Originally Posted by ratter
it would have been interesting to see if they made better gain if the bike was mapped to suit them
Funny you should say that... this is actually something I wanted to bring up. The point of the exercise though, was to prove/disprove Factory Pro's claim of increased HP on a stock bike.
HOWEVER - the interesting thing was the a/f ratio (which is not printed on the dyno charts that are getting emailed to me - but anyway, I studied them long enough to convey the message)
The a/f ratio chart with the stock stacks started out at about 15:1, and dropped to about 13.6::1 as the rpms rose to about 9000rpm, before going north again to 14:1+ (zero map)
This also happened with the euro map with the stock stacks.
Enter short stacks..
Guess what? the a/f map was cleaned right up, and very flat, small variation at about the 2k-3krpm range, also small variation above about 10krpm, however between these, the a/f ratio stayed pretty level at about 12.5:1...
This was also the case with the Euro map installed on the PCIIIr
. Very interesting, I suspect that the short stacks just may make a difference (in the positive) IF the PCIII
is mapped for it (which in this case it wasn't - seeing as the claim was improvements to a stock bike...). I think with a custom map, it just may give oyu a boost. But that will have to wait another week before I do that... coughing up for 2 maps is not easy...
Basically, the short stacks richened the mixture, and flattenned the curve to look like a table top instead of the valley that appears with the stock stacks.
Another not of interest, the original dyno run of 136.3 overlapped with the 137.4 hp graph showed very little variation (the only real difference is the removal of the flapper) the from of the graph was almost identical, except for the odd small gain on the later run. In other words, I don't actually think the flapper does much. Anyway, as soon as I get the dyno graphs, I'll post them..