Quote:
Originally posted by boostedVR4
My combs were glued very slightly. Nothing a little alchy and the back of a screw driver didn't take care of.
I have Denso 550cc injectors, Supra pump (hotwired) and the IPO dual feed fuel system. Right now, my AFC is set to around the -36 to the -37 range.
I have looked back on quite a few logs, and noticed one major detail about my knock. It ALWAYS, (and I mean always) starts at 33 degrees TA. I'de never really paid alot of attention to my timing before, now I am. Every single run, 02's are at .94 -.96, duel, all the way up to about 5k. My timing starts at about 18, then goes up. When it hits 33, (and this is each and every time) I get knock. Then down comes the timing. I'm talking knock over 10. You can see my log up a few posts. The only way I can stop the knock is to add fuel, which runs it rich.
So how can I stop the ECU from advancing the timing so much?? My base timing is right where it should be. I'm going to try this gutted MAF trick, mainly for the added flow/spool up. But if it lowers my timing enough to get it to stay below 33, that would be perfect.
I still don't see how this is going to effect the timing at all, but I'll try anything for fun. 
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Welp, I did it this morning. Unplugged the battery, installed my spare MAF with combs removed. Started the car, and of course it was a riot. Idled like a monster truck, revved like a 30 year old weed wacker. Anyway, it took me a total of about two mintues with my Pocketlogger to figure out how to smooth out the idle, smooth out the throttle response, and get the car into closed loop. I set my low throttle 1k to about +12, and 2k to about -5. Anyway, the low fuel trim after driving is 108, high is 102.
On for the high settings. I started out by adding 10% more fuel accross the board to be safe. Turns out, it was damn close to being perfect. As of now, I have it about 10-12% richer across the band than before, but its still a little lean for my tastes. I had to stop making passes when my brakes started to smell and stopped working....
Anyway, I got a log, 2k to redline, 02's start at .92, then go into .94 all the way to about 6500 rpm, where it goes .96. No knock, with 1.1 bar. (higher than my first log) BUT, the timing is still crazy high. (I'll post a log pic soon) It still gets into the upper 30's.
So, in conclusion, it took me about 45 min to change the MAF, tune the idle, then tune the high settings by making about 5 passes in 2nd gear. I still don't know about a 3rd gear run, it might be a tad lean yet. Its not like my VPC, but I like it. Throttle response is 100% normal, the car goes into closed loop just fine. Pretty much the car is EXACTLY the way it used to be, only it spools quicker, pulls a little harder, and holds a little more boost to redline. I'll be doing this mod to my friend's VR4. (Adler's old car)
Pros:
*easy and fast mod
*spooled quicker
*pulled slightly harder
*held a little more boost to redline
*using about 10-15% less of my S-AFC
Cons:
*didn't solve my timing mystery