Wouldn't it be easier to leave it at 6 degrees and forget the whole thing? Since you are already changing the configuration, might as well get the thing dyno tuned and the tuner can advance it as much as it allows in the EPROM?

Mine is set to 0 degrees (long story) but the ECM program was adjusted for that so it was fine.

 

This is the best way to do it since your having it tuned anyway...My tuner did all the changes in the tune with my timing set to stock 6 degrees BTDC.. Then there's no guesswork as to the best setting...WW

 

I can never understand the tweaking of the distributor myself. Why not change the advance in the tables instead of across the board? That runs the risk of it advancing too little for the setup at some points, right for other points and too much for yet others. Tuning at the dragstrip is kinda weak, IMO since it gives you overall performance and not allow you to tweak where necessary for optimum performance.

 

Not everyone has the gear or knowledge to tweak their tables. A turn of the dizzy a few degrees may or may not help, but it certainly is a possibility, depending on which factory tune you have and mods, octane etc. IMHO.

 

Exactly...and the question was already answered WAY back in post #11, when I said:
No one is arguing that ECM tuning is the BEST way; it IS the BEST way...but it's not the ONLY way.

The OP asked how to determine the timing requirements for his new engine. Two members posted saying (or implying) that you can't or shouldn't advance timing by rotating the distributor...and that just ain't true! THAT is what most of this discussion has been about.

*You CAN effectively advance timing by rotating the dist.
*You CAN see very meaningful gains by doing this (depending on the engine)
*It costs nothing to do, takes very little time so why would anyone post a recommendation to not try it?? Ya can always put it back, right? In something like one minute
*This is some of the LOWEST HANGING FRUIT in "hot-rodding" and worth experimenting with.
*Tuning at the drag strip is an objective way to tune. Again, not the BEST way...but it's infinitely better than the good 'ol SOTP tun-o-mometer. It certainly has been a good, effective tuning tool for me in the past.

 

I have picked up as much as ~20 hp by "tweaking the distributor" in a couple past cars that I've owned. Why would I NOT do it?? Show me a better gain for the money...

 

I have neither the gear or knowledge to tweak my tables. I farm it out to someone reliable.

 

My bad. I don't consider hacking a way of getting things done. All too often, it has come back to bite me in the butt and make me wish I had put the money and time the first time to get the results since now I have to pay to undo something that wasn't good.

And his engine is also now "NON STOCK" so who knows what effect cranking up the distributor will have throughout the curve.

* Yes you can
* You might at some points but throughout the curve?
* You can try it but how will you monitor what it is doing throughout the entire range?
* I guess you are right that it is a low hanging fruit. Just not my taste. I prefer to get it done right the first time instead of trying to chase down future problems but that is me.
* It IS better than the SOTP dyno which, IMO, is worst than worthless but how do you adjust it at the right points? What about the parts that need more timing and what about the parts that need timing taken out? Is the curve linear? Last one I saw wasn't.

Anything "CAN" be done. As someone said, just because you "CAN" marry your cousin doesn't mean it is a good idea or you should attempt it.

 

Let go with that. At what point did you pick up 20HP? How did you measure it? Was it just based off the total ET or did you manage to see which part you might be giving up and which you might be gaining? Say you gained 40HP but lost 20, you have your net gain of 20 but at which point?

Yes you are right that if you are not particular and just want a "beer drinking number", as some have called it, you can't beat a twist of they distributor. If you want it to be smooth and even throughout, I fail to see how an advance will make that.

I suppose it is all what you are willing to accept. I have used Chinese made tools and for the money they too can't be beat. OTOH, I think those are too expensive in the long run and prefer to get say Craftsman, Snap-On, Matco, etc, etc. I bought one out of necessity but it broke in my hand and almost gashed me. Thanks but no thanks. I can't afford that cheap way out. I'd rather save up and get something more reliable than that low hanging fruit.

 

Years ago, I thought of a smart trick. I could buy the newly produced TFS heads. Numbers looked good and they were WAY cheaper than what Lingenfelters wanted for their D-Port heads. Bought them and installed them on my LPE shortblock and saved myself a lot of money.

I was happy for a while until I found the valve spring on #4 broken. Changed it and life was good. Compression was ok so we let it be till spring where I could pull the heads. Valve kissed the piston and a chunk scored the bore and broke a part of the piston. When the head was removed, we found that the even side had valves wobbling around in the guides while the driver side was good.

