| Author | Message | ||
     Ttags |
ok, so our compression ratios are pathetic. if i throw the 9 pistons in my motor i'll be somewhre in the range of 11.25 : 1. Questions being, have many people done this? reliability issues ? and most of all, fuel maps, timing maps??? appreciate the help. winter is coming soon! would love to persue this project! | ||
| Xb9ser |
Compression ratio is 10 to 1. I think with 9 pistons in a 12 it is more like 12 1/2 to 1. Unleaded race gas only. | ||
| Xl_cheese |
I've hear the 9 pistons bring it up to 11.5:1. Of course it's all hearsay. I have a set of 9 pistons sitting on my bench.  | ||
| Fast1075 |
Be advised that proper setup and tuning is required or it will detonate its self to pieces....that is a LOT of compression in a street motor...it has been done...and with success...use VERY good fuel. | ||
| Steve_mackay |
Unleaded race gas only. Bud at Hals is runing on normal 93 octane pump gas with 9 pistons in a 12 with a daytona twin tech without issues.} | ||
| Hogs |
I think it works out to 12.3:1 But When I do it, Having another set of 9 cyls. and pistons complete to put in my 12, I think I will CC the heads and in doing so will lower the compression down to 11.5:1 or perhaps 11.25:1.. Btw this Twin tech unit is that not similar to them old T.Boxes that were an add on, or What else do they compare to? And yeah good gas is a must... (Message edited by hogs on June 30, 2009) | ||
| Hr_puffinstuff |
the lead is for the valves, not the compression | ||
| Xoptimizedrsx |
its a actual 12.34:1 on my bike i built. read the cc fill after that. it drops. run the zero base and .030 head you drop to the cc less than 1203. mine is aprox 1170/1180 now set up this way. the fuel will need to be 91 min but race fuel is better. if your running a o2 sensor system run unleaded only. sonoco 260gtplus or mrpro4.1 vp fuel is best there are others in each of those brands to use. the vp rep. emailed me and said to use the m109 or the mrpro fuel with the afr set at 13.43 if possible. but use unleaded only. before you button it up check the exhaust valve min clearance. i dont like below .95 squish. i triple checked this value with a few known places who race. be sure to let the tapits bleed off then turn the motor over to check the squish. over all a good cheap upgrade on pump gas. dyno said the fuel was just fine as it sat. tuning will help. (Message edited by ••••••••••••• on July 03, 2009) | ||
| Hogs |
Thanks MIke... | ||
| Jdemoxb9r |
winter is coming soon! NOOOOO!!!! oh wait its only July.....Scared me for a minute | ||
| Ttags |
alright... thanks... how bout another piston combo? i wanna be around 11:1... any ideas? or should i have a machine shop shave the top of the 9 pistons? | ||
| Hogs |
Check the on line sponsors within ,If ya want some Nice Forged units etc... Yeah you could do that,But they would really have to know their Stuff...,also dig out the Combustion areas abit cc them, thicker head and base gaskets and better quality gaskets... Don`t think ya would have to do much to get em around 11 or 11.25 or so | ||
| Tattoo72 |
Great guys and they are sponsors here. They will machine the pistons to what ever compression ratio you want. http://www.jetroadracing.com/racing_pages/parts/bu ell_engine_parts.html |
