SD vs MAF performance discussion....
Thread Starter
Melting Slicks
Joined: Nov 2009
Posts: 2,536
Likes: 15
SD vs MAF performance discussion....
I'm relatively new to tuning my car and would like to discuss the pro's and con's of either tune.
Where I race we get a DA swing from -1500 to +3500 through out the year. And with my novice tuning tenure I feel the "card style" MAF tune would suit me better...??.. I personally feel if my tuning abilities were up to par, a SD tune that I could log and adjust at the track would be the best for ET's....??...
For those that run a SD tune, do you guys adjust for fuel table every trip to the track (depending on the DA & grains) ??
Just looking to discuss the topic further..........I also picked up some reading material to help me understand this stuff (Greg Banish & Dan Maslic).
Thanks............fyi, the inlet consists of a 4" tube from the vararam, so a card MAF should not be close to maxed if that option is used.
Where I race we get a DA swing from -1500 to +3500 through out the year. And with my novice tuning tenure I feel the "card style" MAF tune would suit me better...??.. I personally feel if my tuning abilities were up to par, a SD tune that I could log and adjust at the track would be the best for ET's....??...
For those that run a SD tune, do you guys adjust for fuel table every trip to the track (depending on the DA & grains) ??
Just looking to discuss the topic further..........I also picked up some reading material to help me understand this stuff (Greg Banish & Dan Maslic).
Thanks............fyi, the inlet consists of a 4" tube from the vararam, so a card MAF should not be close to maxed if that option is used.
Thread Starter
Melting Slicks
Joined: Nov 2009
Posts: 2,536
Likes: 15
Anyone with firsthand knowledge on this ??
Or theories on which tune favors certain conditions ??
Or examples of a SD tune in the summer with fuel maps looking "fat" when the air gets better in the fall/winter ??
Thanks.......
Or theories on which tune favors certain conditions ??
Or examples of a SD tune in the summer with fuel maps looking "fat" when the air gets better in the fall/winter ??
Thanks.......
Burning Brakes
Joined: Feb 2004
Posts: 1,069
Likes: 8
From: Sanford NC
I went from the MAF to a OLSD COS3 tune. I was maxed out though so I gained quite a bit of power. When you use the COS3 you can use the IAT sensor to adjust fueling so you don't have to worry about the retunes. I had a large cam and what not so being able to command what ever fuel I wanted was highly beneficial.
Thread Starter
Melting Slicks
Joined: Nov 2009
Posts: 2,536
Likes: 15
I went from the MAF to a OLSD COS3 tune. I was maxed out though so I gained quite a bit of power. When you use the COS3 you can use the IAT sensor to adjust fueling so you don't have to worry about the retunes. I had a large cam and what not so being able to command what ever fuel I wanted was highly beneficial.
But for the novice tuner that I am (if I can even be considered novice...lol) I feel the card MAF will be better suited for right now.
How did most of you guys become component in the tuning arena ?? Just time behind the laptop ?? Or a class ?? Or what ??
Thanks........
Thread Starter
Melting Slicks
Joined: Nov 2009
Posts: 2,536
Likes: 15
So I guess my question is, what about density correction ??
I would think that a "boosted" atmosphere would be the best scenario for a SD tune. But what about nasty NA setups ??
Thanks.............
Burning Brakes
Joined: Feb 2004
Posts: 1,069
Likes: 8
From: Sanford NC
Time behind the lap top bro. Just building a variety of nasty rides and having to figure out how to make them run right. Plus I DD all my combos as do my customers so I needed them to run right. Trial and error and lot of reading on the tuning forums.
Thread Starter
Melting Slicks
Joined: Nov 2009
Posts: 2,536
Likes: 15
That being said, the car is sd tuned by "him" but with "him" being so far I'm kind of forced to learn it for myself. The car is a case study in the evolution process...lol. And as I'm able to apply the power I will keep adding some...therefor I need to get a handle on the software architecture and tune.Thanks for the feedback......guess its time to hangout on the HP forum...and read...a lot !!
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Race Director
Joined: Jul 2005
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From: Think BEFORE hitting "Submit Reply"
I ran OLSD on my car, and spent the time to log, log, log.
