Register now to get rid of these ads!

Tech: Octane boost

Discussion in 'The Hokey Ass Message Board' started by MrExotica, Aug 22, 2005.

  1. 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?
  2. Steve
    Joined: Mar 5, 2001
    Posts: 1,010


    you should be able to run 91 just fine
  3. 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.

  4. 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?
    Register now to get rid of these ads!

  5. Tolulene. is good for improving octane ratings.

  6. AHotRod
    Joined: Jul 27, 2001
    Posts: 10,542


  7. fastfrankie73
    Joined: Apr 14, 2005
    Posts: 450


    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.
  8. 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.??
  9. blown240
    Joined: Aug 2, 2005
    Posts: 1,656

    from So-cal

    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
  10. Ramblur
    Joined: Jun 15, 2005
    Posts: 2,101


    I'll second the tolulene. (industrial paint thinner) Buy a drum and its much
    more cost effective (if you have someplace to store it).
  11. Blair
    Joined: Jul 28, 2005
    Posts: 361

    from xx

    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.
  12. TriFiveChevyJohn
    Joined: Apr 18, 2005
    Posts: 212

    from TEXAS!

  13. REJ
    Joined: Mar 4, 2004
    Posts: 1,612

    from FLA

    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.
  14. old beet
    Joined: Sep 25, 2002
    Posts: 5,750

    old beet

    Don't care what the chemist says!!! I have used it to boost octane. Engineers say bumble bees can't fly also..........OLDBEET
  15. Godzilla
    Joined: Jul 26, 2005
    Posts: 999


    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 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.
  16. QQMOON
    Joined: Oct 7, 2002
    Posts: 1,309


    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........................ :D
  17. old beet
    Joined: Sep 25, 2002
    Posts: 5,750

    old beet

    Correct, the old ones contained Naptha. Seemed towork in the 50s!!.....OLDBEET
  18. mojo66
    Joined: Nov 4, 2002
    Posts: 367


    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.
  19. RacerRick
    Joined: May 16, 2005
    Posts: 2,753


    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.
  20. k9racer
    Joined: Jan 20, 2003
    Posts: 3,117


    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..
  21. Lucky Strike
    Joined: Aug 14, 2004
    Posts: 1,666

    Lucky Strike

    Tolulene is also good for causing serious health problems with your lungs down the road and grows cancer like weeds. But sure gets a carb clean!
  22. scottrod
    Joined: Nov 5, 2002
    Posts: 92


    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.
  23. mojo66
    Joined: Nov 4, 2002
    Posts: 367


    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.
  24. Flexicoker
    Joined: Apr 17, 2004
    Posts: 1,416


  25. I love my E85! Smells good too!:D

    Seriously, I am going to set the Model A up to run on it.
  26. Ramblur
    Joined: Jun 15, 2005
    Posts: 2,101


    Joined: Jan 13, 2004
    Posts: 2,757


    He said he had a retarded cam.

    Hey hey hey oh oh oh thats funny shit !!!
  28. Darkharts
    Joined: Aug 24, 2004
    Posts: 117

    from Corona

    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
  29. 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.
  30. Django
    Joined: Nov 15, 2002
    Posts: 10,197

    from Chicago

    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.

Share This Page

Register now to get rid of these ads!


Copyright © 1995-2020 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.