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Discussion Starter · #1 ·
I recently had thread(s) involving how much timing could you KB guys run on 100 octane and 20 psi. I was using the Torco unleaded race concentrate which in a mix of 2 cans per 20 gallons was supposed to get me to about 102 octane. But I was only able to run 14 degrees of timing before wot detonation. Solution was that after speaking with the engineer who developed it, the leaded concentrate will gain 10-11 full points of octane in the mix, but the unleaded version will only raise it a max of about 3 points. Since I start with 91 in reality I had only 94 octane when I thought I had 102. They said they'll change the webpage, very nice people.

I then turned my alcohol injection back on to check timing limits. When going wot from second to third gear the truck completely died as soon as third gear was engaged. Raised the rev limits and it did the same thing on the next drive. So I started thinking about spark blowout from too rich of an A/F or too much alcohol (A/F with alcohol was showing 10.8 at the shift, the alcohol richens it about .5 of a point). I have had custom tunes in the past that were much richer than this and never shut the truck off. But I had not been running 20 psi of boost.

I threw the last of my Xylene into the tank, shut the alcohol off, and pulled the timing back to 12 degrees. The problem is gone, the A/F was right at 11.3-11.4 which I'll leave it at. With the built motor and ported heads/cams I had changed the alcohol nozzle back to the large one I had received initially. I'm going to replace it with the smaller nozzle again. So it appears that under heavy load and high boost you cannot inject a lot of extra alcohol without snuffing out the spark.

Sorry for the long read but I wanted to update my findings in case anyone else searches for these problems in the future. Thanks to all that helped.

Jody
 

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Discussion Starter · #3 ·
KB ZILLA said:
Good info Jody, how are you checking the A/F if you dont have the wideband hooked up yet?
I always have it hooked up when tuning, it's just not set up permanently through the Raptor which is an option. I run it as a standalone unit, adding an additional O2 bung in the drivers side pipe before the cats.

Jody
 

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camcojb said:
KB ZILLA said:
Good info Jody, how are you checking the A/F if you dont have the wideband hooked up yet?
I always have it hooked up when tuning, it's just not set up permanently through the Raptor which is an option. I run it as a standalone unit, adding an additional O2 bung in the drivers side pipe before the cats.

Jody
Okay, cool...thanks for the info :D
 

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You just gotta love xylene for an octane boost. Good info, what plugs are you running and what gap. [smilie=popcorn.gif]
 

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Wow! That's a small gap. I've ordered a set of BR7's from sal I'm going to try them at .36 but thanks for the info!
 

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Discussion Starter · #8 ·
That gap was provided by Dante at Modular Performance. That was the gap he used when assembling the engine.
 
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