Ok, I 'm catless, been fighting issues with Knock Retard on tunes that others in a different region and 93 octane fuel see no knock.

I want to blend in some 110 octane leaded race fuel (all I can find locally @ $5.56/gal), maybe 4 gals or so a tank to up the octane a bit to see if that solves the issue, or if I'm getting 'phantom' KR from a flaky sensor, ect.

Question is, will the leaded fuel contaminate any sensors like the exhaust 02 sensor?

Opinions appreciated.

Thanks.

 

It will shorten the life of the O2 sensors but I dont think one tank of a blend will cause any huge issues.

 

Please let us know your results, you`re a brave soul...

 

Agreed....most modern cars have big problems with leaded fuel, but if you are going to give it a shot, I am sure we would all appreciate a detailed analysis of your results.

 

Why not try a different tune? Maybe try a little less timing, or some more fuel?

I know you have tried alot, but if you don't mind, you could send me your map and some logs, I would take a look at it. Maybe if I get to the city we could get together and i could explore some options.

 

i was tuned on racegas before most people even bought their cars lol

and it will also shorten the life of your spark plugs

 

I've tried down to .85 lambda up to .89, I had to cut the timing to about 13 degrees to kill all the WOT KR when catted.

I haven't tried that much since going catless. Loaded a 14* tune now to log this week.

I prob won't try the race fuel until next week. Gonna play with this tune some more.

Not too worried about the plugs, I'm used to burning those up from when I was a kid on leaded in the '65 Chevelle Malibu SS. Any sensor issues your way?

 

i wanna do it, too bad its going to clog my cat, spark plug, and spark plug.

 

i run 110 when i go to the track. i drain the 93 and run straight 110. usually go through 2 o2sensors a summer.

 

I mean, yeah, race fuel is good if you can tune for it, but there HAS to be something else wrong that the fuel itself won't cure. More octane in this case would be a bandaid of sorts.

 

It is strange for some reason his car acts like it is on 91 octane all the time not 93 octane. I can get 14-15* of advance on 91 octane normally even at 12.8-12.9 A/F.

Tom, Just run it at 14* and 0.88-0.90 lambda. That would be far better than running at 0.83 lambda and 16*. Better to tune for the A/F that makes the most power and adjust timing to fit that A/F than to advance the crap out of the timing and then richen until the knock disappears.

 

Yeah, I'm not giving up yet, just frustrated. I loaded up the 17* .9 lambda just to verify the KR is actually worse that lean. Same as the 14* tune, just more timing.

The only reason for the race fuel will be a test to see if the knock goes away or if I have a sensor issue picking up other hf vibrations somehow.

You guys are scanning knock retard, not total KR right?

 

I scan both knock retard and total knock retard.

 

^^ As do I. Could it be that the knock sensitivity somehow got turned up on your car? Isn't there a way we can turn that down?

 

Not that I know of.

 

Hmm, i thought i saw that somewhere. Guess not. Do you think it could be a bad coil or something that is causing the knock?

 

is it bad to just throw in say c16 gas for a dyno run to see what it puts down? or do u need tuned for it just to run it that couple times to see good results?

cuz i was kinda interested in seeing what the car put down on 93 then race gas..

 

The LSJ MIGHT adjust a little bit of timing, but not enough to make a noticeable difference. The LNF on the other hand probably will not pull any extra timing. (Not sure what motor you have, assuming LSJ?)

 

Gains will be nearly non existant unless you retune your timing for the C-16. Not worth the effort IMO.

 

I don't see any misfire, I would expect to see that with a flaky coilpack. I know it's not the plugs, downpipe or intake 'cause I had it before those mods too & also with the air box K&N drop in mod.

EDIT: Upping the timing 3* today, the KR is still 3* 200+ load above 5k rpm, WOT, no difference.
I'll add total KR to my scan and try again tomorrow. Race fuel Saturday for the ping test looks likely.

Boost dropped a bit when I went catless but increasing the flow will cause the pressure to drop me thinks.

 

yeah i have the LSJ ... my bad for not mentioning that

ahh..that kinda sux.. but i understand it would change some things so it makes sense that id need a retune..hmm

 

Yep the higher ignition temperature of the C-16 means that unless you adjust the ignition timing and maybe lean the A/F out a tad depending on where you are currently power loss can occur because the mixture will not have sufficient time to burn completely.

 

Dang, almost makes me wonder if there is possibly a slightly clogged injector or fuel line/filter. I have had instances where I can't shake the knock ti I turn the car back off and back on. Its odd. I figure its just a whacky anomoly in the beta tuner. But yours is constant and predictable, yes?

 

WOT Lambda is dead on right after any pull starts. Stays on through the entire pull. Kinda doubt clogged injector, but keep the thoughts coming.

My KR was 3* today, except when I NLS 3-4, forgot the rev limiter was 7400, got some 4.5* KR during that ****.

I could take timing out of the whole curve, but then it wouldn't be the Terminator2 tune anymore. It's predictable, yes.

I'll send you a log & config via email from today. Can't send the tune, it isn't mine to disclose.

 

Isn't there a place online they will ship you 115 or something??

I just looked it up, www.buyracegas.com Sunoco 100oct $70.52/5gal....