what is better, more timing or leaner mixture???

[91-gsx]

i was thinking about this right now and was wondering which one is better; to run rich but have high timing?(by high, i mean 20+) or to run leaner and have like 18 degrees of timing? it could be done through the CAS, and my afpr. i am trying to get this right using my maft but it either gets to rich(or running to much timing, do not know which one yet) because it bucks at higher rpms but their is no knock so i am guessing it is richness. or it gets to lean or runs to much timing when i lean it out by 5% and it knocks like all hell but still pulls hard, and that tells me that it is trying to retard the timing but it is still too high. maybe somebody with experience can help.
thanks in advance

 

[andymoraitis]

That's a great question! In my experience, a combination of both seems to generate the best power, but you can break it down like this. Let me add that these are general parameters and that every motor responds a bit differently.

Pump gas: 11:1 to 11.5:1 A/F and 18-19 degrees of timing advance
Race gas: 11.5:1 to 12.5:1 A/F and 22-23 degrees of timing advance

Since we both have a chip to control our injectors, you can also have Jeff run you a custom A/F map as well as an upgraded timing map. I saw the greatest gains going from a 9.5:1 A/F at 16 degrees to an 11:1 A/F at 23 degrees (1.2 seconds and 6 mph in the 1/4 mile). Since then, Jeff has made me additional chips with a leaner A/F and less timing and the car slowed down in a big way, so I would have to infer that timing made the most difference as opposed to leaning out the A/F beyond a certain point. Here's an example of what I mean:

9.5:1 with 16 degrees advance - 14.0 at 100 (20 psi)
11:1 with 23 degrees advance - 12.82 at 106.10 (22 psi)
11.7:1 A/F with 19 degrees advance - 13.0 at 104.90 (22 psi) - less timing killed it!
11.7:1 A/F with 23 degrees advance - 12.78 at 106.50 (22 psi)
11.7:1 A/F with 23 degrees advance - 12.57 at 107.85 (24 psi)

Accepted methodology is to run a bit more rich with moderate timing on pump and leaner with plenty of timing on race gas. The key to all of this is either controlling the burn rate of the combustion cycle (race gas or water injection), or cooling the intake charge sufficiently with a larger intercooler. Since I don't run an FMIC or water injection, a mix of pump and race gas allows me to run my current setup of 11.7:1 A/F and 23 advance at 22psi daily with only 3 counts of knock at the top of third.

In the final analysis, take a look at your combination and try a few different chip configurations. Three counts of knock should be the edge of your tuning limit as it's still safe and not causing any timing to be pulled. You will likely find that past a certain point, leaning out the A/F will only give you a certain amount of gain, but that bumping timing from 16 degrees to 20+ will make a huge difference in the way the car performs. If you have the luxury, go with a fairly lean A/F and strong timing on solid boost and you'll see the greatest gains.

When I first started to get involved with fuel tuning, I posted this thread which you may find helpful:

http://www.dsmtuners.com/forums/showthread.php?t=180544

You can even see how much of a newb I was back then and how some of my misconceptions needed to be set right. I'm still learning more each day, but you'll find that with some basic principles and a bit of trial and error, you'll see what works best for you.

I hope that helps!

Andy

 

[bfdahl]

having control over timming is more important when fuel qualitiy is of a concern.

manily if you using pump gas or lower quality fuel. advancing or retaring timming will lean or richen fuel mixtures.

 

[Maglin]

I like tunning my AFR to 11-11.3:1 with lower timing first. Then I raise timing slowly and kept it 2* under where it starts to knock. I've tried low timing and running rich it just doesn't seem to net anymore butt power. Plus I drive my car hard all the time and my fuel miliage is still 22 mpg even with my very sprinted driving.

I have to go to my local AWD dyno and see about getting a few hours of dyno time and I'll try out both to see what yeilds better power. Most say more boost is better.