This was after I had upgraded valve springs from TFS. I should have realized something was wrong when they sent me a set of guide plates because some had failed QC. But hey, it was cheap and way less than what LPE wanted. I fugured LPE was trying to sell me a more expensive set of head and this would work better.

I got it cheaper but ended up tossing the heads for AFR sets and getting a new short block. But it was good that I saved a few bucks on the heads, or was it? Were they heads cheaper IN THE LONG RUN?

 

The timing should be set at 6 degrees. I do not recommend setting it at any other position unless you know how much total timing is in your chip. The stock timing is fairly aggressive and the engine may not want any more timing then what you have in the stock chip. Most SBC engines want anywhere from 32 to 36 degrees of total WOT timing and I have not seen a stock chip that does not give you that much at some RPM with a stock chip. The older chips are fairly conserative at 3500 RPM but they are aggressive by 4800 RPM so play with it to get best performance but be aware you could experience knock retard or reduced performance from too much advance.

 

Unless it is beyond ECM adjustment, you probably won't see or feel it since the ECM will quietly retard it.

Still, I think the increase in timing is going to have some effect during non-WOT situations like idle and normal running and could change the injector pulse width based off the O2 sensor readings. I think it is best to get it set up right otherwise one can be chasing ghosts all day long. BTDT.

 

How do they do any better than "turning the dist. w/o the car?

 

That is the response of someone who simply "doesn't get it". Since you can't explain how the thing works, you post up with "do it right" even though you can't see or explain the difference...or if there IS a difference.



And how is this difference then changing the timing points in the tune?? Ya DON'T know...either way!! That is why we TRY...and see what the results are with some objective testing of some type. EITHER WAY we choose to do it.


Yes. Why not?


Do I really need to explain this? You monitor knocks. You measure the power/tq. You measure your fuel economy. In short...ya pay attention to what your motor/car is telling you. Not that hard.


Again you don't understand what you're talking about here. if you did, you'd understand that adjusting the timing with the distributor invites no more "future problems" than does messing w/the timing in the ECM! It's been stated multiple times in this thread; THE RISKS ARE THE SAME< NO MATTER WHICH METHOD YOU USE.


Lots of questions in one bullet here.
1. How do adjust it "at the right points"? The assumption here (that proves true 100% of the time, in my experience), is that GM installed conservative timing to accommodate the worst condition (this has been covered in this thread already too). That means that if you take care of your car, pay attention to what it's "telling you", run good quality gasoline, etc. there is power and economy left on the table with the stock timing. So you advance the timing (using which ever method)...then you MONITOR the results. When you get the best power/economy and drivability w/o detonation, that is the best that you can do...no matter which method you use (once again). The ECM method will more precisely taylor the curve to the motor, but we can fairly safely assume that if GM installed a conservative spark timing at one point in the tune, it is conservative at all points and the entire curve can be raised. Several poster in this very thread have confirmed that with their positive results of adding a few degrees of base, and I've experienced the same.
2. What about the parts that need more timing and what about the parts that need timing taken out? You can't affect those points with the dist. turning method. What ever the SHAPE of the curve in the stock tune, that timing curve SHAPE remains mostly the same...which is why (also already stated) the ECM/dyno tune is better.
3. No the curve is not linear. in fact it's not even a 2 dimensional curve...it's "3d". It is still "3d" after you turn the distributor....just the entire topography of the "curve" has risen by what ever amount you added....which as I said above, there is usually room for on a stock tune.



Yeah....I don't think that annalogy has any place here what so ever. Not even remotely relevant. Turn it around. When you can do a mod that is SO SIMPLE....and SO CHEAP, and it has so much potential...how on earth coudl you possibly argue with it?? Yeah, you can point out a "better" or more accurately a more thorough way to do it, but to post up and claim it's no good?? That's just hurting people who are looking for that low hanging fruit that IS hanging there! Yikes.

I "Get" that you're not comfortable with something as rude and offensive as "turning the distributor" in an effort to get more power...but the **** works and telling folks that it doesn't or that is the wrong way, is just plain wrong. WRONG man...Get it? Wrong.

 

No man....nope. You're making stuff up to worry about now, that doesn't exist and isn't worth worrying about. Injector pulse width? O2 readings? Chasing ghosts? With the exception of knock, there aren't any other meaningful concerns...NO MATTER WHICH METHOD YOU USE to advance the timing. Risk is the same either way. O2 sensor doesn't care if the timing is advanced in the ECM or by the dist orientation.

