John, I know a guy who did some asphalt racing with a mach with dyno-ports, they could not get it to go much faster then a stocker. The D.P's were tossed and replaced with jaws pipes and I think then they got in to the low to mid 10's. I can find out the facts if you want more info.
John fill in your location, are you in Ontario??
Thanks 670,any info would be great.Im only about 45 mins away from you,Im in Stayner,about 2mins from Wasaga Beach.Is there anyone in the Barrie area that has an in frame dyno????Our local guys sold theirs.I have tried Jaws,99s stock and the stock 98 s work better with my sled anyway.I bought a set of used dyno ports as they make their peak power 600 to 700 rpm lower than the competitors.I want to get some dyno time and try all 3 or 4 sets and see what really is going on.
Mr670 if you are talking to the guys who tried the dp on their pavement mach could you ask them if they retarded the timing??I was reading the instructions on the pipes and he wanted the timing retarded .020 to .025 thou. if this is the case I know how much of a diff this made on my sled with the stock pipes.Im sure they are doing this to keep the pipe temp hotter ,this could have caused some performance problems.
I have DP's installed on my 97 Mach Z and love them. Seemed to get alot stronger out of the hole, good sound, and mid range feels almost out of control. Like I said I had them installed for me by Jeff Ludwig ( Oval 440 champ racer )
I always thought that retarding the timing in a two stroke(firing later)raised pipe temperature because flame front had less exposure to cooling system and as combustion occured closer to tdc or after tdc the flame front had less time to cool before being exposed to exhaust port.This should in theory lower coolant temperature (less saturation time)but raise pipe temp>In any event Im sure skidoo retared the timing to prevent burn downs,im sure they wouldnt do it to increase performance,but a quick before and after drive was an eye opener.I know in 4 stroke theory retarding the timing should make it lazier at lower rpm,but in the 98 mach case it had the exact oposite effect.Go figure
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