A few weeks ago I had this odd phenomenon that I'm trying to figure out. The car was giving kr at WOT when it was hot out, so I played with pulling the timing back to 17 from 19 on the gen II translator. It pulled strong with no knock for one pull and then started breaking up under WOT every time after that with no knock on my casper's gauge. This is pump gas plus slky with 24psi of boost. It seemed like the spark was getting blown out. I then tried adding fuel in the top end to no avail. This was just while I was out cruising around one day and did not have the laptop with me. I was also driving around with the dump open. Unfortunately my WBo2 is downstream far enough that I won't get a good reading on it with the dump open since it is at the bottom of the DP, so I did not bother to log it that way. So I finally got around to logging it with PL and my wbo2 tonight. It is a bit cooler out (81 vs 95) and I closed the dump this time, but did a few WOT blasts and all was good. Only 1 knock count and that was in the 2-3 shift. Timing is still at 17 and AFR was set fat over 5100 RPM from me screwing around. Below that was 10.8:1 and it went to 10.3:1 at the top end, but I pulled a little fuel out to set it back. It pulls strong now. Maybe I should just stay out of it over the summer, but what would cause the motor to break up at WOT with no knock readings? Is it possible it was running super lean with the dump open?
Ignition breaking up at WOT and now it is gone. Thoughts?
- Thread starter BuickMike
- Start date
The higher air temp's may have required an increase in alchy volume and/or to come on at an earlier boost value. The open dump reduced your back pressure and made a hit on your tune. What spark plug gap are you running? when the temp's ran into the 100+'s, I had to decrease the alchy turn-on from 12# of boost to 8/10#s w/increased volume and close the gap on the plugs to .028"
Thanks for the feedback. Gap is at .032. Alky is already set to come on around 8 already. It is cooling off around here, so I'll run it again with the dump open and see what happens. If it is fine, I'll tighten up the gap next summer and see if that helps. It really did sound like the spark was getting blown out. decreasing the timing could have contributed to that.
achalmersman
Well-Known Member
- Joined
- May 28, 2012
What plugs are you running? Must be resistor type plugs
josh young
Member
- Joined
- May 12, 2008
I had the same issue your describing, it would start to break up at WOT as soon as it got to about 15#'s. It had no knock and all numbers were good. It turned out to be a bad cam sensor cap. Have your's ever been replaced? If you find it doing it again, unplug it right then and see how it runs. If issue goes away, you've found your problem. It could be other things as well, but you have an issue with the car acting up in hotter weather to. like I did.
the 42 plugs need to be gapped down more they are much colder.i like the 43 plug better with the pump gas alky
TT/Ameasap
The White Blur
- Joined
- Jan 31, 2002
Close the spark plug gap. WOT spark blowout doesnt happen everytime, but maybe 75% in all of my cases.
Do you run at the track with this setup? What is your combo? I think I may have a set of R43TS's laying around that I can give a shot. I went to the 42's because that seemed to be the standard for Alky. I'd rather go with a hotter plug with a wider gap because this car cruises more than gets hammered on. That being said, I don't need to go scratching my head when I start getting KR in the top of 3rd because I went with too hot of a plug for my combo.
if you truly want to know if the plug is right you need to pull the plugs and read them.
I have run the 42 and 43 at the track and on the street on multiple combo's,both plugs work.on the 43 plug i have run 31psi with a billet 64/68bb turbo on an aggressive combo with o knock,even sprayed nitrous on that plug.
I word it this way you can run your 44 turbo all out on either plug with pump gas alky if everything else is there,however the car may run a little smoother with the 43.
.024? Holy crap that seems tight. I thought that I would be able to run a wider gap on a hotter plug.
you might be able to,you have to play with it.start at .28 or .30 see how it runs
you asked
Cool. Thanks for clarifying. To keep things simple I'll keep the R42's in and gap them up to .028 for now and see how it runs. Even though I only experienced the cutout on really hot days, this may explain the few knock counts I get sometimes at the top of 3rd even though AFR is good. I only get away with 19 degrees at WOT with pump gas and alky on good days when most people seem to run 21.
