View Poll Results: SD or MAF tune
SD
43
61.43%
MAF
27
38.57%
Voters: 70. You may not vote on this poll
Speed density or MAF tune??
03-02-2009, 08:59 AM
#22
Hey George, you and I have had this exact conversation before haven't we? I'm a firm believer in this practice. If it's tuned right, you shouldn't be able to tell the difference. Even most big cam motors can run a MAF. Some motors don't like MAFs, but most are ok running them.
As for the power levels, I've seen many over 500 rwhp on stock MAFs.
As for the power levels, I've seen many over 500 rwhp on stock MAFs.
03-02-2009, 09:39 PM
#23
If the tuner knows what they are doing, you will be hard pressed to notice a difference from a MAF tune versus an SD tune. One example I always reference is a customer that had a 2000 Camaro convertible. It had a 224/230 cam and heads. I tuned the VE tables and MAF table. A couple of months later he returns with a check engine light, but he had no idea what it was as the car drove just as I tuned it. I scanned it and low and behold he had a low frequency MAF code. I verified if the MAF was reporting a signal and nothing from the MAF. He bought a new one and was on his way.
Throttle transients are handled by the VE table, while steady state cruising is handled by the MAF for all conditions under 4000rpms. Over 4000rpms under WOT is MAF exclusively. This is for a stock OE calibration. Although you can run strictly off of the MAF by changing the dynamic airflow disable parameter to say 1000rpms.
A good way to figure out if you have a good tuner is how long he invests in your tune. If it is just an hour or less, you will have issues. If he rides along with you and spends hours on it finely tuning things (and explaining what he is doing), then you have a great tuner. Also, to get an idle tune just right, the car will need to sit over night to verify cold start up to warmed up conditions. I always do at least two cold starts on M6s and four on A4s (because of the park/neutral and drive tables).
I will tune it how ever the customer wants, but don't give me this bullshit of SD > MAF or MAF > SD driveability. I will go SD-only on cars with over 5psi (MAF gets pegged) or if the overlap causes to much reverse air flow over the MAF.
Throttle transients are handled by the VE table, while steady state cruising is handled by the MAF for all conditions under 4000rpms. Over 4000rpms under WOT is MAF exclusively. This is for a stock OE calibration. Although you can run strictly off of the MAF by changing the dynamic airflow disable parameter to say 1000rpms.
A good way to figure out if you have a good tuner is how long he invests in your tune. If it is just an hour or less, you will have issues. If he rides along with you and spends hours on it finely tuning things (and explaining what he is doing), then you have a great tuner. Also, to get an idle tune just right, the car will need to sit over night to verify cold start up to warmed up conditions. I always do at least two cold starts on M6s and four on A4s (because of the park/neutral and drive tables).
I will tune it how ever the customer wants, but don't give me this bullshit of SD > MAF or MAF > SD driveability. I will go SD-only on cars with over 5psi (MAF gets pegged) or if the overlap causes to much reverse air flow over the MAF.
Then if the MAF only takes over at 4,000 rpm at WOT, then how does the
MAFT work? Cause the MAFT makes a change to the A/F ratio at all rpms at cruise and WOT. I know if u unplug the MAF at idle the car will surge or even stall...sounds to me the MAF does more than just 4k rpm at WOT....can this be better explained? From what read years ago that the SD tuning in the PCM from GM is there so you aren't dead on the side if the road when the MAF craps out.
The MAF, atleast from GM, is used to report to the PCM the amount of air the engine is about to see so the PCM can react faster for proper fueling and timing.
Last edited by BlackNiteWS6; 03-02-2009 at 09:44 PM.
03-02-2009, 10:00 PM
#25
I think people actually believe that SD tuning is a way of unleashing the magic genie
that guys think is hidden in the pcm..lol. When it comes to tuning don't over think things.
That old saying, use the " KISS " method and be done with it. Now on FI setups especially blowers since they are linear i can see why people try it. But the problem most guys dont report that their SD tuned cars could act different due to weather changes or if any other mods are made without retuning. Its the same way how so people will say their 224 duration cams are just like stock..lol. That is so misleading. It comes down to each persons perspective what feels like stock. Atleast the MAF can seamlessly adjust the A/F. I rather just use what GM gave me and mod it to my advantage instead of thinking i can outhink GM's tuning guys
that guys think is hidden in the pcm..lol. When it comes to tuning don't over think things.
