Timing on Modded Camshaft
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From: Derry nh
Timing on Modded Camshaft
My 91 has a modded cam, don't know brand or how much mod but at idle the car sounds a little like a Harley. Does a modded cam affect the setting of ignition timing? Sticker under hood says 6 deg BTDC.
Le Mans Master
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From: Australia
I find the more advance at idle I run the smoother the idle however too much advance will give you knock under load.
Safety Car
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From: Salem NH
Generally bigger cams want more timing at idle and cruise. I run around 25 degrees total timing at idle, upwards of 40 degrees in cruise and decel, and 26* WOT. This is all done in the computer.
-- Joe
Melting Slicks
Joined: Jan 2002
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From: Milan
or 26 + 6 = 32 ?
I ask because I'm really interested to know if you had worse results with more timing.
-Beppe-
Safety Car
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From: Salem NH
I'm focusing on WOT timing now. When you say 26 deg Are you saying total timing? (I mean with the 6 deg initial included -if 6 in the chip and at the balancer- )
or 26 + 6 = 32 ?
I ask because I'm really interested to know if you had worse results with more timing.
-Beppe-
or 26 + 6 = 32 ?
I ask because I'm really interested to know if you had worse results with more timing.
-Beppe-
I run 8 degrees of initial, which is enough that if my EST fails my module will still have a decent advance curve. I idle around 25 degrees and my WOT is set to 26 degrees. This is almost like 'locked in' timing on a drag car, except I have a lot of cruise advance and decel advance. (similar to a vac distributor).
With any performance application, the more advance you'll get away with the more power you can make (at WOT).
I usually zero out the PE spark advance and just run everything on the main table. In by 3,000 RPM.
Everyone has different ways of doing things.
-- Joe
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From: Winnipeg Manitoba, Canada
Melting Slicks
Joined: Jan 2002
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From: Milan
Yes, 26 total - I'm running a supercharger.
I run 8 degrees of initial, which is enough that if my EST fails my module will still have a decent advance curve. I idle around 25 degrees and my WOT is set to 26 degrees. This is almost like 'locked in' timing on a drag car, except I have a lot of cruise advance and decel advance. (similar to a vac distributor).
With any performance application, the more advance you'll get away with the more power you can make (at WOT).
I usually zero out the PE spark advance and just run everything on the main table. In by 3,000 RPM.
Everyone has different ways of doing things.
-- Joe
I run 8 degrees of initial, which is enough that if my EST fails my module will still have a decent advance curve. I idle around 25 degrees and my WOT is set to 26 degrees. This is almost like 'locked in' timing on a drag car, except I have a lot of cruise advance and decel advance. (similar to a vac distributor).
With any performance application, the more advance you'll get away with the more power you can make (at WOT).
I usually zero out the PE spark advance and just run everything on the main table. In by 3,000 RPM.
Everyone has different ways of doing things.
-- Joe
Me too I have around 25 at idle.
Me too I have my max advance from 3000 rpm to rev limiter.
My problem is that I haven't understand if my car likes 25 Deg at WOT, 38, or any value in between.
Now I'm at 32 deg and it seems it likes this amount of advance only in first and second gear (not in third... I have spark knock retard).
Without a Dyno run and or a 1/4 miles test I can't say if it likes more or less timing.
There are people that are happy with fuel inj. engines with 28 deg total advance. But, are the engines also happy with this timing? ...Or the 28 deg are because at 30 deg of advance it pings? And, if the cause of the detonation is removed, are we sure that the engine likes for real the 28 figure?
I'm in this situation with my 3rd gear where 4-6 deg are removed from 32 by the knok sensor activity.
-Beppe-
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Safety Car
Joined: May 2006
Posts: 4,290
Likes: 140
From: Salem NH
Me too, 8 deg initial (on damper and in the chip) , I zeroed out the PE spark advance too and I have all on SA main table.
Me too I have around 25 at idle.
Me too I have my max advance from 3000 rpm to rev limiter.
My problem is that I haven't understand if my car likes 25 Deg at WOT, 38, or any value in between.
Now I'm at 32 deg and it seems it likes this amount of advance only in first and second gear (not in third... I have spark knock retard).
Without a Dyno run and or a 1/4 miles test I can't say if it likes more or less timing.
There are people that are happy with fuel inj. engines with 28 deg total advance. But, are the engines also happy with this timing? ...Or the 28 deg are because at 30 deg of advance it pings? And, if the cause of the detonation is removed, are we sure that the engine likes for real the 28 figure?
I'm in this situation with my 3rd gear where 4-6 deg are removed from 32 by the knok sensor activity.
-Beppe-
Me too I have around 25 at idle.
Me too I have my max advance from 3000 rpm to rev limiter.
My problem is that I haven't understand if my car likes 25 Deg at WOT, 38, or any value in between.
