fbt551 Posted October 18, 2014 Report Share Posted October 18, 2014 Im going to be running a 7mm long rod 68mm bore stock cylinders should I go with big bore pipes or small bore? Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted October 18, 2014 Report Share Posted October 18, 2014 Depends on the set up, but IMO I'd say small bore. CC wise that motor is getting close to big bore territory, especially if you take it to the dunes and hot lap the hell out of it. However, if those cylinders don't have the transfers welded up, there is no way that thing could make the volume needed to run the big bore pipes. Typically on big bore stock cyl stuff the transfers get a bit choked down after the bigger sleeve is pressed. Quote Link to comment Share on other sites More sharing options...
fbt551 Posted October 18, 2014 Author Report Share Posted October 18, 2014 The transfers have been welded Quote Link to comment Share on other sites More sharing options...
fbt551 Posted October 18, 2014 Author Report Share Posted October 18, 2014 What is the power delivery diffrence? Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted October 18, 2014 Report Share Posted October 18, 2014 The intent was for the big and small bore to deliver the same way granted they are put on motors set up to need them. If a motor is to small for big bores it will feel flat and make less power. A motor to big for small bore will be choked out or either make one good pass, then start to fade on power as it gets heat soaked if you got lap it. There is some grey area though and it may apply to your situation. If you're in the dunes and hitting the strip or hill repeatedly, you could possibly benefit from the big bore pipes. The first run may be ok but not impressive. But if it stays hot and you get right back in to it again the bigger pipe could really shine. On the flip side. I feel your motor may probably run best on a dyno pull or 300' track with a small bore but in the dunes or a place where you get to hot lap the power could fade. I would definitely talk to whomever did those cylinders and try to get your hands on both pipes and see what happens. 1 Quote Link to comment Share on other sites More sharing options...
fbt551 Posted October 18, 2014 Author Report Share Posted October 18, 2014 Thanks for the input reqlly helpfull will try out both Quote Link to comment Share on other sites More sharing options...
817DMX Posted November 11, 2014 Report Share Posted November 11, 2014 small bores, will work great Quote Link to comment Share on other sites More sharing options...
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