 

[andymoraitis]

I agree that dyno time is the best way to see what the motor seems to respond to. In my experience, if you're not too rich (below 11:1), then timing will make the most difference up to a certain point. I've read a number of posts on other sites that past a certain A/F, gains are minimal, but equivalent changes in timing will produce more pronounced results.

I really think that once you get the timing where you want it, changing A/F will be more fine tuning than anything else. As an example, I think my 11:1 tune made little change over my first chip, but the 23 degrees of advance is what helped the motor make much more power. In that context, by leaning out the A/F to 11.7:1 with the same timing may help, but nowhere near as much as bumping another 7 degrees of advance did in the first place.

As I mentioned above, the best combination is a lean A/F, plenty of timing and plenty of boost. That's where the most power is made. Just keep in mind that there is such a thing as too much timing or too lean an A/F. The most important factor is to find the point at which things start to taper off and not pass the point of diminishing return.

Hope that helps,

Andy

 

[bfdahl]

I agree that dyno time is the best way to see what the motor seems to respond to. In my experience, if you're not too rich (below 11:1), then timing will make the most difference up to a certain point. I've read a number of posts on other sites that past a certain A/F, gains are minimal, but equivalent changes in timing will produce more pronounced results.

I really think that once you get the timing where you want it, changing A/F will be more fine tuning than anything else. As an example, I think my 11:1 tune made little change over my first chip, but the 23 degrees of advance is what helped the motor make much more power. In that context, by leaning out the A/F to 11.7:1 with the same timing may help, but nowhere near as much as bumping another 7 degrees of advance did in the first place.

As I mentioned above, the best combination is a lean A/F, plenty of timing and plenty of boost. That's where the most power is made. Just keep in mind that there is such a thing as too much timing or too lean an A/F. The most important factor is to find the point at which things start to taper off and not pass the point of diminishing return.

Hope that helps,

Andy

or thermo-nuclear meltdown
whichever comes first !

 

[sweet97]

or thermo-nuclear meltdown
whichever comes first !

Andy made some good points with actual track results. Not sure what you are trying to say here. I think Andy said that there comes a point where there are diminishing returns and of course a dangerous point. Mark

 

[91-gsx]

ya thanks that did really clear up a lot of things for me. I'm not int he right mood of thought right now because I'm tired and i just floored it on the way back from school only to find out that boost was hitting 21-22psi in my 14b on pump and lots of knock, thanks god nothing happened so far. what is a safe boost to run on the 14b on pump gas? is it better to run more timing on this turbo due to its hot air passed a certain boost level? when i first put my fmic on the maft was set for 5% leaner in the mid and 5% leaner in the top, but i was still getting like 12-17 counts of knock. what do you guys attribute this to? i was running like 18-19 psi on pump with 14b. I'm only using this opportunity to ask you these questions because i have not seen andymoraitis post here before and it seems like you know what you are doing.
thanks for the help

 

[andymoraitis]

Oh, I've been around for almost a couple of years, but I only bought my GSX less than a year ago so that's whay I don't have tons of posts. Nevertheless, I've done plenty of research to combat my own similar problems.

Anyway, what you'll find is that pump gas will always limit what you can do and it creates a trade-off situation. What I would advise is that you turn the MBC down to a point at which you will see no more than three counts of knock. The 14B can make plenty of power, but it does generate plenty of heat like many 16G variants on pump gas. There are two ways you can tune out of the knock and run solid boost. Either up the octane rating of your fuel, or consider water injection as an option.

As far as MAFT settings, I won't profess to know anything about them and maybe someone with more experience than me would recommend richening it up a bit, but I'm really not sure. I can tell you though that your knock count is way too high. Shoot for 3 counts and you'll be right where you need to be.