Now I'm at 32 deg and it seems it likes this amount of advance only in first and second gear (not in third... I have spark knock retard).
Without a Dyno run and or a 1/4 miles test I can't say if it likes more or less timing.
There are people that are happy with fuel inj. engines with 28 deg total advance. But, are the engines also happy with this timing? ...Or the 28 deg are because at 30 deg of advance it pings? And, if the cause of the detonation is removed, are we sure that the engine likes for real the 28 figure?
I'm in this situation with my 3rd gear where 4-6 deg are removed from 32 by the knok sensor activity.
-Beppe-
-- Joe
Melting Slicks
Joined: Jan 2002
Posts: 2,238
Likes: 4
From: Milan
With a laptop, and a slight hill you can test acceleration. Don't even have to hit the speed limit. Can do 2nd gear runs and measure how long it takes to get from xx mph to xx mph on each WOT run. Keep adding advance until it doesn't go any faster or pings. Generally speaking, more advance will build more power. A bad combo with too little compression will seem to want too much advance, and a bad combo with too high compression might ping on pump gas. I don't know what your combo is.
-- Joe
-- Joe
I tried with strange results.
If you decide to test a 30 mph to 65 mph in 2nd, you need to stomp in it in the same istant you stomped for the previous test.
OK, you can start at 28 and end at 70 and measure in the excel file only the speed from 30 to 65. My measurements were different in regard of the moment I stomped on it.
My combo? I don't think it's a "bad combo"...with too much or with
too little compression.
-Beppe-
Le Mans Master
Joined: Aug 2000
Posts: 8,838
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From: Australia
"Now I'm at 32 deg and it seems it likes this amount of advance only in first and second gear (not in third... I have spark knock retard)."
Joe ,
how do you work around a problem like Beppe's where you are only getting knock counts under max load in 3rd?
Before I knew better ( thanks 3rd Gen tuning ) I ran a stock ARAP with my ZZ4 cam and always ONLY got KC going through the traps in 3rd.
Joe ,
how do you work around a problem like Beppe's where you are only getting knock counts under max load in 3rd?
Before I knew better ( thanks 3rd Gen tuning ) I ran a stock ARAP with my ZZ4 cam and always ONLY got KC going through the traps in 3rd.
Safety Car
Joined: May 2006
Posts: 4,290
Likes: 140
From: Salem NH
"Now I'm at 32 deg and it seems it likes this amount of advance only in first and second gear (not in third... I have spark knock retard)."
Joe ,
how do you work around a problem like Beppe's where you are only getting knock counts under max load in 3rd?
Before I knew better ( thanks 3rd Gen tuning ) I ran a stock ARAP with my ZZ4 cam and always ONLY got KC going through the traps in 3rd.
Joe ,
how do you work around a problem like Beppe's where you are only getting knock counts under max load in 3rd?
Before I knew better ( thanks 3rd Gen tuning ) I ran a stock ARAP with my ZZ4 cam and always ONLY got KC going through the traps in 3rd.
There had been some discussion in the past about adding a MPH vs MAP spark table, and I think some other ECM's actually have one from the factory. This would allow different advance curves based on what gear you're in.
Again, I'd need to see the log.
Edit - Beppe email me a log and your bin.
-- Joe
Melting Slicks
Joined: Jan 2002
Posts: 2,238
Likes: 4
From: Milan
Joe, rodj, I discussed the problem in the TGO some weeks ago....
Here is not a matter to find the way to have the correct timing in 3rd only...
If Even I can find the way to have a different timing on different gears, it should be around 32 in first and second and 26 on third.
This is NOT my goal.
In addition this timing applied by the ECM is in effect like this.
The ECM remove the 6 deg from the 32 total only in third.
The cars is now running 32 deg in 1st and 2nd, and at 26 deg in 3rd.
Scenario ASSUMING I found that 32 deg is the BEST timing advance on 100 Kpa and from 3000 rpm to 6000:
1) I have to be sure that the detonation felt by the KS is real knock
(I think yes due to the additional drag and load at the increased speed)
2) I have to fight it in third gear only (because I want run at 32 in third also)..
Edit- I haven't a log... I send you if you want the bin.
Here is not a matter to find the way to have the correct timing in 3rd only...
If Even I can find the way to have a different timing on different gears, it should be around 32 in first and second and 26 on third.
This is NOT my goal.
In addition this timing applied by the ECM is in effect like this.
The ECM remove the 6 deg from the 32 total only in third.
The cars is now running 32 deg in 1st and 2nd, and at 26 deg in 3rd.
Scenario ASSUMING I found that 32 deg is the BEST timing advance on 100 Kpa and from 3000 rpm to 6000:
1) I have to be sure that the detonation felt by the KS is real knock
(I think yes due to the additional drag and load at the increased speed)
2) I have to fight it in third gear only (because I want run at 32 in third also)..
Edit- I haven't a log... I send you if you want the bin.