So contribute.

"it doesnt make a difference where you base" That is not true. Low rpm performance is very dependent on the timing. I agree that the total is important. However I can't check my total, because I don't have a scanner. I have my timing set, based on 1/4 mile performance.

Unfortunately, this does nothing to contribute to the debate over the ramifications of disconnecting the knock sensor.

RACE ON!!!

 

cfi.. im not joining your debate on the knock sensor. i dont quite know the correct answer.

but i will comment on timing. adjusting the base timing is not the correct way to modify your timing curve. period!!!
the spark tables are there for a reason. the base is made to be set at 6* and timing curves modified in the spark tables. global adjustments like moving up your base may gain hp at certain rpms but can hurt many other rpms ranges. you need to make gradual change in the table, datalog, then make more changes. really the only way to do this is on a dyno.

but realisticly who gives a crap if you make 10hp more at 2500 rpms at half throttle . it is about hp a wot that is your main concern, or at least mine.

 

Me too!

 

Me too!
I add timing till it knocks then I back it off a fuzz!

 

45* total. I have checked it @ wot as well. No ping. 93 octane

 

well put vinnie. To the original question, I set my base
timing at 8 degrees on my L98.Thanks for the diagram Mikey.

 

The thing about this is that, how many people have had their cars on a chassis dyno to be meticously dyno tuned for hours on hours to find out exactly where each rpm band likes for best timing advance ? Maybe 1-1000 on this forum...... Maybe 1-10 have put them on the dyno for some quick base tuning, but certainly nothing as detailed as to go through the rpm band increment one at a time and making single changes to the timing advance at a given rpm level, documenting the effect and then going on to the next area..... its just not practical for street cars like most here on the forum.

Thus, many people will adjust the base timing for effect, and trust me, it can make a difference in performance..... would it be better to put it on the dyno for a full day of well detailed testing...... sure !! But who's doing that?

The difference between 6 degrees and 10 degrees base advance can easily be 10-20 hp on a lot of set-ups, this is seen on the timeslip.

I recommend to all forum members to experiment with base timing at the dragstrip.... start at 6 advance for a couple of passes, get yourself a couple of timeslips. Then try 8 for a couple of passes, compare and learn, you might want to go ahead to 10 or maybe back down to 6....

On my old 350 set-up that ran low 12's..... the difference between 6 degrees initial and 10 was somewhere around 1.5 tenths.... which in theory was right around 15 hp..... some here on this forum would see similar results, others going from 6 to 10 will produce detonation and slow you down.... you don't know until you try and trying really doesn't hurt anything and quite frankly trying to find et at the dragstrip is the funnest thing about this hobby, or at least to me it is.

Beach Bum

 

beach ... you are right. but all im saying is that is not the best way to adjust timing. the problem i had was i needed more timing at wot, but didnt need timing at partial thottle. my car liked 12* base also but i was picking up knock a part thottle. so i needed to adjust just wot timing values. the only way to do this is to burn a new chip.

the tack is hard to judge if you really gained or loss hp if your talking 10 hp. the dyno is best best. what i did was spend an hour on the dyno $75 and adjust my base timing for max hp. then burn a chip just for wot timing i added. so i added 6* to spark table above 3000 rpms and above 70 kpa, but i brought it in fairly soft.

 

For those who burn chips another useful tool is a G-tech (or a stopwatch). It is more painful than a dyno session, but you can make timed runs on your favorite hill and change one area at a time and see what gets you the best performance at various loads and rpms. It obviously takes a lot of work and careful record keeping to get it optimized.

Adding or subtracting timing globally will not optimize the whole curve, but it can still help depending on your combination.

Good luck

 

That's honest. If you don't know...You don't know. I THINK I know, and have documented the back up for my reasoning. I am open to correction. If I am wrong, I want to know it. However there is no point to stating I'm wrong and then posting a scan of a system that is off topic. Then a quote I have used, is reused, supposedly to back up the opposing viewpoint, but with no explanation.

I absolutely agree. I don't think I said that changing the base timing will change the timing curve. But if I did, I take it back. I was wrong, if I said so. The curve is the rate of advance internal to the distributor (in the old mechanical distributors) or the prom (with electronic controls). Is either case, the total timing is the sum of the initial (base) timing plus what the curve adds. No WAY altering the base, changes the curve.

Back in the olden days, we could block off the vacuum advance and check the mechanical advance (the only advance that functioned at WOT) and change the weights, springs, and the length of the slot, to tailor a curve to out liking. It isn't quite so easy, today, without the right equipment. As I mentioned, I don't have a scanner, so I don't even know what my total, WOT, advance is.

Once again, I agree. However, lacking a scanner, a dyno, and a means by which to burn chips, I used a little old "Yankee ingenuity" and gradually advanced my base timing until my car quit going faster. I realize it is crude, unsophisticated, and lacks addressing the timing curve, but in the meantime, you can't knock success. There is no question that a dyno session or two and a different curve would improve performance.