I can tell you what I used to run on each chip, what kind of fuel and the knock counts if that will give you a general guide. For reference purposes, my race gas is Citgo 110 and not VP C16

9.5:1 A/F - 16 degrees - zero knock at 20 psi on pump (too rich - not enough timing)
11:1 A/F - 16 degrees - zero knock at 22 psi on pump (not enough timing)
11:1 A/F - 23 degrees - ten counts at 22 psi on pump (too much timing on pump)
11:1 A/F - 23 degrees - five counts at 22 psi on a 70/30 pump/110 mix (better)
11.7:1 A/F - 19 degrees - five counts of knock at 22 psi on pump (slower from less timing)
11.7:1 A/F - 23 degrees - three counts at 22 psi on a 60/40 race/pump mix (just right)

If it was up to me, I'd get the car on a dyno and see what A/F you're running. You may find that having the MAFT leaned out could simply be too much for your setup and that adding a little fuel back in would make a world of difference.

Let me know if that helps,

Andy

 

[andymoraitis]

I just noticed that you're still running BPR6ES plugs. If that's the case, change them out for BPR7ES (one range colder) and gap them to 0.028". Those 6ES are not made for the high boost levels you're running. I'm wondering if these couldn't be contributing to hot spots.

Experienced fuel tuners, please chime in and let me know if I'm way off here.

Andy

 

[TSIfreek]

I would keep it under 15 psi. The intercooler will stay cooler longer and you will be abe to tune it then. You may be heat soaking your intercooler and trying to tune off that. Your motor will be much happyer and will see more power from a cooler air charge and a good tune.
Since I think you have no AF gauge tune off the logger to see less than 5 on the knock on a full 3 gear pull to 6500. Set your AFPR at 38 with the vacume line off as well. If you are seeing knock up top add or subtract fuel there (but start buy adding fuel and see what it does) with your AFC if you have one until you have little knock. Your timing will come around once you get little knock.

 

[91-gsx]

ok this sounds good, just a quick run through what happens for you that do not know much about the maft but that can also offer me lots of help. i have set the mbc for 18 and it went up to 21-22 for some reason, why, is it because of whether or what? next thing i have my chip programmed for 750cc injectors when i set the maft at 450cc injectors. the whole point of this is to start off like you have a stock car so tuning will be easier. anyway when i keep it set at 0 which is no leaner or richer it is a, wait ill make a table like andymoraitis.

this was done on 18-19psi on the 14b
when set on 0% change i get 18 degrees of timing and zero knock but it seems to run to rich because it bucks after 4000 rpms.
when i leaned out the mid and wot switch by 5% it would knock about 17 times and fall i believe to 17-18 degrees of timing.
when i put my front mount intercooler on, i tried to tune it but got the same numbers, as if the 14b was even heat soaking the fmic at 18-19psi. but when i drove it for a few days it would start to buck again whenever i went past 4000 rpms so i leaned it out an additional 5% at wot and it took away the bucking and it would pull throughout the rpms, but i have not checked what type of knock i am getting yet, must be a lot, like 20-25 counts.

so what i think i am going to do is lower the boost first off, still do not know how far because the car feels a lot stronger at 18-19 psi as compared to 15psi.
what i need to do is set the maft at 0% and take out some fuel pressure, because i have such big injectors and when they open up 36psi on the fpr is a different amount of fuel on 450cc injectors then it is on the 750cc's right, i would be dumping in way more fuel at the same fuel pressure?
i need to do it this way because when i lean it out using the maft it seems to add to much timing with it and i still need to lean it out the extra 5% sense i put the fmic on. with fpr i can reduce the pressure until the car stops bucking, and i hope at that point it will not knock because the timing is not going up.
thanks for the info it is really helping

 

[TSIfreek]

FMIC does help but yea I would lower the boost. You may find it runs better.

 

[TSIfreek]

Also keep an eye on your fuel trims they take a while to adjust.