 

Data log. With Lingenfelter, we got it close since it was his combination, drove it to him and he cut a hole for a wide band sensor and hooked it up to equipment for hoad test after dyno tuning. With HiTech Motorsport wwe have him dyno tune it. With Jim Firmato we captured data logs using DIACOM and he made adjustments.

 

What is there that you seem to think you understand that I am not seeing? Either you set the timing using precise methods or you simply slop more fuel or timing or whatever. One is precise, the other isn't. Is there more?

Advancing 2 degrees adds 2 degrees all over the curve. IS there more? As to objective testing, do elaborate how you would do it without testing equipment that is accurate and not an estimate?

Fair enough. Tell me, how much extra timing is enough and at what points of the curve?

Yeah, if it were that simple, why do people make dynos and scanning devices, etc, etc? The theory is simple. Execution is harder. How do you measure TQ/HP? All your run tells you is the average and not what it is doing at a given RPM or can you? I can't.

ASSUMING all is done right, sure. If someone is debating about having the car dyno tuned, I'm sure they have all kinds of testing equipment lying around. And pigs fly. I have seen people simply crank the distributor on a 5.0 Mustang and it ran great at one point but it had issues on others.

I have not done any analysis on the ECM programs GM used so I am not sure how conservative or not they are. Have you actually done analysis on the programs? IF you have, please elaborate. Even if it is conservative throughout, how much? Is it linear? As to people telling me they get more power, I don't know how to interpret that. I know how to interpret dyno numbers. I know how to see that it picks up say 20HP all over. I don't know how to interpret a calculated 20HP at the dragstrip based on a timed run. I'd like to see a curve before and after.

I understand that. Which is why I prefer to go thru the ECM and have it dyno tuned or at least tuned with a data log which is reasonably close.

Yes, I have seen the maps on a computer screen. What it doesn't tell me is how much you can adjust. I don't know how much room there really is. I agree that there is room but without knowing how much there is, all you are saying is adjusting it blind or at best, semi blind since you don't know what it is doing and all you have is an average.

I tend to steer clear of those kind of cheap mods. IF I wouldn't do it to my own car, why would I recommend it to you?

I suppose you are right in that it works if you are willing to settle for something that sloppy with some gains. I prefer not to take shortcuts since my experience with shortcuts has been poor. My preference is to avoid those things and go for a more precise solution. Will you get some gains? Assuming you maxed it out, probably. How much? Hard to say. Will the ECM pull out timing more at some points than others? Probably. Again, if you simply want say 20HP at the dragstrip as a verification, I have to admit that it works from that standpoint. Would I allow you to touch my distributor? Not a chance. I prefer to have the entire program adjusted to max it out and with some safety margin as opposed to simply slopping more timing all over. So once again, what do you expect me to say if I will not even consider doing it to my personal car? That it is a good idea but I will not do it myself?

 

I don't know what to tell you other than we tried it quite a few years ago. Unfortunately, I didn't have the tools to measure it on a computer at the time. All I can say is that at 6 degrees vs 10 degrees there was a difference. On my Auto X-ray scanner that displays 1 value at a time, when switching from 6 to 10 and down to 2, there was a change and the pulse width did change. There was a momentary change is 02 readings till the ECM settled down and not the usual up and down.

 

But you don't know WHY ^those things^ happened. The pulse width changed b/c you changed the efficiency of the motor; you made it more efficient at 10* than it was at 6. Then you made it way less efficient at 2* than at 10*. That changed the percieved "load" on the engine, the air requirements to maintain idle speed and consequently, pulse width and the O2 had a reaction as you said. Thing is...SAME THING would happen, if you adjusted timing in the ECM! It isn't a detrimental thing at all...it's the ECM responding to changes in the way that the engine is running....no different than changes when you open the throttle. There is no "consequence" there, and if there is, it would be no different than any from adjusting timing w/in the ECM.


O.K. that works....but it's going to (or did) take a looooong time to get it as "right" as you claim yours is. Using your line, the "RIGHT way to do that" is get on a dyno for hours, and tune right there, on the dyno. But as I've said, there are more than one way to accomplish the same goal. Your way is cumbersome and time consuming, but it will work, eventually.