My car ran perfect no matter the temp, whether in cold fall/winter or the heat of the summer.
AF ratios were always within proper parameters no matter the weather.
I'm guessing HPT has some additional tuning that can be done beyond my old tune, but it worked very well for me.
I think it has to do with how thorough you are with the overall tune.
Thread Starter
Melting Slicks
Joined: Nov 2009
Posts: 2,536
Likes: 15
[QUOTE=mdaniel;1580973798]Mine runs 9s with an SD tune that hasn't' been touched since it was set up. Unless you're making changes to the car you shouldn't need to retune.[/QUOTE
Thanks for the response....but, in my situation it does not seem very logical....
. You/we/us speed tons of money to get the last 5-10hp out of our cars then we SD tune it in the summer +2500 DA and run that tune year round...effectively giving up hp in the winter when she leans out.... Or vise versa winter to summer...
Not sure where you live...but a stab in the dark tells me Michigan. Summer DA at Milan drag strip is in the +2500 range and in the fall she can drop to -2000......can you please explain how you compensate for density correction ??
I agree with the 12.8 to 13.1 range for N/A. The only thing that I will add is that these cars perform better at different A/F ratios depending on what gear you are in (and acceleration rate). It takes a bunch of logging and ET slips to figure out the "sweet spot". DA also becomes a factor." It's not perfect like a lot of people want to make it. It is just a point of reference. You have to actually test to find what your vehicle likes. The MPH on your time slip is the answer when tuning for the DA.
Do not take this as an attack...I'm just playing the devils advocate.....in an attempt to learn the "real" pro's and con's of the "tunes", with all out et/performance in mind. Not just a "fun" daily driver....
And FYI, this Maslic book is the ****... Dude seems real sharp.....
Thanks..........
Thanks for the response....but, in my situation it does not seem very logical....
. You/we/us speed tons of money to get the last 5-10hp out of our cars then we SD tune it in the summer +2500 DA and run that tune year round...effectively giving up hp in the winter when she leans out.... Or vise versa winter to summer...Not sure where you live...but a stab in the dark tells me Michigan. Summer DA at Milan drag strip is in the +2500 range and in the fall she can drop to -2000......can you please explain how you compensate for density correction ??
I agree with the 12.8 to 13.1 range for N/A. The only thing that I will add is that these cars perform better at different A/F ratios depending on what gear you are in (and acceleration rate). It takes a bunch of logging and ET slips to figure out the "sweet spot". DA also becomes a factor." It's not perfect like a lot of people want to make it. It is just a point of reference. You have to actually test to find what your vehicle likes. The MPH on your time slip is the answer when tuning for the DA.
Do not take this as an attack...I'm just playing the devils advocate.....in an attempt to learn the "real" pro's and con's of the "tunes", with all out et/performance in mind. Not just a "fun" daily driver....
And FYI, this Maslic book is the ****...
Dude seems real sharp.....Thanks..........
Pro
Joined: May 2007
Posts: 532
Likes: 7
From: north vancouver british columbia
I think keep MAF unless you need to get rid of it. I'd even say upgrade to Z06 MAF, they just work so well and simplify tuning so much, why get rid of what works?
I still believe you should get SD tables right down low (below 4k) in all MAP vs. RPM ranges especially if you are runing dynamic ve. However I wouldn't get rid of a MAF unless you are exceeding it. As for runing Open loop, I believe in Open loop, just need to dyno tune for it on a Mustang or other Eddy Dyno.
I still believe you should get SD tables right down low (below 4k) in all MAP vs. RPM ranges especially if you are runing dynamic ve. However I wouldn't get rid of a MAF unless you are exceeding it. As for runing Open loop, I believe in Open loop, just need to dyno tune for it on a Mustang or other Eddy Dyno.
Pro
Joined: Feb 2003
Posts: 745
Likes: 136
From: Detroit MI
Ideally, both the MAF and SD calculations should come up with the same number for airflow (and individual cylinder air charge). The trick is that MAF sensors are great for large, steady flows and SD excels at transient conditions where the instantaneous flow at the MAF sensor may be unsteady but the individual cylinder filling events are more consistent. Each method has its own strengths and weaknesses, which is why the factory GM calibrations use both. It allows them to get the best of both worlds, each at the right time. Tuners who turn one of the two off are often making a tradeoff for ease of tuning at the possible expense of accuracy under some conditions.
