mazdaspeed7

Does your car shoot flames? I was thinking about this some, and advancing timing reduces the EGT because the mixture is ignited sooner, and burns more ocmpletely before it gets to the exhaust. Ive had my timing advanced pretty much since I got the car, and I have never been able to shoot flames, even with the true dual exhaust that I have had for a while.

SpeedRacer

I've never shot flames with or without advanced timing. I have headers, gutted cat(soon to be racepipe, once i have it cut and have the flange re-welded on)and stock catback. Before my headers, when I had my racepipe my car would backfire after high rpm shifts, like most other people here, but as soon as the airpump came off, it stopped backfiring. It backfires sometimes, but its quiet, and usually, when I am just cruising at 4-5k and let off, but its barely audible. I assumed it had something to do with how the airpump and acv supply air into the intake stream when you let off the throttle. I can't think of any other reason why my car won't backfire anymore. My dashpot is set so the throttle plates snap shut when I let off the throttle, without touching the dashpot at all.
I would think you'd be shooting mad flames with your setup, even with advanced timing(if that truly effects EGT, which what you said makes sense to me)

niner

i think that applies more to people who have their timing retarded
like the opposite of what you said, the mixture would be ignited later

Bambam7

I shoot flames ONCE IN A WHILE.... I especially notice it more if my TPS is out of adjustment, or I have my timing set to stock.
With my timing advanced I backfire much less. I can tell whan it's a flamer bacause it gives a loud boom from the back of the car, instaed of the normal pops.
I see that as a function of running rich more than anything.
When I'm on the throttle, I see .9's from the o2 sensor...plus I think I have a squirty injector or two.
I assume mazdaspeed7 doesn't see those because he's running on the leaner (and more desirable) end of the scale.

mazdaspeed7

I have never shot flames, or even backfired for that matter, even when I was running grossly rich from the TII fuel pump and 550 cc secondaries.

BlackRx7

come on now mazdaspeed, you've never been hauling *** like up in 7k-8k then just let off the gas, in first gear and throw flames? I can throw like 5 inch flames from my 2 dual tips, if I had just a large single tip I could prolly throw 1 foot flames. dunno, do you have 550 cc 2ndaries?

mazdaspeed7

I took the 550 cc secondaries and TII fuel pump out, and put the stock injectors/fuel pump in. My car runs much better. My dyno problems were largely due to running way too rich.

Even when I had the TII pump and injectors, I still could not backfire or shoot flames. If I take it up to redline in gear, and just let the rpm's fall without letting otu the clutch, I get one or 2 very quiet pops occasionally, but its way to quiet to be flames. Shifting at redline, nothing, ever.

Another thing that Ive heard is that taking the airpump off makes it much harder to backfire/shoot flames. Theres an anti-afterburn valve in the ACV, which I think makes it easy to backfire when it goes bad, which is the case on nearly all FC's since theyre so old. But since I dont have ANY emissions stuff...

von

Its wierd but I notice that only at nite when im going to redline in fourth gear just before I hit the buzzer I let off and see this huge flash of light like someone blinded me real quick. It is silent and reflects off all the glass and the rear view mirror and I also see the reflection off the side wall. I have super advanced timing and have my acv and pump off. This rarely ever hapens when im driving but i do hear lots of pops when driving normally... just cant get my tps adjusted right. Pluss i know my injectors are dirty.

j9fd3s

iTrader: (3)

it is easier to do with the air pump, for some reason
on my car the big pops were not flames, it was the real quiet ones.

mike