silencethevoice Posted October 30, 2006 Report Posted October 30, 2006 Whatsup guys... I blew up my last engine build running on 91 octane, and this time I don't want to make the same mistake.. I have 172psi compression and am running +4 timing. The bike is run only at sea level.. I am running 32:1 Super M with VP C12 right now (108 octane) and was wondering if I am safe with this gas. It's just that I don't really trust my ears enough to actually hear detonation or pinging, the last build pretty much went without me even knowing there was a problem.. Thanks in advance to everyone, this forum is so awesome.. :beer: Quote
thegroup Posted October 30, 2006 Report Posted October 30, 2006 im running 100 oct AV Gas and im at about 160psi i believe and havent had any problems Quote
silencethevoice Posted October 30, 2006 Author Report Posted October 30, 2006 im running 100 oct AV Gas and im at about 160psi i believe and havent had any problems Just thought I would make sure... How much compression/timing would you be running to need a 110,112 or 118 octane gas? or is that just a matter of preference? Quote
sheefreak Posted October 30, 2006 Report Posted October 30, 2006 I run +6 degrees of timing and 190 lbs per cylinder on 110(cam2) Top end looks great after a whole dune season. You are fine w/the fuel you are using. Quote
noslo98 Posted October 31, 2006 Report Posted October 31, 2006 I run +6 timing and 180 psi compression and have been running VP110 for the last 2 years with no problems besides my own stupidity that leaned one side out blowing a hole through the piston. C12 is nice stuff but VP110 will work fine for what your running, the C12 may be overkill in the pocket book. Quote
Bansh-eman Posted October 31, 2006 Report Posted October 31, 2006 hey silence check your compression tester... i was thinking about it and your motor dosent have a stroker and you on a stock bore with 21 domes right? if so your tester might be off seems really high for that motor.... Quote
BANSHEEPRO Posted October 31, 2006 Report Posted October 31, 2006 hey silence check your compression tester... i was thinking about it and your motor dosent have a stroker and you on a stock bore with 21 domes right? if so your tester might be off seems really high for that motor.... YES IT DOES SEEM HIGH BUT IF THATS THE CASE ID SAY YOU ARE FINE WITH FUEL YA GOT Quote
silencethevoice Posted October 31, 2006 Author Report Posted October 31, 2006 (edited) hey silence check your compression tester... i was thinking about it and your motor dosent have a stroker and you on a stock bore with 21 domes right? if so your tester might be off seems really high for that motor.... I am running 1 bore over standard at .012 end gap, with .036-.042 squish and 21cc domes. I have two compression testers, one that is a hand me down old snap on tester, and it reads at 180-185 per side. But I went down and bought a brand new Actron guage as a second opinion, and it reads at 172... So either way I am guessing I would still be above the 160 mark.. Most people seem to think the actron's are fairly accurate.. I was also thinking that maybe the cylinders I bought were milled at the bottom to change port timing. I bought them used and they had the Eric Gorr Mo' Power port on them, and doing some searching, I heard of some people getting that done with Eric's cylinders.. What do you guys think? Edited October 31, 2006 by silencethevoice Quote
Leadfoot350 Posted November 1, 2006 Report Posted November 1, 2006 mix your gas 50-50 110 and 91. I have 185 compression and +6 timming and ride at glamis. Your wasting your money with straight race gas. Quote
Bansh-eman Posted November 1, 2006 Report Posted November 1, 2006 mix your gas 50-50 110 and 91. I have 185 compression and +6 timming and ride at glamis. Your wasting your money with straight race gas. 185 psi and 50/50 your taking a chance... that high of comprssion ytou should be running 110... Quote
Leadfoot350 Posted November 1, 2006 Report Posted November 1, 2006 Do you think I would take chances with a exspensive 7mm stroker engine? I would run 110 straight if I had 200 compression. There is no need to waiste money on gas. Quote
Bansh-eman Posted November 1, 2006 Report Posted November 1, 2006 Do you think I would take chances with a exspensive 7mm stroker engine? I would run 110 straight if I had 200 compression. There is no need to waiste money on gas. your a fool if you think 200 is where to start running race gas... Quote
noslo98 Posted November 1, 2006 Report Posted November 1, 2006 (edited) I have been running race gas ever since i installed the head with 21cc domes and no porting.Some may say i wasted my money but it is cheap insurance on the motor and peace of mind. Also the bike runs a lot more consistant making it easier to get dialed in.With race gas you know what your getting every time and pump your just rolling the dice for a good batch of alhambra fuel. The other factor is that most of the time your not running balls out 7 days a week in my case its once or twice a month for 2-3 day trips so 15 gal of 110 @ 95.00 isnt bad for insurance sure its twice the price but atleast i know what im getting and dont wonder when im running hard on top im not wondering if i have too much comp for the fuel.Just my personal thoughts. Edited November 1, 2006 by noslo98 Quote
dajogejr Posted November 1, 2006 Report Posted November 1, 2006 110 octane, 185PSI, near sea level...and I have a WHOLE lot of timing, no problems. At that PSI, I think you'll be safe with straight race gas, 108 or 110, and let it be. You could play the guessing/tuning game of mixing pump and race...but, in the end...I think straight race gas is best for you! Quote
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