TeamRealtreeHD Posted July 29, 2009 Report Share Posted July 29, 2009 (edited) Compression on the cub is at 160-170 PSI (I tested on 3 different testers, every one is different). Got 155 on mine, which the threads are not quite as long as the spark plug threads. Got 160 on one that is slightly longer, but not as long as the threads on the spark plug. And got 165 on one that is about right in terms of length of threads. Wondering if I can safely run pump gas... been mixing half and ha;f but that is really getting old, and expensive. Just bought another 5 gallon of 114 today, and mixed it half and half with 93. So I got 10 gallon, and that should last me a few weeks. Running my timing on +4 right now, thinking of trying +6 as I didn't play with the timing yet. Really haven't put too much time on it. 20 gallon so far in 2 months, which isn't alot considering how much I used to ride. Just wondering what you guys thought about that compression, and the octane this motor requires. I can't find race fuel any cheaper than $9 a gallon, so it's really getting to me... Wondering if it would be safe to go with 93 pump... and if it would be safe to do so if I planned to go with +6 timing. Kevin Herr, the builder of this beast, says to go half and half like I am, to be safe. He also says it most likely could run on just pump alone. But to be safe, mix. Just looking for others advice, ones who ran cubs and such before... Mods are in the signature... and I am running 158 mains, 50 pilots, CEL on 3rd clip with air screw 2 turns out. It is spot on with the 50/50 mix of gas, with Klotz at 36:1 Edited July 29, 2009 by TeamRealtreeHD Quote Link to comment Share on other sites More sharing options...
00tbanshee Posted July 29, 2009 Report Share Posted July 29, 2009 you cheap ass!!i'd say the 93 octane would be fine but your going to have to keep the timing down at no more then +2, i would think to be safe Quote Link to comment Share on other sites More sharing options...
slopoke Posted July 29, 2009 Report Share Posted July 29, 2009 av gas 4.00 gallon 100ll this will start some debate but been using it for years and it is very high in octane. It is rated at 100 octane on the lean setting for an aircraft. It will be more like 110 when itis all said and done Quote Link to comment Share on other sites More sharing options...
okbeast Posted July 29, 2009 Report Share Posted July 29, 2009 91 pump with around 40oz's of methanol mixed in with it. Ran fine ever since i've been doing this. Quote Link to comment Share on other sites More sharing options...
TeamRealtreeHD Posted July 29, 2009 Author Report Share Posted July 29, 2009 I will keep buying the race gas if need be, I just get mad at times, especially the day I buy the stuff (today). I am too afraid to run av gas through this motor... Quote Link to comment Share on other sites More sharing options...
TeamRealtreeHD Posted July 29, 2009 Author Report Share Posted July 29, 2009 pabansheematt has 170 PSI on each side of his 492 PV cheetah and is running pump 93 for 3 years Quote Link to comment Share on other sites More sharing options...
POORBOY350 Posted August 14, 2009 Report Share Posted August 14, 2009 pabansheematt has 170 PSI on each side of his 492 PV cheetah and is running pump 93 for 3 years i know this is an old thread an all but i wish i could 'safely' run pump gas to man its a pain in the ass i gotta drive like 50miles to get some 111 instead of 2miles the store to get 93... i would say go for it tho. i do like the smell of some 111-114 tho lol. i run 111 tho not sure my compression but its a 4mil cub with 20cc domes Quote Link to comment Share on other sites More sharing options...
bode1 Posted August 14, 2009 Report Share Posted August 14, 2009 I don't have a cub, but my compression was a little higher than planned after I rebuilt it. I wanted to run pump but ended up needing 50/50 pump/race fuel. It was just a pain in the ass mixing the gas the way I was doing it, Kevin told me I'd be good with the av gas and that's what I've been running. I guess I could go bigger in the domes and burn pump, just have had no time to mess on it with work this summer. I feel your pain, I really hated mixing the fuels Quote Link to comment Share on other sites More sharing options...
kr0nic Posted August 14, 2009 Report Share Posted August 14, 2009 355 cub, jetting varies, 20cc domes, +3-5deg on 92 w/ 32:1 benol (+7-8 on 110 works killer for racing, haven't tried AV on this motor but had good luck with it on past motors). No problems with premium (have been running it for 3 years), and its a hell of a lot cheaper, unless you want to drag race, I say goto 76 and fill it up :thumbsup:. Although if you do have the money for it, you will be able to tune more power out of race gas, no question. Quote Link to comment Share on other sites More sharing options...
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