What spark plug number/code for uprated 10v turbo.

[JP]

Pretty much as title says what plugs do you guys recommend on a 10v turbo on kjet. As I have misfire issues on the standard ones I'm looking to find an alternate plug number that copes with 17-18psi boost.

Cheers JP

[Audi Parts Guru]

What makes you think that it's your plugs that need changing?

[pixsaudisex2]

as his other post says////////


've just read this thread and by pure chance I was going to ask something similar. A little background on mine along with problem and findings.

First of all I'm running a 10v Turbo on Kjet. What I found was when under full load from around 4000rpm I get quite harsh stuttering/misfiring. So I figured I'd systematically work through. I've done the zener diode mod first of all incase it was the fuel pump cutting out. No difference.
Next it became less frequent and less pronounced by fitting an electronic boost controller as it eliminated rapid rise of boost and over excessive spiking. Which was when the issue was most pronounced.
However the problem still persisted so I figured I may be running lean so I added a 5th injector (or 6th in this case). Again the car pulled smoother but under full load it still persisted.
Except when the engine was cold ?!?! Rather strange I thought and then figured when the engine is cold I got a higher fuel pressure as it is a kjet so maybe the 5th injector wasn't upto the job?.
ok so next I fitted a wideband data logger. Under full load at 17psi it was holding fine at 11.5:1 afr if fed in gradual with no stuttering. However if I floored it the afr dropped to 10.6:1 and the misfiring/hesitation occurred.
This led me to the conclusion that the issue isn't fueling but quite clearly spark. A change of leads and coil has not resolved it nor a fresh set of plugs.
This however where the issue lies the plugs. From experience running 9sec v8's with nitrous trackside we used to have similar issues where the increased combustion temperatures and pressures of nitrous or forced induction caused problems with the spark jumping the plug gap (in effect you blow out the ignition spark). This was resolved in 2 ways. #1 was to lessen the spark plug gap in 2 thou increments until the desired result was achieved. This worked in conjunction with dropping a heat range on the plug to stop predetonation. #2 solution was to uprate the coil to a high voltage one to aid the spark in jumping the gap.
I feel that your misfire is the result of the spark plug type and gap. Which is the same conclusion I have come to on mine.
This however is where I was going to ask the following. Which is which spark plug do people run on the tuned 10v's? As all the literature I read people say my symptons come from running single groundstrap plugs and you are best of sticking with the standard 3prong ones. However it has come to my attention they appear not to be upto the job.
For your engine I would start by looking at which is the best plug and gap for your application and see if this resolves your issue.
HTH JP

[pixsaudisex2]

also have you any pics info on your mk1 golf it sounds intresting..

[JP]

got all excited 3 replies overnight, and no answer

Anybody else?

in the meanwhile for pixsaudisex2 here's a linky to the build up thread on edition 38 forums. Although I think you need to register to view that section of the forum. Car's not finished yet but almost there. Although dont start reading the thread unless you got a spare 2hrs

[caterpillar]

i used a crane ps 91 and kill the misfire( ups- the coil want low imp leads and no cap on....!!) and 14,4 -14.7volt at the battery charge....and org spark pluggs.