That old saying, use the " KISS " method and be done with it. Now on FI setups especially blowers since they are linear i can see why people try it. But the problem most guys dont report that their SD tuned cars could act different due to weather changes or if any other mods are made without retuning. Its the same way how so people will say their 224 duration cams are just like stock..lol. That is so misleading. It comes down to each persons perspective what feels like stock. Atleast the MAF can seamlessly adjust the A/F. I rather just use what GM gave me and mod it to my advantage instead of thinking i can outhink GM's tuning guys
03-02-2009, 10:23 PM
#26
Whenever i tuned my car for heads/cam, converter and bolt ons and i still use my MAF
i never just tuned for WOT only. I start by getting the idle as perfect as possible.
I get it were there's no hot or cold start issues even in my A4. Then after i'm happy with that i tune for part throttle by logging my LTFT's. And again since i'm still using my MAF i dont know why you even need to touch the VE table at all. I only adjusted the IFR table to get my LTFT's to +1 to -1 basically as close to 0 as possible. Then after thats all setup correct i adjust the PE table since thats what its there for and hence its name.
Then you can play with timing for tweaking the setup. So i dont who why the guy in this thread said that guys with their MAF only tune for WOT above 4,000 rpm. Not me. And the times in my sig. shows i did something right for only tuning on the street only. So my MAF and MAF tuning worked out for me.
Oh when i bought my 2002 SS A4 w/ 2,009 GM cert. miles i found out the hard way that the first owner took the car to Cartek and had it SD tuned. How i found out is the car kept stalling once the outside temps. dropped below 45 degrees
I first thought my MAF died, until i scanned my PCM and seen that the VE table wasn't stock and the MAF codes were switched to off. After i had the stock file flashed back in the car idles perfect now but even runs better than it did before i retuned it back to MAF setup. And Cartek knows their stuff...That was my reason for not liking SD...just cause the temp dropped the damn thing doesn't want to idle...turn MAF back on no issues.
I'll keep the thing until my setup is so wild that the MAF cant be used.
i never just tuned for WOT only. I start by getting the idle as perfect as possible.
I get it were there's no hot or cold start issues even in my A4. Then after i'm happy with that i tune for part throttle by logging my LTFT's. And again since i'm still using my MAF i dont know why you even need to touch the VE table at all. I only adjusted the IFR table to get my LTFT's to +1 to -1 basically as close to 0 as possible. Then after thats all setup correct i adjust the PE table since thats what its there for and hence its name.
Then you can play with timing for tweaking the setup. So i dont who why the guy in this thread said that guys with their MAF only tune for WOT above 4,000 rpm. Not me. And the times in my sig. shows i did something right for only tuning on the street only. So my MAF and MAF tuning worked out for me.
Oh when i bought my 2002 SS A4 w/ 2,009 GM cert. miles i found out the hard way that the first owner took the car to Cartek and had it SD tuned. How i found out is the car kept stalling once the outside temps. dropped below 45 degrees
I first thought my MAF died, until i scanned my PCM and seen that the VE table wasn't stock and the MAF codes were switched to off. After i had the stock file flashed back in the car idles perfect now but even runs better than it did before i retuned it back to MAF setup. And Cartek knows their stuff...That was my reason for not liking SD...just cause the temp dropped the damn thing doesn't want to idle...turn MAF back on no issues.I'll keep the thing until my setup is so wild that the MAF cant be used.
Last edited by BlackNiteWS6; 03-02-2009 at 10:34 PM.
03-02-2009, 10:49 PM
#27
TECH Regular
And again since i'm still using my MAF i dont know why you even need to touch the VE table at all. I only adjusted the IFR table to get my LTFT's to +1 to -1 basically as close to 0 as possible. Then after thats all setup correct i adjust the PE table since thats what its there for and hence its name.
This is not the correct way to tune. I agree if you have your MAF and VE tuned correctly it should drive the same as if it was just SD.
03-03-2009, 10:23 AM
#28
), weather has absolutely 0 effect on my car, properly tuned speed density accounts for weather.Then if the MAF only takes over at 4,000 rpm at WOT, then how does the
MAFT work? Cause the MAFT makes a change to the A/F ratio at all rpms at cruise and WOT. I know if u unplug the MAF at idle the car will surge or even stall...sounds to me the MAF does more than just 4k rpm at WOT....can this be better explained? From what read years ago that the SD tuning in the PCM from GM is there so you aren't dead on the side if the road when the MAF craps out.