RACE ON!!!

 

not doubt adjusting your base is an effective way to gain performance and for the guy that does not have the time or chip buring capabitiies it will work well, but you need to be very careful that you over do it. at least hook up a scanner and watch you knock retard.

before i had a scanner and chip burning hardware i tried this same method. i had no way to check for knock. hell, i didnt even know what knock was . i went to far and i noticed a huge lag at part thottle, come to find i was getting massive knock and a lot of retard.

all im saying, and this is not directed to you, is before you start fooling around with your base, make sure you know what your doing.

 

I'm guessing you just jumped in at the end of this thread. No knock counts. No knock retard. Because NO KNOCK SENSOR.

That is what all the bickering is about. There is disagreement as to the ramifications, other than the obvious, as to the effects of disconnecting the knock sensor. I maintain that there are none. I have quoted from my Helms to back up my position. Others say I am wrong. I can accept that possibility. I would love to be shown and have it proved. Can you help set us (me) straight?

Alvin jumped in and said I was wrong, but he used a schematic and text for a different set up. We are talking L98, here, with a separate ESC module. He never did explain that, he only got defensive when challenged. Then, he posted a different quote, one that *I* had used to support my position, but he failed to explain how it made HIS point, rather than mine. Help?

Beach bum,
Can you back up your position? Can you tell me the error in my reasoning?

RACE ON!!!

 

I'm guessing you just jumped in at the end of this thread. No knock counts. No knock retard. Because NO KNOCK SENSOR.

That is what all the bickering is about. There is disagreement as to the ramifications, other than the obvious, as to the effects of disconnecting the knock sensor. I maintain that there are none. I have quoted from my Helms to back up my position. Others say I am wrong. I can accept that possibility. I would love to be shown and have it proved. Can you help set us (me) straight?

Alvin jumped in and said I was wrong, but he used a schematic and text for a different set up. We are talking L98, here, with a separate ESC module. He never did explain that, he only got defensive when challenged. Then, he posted a different quote, one that *I* had used to support my position, but he failed to explain how it made HIS point, rather than mine. Help?

Beach bum,
Can you back up your position? Can you tell me the error in my reasoning?

It's OK to direct that at me. Knowing what I'm doing is the purpose of this discussion. I thought I did, but there has been doubt put into my mind, by normally, credible sources.

RACE ON!!!

 

Let me clear things up.... I didn't get pissed or angry at you. I got irratated at the smart remark the other fellow made.. "you would think a supporting tuner would have a better idea of how this setup works"

In my mind, the way I read here I take it as hes calling me a idiot.. After all of the experience I have tuning efi cars and all the help I offer to people here.. he has the nerve to say somthing like that? Theres better ways of saying I think your wrong.. Like, I think you don't have that right.. , or I have found in my experience this....

I posted the scans of the DTC charts I have here and even quoted a helms on a 90 model L98

I do not have a helms on any vette 84-89 nor am I going to go to the library and check one out just for this thread.





I've been staying out of this thread because quite frankly I have better things to do than argue with someone... You keep doing things your way... globally advancing timing, and I'll keep doing things mine.. By re-arcing timing advance and adjusting total timing to reach a all-round kick *** timing table.

 

that is what makes my nervous. sometimes you cant hear detonation and if you dont inspect the plugs carefully and know what you are looking for you can do damage.

 

If I thought it would be meaningful, I would apologize for the third party. At this point, I would like some help. Just like the help we both give to others, everyday. May I have a turn, please?

If I understand your reference, here, the "DTC chart" was for an LT engine where the knock senor was wired directly to the PCM in a system that uses no ESC module. The quote from the "helms on a 90 model L98 " is the same quote I had used earlier to back up my position. It says:
The above clearly states that no signal from the knock sensor causes continued voltage on CKT# 485, and therefore, no timing retard. There is no indication, here, that there is any other interaction with the knock sensor or any other effects of CKT# 496. If you, or anyone knows that there is, please pipe up.


No need. What you (and I) have provided is close enough.


I am well aware this is not the best method. For now, it's the best I've got, and I need to be sure I understand how it works. Will you help me?

RACE ON!!!

 

I feel that all the bases have been covered... contribution to this thread was in my note: Work together not testrone battles...

 

Not getting in this debate...
Mine was set at 8º and we datalogged it and I was getting a BIT of spark knock (Still getting 41º total timing), but I backed it off to 6º, and now I'm getting maybe 5 knock counts.
Also,
Glad to see you posting again BeachBum

 

The original question (Where do you guys set your base ignition timing (L98)?) has long since been answered, by many of of us.

Can, will, no one help with my side question? There were a few shots made, but no back up.

RACE ON!!!