hey everyone ,been having dramas with my a15 and im thinking of ways i can fix it

well i have a fairly worked a15 with twin 40mm carbs 12:1 comp cam and a rebuild aswell as a heap of other stuff

at the moment im running an msd 6al2 ignition box with a bosch mec717 coil and has been awesome and was a noticable different in torque from my old stock coil and points ,plus it has a limiter and launch control

now ,when i am doing (i know it sounds bad ,but its at the drags) a burnout ,it will be fine and easyily hold 3rd gear on the spot with both wheels

1) under load for 20 odd seconds ,starts to ping when slightly past half on gauge
2) 3/4 down the track it will splutter and miss so i get off the throttle ,as i come back to the pits it is running on 3 cylinder(maybe 2! ) and then if i give it a squirt in a straight line after letting it cool down it will clear up and be fine again
3) if i hold a burnout on the spot for about a minute it will start pinging and will only be slightly over half on the gauge


motor never gets hot ,it sits on half on the gauge on the freeway fine and doesnt get hot in traffic

so im thinkiing the plugs are getting too hot and are glowing and causing the missfire ,that cylinder floods then clears up after a big squirt

im running bpr6es plugs and it didnt used to do the misfire when i was running bp4es plugs

i was looking on youtube and am considering water injection as a fix for the pinging as it would lower intake temps and control pinging at the same time as giving it a little more power

anyone know what plugs i should be running and if water/meth is a doable thing with 4 intake tracks???

also i have the timing set at 10 deg static but need to recheck total timing ,if i run water injection i can run timing to make more power but still have the pinging sorted

cheers

http://www.youtube.com/watch?v=Zeervwwj_IQ drags

Thats pretty high comp are u running a race fuel or premium fuel in it. Poor quality or low octane fuel could cause that maybe. Usually pinging is caused by 2 much advance but surely 10 deg would be fine unless ur dizzy is advancing heaps but that would be a constant problem in revs not just when hot. I would try hotter plugs. I dont have a part number but i have some that would handle what u need. i can check part numbers tomorrow if needed.

Just a heads up.
I run bp5es in mines.

try one range colder, try BP7ES.

The temp guage only tells part of the story. I`d recommend running a genuine water pump(with a cast impellor) and a high presure cap. This will help maintain block presure and prevent nuculate boiling of the coolant around the combustion chambers and exhaust seat area. This will drop combustion chamber temps and help prevent detonation.

I`d also be using 6`s or 7`s(plugs).

What is the Air/fuel ratio under full load, and what fuel are you using?

Why are you running a resistor plug ?

And start saving for a stronger diff with LSD

BP6EY would be something to try
Non resistor and the Y plug has a V groove electrode for a fatter spark

The other thing it could be is, fuel vapourising in the lines after a long burnout causing high under hood temps.

I am running A15 with 12.5-1 comp ratio and i mix 20% toulene with 98 octane fuel to boost "RON" to approx 102,that sorts pinging out quick smart.You could try some octane booster from your local automotive supply stores i.e. autobarn,supercheap etc.That would be a cheap way to check if it sorts it out or not!Also depending on winter/summer conditions i do use BP5EY/BP7EY respectively.Hope this can be some help.

Awesome fellas

i went to buy new plugs and was told bpr plugs were the same as normal bp plugs

ill definitely change the plugs today

as for fuel i only ever run bp 98 , sometimes i add octane booster but it does do much apart from make my plugs orange ! Haha

what gap should i be running them aswell? .8?
diff is the next thing im going ,looking at getting a ute diff shortened ,as im running a h145 locked at the moment


where can i buy toulene? Just a panel and paint shop ?

Also the water pump is new ,does it have to be te cast impeller? also what do you mean by high pressure cap ? Would a 13psi cap be enough?

Thanks everyone!

You can get 20 litre drums of Toulene from your local Paint supply depot or distributor,i get mine from Wattyl Paint Depot,$77.00!It works out approx $2.05 liter mixed depending how much you pay for 98 fuel.I mix 4 lt toulene with 16 lt 98 fuel.