2MCHPWR

iTrader: (10)

during my last two outings at the track, i recorded some atap logs and it showed some KR. one run even had it as high as 3.70 degrees of KR, but my other run (different day) was 1.10. outside temp was 50 on one day and 68 on the other. injector pulse width on both days was between 21 and 23. both runs i got a 12.0 at 118.

i was concerned about the KR so i did more runs on the street. each run i had some KR. i thought maybe it was an exhaust rattle or rough road surfaces causing the KR. but i didn't hear any rattles and i also ruled out the rough roads.
some of my friends just told me to accept the KR because the numbers weren't that high (i think phil was telling me that because he doesn't want me beating him <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> ). But i thought i could totally eliminate the KR...

i usually use gulf super 93 octane because it's cheap. i thought super was super and 93 octane is 93 octane regardless of which brand it is. but LS1LT1 told me to try sunoco ULTRA 94 octane and see if that helps. so i did. and it did help!!! <img border="0" alt="[Fluffy]" title="" src="graemlins/fluffy.gif" /> i did two atap runs yesterday on the street. the outside temp was WAY hotter than all my previous atap runs (around 90). the runs were full boogy all the way to 6400 in 4th gear. i got my full timing (27.5) and ZERO KNOCK RETARD!! also, the injector pulse width was between 20.00 and 21 (which is much less than my previous readings).

i can't wait to get back to the track now. no more GULF gas for me. but for my next experiment, i want to see if EXXON/MOBIL super 93 octane will affect KR in my car...

The Alchemist

iTrader: (19)

Sunoco 94 is some pretty good stuff. It contains a 10% ethanol blend and very low sulfur content (less than 20ppm if memory serves correct). If you're getting octane knock, Sun 94 is the next best thing to race gas, but race gas doesn't contain detergents or cleaners.

One of the reasons your injector pulse width might be lower is the fact that it was a warmer day. Being a warmer day, your not getting as much air in, so you need less fuel to maintain a constant air/fuel ratio. Just a thought.

2MCHPWR

iTrader: (10)

thanx Alchemist. that is a good point about how the warm weather affects air/fuel ratio and injector pulse width. i forgot about that...

The Alchemist

iTrader: (19)

No problem scott.

While working at Sunoco, I worked along side the race fuel devision doing emission testing of different grades of product. It was defenitely an eye opener.

Lets just say that you don't "NEED" cats to run clean, but they are a cheap fix compared to running "clean" gas. Too bad I no longer have access to this "clean" gas when I needed it. Oh well, the cats work very well.

EDIT: I just had another brain storm. When you experience KR, the natural progression for the pcm is to pull timing and inject more fuel as well. If you eliminate your KR, you need less fuel as well, possibly another reason why your injector PW might be lower.

Just a thought.

<small>[ June 10, 2002, 08:10 PM: Message edited by: The Alchemist ]</small>

NewZ

Yeah, count your blessings, pal. Here in California we only have 91 octane at the pump.

Can anyone say additive?

Good job, Scott. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

Alan

LS1LT1

iTrader: (16)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by 2MCHPWR:
<strong>but LS1LT1 told me to try sunoco ULTRA 94 octane and see if that helps. so i did. and it did help!!! <img border="0" alt="[Fluffy]" title="" src="graemlins/fluffy.gif" /> ......i want to see if EXXON/MOBIL super 93 octane will affect KR in my car...</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif"><img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

Yes, even a 'good' (better than Gulf etc. <img border="0" alt="[barf]" title="" src="graemlins/gr_barf.gif" /> ) 93 octane gas should work well also I think. I prefer Amoco or Mobil only. Use one of them (try and find a station with a '5 cents off per gallon' day to keep costs down) and see if there are any changes for the worst, if so, then maybe only Ultra 94 will be your fuel.....at least just prior to and during racing of course. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> <img border="0" alt="[Firebird]" title="" src="graemlins/formula.gif" />