Can you backfire out of the itbs?

Whizbang · 02-21-2010, 01:20 PM

been doing some tuning and we seem to be getting a loud noise under WOT at higher rpms. Not sure if its the exhaust blowing through something or if the engine is back firing through the ITBs. Trying to determine the possibility of that.

FujiRacing · 02-26-2010, 07:18 AM

Never experienced that at WOT.

RotaryProphet · 02-26-2010, 08:18 AM

You would have to have your trailing spark really -really- advanced, I would think. So advanced that the trailing was firing about 90 degrees BTDC or such.

Easy check, disconnect the trailing spark and run it and see what happens. I don't think it's possible to have the leading plug open to the intake valve, so without trailing, it should be impossible.

02-21-2010, 01:20 PM	#1
Whizbang Respecognize! Join Date: Jul 2008 Location: Δx = ħ/2Δp iTrader: (5) Posts: 3,190 Rep Power: 20	Can you backfire out of the itbs? been doing some tuning and we seem to be getting a loud noise under WOT at higher rpms. Not sure if its the exhaust blowing through something or if the engine is back firing through the ITBs. Trying to determine the possibility of that. __________________ For current updates and event coverage check out Follow on Twitter! @WhizbangRally Whizbang Rally's Webpage \| Facebook

02-26-2010, 07:18 AM	#2
FujiRacing Rotary Fan in Training Join Date: Dec 2009 iTrader: (0) Posts: 90 Rep Power: 15	Never experienced that at WOT. __________________ Jimmy FujiRacing www.fuji-racing.com *2010 13B Rotary Miata Semi-PP* 2009 REDLINE TIME ATTACK Modified Class Winner Nashville & Englishtown NJ.(Miata Piston Motor n/a) 2008 REDLINE TIME ATTACK Overall Winner VIR Street Class (Miata Piston Motor n/a) 1990 FC3S Street Car

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02-26-2010, 08:18 AM	#3
RotaryProphet Rotary Fanatic Join Date: Sep 2008 iTrader: (0) Posts: 147 Rep Power: 17	You would have to have your trailing spark really -really- advanced, I would think. So advanced that the trailing was firing about 90 degrees BTDC or such. Easy check, disconnect the trailing spark and run it and see what happens. I don't think it's possible to have the leading plug open to the intake valve, so without trailing, it should be impossible.