Info,was watching drag racing yesterday and a question came to mind.Why is it that the alcohol engines surge so much but the fuel(nitro) engines don't? From what I understand surge is caused by the interruption of airflow when the blower tries to put too much air into the engine at low RPM.So what is it about Nitro that prevents that?Just curious.....
Interesting question. I'll add one. When I had my Cal Perf boat with the blower motor it would surge like a mother when it was cooler. After a trip up river when the motor was hot the surge was less dominating. Why is that? Does it have anything to do with the density of the air/fuel going into the motor?
Was it intercooled?
HighRoller:
Was it intercooled? Nope.
Yeah,my uneducated guess would be that the intake charge was a lot hotter after running.Unlike when you have an intercooler to pre cool the air.Was the carb under the engine hatch?I've heard some unreal numbers as far as under hatch temperatures while running.Like 170-200 degrees.But you'd have to ask an expert like Info to know for sure.I'm just a trashy ex race car mechanic with a scattering of here and there knowledge.
I will throw my two cents in, I was told it surges cuz it is lean, my race blower does it when it is cold and the case has not expanded yet settles down when the case gets hot and expands.
Info told me that is has to do with the bypass or the pill.
[ May 20, 2003, 06:08 AM: Message edited by: Blown 472 ]
I'd like to know also....
One friend has a Jet ..454 w/tunnel ram & 750's
no Blower ...but surges at idle like a MoFo
cam is hyd.flat nothing large or special want to say like a Comp.Cams 280 or 292 Marine grind ??
makes my Blown motor sound stock next to his cry
Gopherrr
The idle mixture causes blower surge.
An injected engine has no accelerator pump so it has to be rich enough at idle to not hesitate when you give it throttle. The barrel valve is adjusted that way.
Changes in engine temp affect mixture as you already figured out.
Some tune it that way on purpose for the cool sound.
I think a nitro engine idles too fast for surge. Plus that fuel acts completely different than any other.
Gopherr - Yours is tuned/set-up properly.
When did I become an expert?
[ May 20, 2003, 06:43 AM: Message edited by: Infomaniac ]
Some tune it that way on purpose for the cool sound.
Heheheheeee, quilty.
Quoted by Info "When did I become an expert?"
When you released that BadAss Video I think has alot to do with it.
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