Octane and compression discussion
#21
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Mixing race gas is definitely the best way to know exactly what you're getting, but the "NOS racing formula" booster works really well. We've tested it on the dyno and the track and have used it in the boat for two seasons with 89 octane. I've heard the Torco stuff is good too and you can buy it in five gallon pails but have never tried it. Also, on your engine an option would be to contact Bob Madara and see if he could design a cam for you that will bleed off enough cylinder pressure to run 89 and not cause reversion. I've got a couple customers running 10.2:1 on 89 whithout any issues. Good luck either way
Last edited by HaxbySpeed; 05-18-2010 at 08:39 AM. Reason: spelling
#22
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Wow I'm surprised someone else has heard of toluene! I used to use it in my high compression jet boat in the early 80's. I mixed 1 Qt. to every 10 gals 91 octane and it ran great. I ran that boat for about 3 years hard with no problems. There are a lot of articles on mixing it if you do a search. I also ran 50/50 AV gas with 91 octane with good results.
Toluene sells for about $35.00 5 Gals. and can be found at petroleum distributers and paint stores.
Toluene sells for about $35.00 5 Gals. and can be found at petroleum distributers and paint stores.
#23
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Toluene has an octane of 114, so plug that into your formula. It is probably the best option. The other real options are either race fuel or the Torco octane boost.
80 gallons of 89 octane and 7 gallons of Toluene puts you right at 91 octane.
80 gallons of 89 octane and 7 gallons of Toluene puts you right at 91 octane.
#24
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So you think I should add some race gas to it? I like the idea of what I have now having no ethanol or additives, less water issues etc. Does not having the ethanol help with detonation? Can I get by with the 90 as it is? Hard to get good race fuel around here, can maybe get Torco or Cam2 somewhere or have to drive an hour to the refinery and by a 55gal drum of the good stuff.
Ethanol will make the fuel burn quicker that is how it attempts to make up for the loss of btu's... Unfortunately I can tell you that every motor runs a little different. We build stock 03 cobras with some running to the chip and one will run great with 102 and the other will want 105... Fuel is something you just have to pick a median and play around with until the motor runs smooth. If you can still find torco then It is a pretty good fuel but they have been in the process of shutting the doors. Let me know where you are located. We have distributors in 23 states and ship to your door also.
#25
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You can also use Xylene instead of Toulene. You can purchase Xylene at Home Depot and Lowe's.
Kemco Oil's Supreme 130 is good stuff but it will clog C02 sensors.
Torco's unleaded Accelerator is a good concentrated race gas.
http://www.easyperformance.com/Tech_...d_Content.html
Kemco Oil's Supreme 130 is good stuff but it will clog C02 sensors.
Torco's unleaded Accelerator is a good concentrated race gas.
http://www.easyperformance.com/Tech_...d_Content.html
#27
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I add some of the Supreme 130 (TEL) at the begining of the season and then again mid season to coat the top end with lead.
As for the 10:1 @ 36*...89 would be fine, I would take out 2* of timing for peace of mind or drop 1 heat range on the plugs. F all that mixing sh*t.
http://www.hi-flow.com/HPOP4.HTM
http://en.wikipedia.org/wiki/Tetraethyllead
As for the 10:1 @ 36*...89 would be fine, I would take out 2* of timing for peace of mind or drop 1 heat range on the plugs. F all that mixing sh*t.
http://www.hi-flow.com/HPOP4.HTM
http://en.wikipedia.org/wiki/Tetraethyllead
Last edited by Back4More; 08-03-2010 at 09:48 PM.
#28
I hate the winter!!
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Wow, this thread came back to life again. Since I started this some time ago, I have been running 89 octane, but with the timing set to 32*. I keep the mixture richer than I would normally as well. I dont run the engine hard. I keep it to max 3/4 throttle. The plugs are looking great. The timing burn is just right. I may be too cautious but I run alot of miles each time out. I would rather run safely today and still be able to run it tomorrow. My plans are a new set of pistons for this winters project. I have been working with Wiseco on having a set made that match my current pistons exactly, with the exception of the dome. Bore, pin location, ring package, even the weight, can be duplicated. That way, all I have to do, is swap pistons. No need to rebalance the rotating assembly, no need for new rings or even honing the bores. Remember, this engne was newly done just last winter. If the bores look good, I plan on just swapping pistons. I have calculated what I need to make the compression ratio a safe and conservative 9.25 to 1.
Last edited by Vinny P; 08-03-2010 at 10:00 PM.
#30
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Funny, I was talking to a fuel rep last week, he was telling me todays fuels only maintain there octane rating for 30 days...then fall off..so be aware sitting on fuel or where you buy if they do not move it fast....Vinny, I still think you are really close with the comp you are running with that much timing, the aluminum heads will help some as will the cam...they can grind the cam so the engine "thinks" it has less static compression..although might not be a good cam for your marine app. I said this before I would run a good water/alcohol injection system, it would give you extra insurance over the fuels...Rob