The MAF, atleast from GM, is used to report to the PCM the amount of air the engine is about to see so the PCM can react faster for proper fueling and timing.
MAFT work? Cause the MAFT makes a change to the A/F ratio at all rpms at cruise and WOT. I know if u unplug the MAF at idle the car will surge or even stall...sounds to me the MAF does more than just 4k rpm at WOT....can this be better explained? From what read years ago that the SD tuning in the PCM from GM is there so you aren't dead on the side if the road when the MAF craps out.
The MAF, atleast from GM, is used to report to the PCM the amount of air the engine is about to see so the PCM can react faster for proper fueling and timing.
On the LS1 PCM's, the MAF and Speed Density stuff all blends below 4000 RPM (it's called dynamic airflow), above 4000 RPM it is then strictly MAF based. There's a LOT of guys adjusting MAF tables to get everything in check below 4000 RPM...this is very very wrong (in my opinion), MAF tables are the calibration of a sensor (a very delicate sensor)...a lot of people don't realize that below 4000 RPM on LS1's it's a blend of MAF and speed density.
03-03-2009, 01:39 PM
#29
On the LS1 PCM's, the MAF and Speed Density stuff all blends below 4000 RPM (it's called dynamic airflow), above 4000 RPM it is then strictly MAF based. There's a LOT of guys adjusting MAF tables to get everything in check below 4000 RPM...this is very very wrong (in my opinion), MAF tables are the calibration of a sensor (a very delicate sensor)...a lot of people don't realize that below 4000 RPM on LS1's it's a blend of MAF and speed density.
I agree with what you're saying about adjusting the MAF table.
I agree with what you're saying about adjusting the MAF table.
03-03-2009, 01:53 PM
#30
This is not correct. Major mods yes, SD requires a re-tune (here's a hint, so does a MAF car ), weather has absolutely 0 effect on my car, properly tuned speed density accounts for weather.
Since i've always did my own tuning i know that whether you tune MAF or SD fine tuning is the key to get the most performance. And for the guy that said that tuning the LTFT's for dialing in for idle, part throttle and PE for WOT is a wrong way to go. On a 125 wet shot i ran 10.9's at 127+ mph on a stock 10 bolt with 3.23's tuning my car the way i described. I never had any issues at all. Idle was perfect, my LTFT's ranged from +1 but mostly hung around 0 to -2. So if you say that my way isn't right well it works for me I like using the MAF maybe just because i always tuned with it in place, and guys are still making great power with the MAF in place. Some say that SD tuning is easier.
Maybe i'll try it some day, but until then i like my method for it's performance and street manners in any condition.
Since i've always did my own tuning i know that whether you tune MAF or SD fine tuning is the key to get the most performance. And for the guy that said that tuning the LTFT's for dialing in for idle, part throttle and PE for WOT is a wrong way to go. On a 125 wet shot i ran 10.9's at 127+ mph on a stock 10 bolt with 3.23's tuning my car the way i described. I never had any issues at all. Idle was perfect, my LTFT's ranged from +1 but mostly hung around 0 to -2. So if you say that my way isn't right well it works for me
I like using the MAF maybe just because i always tuned with it in place, and guys are still making great power with the MAF in place. Some say that SD tuning is easier.Maybe i'll try it some day, but until then i like my method for it's performance and street manners in any condition.
03-03-2009, 07:09 PM
#31
Whenever i tuned my car for heads/cam, converter and bolt ons and i still use my MAF
i never just tuned for WOT only. I start by getting the idle as perfect as possible.
I get it were there's no hot or cold start issues even in my A4. Then after i'm happy with that i tune for part throttle by logging my LTFT's. And again since i'm still using my MAF i dont know why you even need to touch the VE table at all. I only adjusted the IFR table to get my LTFT's to +1 to -1 basically as close to 0 as possible. Then after thats all setup correct i adjust the PE table since thats what its there for and hence its name.
Then you can play with timing for tweaking the setup. So i dont who why the guy in this thread said that guys with their MAF only tune for WOT above 4,000 rpm. Not me. And the times in my sig. shows i did something right for only tuning on the street only. So my MAF and MAF tuning worked out for me.
