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Max engine size for a single engine nitro

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Danny King

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Nov 26, 2012
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I can’t find the impba rule for it. I may be confused with Namba. But what is the limit for a single engine nitro in impba?
 

SayMikey

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Feb 23, 2003
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Class Cubic Inch Displacement Metric Class A 0.000 thru 0.129 2.1 CC B 0.130 thru 0.219 3.5 CC C 0.220 thru 0.300 4.9 CC D 0.301 thru 0.458 7.5 CC E 0.459 thru 0.670 11.0 CC F 0.671 thru 1.830 30.0 CC
 
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Buckshot

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I can’t find the impba rule for it. I may be confused with Namba. But what is the limit for a single engine nitro in impba?
Danny,
No such official class as “Single Engine” in IMPBA or NAMBA, only offered as a specialty class at a few events and the hoist would have to specify (if any) displacement limits.
 

Bradley Maglinger

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Sep 23, 2012
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You can only run a single motor in sport 40, which I think they should be allowed to run twin motors....but that is just me. 🤷‍♂️
 

dave roach

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Marty Davis and Bobby Coleman had one years ago with two 21 engine and it was fast.I think that's the one Julian has now.
 
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dwilfong

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I built one for Julian but he has passed it on to some one new.
 

RaceMechaniX

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I know QD ran several of their gas motors on low mixes of nitro and full methanol with pretty good performance. The big benefit was cooling of the big end of the rod. They used a larger 3/4" bore chainsaw crab designed for methanol to get the fuel flow where it needed to be. I believe in both IMPBA and NAMBA spark ignition is not allowed in a nitro class. To work around this I machined some 10mm to 1/4-28 thread adapters to run glow plugs in a gas motor. Never got around to testing the set-up.
 

Buckshot

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Dec 22, 2003
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Some manufacturers in Europe have started developing small displacement petrol engines as well since they are edging ever closer to a complete ban on the sales of nitromethane there. Wonder how many rrrrr’s we can squeeze out of a 7.5cc petrol burner.
 

Danny King

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Some manufacturers in Europe have started developing small displacement petrol engines as well since they are edging ever closer to a complete ban on the sales of nitromethane there. Wonder how many rrrrr’s we can squeeze out of a 7.5cc petrol burner.
Not sure why the need for petrol. Just run straight alc much better performance and cooling and no ignition source needed.
shoot even E85 is better.
The low nitro or no nitro will hurt smaller engines more then the
Larger ones.
but I’m sure changes are coming.
 

John Beardslee

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Apr 20, 2011
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Images of the methanol WJ75 carb.

View attachment 283329
Hi Tyler, hope all is well with you.
If I remember from my youth, a few years ago, my dad and uncle tried to get at least 14:1 compression ratio for straight methonal in t our cart engines. They were never able to run more than 15% nitro In those small (less than 15 cu.in.)
In my 327 cu. in. 63 Corvette I ran 12-1/2 to 1 Jans pop up pistons and it would only run on 260 Sunoco or experience detonation, ugh!
I think if the ignition engine design is such that it allows head work and compression ratio adjustment there is great potential in running alcohol in an ignition engine.
Thanks John
 

Samuel Hagan JR

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Jul 18, 2010
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Did a guy from France that raced over here run Alcohol in all his motors. That’s was what I heard many many many years ago. Name was Fran something.
 

Brandon Atwell

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Mar 11, 2012
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Andy and John Brown showed up to the Fall Nats with a junk KB 7.5 in an Eagle SGX-2 running straight alcohol. I believe he showed us where it was leaking around the case seal gaskets even.
Managed a third place and was a quick setup if I’m remembering correctly.
 

dwilfong

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Need to try that carb on a tiger king eng and make a 4 glow plug head for it.
 

MikeStewart

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Oct 20, 2018
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I remember in 1985ish, the scale guys blowing up their Rossi's. They were the crazy ones running 5% nitro.
 

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