So it appears that my engine has higher compression than I had originally calculated. 10.68:1 = not pump gas. I need either race gas or a good additive. any recomendations?
Run it listen for PING. If it pings back your timming off a little. If you must run additive and you want it to really boost octane try MOROSO additive. It comes in one gallon cans. Follow the instructions Donot over mix it.
the machine shop who rebuilt it said to use race gas. It's too loud to hear ping(or I didn't hear it anyway) It blew the first time from detonation & the cam was retarded. Besides, the cheap-o race gas is $3.29 - that's becoming more & more reasonable every day! It's just on road trips that I have to worry. Moroso, huh. Any idea where to find it?
The Pro Blend fuel treatment works good. http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=4262&prmenbr=361
What kind of engine have you built? It should be ok at that compression with 93 octane. I've run 12.76:1 comp. with 93 on the street with iron heads but it has to be set up right.
Try the local autoparts for the MOROSO, O'Rielly used to carry it, and probably any number of other places if you ask. My ride is loud and I don't have any trouble telling if its rattling. But if your machinist says run it on race gas I guess you better or void your warrenty.??
Yup. Toluleny and Zylene are both 116 octane. But you have to mix it about 4/1 with gas. But 3 gallons of that with 9 gallons of 91 = 97 octane
I'll second the tolulene. (industrial paint thinner) Buy a drum and its much more cost effective (if you have someplace to store it).
I'm not an expert of fuels, but I talked to a VP chemist and he said that tolulene is the old way of increasing octane and that it dilutes the iso-octane (because you have to add so much to get the octane increase). So you will lose power because the density of the fuel decreases along with the lower heating value of the fuel. But it will add knock resistance if the small drop in power is more important to you than paying for race fuel.
I'm running a blown slant six and mix one gallon of 110 racing fuel($4.50 a gallon) with six to eight gallons of 93 from the pump and it cures my detonation. If I run 93 from the pump, you can definitely hear the detonation when it is on boost. With the mix in the tank, I do not hear any.
Don't care what the chemist says!!! I have used it to boost octane. Engineers say bumble bees can't fly also..........OLDBEET
If you feel that you are in too deep with the compression you can change cams to one that will bleed off the compression a little...When you retard the timing and/or run the carb richer you just create new problems...like a gummy buildup on the top of the pistons. If it is a weekend rider consider water injection. A little dab will do ya...and keep it from poping the top ring land.
Dont laugh i hear a hand full of Mothballs also works in the tank i have not tried it but it sounds like it might work........................
Are you running iron or aluminum heads?? I have a stroked 427 Ford(488cid) with aluminum heads and 10.6 compression and I run 38 degrees total on 93 octane. I haven't heard any pinging. It might like a little more octane though.
I think you should be able to get away with that compression. I ran 10.5:1 compression in a 340 until 2 years ago. The trick is the 241@50 camshaft that bled off a little cylinder pressure. I could run 91 octane with 38 degrees total timing with stock iron heads with no problem.
I have used Tolulene for over 45 yrs. Years ago you could not get race fuel so we made our own. 25 gal av gas 25 gal the best high test and 5 gal tolulene.only problem with av gas is made for high altitudes.and to buy you need a tail number.not a real problem at small air ports. if you need one I will PM the tail no on my plane. also no road taxes on av gas so say for race car only.You can mix some av gas with your pump gas. keeping your engine in good tune always helps.. Tolulene makes a great tire softner but watch out highly flamable and the fumes are bad. lots of people sniff the stuff to get high. Some paint suppliers want a purchase order to sell. so let them know what the end product is and no problem.. I hope this helps Bobby..
Tolulene is also good for causing serious health problems with your lungs down the road and grows cancer like weeds. But hay....it sure gets a carb clean!
Where the hell are you guys getting 93 octane from? I can't get anything higher than 91 in Caifornia unless I go to an airport or dragstrip! Does this mean that Californians are not only paying 40 cents more per gallon, but also getting 2 less octane? On top of that I've been told that the octane rating in California can vary up to 5 points and still be legally sold.
In the Midwest(I am just outside of Chicago) 93 octane is the norm. I guess you Californians are getting screwed there too. But seriously don't alot of the higher altitude states have lower octane ratings as well? I was in Michigan and they had 85 octane.
My daily sounds like a bunch of tap dancing midgets are having a party in the top end of my motor under load because of the crap gas most of the year. Been trying lucas's tune up in a bottle- octane booster stuff. I bought the one time bottle and then a big bottle for like $7. I Just make up a bottle when i hand over my $55 to fill up. It's works- right after a fill up it will ping until it mixes up then no more. Don't know if it will do enough for you but it's cheap and any autoparts store has it - only thing i found thats cheap and fixes the crappy gas were stuck with. Local small airports are real hard to just drive on and buy av gas now. For cheaper race fuel call your local moto x dirtbag hangout and ask where they get the high test. We have a local place you can get it by the drum if your into having a fuel dump on site. good luck, danny
Something is not right. I ran a 427 at 11 to 1 w/ a pretty serious hydraulic roller and HEI on the street w/ no problems. Just a little retardation on 91 and it was fine.
MrE, are you sure he didn't just mean when you take it to the track? A 10.5:1 motor should run fine on 93. Hot Rod's Pump Gas drags has bigger meaner motors with more hp than your and my car combined running on pump gas.
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