Oh when i bought my 2002 SS A4 w/ 2,009 GM cert. miles i found out the hard way that the first owner took the car to Cartek and had it SD tuned. How i found out is the car kept stalling once the outside temps. dropped below 45 degrees I first thought my MAF died, until i scanned my PCM and seen that the VE table wasn't stock and the MAF codes were switched to off. After i had the stock file flashed back in the car idles perfect now but even runs better than it did before i retuned it back to MAF setup. And Cartek knows their stuff...That was my reason for not liking SD...just cause the temp dropped the damn thing doesn't want to idle...turn MAF back on no issues.
I'll keep the thing until my setup is so wild that the MAF cant be used.
i never just tuned for WOT only. I start by getting the idle as perfect as possible.
I get it were there's no hot or cold start issues even in my A4. Then after i'm happy with that i tune for part throttle by logging my LTFT's. And again since i'm still using my MAF i dont know why you even need to touch the VE table at all. I only adjusted the IFR table to get my LTFT's to +1 to -1 basically as close to 0 as possible. Then after thats all setup correct i adjust the PE table since thats what its there for and hence its name.
Then you can play with timing for tweaking the setup. So i dont who why the guy in this thread said that guys with their MAF only tune for WOT above 4,000 rpm. Not me. And the times in my sig. shows i did something right for only tuning on the street only. So my MAF and MAF tuning worked out for me.
Oh when i bought my 2002 SS A4 w/ 2,009 GM cert. miles i found out the hard way that the first owner took the car to Cartek and had it SD tuned. How i found out is the car kept stalling once the outside temps. dropped below 45 degrees
I first thought my MAF died, until i scanned my PCM and seen that the VE table wasn't stock and the MAF codes were switched to off. After i had the stock file flashed back in the car idles perfect now but even runs better than it did before i retuned it back to MAF setup. And Cartek knows their stuff...That was my reason for not liking SD...just cause the temp dropped the damn thing doesn't want to idle...turn MAF back on no issues.I'll keep the thing until my setup is so wild that the MAF cant be used.
03-03-2009, 07:35 PM
#32
Well that was in a full weight WS6 with no weight reduction or cage, with stock 3.23's with only a set of cleaned up 241 heads and a little 216/220 cam. And i used a NX TPS switch that triggered the noids after the car rolled out so it didn't work correctly . So i was never leaving out of the hole with the N2O spraying. Its plain to see that my trap speeds showed that the tuning wasn't and issue. Seemed while you were trying to be a smart *** you left out my 127.71 mph and that was just a shake down run. I literally finished installing the nitrous kit and drove straight to the track. So you dont know dick about my car or what heads/cam i used so your smart *** comment is unfounded
P.S. Thats your best times in your sig?? My 1/8 miles times were close to what you run when i ran n/a with a way smaller cam and stall. Maybe you need to retune yourself, unless your setup just plain bites. Actually i'll bet my car out 1/4 miled your car
P.S. Thats your best times in your sig?? My 1/8 miles times were close to what you run when i ran n/a with a way smaller cam and stall. Maybe you need to retune yourself, unless your setup just plain bites. Actually i'll bet my car out 1/4 miled your car
Last edited by BlackNiteWS6; 03-03-2009 at 07:46 PM.
03-03-2009, 08:01 PM
#33
There is a reason its called air fuel ratio. If you change the cam and heads setup then you are introducing MORE AIR hence why you have to change the VE table. IFR tables are to be set for the injector and the fuel pressure that the injector is ran at. So that is constant.
I went to the track one time with that setup, got the turbo on there now. I'll be tuning shortly and heading to the track, you wont even be close when I'm done.
EDIT: No need for name calling on my part
I went to the track one time with that setup, got the turbo on there now. I'll be tuning shortly and heading to the track, you wont even be close when I'm done.
EDIT: No need for name calling on my part
Last edited by 98Camarod; 03-05-2009 at 05:03 AM.
03-03-2009, 11:02 PM
#36
GM used the same injectors in the 01-02 F-bodies and the 01-04 Vettes. Look at the IFR tables GM uses in the 01-02 F-bodies compared to the 01-04 Vettes. So which calibrations got their IFR tables raped? Have you ever flowed a set of injectors with 70K miles on them? I have. They don't flow what a set of 0 miles injectors flow, but their flow rating in the IFR table is supposed to be an absolute which should never be changed. Do you ultrasonic clean the injectors in every high mileage car you tune. Is there 0% error in every injector manufactured? Does every car run exactly the fuel pressure that the injectors are scaled for? What is the error in the gauge used to measure the fuel pressure? Why is it never MAF table raping? isn't this a calibrated air metering device? Just throwing all this out here for thought.
