What happens when spark blow out occurs?

 

Usually the engine sputters

 

Not sure if this will help you Easter but at this site he describes blowout this way...

"The compression will blow out the flame - or at least upset it a lot.
This makes for an engine that sounds rich and blubbery, though in fact it is running poorly
because the spark cannot jump the gap and ignite the incoming charge under pressure.

My F150online Photo Gallery.....My Modifications


Have a great day eh!! ........................ Dave

 

I am getting a backfire pop sound and the engine dies...Only at WOT usually around 80-120 mph. That is with the 26psi or 20 psi. It happens when the MAF is pegged at 5 volts and the alcohol is on. It happens with BR7EF's at .036 and TR^'s at .040 gap.

 

I've always been told (about methanol anyway) that you don't want to go more than a 50/50 mix of methanol and water because it will actually lean it out. Also, too much volume of the mixture will produce the symptoms you are experiencing (by basically blowing out the spark).

 

There is an override button for the alcohol which allows me to spray any time. I push that button and can spray the alcohol just fine at 2000 rpm running normal...

 

So you can spray the alc. when cruising at 2000 rpms and not in the boost and it will seem to run fine? Still...why don't you try putting a smaller nozzle on the alc. inj. and see if the problem goes away. My thought behind this is that if too much alc. is in fact leaning it out a little, when you are pushing that much boost and maxing out the MAF at the same time, try less alc. or mix it with water as a test to see what happens.

Does this phenomena happen when you are not using the alc. at WOT?

 

I bought several gallons of distilled water this morning to try out tonight.
I can't try no alcohol because it detonates under WOT w/o it. I suppose I could switch to another chip with lower timing and give it a try.

 

I would try mixing it with water and also try turning on the alc. at a higher boost pressure. It just sucks that if it is detonating...you are playing with fire every time you test it.

Or you can try using Denso plugs. Densos are supposed to be a little more tolerant.

 

with that kind of boost, 20-26psi plug gap would need to be around .030 to .026 for a starter.

 

I'm going to gap some BR7Ef's down to .030 today and try with 100% alcohol. Then if it still does it I'll add water to make around a 50% mix. Lucky I have an hour commute to try this stuff out.

 

Since I have done the mods in my sig I can no longer top the truck out. Once I hit 125 or so the motor starts to break up. I've been trying to fix the problem for a while now. Am I getting spark blow out? Should I close the gap on the plugs a little?

--Steele

 

ANY, any boost increase requires plug gap modification. Closing the plugs .001 per 1 lb of boost increase over stock is a good rule of thumb. 6lb lower = close by .006 from stock settings. To close = loss of power, to wide = blow out.
Factory specs = .042-.046 - .006 = .036-.040

 

There are guys running Tr6's with 20 psi and have a plug gap of .038...

 

Running rich is my guess also, I tried the TR6's at .038 with only 15psi and a nice stochic A/F Ratio and would burn the tips off at each event. Tried .036 and was better but still burning off tips. Went to the IT22's at .036 and all is well. A .038 and 20 psi with a rich mix is ok, but there is HP loss in the A/F's is my guess.