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Initial tuning results

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Pablo

Active Member
Joined
Sep 12, 2004
Messages
3,430
Well I think I've concluded that the gasoline I get is crap. Unfortunately we only have 91 octane available around here.

This has become apparent in my alcohol use. Right now I have the boost at about 24.5 lbs and the car is hauling ass. I had to make a few changes to my chip though. So right now im running 26 deg up till where my converter flashes to and then back down to 24. This brought the egt's way way way down from what the chip had before which was about 17 deg. Ive also had to remove quite a bit of fuel from the WOT fueling.

Now for the shocker.. in order for me to get any kind of performance without knock on this thing I have the alky dang near maxxed out. turn on knob is set at the lowest turn on point, the initial (blue knob) is maxed, and the ramp (i forgot what you call it) knob is well beyond the out of the box spec. I havent looked at the clock position.

I also believe I may need more alcohol initially than what I am getting because the knock I get if i lean things out a little is always initial, right when the boost hits Ill get a couple degrees knock and then it vanishes and will not knock for the rest of the run

This has me contemplating moving up the nozzle size or going dual nozzle.

EGT is now around 1600 thats pre turbo

I mounted the wide band but its basically useless its too close to the turbo so its reading very rich, like 9.6. Its obviously leaner than that, just the temp at that location is far more than 1300 deg. Not to mention ive been testing with my dump capped and a fairly restrictive (quiet) exhaust so the back pressure is pretty substantial.

Ill be mounting the wide band in a better location shortly and will have data logs with wide band, egt, and map kpa etc

btw even though the tune is still rather rough the car is flying. I can basically lay rubber from a 45 mph roll on command
 
I forgot to mention im using industrial grade isopropanol. The specs on it are very similar to methanol from all the information ive gathered.
 
I meant to ask for advice on the initial knock issue... would you guys agree that a nozzle size increase is in order?
 
There are ways to increase delivery of the system. And the dual nozzle may be a neat alternative.

There are no single nozzles larger than the M15. Altho pressure can be increased. This info I will not post :)

Be curious to see DS data logs of your runs.

Any knock can be cured by adding alcohol as long as the AFR is within range 10-11.5

HTH
 
You say you get the knock when the boost kicks in. Could it be that it is false knock from a hard downshift, downpipe contact, or just the torqueing of the motor against the mounts. Sounds like the kind of knock I get on the 1-2 shift that goes away on the next frame.
 
pablo, we'll have to meet up at the track when I get my vette dialed in on the alky. I'm in OC.
 
No its real knock, I can actually hear it. My exhaust is pretty quiet

Qwiketz: sounds like a plan, pm me next time you plan on heading out. I hope to head somewhere this weekend and get some runs in. Havent decided where yet.
 
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