No. There is less to it than that. Your method no more "precise" than the other method being discussed. IN BOTH SITUATIONS, YA DON'T KNOW WHAT THE MOTOR WANTS! Get that into your head, man! It's a "crap shoot" in both cases. You can add timing until there is a negative consequence, then back it off some. You do the same in both situations. Who was talking about "slop more fuel"?? Not me. I was talking about timing. This thread is about timing.



NO there is not more. Adding 2* w/the distributor adds 2* everywhere...already covered in this thread earlier. Who said that I advocated testing w/o accurate test equipment? Where did I say that? I guess that you'll have to quote where I said that so that I can correct it.


You SHOULD know, but obviously don't seem to, that I can't answer that w/o knowing what motor we're talking about. In fact, I really can't answer that w/o a motor, a dyno, and a good scan tool.


This is painful. I feel like I'm talking w/my 9 yo. "Think. Why do people make dyno's?" So that you can produce an accurate tq curve of an engine.



I'm sure. I've seen people "tune ECM's" and the result was an engine that lost power and ran like garbage. SO....does that mean that tuning ECM's condemns an engine to run poorly? Of course not. Does your witnessing of 5.0 dist "cranking" condemn an engine to run poorly, of course not. Think, man.


That's fine that that is what "you like"...but again (this is getting tiring) there is more than one way to skin a cat. An accomplished drag racer and sharp car owner will see tangible, repeatable results at a drag track. Changes are observable. You are "accustomed" to your dyno charts....I am too, but I'm also equally accustomed to drag track results, data, etc. I have not analyzed ECM data, but even if I had, that would tell me nothing about "how conservative" the timing is. GM didn't leave "notes" in the tune to tell tuners how much they could add. I know...most of us who have experience with engines know that the timing is conservative b/c an OEM...ANY OEM has to make a conservative tune for several reasons; LCD owner. Fuel. Temps. Carbon build up. Warranty. And on and on. We all, already know that every motor than comes from OEM's isn't tuned on the cutting edge of A/F ratios and timing. They've left some on the table to protect themselves. I "know" this b/c I've added timing to so many engines, and gotten such fantastic positive results, that I know that...something was left on the table. A lot was, clearly. ...And YOU know that too, it would seem right? B/c didn't you pay for a "program adjusted to max it out and with some safety margin"?



Great. That is (as has been stated many times now, in this thread) the BEST way to do it. Glad that you have the money, time, and resources to have had your car done that way. Also glad that you are happy with the results.



A-Gain. Same is true, whether you do it through the ECM or the dist. Ya don't know! NO ONE KNOWS! That is precisely why, you "test 'n tune"! That IS the essence of "tuning" man! Clearly you don't "get" this, b/c you bought a tune from a tuner. It is trial and error...just the same as when you build a fuel map for a new motor....ya don't know what the injector pulse width should be at all points, right? So you put on a WBO2 and see what the motor wants! Then ya "feed it what it want's"! That IS, "Tuning", right there. Whether you're "twisting a distributor" or tapping away on a key board, the real world goal is the same, find out what it likes.



I didn't say that you were obligated to recommend something that you aren't in favor of. What I DID say was (and I'll quote it here...)
I also said;

Sure. B/c it IS a good idea. It DOES work. It's free (which does not mean that it's "no good"). You could say that the way YOU would do it is........b/c it's better for "these reasons" (then make sure that you get the reasons right). And let the OP decide. But to say that turning the distributor won't work for the reasons that you cited...you're wrong. It works and in many cases works very well. The way that you did it, custom tuning the ECM, that is the BEST way. But for no money and very little time, turning the distributor is absolutely an effective way to improve power and efficiency.

 

I'm lost here. Maybe it is semantics but the way I see it, if you up everything by 2 degrees, it doesn't matter whether you do it in the ECM or on the distributor. 2 degrees is 2 degrees. Engine won't know. What I am saying is that with the distributor adjustment, it puts 2 degrees all over regardless of whether the point on the curve could use 2 degrees or 4 or none. My point is that in the ECM, you can adjust it as you see fit whereas on the distributor, it gives more timing whether it is at 500 rpm or 5000. To me, one just makes it universal whereas going thru the EPROM you can increase it more or less at different points. Do you disagree with that?