 

[sweet97]

ok this sounds good, just a quick run through what happens for you that do not know much about the maft but that can also offer me lots of help. i have set the mbc for 18 and it went up to 21-22 for some reason, why, is it because of whether or what? next thing i have my chip programmed for 750cc injectors when i set the maft at 450cc injectors. the whole point of this is to start off like you have a stock car so tuning will be easier. anyway when i keep it set at 0 which is no leaner or richer it is a, wait ill make a table like andymoraitis.

this was done on 18-19psi on the 14b
when set on 0% change i get 18 degrees of timing and zero knock but it seems to run to rich because it bucks after 4000 rpms.
when i leaned out the mid and wot switch by 5% it would knock about 17 times and fall i believe to 17-18 degrees of timing.
when i put my front mount intercooler on, i tried to tune it but got the same numbers, as if the 14b was even heat soaking the fmic at 18-19psi. but when i drove it for a few days it would start to buck again whenever i went past 4000 rpms so i leaned it out an additional 5% at wot and it took away the bucking and it would pull throughout the rpms, but i have not checked what type of knock i am getting yet, must be a lot, like 20-25 counts.

so what i think i am going to do is lower the boost first off, still do not know how far because the car feels a lot stronger at 18-19 psi as compared to 15psi.
what i need to do is set the maft at 0% and take out some fuel pressure, because i have such big injectors and when they open up 36psi on the fpr is a different amount of fuel on 450cc injectors then it is on the 750cc's right, i would be dumping in way more fuel at the same fuel pressure?
i need to do it this way because when i lean it out using the maft it seems to add to much timing with it and i still need to lean it out the extra 5% sense i put the fmic on. with fpr i can reduce the pressure until the car stops bucking, and i hope at that point it will not knock because the timing is not going up.
thanks for the info it is really helping

The DSMchip compensates for the larger injectors through the RPM range. Jeff asks what fuel pressure you are running and adjusts the amount of inj open time for that. You should have gotten a little sheet from Jeff with all of what he put into the chip. Just lower the boost to something that you can tune without knock. Then up the boost a lb or so and see if you can tune without knock there. Once you reach the point that you cannot tune the knock out then back off the boost 2 psi.
You will make more power with less boost and NO knock which will give you more timing. Then you can move on to RPM WOT tuning. I run a big turbo with a decent amount of boost(25-27)psi on pump. I need way more fuel up top than down lower so the RPM tuning is critical. Mark

 

[91-gsx]

he gave me a sheet that includes what is in it, but nothing about fuel pressure. should i also change me spark plugs to the one range colder?

 

[andymoraitis]

he gave me a sheet that includes what is in it, but nothing about fuel pressure. should i also change me spark plugs to the one range colder?

Definitely change to BPR7ES and gap at .028"! That alone can make a difference. As far as the fuel pressure settings, it may be best to get in touch with Jeff directly since he saves your chip parameters.

Andy

 

[91-gsx]

if i am going to runa low boost like 15psi, should i use these spark plugs or the colder ones? i still want to run 18 psi becuase it feels so much faster.

 

[sweet97]

Try the 7's. 15psi on the stock turbo is really not low. You could still be pushing hot air into the motor. Summitt sells a gauge and sensor that I added to my TB elbow so I can measure the inlet temps, only $60. Great addition to the normal gauges and nicely priced too.
Remember to run the most boost that will still give you a minimum of 15* of timing. The RPM/fine tuning feature of the MAFT wiill help tune for the higher boost/rpm's. mark

 

[91-gsx]

what program do i use to get my logs off of my mmcd palm on to my computer in a spreadsheet? i have the files to do it but do not know how to.
plz help me do this first then i will post the results i just took.

 

[andymoraitis]

what program do i use to get my logs off of my mmcd palm on to my computer in a spreadsheet? i have the files to do it but do not know how to.
plz help me do this first then i will post the results i just took.

I don't have a logger, but if you do an advanced search on the site for "palm" and set it to search thread titles only, you'll wind up with a bunch of threads that may answer your question. I believe you need hotsync to move them to your PC.