03-03-2009, 11:27 PM
#37
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Always an interesting debate.
Well, I think many people successfully tune SD for their driving experience.
Personally, I found closed-loop a little more forgiving for my own circumstances. Elevation, density differences etc. In my case experimenting with SD was a little more frustrating. It was harder for me to get consistent idle AFR's, and quite frankly it requires exactness and patience.
Also have 'experimented' with both MAF and IFR calibrations at times. There is no doubt that I can get a 1:1 LTRIM relationship with 'adjusting' the Injector Flow Rate. Likewise have used MAF airflow re-calibrations to accomplish the same result (with timing/load change).
I also have wondered to myself if both methods obtains the same result, is one better than the other? Perhaps IFR 'jacking' effects you everywhere, but could not MAF adjustments do the same?
Seems like Trims are the ultimate issue in the IFR or MAF debate. Any new insights into this issue?
Well, I think many people successfully tune SD for their driving experience.
Personally, I found closed-loop a little more forgiving for my own circumstances. Elevation, density differences etc. In my case experimenting with SD was a little more frustrating. It was harder for me to get consistent idle AFR's, and quite frankly it requires exactness and patience.
Also have 'experimented' with both MAF and IFR calibrations at times. There is no doubt that I can get a 1:1 LTRIM relationship with 'adjusting' the Injector Flow Rate. Likewise have used MAF airflow re-calibrations to accomplish the same result (with timing/load change).
I also have wondered to myself if both methods obtains the same result, is one better than the other? Perhaps IFR 'jacking' effects you everywhere, but could not MAF adjustments do the same?
Seems like Trims are the ultimate issue in the IFR or MAF debate. Any new insights into this issue?
03-03-2009, 11:36 PM
#38
Error creeps into every portion of what we do, but that doesn't mean we should load it up intentionally.
I have retuned about 30 cars from a somewhat local shop. This tuner, instead of tuning the VE and MAF, will leave them both stock while moving around the IFR (pretty seriously in the more radical setups too) to get the trims right at that moment and then PE tune WOT. These cars have whole lists of issues that are common to them all, such as very FAT OL operation, stalling, and bad trouble with hot starts. They had been back to the tuner in most cases for him to try and work on those issues before coming to me. Setting the IFR back to stock (new OEM file) and tuning part-throttle through VE and MAF tuning meant that I never ran into any of those issues.
George mentioned his customer with a failed MAF that never knew anything was really wrong because the VE was tuned, so it drove well when it failed. If the car had been "tuned" with the IFR alone, you certainly should not expect the same to be true if the MAF were to fail.
I have retuned about 30 cars from a somewhat local shop. This tuner, instead of tuning the VE and MAF, will leave them both stock while moving around the IFR (pretty seriously in the more radical setups too) to get the trims right at that moment and then PE tune WOT. These cars have whole lists of issues that are common to them all, such as very FAT OL operation, stalling, and bad trouble with hot starts. They had been back to the tuner in most cases for him to try and work on those issues before coming to me. Setting the IFR back to stock (new OEM file) and tuning part-throttle through VE and MAF tuning meant that I never ran into any of those issues.
George mentioned his customer with a failed MAF that never knew anything was really wrong because the VE was tuned, so it drove well when it failed. If the car had been "tuned" with the IFR alone, you certainly should not expect the same to be true if the MAF were to fail.
03-03-2009, 11:51 PM
#39
My points have nothing to do with VE tuning. Only that absolute that the IFR should never be touched to the point that if it is, it called raping it. I'm sure your tunes are great as you have people attest to that here. I'm not challenging your method of tuning. Only that absolute that the IFR should never be changed ever. Is it introducing error when the injectors are not that exact of a device or the methods we use to scale them are imprecise?
03-04-2009, 12:07 AM
#40
I'm calling IFR raping pushing around the IFR to bring trims into line. Obviously if you have data for your injectors such as flow, then use what you have observed in testing (or the results you receive if you farm it out). I'm not saying that there is only one absolute IFR for each injector, I'm saying that "tuning" a H/C car by pushing around the IFR causes a myriad of issues and is not working towards the best overall driver experience.