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Discussion Starter #1
I'm using my Techtom MDM100 to detect my ignition timing. its displayed in degrees. however, I have no idea what those #'s mean. at idle it jumps around 12-25degree, at part throttle sometimes it jumps to 45-50 degree. can anyone help explain these #'s for me?

thanx

Jonas
 
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Zerosoul said:
I'm using my Techtom MDM100 to detect my ignition timing. its displayed in degrees. however, I have no idea what those #'s mean. at idle it jumps around 12-25degree, at part throttle sometimes it jumps to 45-50 degree. can anyone help explain these #'s for me?

thanx

Jonas
You only care about ignition timing under load, most likely at WOT. So knowing what you just told us is really kind of useless. Or are you asking for an explanation of what iginition timing is?
 
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Discussion Starter #3
I know timing, I just dont know how the # on Techtom translates.
I havnt tried at WOT yet, but I guess at WOT the # will be more stable? I need to know at what # will it represent timing retard...
I was told Supra normally runs 20degree advanced timing? so when it retards timing, I would get alot less than 20 degree?
 
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Discussion Starter #4
Zerosoul said:
I know timing, I just dont know how the # on Techtom translates.
I havnt tried at WOT yet, but I guess at WOT the # will be more stable? I need to know at what # will it represent timing retard...
I was told Supra normally runs 20degree advanced timing? so when it retards timing, I would get alot less than 20 degree?
At WOT, the timing will be more stable, but may still fluctuate depending on what rpm you are at. But you should see a consistent timing curve.

Yes, if you have knock retard, then your timing will go down. How much depends on how bad the knocking is. It could be 1 degree or 10 degrees.
 
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Discussion Starter #5
I was reading my timing at WOT today and it reads around 12.6-13 running 17psi/91octan. I guess that is retard tming already since normally supra timing should be at 20degree advaced as I was told.
 

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Zerosoul said:
I was reading my timing at WOT today and it reads around 12.6-13 running 17psi/91octan. I guess that is retard tming already since normally supra timing should be at 20degree advaced as I was told.
Hooollllyyyy SHIT thats horrible timing. I really feel sorry for you guys with Cali gas. Is your car still running lean?
 

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Did you reset your ECU before you ran around doing the testing? Maybe you had higher boost at one point and the ECU has a much less aggressive timing mapped out.

Zerosoul said:
I was reading my timing at WOT today and it reads around 12.6-13 running 17psi/91octan. I guess that is retard tming already since normally supra timing should be at 20degree advaced as I was told.
 
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Discussion Starter #8
I didnt reset my ECU...91octan all the way. too bad I just sold my TEchtom so I will never know what degree timing I would get after restting my ECU...anyway, its just gonna piss me off finding out how much timing it pulls on 91octan.:mad:
is 13 degree that bad? what # you guys normally get? around 20?
 
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Discussion Starter #9
How much was your Techtom and where did you get it. I'm looking for a cheap reliable way to monitor my ignition timing while I'm experimenting with an alcohol injection kit.
Thx

Dan
 
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Discussion Starter #11
Zerosoul said:
I was reading my timing at WOT today and it reads around 12.6-13 running 17psi/91octan. I guess that is retard tming already since normally supra timing should be at 20degree advaced as I was told.
Well, the only way for you to find out for sure on your car would be to go pump 100 octane in your car and reset your ECU. Whatever timing you get then should be the baseline, and if your timing on 91 is below that, then it's getting KR.

I guess you sold the gizmo too soon, so you'll never know now.
 
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Discussion Starter #12
I just measured timing in my car with the following setup:

Large single turbo
Upgraded fuel system
Intake air temp ~70-80F
114 octane gas
4th gear WOT to redline
18psi boost

It stayed at 28-29 degrees the entire time. So 13 degrees is VERY bad. This is also why your EGTs are high, most likely.

I'll be doing this again with Chevron 92 octane soon.

Sean
 

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Sean McElderry said:
I just measured timing in my car with the following setup:

Large single turbo
Upgraded fuel system
Intake air temp ~70-80F
114 octane gas
4th gear WOT to redline
18psi boost

It stayed at 28-29 degrees the entire time. So 13 degrees is VERY bad. This is also why your EGTs are high, most likely.

I'll be doing this again with Chevron 92 octane soon.

Sean
With the stock ECU? Its not supposed to be able to give more than 23 degrees of advance, AFAIK. With 114 octane it certainly needs a lot more advance than with pump gas.

Reseting the ECU will help, but it will only take like 2 pulls until it retards the timing back to where it was before.
 
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Discussion Starter #14
Yes, with the stock OBD-I ECU, piggybacked with the VPC/AFC combo. I measured this via the actual Toyota scan tool used by the dealers.

Why do you say the stock ECU won't advance past 23 degrees? And under what conditions is it restricted to 23 degrees?

Also, I did over 10 pulls (3 of which were in 4th gear until redline) and the timing never went below 28 degrees at WOT under boost.

Perhaps the Toyota scan tool displays timing differently than the Techtom unit...although I wouldn't think this would be the case.

Sean
 

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Bryce told me 23 was the max, and thats the most I've ever seen on my OBD2 car. I've used 2 OBD2 scanners and they've both stopped at 23. Might be different for an OBD1 I guess. I've never tried it with straight high-octane fuel though, always a mix.
 
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Discussion Starter #16
Wow...interesting. 5 degrees of timing is a lot...I wonder why the difference. What's your setup, Grant? Under what conditions do you measure 23 degrees advance?

Sean
 
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