Hope that helps,

Andy

 

[91-gsx]

here are the pulls
the first one is done at -5% fuel at mid and -10% at wot.

timing fuel trims, low, mid and high throttle pos rpm knock
31° 119.3% 139.6% 139.6% 56.9% 4438 0
28° 119.3% 139.6% 139.6% 57.6% 4531 1
20° 119.3% 139.6% 139.6% 100.0% 4594 31
7° 119.3% 139.6% 139.6% 100.0% 4750 31
5° 119.3% 139.6% 139.6% 100.0% 4844 30
7° 119.3% 139.6% 139.6% 100.0% 5000 30
7° 119.3% 139.6% 139.6% 100.0% 5094 30
9° 119.3% 139.6% 139.6% 100.0% 5219 29
9° 119.3% 139.6% 139.6% 100.0% 5344 29
8° 119.3% 139.6% 139.6% 100.0% 5438 34
8° 119.3% 139.6% 139.6% 100.0% 5563 34
8° 119.3% 139.6% 139.6% 100.0% 5656 34
8° 119.3% 139.6% 139.6% 100.0% 5750 33
9° 119.3% 139.6% 139.6% 100.0% 5719 33
9° 119.3% 139.6% 139.6% 100.0% 5875 33
10° 119.3% 139.6% 139.6% 100.0% 5875 32
10° 119.3% 139.6% 139.6% 100.0% 6094 32
10° 119.3% 139.6% 139.6% 100.0% 6031 32
10° 119.3% 139.6% 139.6% 100.0% 6219 31
12° 119.3% 139.6% 139.6% 100.0% 6250 32
11° 119.3% 139.6% 139.6% 100.0% 6375 32
12° 119.3% 139.6% 139.6% 100.0% 6344 31
13° 119.3% 139.6% 139.6% 100.0% 6406 31
14° 119.3% 139.6% 139.6% 100.0% 6406 31
14° 119.3% 139.6% 139.6% 100.0% 6469 31
14° 119.3% 139.6% 139.6% 100.0% 6625 30
14° 119.3% 139.6% 139.6% 100.0% 6594 30
15° 119.3% 139.6% 139.6% 100.0% 6719 30
16° 119.3% 139.6% 139.6% 100.0% 6688 29

 

[91-gsx]

2nd pull is done with -5% in the mid and -5% at wot so i actually richened it up at wot by 5%:
timing LT MT HT TP RPM KNOCK
40° 130.3% 139.6% 139.6% 27.8% 3469 0
40° 130.3% 139.6% 139.6% 31.4% 3500 0
35° 130.3% 139.6% 139.6% 34.9% 3531 0
33° 130.3% 139.6% 139.6% 36.5% 3563 0
30° 130.3% 139.6% 139.6% 39.6% 3594 0
28° 130.3% 139.6% 139.6% 47.8% 3656 0
26° 130.3% 139.6% 139.6% 51.0% 3719 3
24° 130.3% 139.6% 139.6% 60.0% 3844 9
16° 130.3% 139.6% 139.6% 100.0% 3938 16
14° 130.3% 139.6% 139.6% 100.0% 4000 15
15° 130.3% 139.6% 139.6% 100.0% 4125 15
12° 130.3% 139.6% 139.6% 100.0% 4188 14
14° 130.3% 139.6% 139.6% 100.0% 4219 14
14° 130.3% 139.6% 139.6% 100.0% 4438 14
14° 130.3% 139.6% 139.6% 100.0% 4563 13
14° 130.3% 139.6% 139.6% 100.0% 4625 13
14° 130.3% 139.6% 139.6% 100.0% 4719 12
16° 130.3% 139.6% 139.6% 100.0% 4813 12
16° 130.3% 139.6% 139.6% 100.0% 4906 12
16° 130.3% 139.6% 139.6% 100.0% 5000 11
16° 130.3% 139.6% 139.6% 100.0% 5094 11
18° 130.3% 139.6% 139.6% 100.0% 5156 15
16° 130.3% 139.6% 139.6% 100.0% 5281 15
17° 130.3% 139.6% 139.6% 100.0% 5344 15
18° 130.3% 139.6% 139.6% 100.0% 5438 18
17° 130.3% 139.6% 139.6% 100.0% 5500 18
18° 130.3% 139.6% 139.6% 100.0% 5563 17
19° 130.3% 139.6% 139.6% 100.0% 5719 17
20° 130.3% 139.6% 139.6% 100.0% 5688 17
20° 130.3% 139.6% 139.6% 11.4% 5594 0

