one molecule of unburned hydrocarbons escapes. But this is what we want to happen for more performance. Using a longer duration exhaust cam allows all the burned gases to exit the combustion chamber and helps draw in the new charge. Overlap (both valves open for a very short time) allows this to happen. More power, cooler engine and more emissions of unburned hydrocarbons. Busa's stock intake cam on the exhaust side with more duration allows this to happen--but don't tell the EPA.  Dave

[fj1289]

Thanks Dave!  Makes sense to me...

Still makes me wonder why they'd spec that for a set of race cams -- maybe it effects how the response from trailing throttle to WOT or something -- but at this time it's pretty much an academic point for me 

[racerrad8]

Still makes me wonder why they'd spec that for a set of race cams -- \

Because they are trying to meet #8 on Pg 74, yet still get additional performance via better grind than stock.

http://www.uslegendcars.com/documents/2016_rulebook_word_-_final.pdf

Randy - RPM

[fj1289]

Still makes me wonder why they'd spec that for a set of race cams -- \

Because they are trying to meet #8 on Pg 74, yet still get additional performance via better grind than stock.

http://www.uslegendcars.com/documents/2016_rulebook_word_-_final.pdf

Randy - RPM

Thanks Randy - knew there had to be a good reason!  And a good reason why you need to be careful piecing togother "performance" parts from different applications