I suppose it depends on what the goal is. If the goal is to get UP TO, and not necessarily that, 20HP, you are right that it is easier and cheaper to adjust the distributor. My point is that going thru datalogs and/or dyno sessions is more difficult but it is going to optimize the system. Do you disagree with that? I admit it takes longer and you have to save up more money to do 3 hrs of dyno time to tune it in but I haven't found anything in life that is worthwhile easily achieved. Perhaps you are luckier than I when it comes to doing that. Having cheap AND easy has always been an issue for me since most times it bites me back. Not today or tomorrow but perhaps next month.

Timing or fuel, the PRINCIPLE is the same. You measure it and make adjustments. Running it on a track is NOWHERE as precise as a dyno that can tell you what adjustments to make at what point. I don't know what the engine needs to run at optimum at any on point but my tuner can make analysis based on the dyno results or see the datalogs and know what the engine is doing.

OK. So what do you use to test, if I might ask. How precise is it? Does it give you breakdowns of what timing is required at every X00 RPM? Do tell. And you are right. I do farm out my tuning and I don't do it myself. I can't afford a dyno or the tools to do it. So tell me about YOUR tuning experience. Do you just dump more fuel and spark or do you craft it to the needs of the motor AT THE GIVEN SUTUATION?

And that is EXACTLY what I am saying. Without the necessary tools, you are guessing what the motor needs. I see only two ways. Farm out the job to someone with the tools and experience or beg, borrow or steal the tools and gain the experience. If you can't or don't want to pay the dyno session or datalogs, you need experience and the tools. Do you think the OP has the tools and experience?

You forgot to mention "so we can adjust the program in the ECM to suit the current needs".

Again, if all you want is to get the skin off, you are right. It won't matter if you use a scalpel or an ax. Perhaps we are talking of different things. You want the skin off and I want a surgical grade cut. You are willing to settle for it missing and/torn hides, I am not.

True. Any tuner can screw up the tune. Even the best have made mistakes.

As I said, a track result is a general number for the quarter of a mile at WOT. Does it give you RPM breakdown like a dyno? I don't see how. As such, I don't use it. AFAIK, it tells me I picked up X HP over the run. Does it tell me anything else about whether the engine is doing ok at 2000 and poorly at 3000 but excellent at 4000? If so, since you are so used to them, please explain how I can tell what a motor is doing at what RPM. I agree with you on the fact that GM did leave something out simply for financial reasons. What I don't know is how much which leads to the next question. How much to add back? Again, I am not comfortable with making universal changes without knowing what was left out or without having measuring devices. Both of which, it seems neither of us have. I guess the only option is to hand it over to someone with the expertise and tools or make a universal increase and accept that at some points it is going to be too much, others it is right and yet others it is not enough but on the average, it is an increase.

Well, you are wrong if you assume I have the money to simply do it and not care. I have to decide my priorities. Quite often, that means what I want takes a backseat to what I need. Sometimes, I have to save up for a while. That is exactly why I don't, as a rule, use the cheap and easy way. I can't afford it. I can't afford to use a cheap butt connector and later spend hours trying to find out where the problem lies. I might not be able to do it today but I have to find some time to take the wire out, cut it, solder it, etc, etc. Again, a bigger PITA but it reduces, not eliminates, the chance of it coming back to bite me. As I mentioned to you, I trashed an expensive short block because I found a different way to skin that cat with TFS heads. Could it have happened with LPE's D-Port heads? Sure. Chances are less and he'd have warrantied it. OTOH, I had to have my short block rebuilt OUT OF MY POCKET from the savings with the cheap heads. Cost me more to do it cheap.

I understand that. So tell me, which is more precise? Twisting a distributor or adjusting the ECM tables at multiple points to the needs based off a dyno or datalogs?

I agree it is a way that MIGHT improve the AVERAGE efficiency. Just that being that imprecise, I would recommend against it and recommend a more precise method that will improve it throughout the curve and not just dump more all over.

I think you misunderstand me when I say that it is better to tune it thru the ECM. Perhaps you think I am advocating increasing everything by a certain factor. If so, let me state that I am advocating adjusting it in a custom fashion so that each part gets as much as it needs. Yes, I realize that it is a more difficult route and some prefer to get away with something quick and dirty. I must admit I have used quick and dirty but only to get me out of BFE when my vehicle is broken down and then to fix it like it needs to be. Obviously, that method isn't for all just as some would like to pass a class with a "C" instead of working their butts off for the "A" but you would be right that either grade is a pass.