 

[91-gsx]

the last pull was -5% mid and the wot was at 0 that means no change at all:

TIMING LT MT HT TPS RPM KNOCK
28° 137.3% 139.6% 139.6% 38.8% 2313 0
28° 137.3% 139.6% 139.6% 38.8% 2375 0
28° 137.3% 139.6% 139.6% 42.7% 2406 0
28° 137.3% 139.6% 139.6% 60.0% 2438 0
26° 137.3% 139.6% 139.6% 82.4% 2500 0
26° 137.3% 139.6% 139.6% 94.1% 2594 0
25° 137.3% 139.6% 139.6% 98.4% 2656 5
23° 137.3% 139.6% 139.6% 98.8% 2719 5
23° 137.3% 139.6% 139.6% 99.2% 2781 4
22° 137.3% 139.6% 139.6% 99.2% 2844 4
22° 137.3% 139.6% 139.6% 99.2% 2906 3
23° 137.3% 139.6% 139.6% 99.2% 3000 3
21° 137.3% 139.6% 139.6% 98.8% 3063 3
20° 137.3% 139.6% 139.6% 98.0% 3156 2
18° 137.3% 139.6% 139.6% 97.6% 3250 2
14° 137.3% 139.6% 139.6% 97.6% 3313 1
15° 137.3% 139.6% 139.6% 97.6% 3406 1
15° 137.3% 139.6% 139.6% 97.6% 3469 1
15° 137.3% 139.6% 139.6% 98.0% 3563 1
17° 137.3% 139.6% 139.6% 98.0% 3656 1
21° 137.3% 139.6% 139.6% 98.4% 3750 1
22° 137.3% 139.6% 139.6% 98.4% 3844 0
22° 137.3% 139.6% 139.6% 98.4% 3938 0
22° 137.3% 139.6% 139.6% 98.8% 4000 6
17° 137.3% 139.6% 139.6% 98.8% 4094 11
17° 137.3% 139.6% 139.6% 98.8% 4125 11
17° 137.3% 139.6% 139.6% 99.2% 4313 14
17° 137.3% 139.6% 139.6% 99.2% 4438 14
17° 137.3% 139.6% 139.6% 99.2% 4438 14
16° 137.3% 139.6% 139.6% 99.2% 4594 14
15° 137.3% 139.6% 139.6% 99.2% 4656 14
15° 137.3% 139.6% 139.6% 99.2% 4719 13
15° 137.3% 139.6% 139.6% 99.2% 4781 13
15° 137.3% 139.6% 139.6% 99.2% 4875 12
17° 137.3% 139.6% 139.6% 99.2% 5031 12
17° 137.3% 139.6% 139.6% 99.2% 5094 12
18° 137.3% 139.6% 139.6% 99.2% 5125 11
18° 137.3% 139.6% 139.6% 99.2% 5250 11
19° 137.3% 139.6% 139.6% 99.2% 5344 10
18° 137.3% 139.6% 139.6% 99.2% 5344 14
19° 137.3% 139.6% 139.6% 99.2% 5375 14
20° 137.3% 139.6% 139.6% 99.2% 5500 17
19° 137.3% 139.6% 139.6% 99.2% 5656 17
19° 137.3% 139.6% 139.6% 99.2% 5750 17
20° 137.3% 139.6% 139.6% 99.2% 5719 16
20° 137.3% 139.6% 139.6% 99.2% 5844 16
20° 137.3% 139.6% 139.6% 99.2% 5875 15
22° 137.3% 139.6% 139.6% 99.2% 5938 22
19° 137.3% 139.6% 139.6% 11.0% 5781 0

tell me what you guys think.
thanks for the help

 

[91-gsx]

if anybody has an idea of what i should do please help.
thanks