Help - timing question for tuners...
Thread Starter
Safety Car
Joined: Sep 2003
Posts: 3,599
Likes: 24
From: Orange County NY
St. Jude Donor '10-'11-'12-'13
Help - timing question for tuners...
I have a question about timing and how it relates to PROM tuning:
The mechanic that built the engine for my '87 (383 - see sig), put it on a dyno and burned a chip for it. He advised me that the best numbers were made with BASE timing set at 17 degrees advance. (FYI - the cam has 4 degrees built in).
While this number seems a lot higher than most of what I've read on the forum, it truly did start up and run it's best with base timing (EST disconnected) set at 17 degrees advanced. I tried to bring it down, but the engine would start to run worse and die by 10 - 12 degrees, so I set it at 17.
Anyway - the original chip that came with the engine was far from ideal, and was really only tweaked for WOT. Long story short, after talking to TJ (Wong), I went with a Formato chip and it is much closer.
My question is (FINALLY :o ) - Is the base timing something that would / should be specific to each individual tune, and therefore need to vary with each tune?
Or, based on my engine combination and how it runs with the EST disconnected, should it always be set at 17 degrees (which is where it seems most comfortable, no matter what chip I put in)? Then I would just need to deal with the additional advance built into the chip, etc.
Hopefully I made some type of sense...
The mechanic that built the engine for my '87 (383 - see sig), put it on a dyno and burned a chip for it. He advised me that the best numbers were made with BASE timing set at 17 degrees advance. (FYI - the cam has 4 degrees built in).
While this number seems a lot higher than most of what I've read on the forum, it truly did start up and run it's best with base timing (EST disconnected) set at 17 degrees advanced. I tried to bring it down, but the engine would start to run worse and die by 10 - 12 degrees, so I set it at 17.
Anyway - the original chip that came with the engine was far from ideal, and was really only tweaked for WOT. Long story short, after talking to TJ (Wong), I went with a Formato chip and it is much closer.
My question is (FINALLY :o ) - Is the base timing something that would / should be specific to each individual tune, and therefore need to vary with each tune?
Or, based on my engine combination and how it runs with the EST disconnected, should it always be set at 17 degrees (which is where it seems most comfortable, no matter what chip I put in)? Then I would just need to deal with the additional advance built into the chip, etc.
Hopefully I made some type of sense...
Pro
Joined: Jul 2002
Posts: 703
Likes: 0
From: Milwaukee Wi
Boy i thought "base timing" was much less. but the base timing is considered in the timing tables in bin much like a constant or underlying value. if base is 10 and you are at 17 and using stock timing tables i beleve you are globally more advanced in all timing cells by 7. maybe tuner wanted to advance across the board rather in certain areas.
Thread Starter
Safety Car
Joined: Sep 2003
Posts: 3,599
Likes: 24
From: Orange County NY
St. Jude Donor '10-'11-'12-'13
That's what I was thinking. And a different tune wouldn't change what BASE timing the engine operates best at, would it? That is simply a function of mechanical set up, how the cam was installed, etc, correct?
Like you stated, it is my understanding that the base timing is a global starting figure that the programmed timing in the chip would be added to.
Is my thinking correct?
Thanks for your help!!
Dan
Like you stated, it is my understanding that the base timing is a global starting figure that the programmed timing in the chip would be added to.
Is my thinking correct?
Thanks for your help!!
Dan
Drifting
Joined: Mar 2005
Posts: 1,923
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From: GA
Originally Posted by byebyeL98
Like you stated, it is my understanding that the base timing is a global starting figure that the programmed timing in the chip would be added to.
Is my thinking correct?
Thanks for your help!!
Dan
Is my thinking correct?
Thanks for your help!!
Dan
Was your cam installed 4* retarded? If it was, maybe that accounts for it wanting so much advance to idle.
