Detonation ?

Anybody have any idea why all of a sudden I have started to get detonation under heavy acceleration ?

Nothing has changed in my set-up. I haven't checked my timing to see if it moved yet. I was running around 15* BTDC base timing and 18 lbs of boost with no problems up until now. If anything with the colded weather I'd think that it would detonate less ???

I plugged my KS back in today and it helped some.

Bad tank of gas maybe ? I always use BP 93 Octance Premium Switch on. I filled up again today so we'll see...but that's my best guess so far ?

Other ideas ?

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Dan Eaves
88TC 5spd, Crower 5.5" Sportsman Rods, Short Wiseco Pistons bored .030" Over, Ported Head with Polished Combustion Chambers, Gutted & Polished Upper, Ported & Polished Lower, Polished T/B, Ported E6, SVO T3 .63AR Turbo, Bosch Bypass Valve, 3" DP w/No Cat, 2 1/2" DynoMax single cat back w/DynoMax Super Turbo Muffler, RR Cam, K&N in Fenderwell, Gillis Boost Valve, Centerforce I Clutch, Removed A/C, Polished Wheels, Polished Valve Cover, Polished Crank and W/P Pulleys, Walbro 255LPH HP Pump, Kirban Adj FPR, and the DAMN Heater Core is new too !

http://www.geocities.com/wot_turbo/WOT.html

NATO MEMBER (Vice Chairman...if it's a vice...I deal with it)

Dan, I wouldn't run BP if it was the last gas on earth. I'm thinking either bad gas or stuck EGR. How heavy do you have to accelerate to get the detonation - light throttle or WOT?

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NATO Member. it's not a vice, it's an obsession
"The nice thing about each new day is nobody ever used it before" Barnaby Jones
88 TC X 2, 86 SVO, mods list at
http://www.turbotbird.com/showroom/pd_88tc.htm

I agree on the bad tank of gas. It's happened to me before, and all I did was flip the switch to REG and turn down the boost till I could get back to Texaco.

I agree... probably the gas. Even down there in the south, I am sure fuel suppliers are going to a "winter mix" fuel, that has a higher RVP (Reid Vapor pressure) so it vaporizes easier on cold starts. How do they get higher RVP? They use shorter hydrocarbon chains in the fuel makeup. These shorter chains also make the fuel somewhat more likely to detonate, even though they still claim the same octane number. Might try a dirrerent brand of gas and see what happens, or throw in a bottle or 2 of octane booster into the gas you have.

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Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 20 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 00 Windstar (wifes vehicle)

What does "detonation" sound like? Is it mix of knocking and pinging?

Originally posted by Scott Evil:
What does "detonation" sound like? Is it mix of knocking and pinging?

It sounds like BB's in a can being shaken...