Running 30% in a 3.3 ?
11-14-2007, 05:23 PM
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Running 30% in a 3.3 ?
So I want to switch to 30% in my Tmaxx, mainly becuase I run that in my buggy and im tired of carring two gallons of fuel. So with the 3.3 do I need to shim the head, or can I get away with just running a cooler plug?
11-14-2007, 06:05 PM
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RE: Running 30% in a 3.3 ?
I had one engine that went from 10% to 20% and then to 30%, becuase I didn't know that the guy I bought it from ran 10% so I bought 20% and then I changed to 30% I didn't reshim the head, or ran a cooler plug, just run a traxxas 3231 or 3232 which are med temp plugs and with 30% you can run a med plug.
11-15-2007, 12:00 AM
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RE: Running 30% in a 3.3 ?
Between the head and the block is a shim/head gasket. These shims come in different sizes and usually when you break in a engine with 20% and want to switch to 33% you have to shim the head for the larger combustion that the 33% will produce. If you dont shim the head it will pre detonate and eventually ruin the motor. Some can get away with just running a colder plug so the nitro does not burn as hot. Some dont have any problems at all and some trash a motor after about 2-3 tanks. Rule of thumb is you run what you broke the engine in with.
11-15-2007, 01:46 AM
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RE: Running 30% in a 3.3 ?
DO IT. I run betweeen 20% & 30% all the time. Its probably gonna need to be re tuned but its little tweeks. Mess with the HSN 1ST. 1/16 turns at the most. If your worrred about loosing engine life it all isss basicaly the same. You might save a bit running 20% but it will run better with 30%.
Im sure someone will beg to differ.
Im sure someone will beg to differ.
11-15-2007, 02:54 AM
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RE: Running 30% in a 3.3 ?
why exactly should you stay with what you broke it in as? i don't see why that is a rule of thumb, change the plug, re shim and re tune and you can run whatever nitro content you want basically, i've even seen guys running 60% boat fuel in there thunder tiger MTA4's..
11-15-2007, 08:22 AM
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RE: Running 30% in a 3.3 ?
Go ahead and use the 30% with a new, colder plug. I highly recommend a McCoy MC9. I went from 20% Top Fuel to 30% Byron's in my original TRX 2.5. Didn't have to shim the head and after retuning it ran really good for over a gallon. Still had good pinch when I replaced it with a Picco. I wouldn't hesitate to throw that 2.5 in another vehicle for a few more gallons.