Thread Starter
Safety Car
Joined: Sep 2003
Posts: 3,599
Likes: 24
From: Orange County NY
St. Jude Donor '10-'11-'12-'13
The cam card says "112 + 4", but knowing the engine builder and my luck, it is absolutely possible that the cam was installed 4 degrees retarded instead.
The strange thing is, at what appears to be 17 degrees base timing, it starts right up (though it runs very rich at cold, open loop idle), and once it enters closed loop, seems to idle / run really well. Even at WOT, it runs strong. Data logs show total timing at 40 degrees at WOT, but that's with the ECM thinking base timing is 6. Is there any way this thing would run (and not blow up!) at 51 degrees TOTAL timing at WOT?
The strange thing is, at what appears to be 17 degrees base timing, it starts right up (though it runs very rich at cold, open loop idle), and once it enters closed loop, seems to idle / run really well. Even at WOT, it runs strong. Data logs show total timing at 40 degrees at WOT, but that's with the ECM thinking base timing is 6. Is there any way this thing would run (and not blow up!) at 51 degrees TOTAL timing at WOT?
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
Although 6 degrees is used as the norm for base timing, I've found my bone stock 87 runs much better at 8 degrees. When I built my 327 it ran best at 10 degrees. What I'm saying is 6 may be the base-but guys find there engines even stock may run better with a little change in timing. 17 degrees sounds like alot though-I'd pose questions to the builder-what I'm really wondering here though is-if you're data logging
40-why do you doubt that? and finally, I do believe timing is related to each individual build and tune.
40-why do you doubt that? and finally, I do believe timing is related to each individual build and tune.
Thread Starter
Safety Car
Joined: Sep 2003
Posts: 3,599
Likes: 24
From: Orange County NY
St. Jude Donor '10-'11-'12-'13
Unfortunately, I am no longer in contact with the builder, so that option is out.
Isn't the 40 degree data log figure a product of the ECM, "thinking" (based on the bin file) that base timing is at 6, and adding 34 degrees of programmed / actual advance? So if my base timing is truly at 17, wouldn't the ECM still add the programmed 34 degrees of advance to bring TTL timing to 51 degrees? (So long as there were no knock counts, etc that would cause the ECM to retard the timing any).
Would it even run (and not blow up!) at 51 degrees total advance (if, in fact, it truly was that number)?
Like Morley said - something is definitely screwy here. I guess the bottom line is that I should just go with what the engine likes and where it starts/idles/runs best. I had it out on Sunday and it has no trouble hazing the tires in 1st and 2nd (had to back off after that - don't want to exceed the speed limit), and there was no audible knock, so I suppose it's at least close to where it needs to be.
Isn't the 40 degree data log figure a product of the ECM, "thinking" (based on the bin file) that base timing is at 6, and adding 34 degrees of programmed / actual advance? So if my base timing is truly at 17, wouldn't the ECM still add the programmed 34 degrees of advance to bring TTL timing to 51 degrees? (So long as there were no knock counts, etc that would cause the ECM to retard the timing any).
Would it even run (and not blow up!) at 51 degrees total advance (if, in fact, it truly was that number)?
Like Morley said - something is definitely screwy here. I guess the bottom line is that I should just go with what the engine likes and where it starts/idles/runs best. I had it out on Sunday and it has no trouble hazing the tires in 1st and 2nd (had to back off after that - don't want to exceed the speed limit), and there was no audible knock, so I suppose it's at least close to where it needs to be.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
If your assumptions are correct-wouldn't you actually be running 11 degrees more-sounds right to me. Again , I've always ran my timing where from start to all out performance where it ran best. You do still have a knock sensor right? so, if your engine started having high knock counts wouldn't the ECM retard timing? Your engine isn't over heating is it? If they find where my computer ended up-that's another storry-I'm gonna love getting into the data logging.