Thread Starter
Melting Slicks
Joined: Nov 2009
Posts: 2,536
Likes: 15
Ideally, both the MAF and SD calculations should come up with the same number for airflow (and individual cylinder air charge). The trick is that MAF sensors are great for large, steady flows and SD excels at transient conditions where the instantaneous flow at the MAF sensor may be unsteady but the individual cylinder filling events are more consistent. Each method has its own strengths and weaknesses, which is why the factory GM calibrations use both. It allows them to get the best of both worlds, each at the right time. Tuners who turn one of the two off are often making a tradeoff for ease of tuning at the possible expense of accuracy under some conditions.
So will "HP" or "EFI" allow you to tune both parameters ?? Or am I miss understanding the concept ??
Hey Greg, it would be nice if you would do a class in this part of the country....the Dallas area. I'm sure it would be a big hit...
Thanks..........
Melting Slicks
Joined: Mar 2005
Posts: 2,225
Likes: 42
From: Okinawa
The Map is a pressure sensnor. You change altitude so does your Map reading. Gm has built a few SD only cars. Dont take it like you should never check up on your tune though. Most people who tune their own cars tweak them constantly. You can get a WOT tune done in a day but everything below that will take longer especially with the large cams.
Last edited by SBCGENII; Jun 8, 2012 at 02:09 AM.
Pro
Joined: Feb 2003
Posts: 745
Likes: 136
From: Detroit MI
Hey Greg, it would be nice if you would do a class in this part of the country....the Dallas area. I'm sure it would be a big hit...
Race Director
Joined: Jul 2005
Posts: 11,220
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From: Think BEFORE hitting "Submit Reply"
Taking my car as an example, since I know how I tuned my car:
When I ran OLSD, I road tuned for hundreds of miles.
For instance, I night be on an open section of highway at 40mph in 4th gear.
Or the back roads.
I would take time to log as I leaned into and out of the gas.
Then I would drop to 3rd gear, at 40mph, the same speed, and load the engine up and down in 3rd, then to 2nd gear at 40mph, and really build a log of AFR's across a broad rpm and load range.
IMO, the key to building a good SD map is to load each gear and try to hit as many cells as possible.
Best done on a dyno, provided you can get the proper airflow across the engine/cooling system.
Greg,
What you are saying is that my car may have run even better had I re-enabled the MAF?
I wasn't really sure how to do it effectively, so I never tried it.
My fault.
When I ran OLSD, I road tuned for hundreds of miles.
For instance, I night be on an open section of highway at 40mph in 4th gear.
Or the back roads.
I would take time to log as I leaned into and out of the gas.
Then I would drop to 3rd gear, at 40mph, the same speed, and load the engine up and down in 3rd, then to 2nd gear at 40mph, and really build a log of AFR's across a broad rpm and load range.
IMO, the key to building a good SD map is to load each gear and try to hit as many cells as possible.
Best done on a dyno, provided you can get the proper airflow across the engine/cooling system.
Greg,
What you are saying is that my car may have run even better had I re-enabled the MAF?
I wasn't really sure how to do it effectively, so I never tried it.
My fault.
Yes. Most popular tuning software packages have access to everything you'd need to recalibrate each model independent of the other. There are "switches" in the software that we use to force the system to only operate on one airflow model at a time. The object is usually to calibrate each airflow model separately (but accurately!) and then restore the "blended" performance where it has the option to work with both of them. It can take a decent amount of time, but the result are almost always better.
I get a lot of requests for local classes and it's just hard to keep up when I have a day job. This is a big reason why I went through all the trouble to start making the DVDs so people could save on travel costs and still get world class training at reasonable prices. I will be adding more videos in the future, which will be available through many CF vendors.
I get a lot of requests for local classes and it's just hard to keep up when I have a day job. This is a big reason why I went through all the trouble to start making the DVDs so people could save on travel costs and still get world class training at reasonable prices. I will be adding more videos in the future, which will be available through many CF vendors.