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Thread Starter
Safety Car
Joined: Sep 2003
Posts: 3,599
Likes: 24
From: Orange County NY
St. Jude Donor '10-'11-'12-'13
Yup - still have the knock sensor - an important safety device for me at this point 
Engine temp generally runs about 180.
After talking with TJ, I think I'll be getting into programming myself. With my combo, it is probably the only way to get it dialed in accurately. I'll be sure to post pictures of the mushroom cloud created when my car explodes
Engine temp generally runs about 180.After talking with TJ, I think I'll be getting into programming myself. With my combo, it is probably the only way to get it dialed in accurately. I'll be sure to post pictures of the mushroom cloud created when my car explodes
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
I'll be looking. You know Bye, I've never had any dealings with TJ or Alvin. But with guys like that and Morley, I think anythingcan be worked out on these. Got my laptop today and I hope Morley
can help me get it up and running Craig Moates. I really have to fight the URGE to modify-but I've had my fun. I just want to be able to scan my motor and maybe make a few improvements, like 600 RWHP-nooooo,
got to fight it. Although a bottle of laughing gas and lt headers wouldn't be-oh no, there I go again, Bye
Thread Starter
Safety Car
Joined: Sep 2003
Posts: 3,599
Likes: 24
From: Orange County NY
St. Jude Donor '10-'11-'12-'13
The help I've received from this forum, especially from TJ, Morley, and COUNTLESS others has been tremendous. I am truly grateful, especially when I actually have a chance to "pay it forward". I would have torched the damn thing long ago had it not been for the support from here
Rick - glad to hear you finally got your lap top. Whenever you get the urge for more horsepower, please do a search for all threads started by "byebyeL98" - that oughtta kill the urge real quick
Morley - it is a brand new ATI super damper, so it should be ok. I do have an adjustable pointer, but it only adjusts up to 4 degrees and it is in the middle, so it wouldn't account for the type of timing figures I'm seeing.
Rick - glad to hear you finally got your lap top. Whenever you get the urge for more horsepower, please do a search for all threads started by "byebyeL98" - that oughtta kill the urge real quick
Morley - it is a brand new ATI super damper, so it should be ok. I do have an adjustable pointer, but it only adjusts up to 4 degrees and it is in the middle, so it wouldn't account for the type of timing figures I'm seeing.
Drifting
Joined: Mar 2005
Posts: 1,923
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From: GA
Pull your #1 plug and rotate the engine by hand with your thumb over the plug hole. When you feel air being pushed past your thumb, slow down. Once theair has stopped blowing out you should be at #1 TDC. Now look at your timing pointer in relation to the damper marks...Is it pointing at 0 or very close to it?
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
I didn't read in your previous post about fouled plugs. Take a good look at them-melted electrodes, white insulators are symptoms of preignition-caused by advanced timing amonst other things like a lean condition.
Last edited by rick lambert; Mar 29, 2006 at 12:31 PM.
Thread Starter
Safety Car
Joined: Sep 2003
Posts: 3,599
Likes: 24
From: Orange County NY
St. Jude Donor '10-'11-'12-'13
That is something I do after almost every time I fire it up. So far, the plugs have never shown signs of detonation, melted electrodes, "pepper" particles, or bone white porceline. Each time, they are simply carbon fouled, with some signs of cleaner burning, probably from when it finally goes into closed loop.
Needless to say, I am an EXPERT at changing the plugs, and with the TPIS headers, it actually isn't too bad at all.
Needless to say, I am an EXPERT at changing the plugs, and with the TPIS headers, it actually isn't too bad at all.
Thread Starter
Safety Car
Joined: Sep 2003
Posts: 3,599
Likes: 24
From: Orange County NY
St. Jude Donor '10-'11-'12-'13
Believe me, the gerbils in my head have been spinning their wheels non stop since Sunday; they haven't gotten very far, though
I'll take another stab (perhaps literally) at the car again this weekend. Should be interesting...
I'll take another stab (perhaps literally) at the car again this weekend. Should be interesting...