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My 1st experience w/SD tuning.

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Old 10-20-2008, 11:16 AM
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Originally Posted by BlackNiteWS6
^^Now when you decide to switch to SD there's already a Main VE table in the pcm that i guess the pcm uses incase the MAF craps out correct? So after you disable the MAF you have a good starting point with the stock VE table...Like in my case my car only has a lid and filter..so making a few small adjustments should be all i need i'm guessing. I used LS1-Edit for like 3 years and got really good with it but after playing with EFILive and HPT they are both great tools. I would have a hard time choosing though. Cause i think i want to go back to SD tuning. The tip in throttle responds faster to me in SD mode.
The Stock VE table is no where near tuned as it comes from factory. It may be better in the US cars but in the early AUS cars its all over the shop. Also be advised that any change in timing will alter VE. Because of this you sort of have to chase yourself a bit if your VE is way off to begin with. What you want to do is have timing around where you think it will be optimal but not quite there (this comes with experience). After that tune the VE. Now that fuelling is spot on you can go about finding optimal timing to meat MBT. These changes will move VE around so just stay on top of it. Its applications like this where EFI LIVE combined with a Road Runner are un rivalled as VE will literally tune itself with zero user input.

Here is an example of a stock VE table pulled from a 2002 LS1 Commodore.



And now a tuned VE from the same car running full time SD.. It might not look like much on a monitor but believe me.. The difference is huge.

Old 10-20-2008, 05:40 PM
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Good info.
Old 10-20-2008, 06:13 PM
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Ok good to know
Old 12-23-2008, 02:10 PM
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Originally Posted by macca_779
I agree with Frost 100% here. If your not seeing substantial improvements in throttle response your not doing it right. SD tuning is more popular in Australia than MAF based tuning. We've been doing it for years and are quite good at it. If there were no benefits to it, no one would bother. The gains at WOT are there too. And once again if you can't see them your not doing it right.
Getting the restriction of the MAF out of there doesn't hurt either
Old 12-23-2008, 03:06 PM
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i have an auto. doesnt the maf play a role in auto trannys?
could i still switch to SD and recalibrate the tranny to work like it should?
Old 12-23-2008, 03:24 PM
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What concerns me if the fact that he couldent get the car to idle in winter. Isnt this the classic issue that non SD tuned people have with SD tunes, which the guys with SD tunes say is a myth..

I live in new England where year round there is about a 100 degree swing between the hottest and coldest days in a given year. I want the tune to be spot on no matter what time of the year it is. Hell if I wanted to constantly be adjusting the tune. I'de throw away all this EFI crap and go carb.
Old 12-24-2008, 02:49 AM
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i read some info in a thread on here and one of the cons to SD was if u had an auto tranny because an auto relies on the MAF. could someone explain this and if i could switch to SD with an auto???
Old 12-24-2008, 07:01 PM
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honestly, if you think about it, what AFTERMARKET efi (standalone) systems use a MAF sensor? how much power are those systems ranging from? and isnt the one huge advantage of NOT having a carburetor is because you dont have to tune it all the time? that the car thinks and adjusts itself?

a PROPERLY tuned SD tune is the most accurate and consistant way to tune a car. if you think about it, the maf is a weak link. i've taken a few efi tuning courses and have become quite comfortable with a mafless tune.
Old 12-24-2008, 07:02 PM
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Originally Posted by sciff5
What concerns me if the fact that he couldent get the car to idle in winter. Isnt this the classic issue that non SD tuned people have with SD tunes, which the guys with SD tunes say is a myth..

I live in new England where year round there is about a 100 degree swing between the hottest and coldest days in a given year. I want the tune to be spot on no matter what time of the year it is. Hell if I wanted to constantly be adjusting the tune. I'de throw away all this EFI crap and go carb.

the AIT sensor placement becomes much more critcal now.
Old 12-26-2008, 05:56 AM
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Originally Posted by nemss1
i read some info in a thread on here and one of the cons to SD was if u had an auto tranny because an auto relies on the MAF. could someone explain this and if i could switch to SD with an auto???
Of the thousands of A4 cars running in Australia SD. ive never heard of a problem. download the HSV GTS A4 tune and compare it to a clubsport A4 one. The GTS was factory released in SD with the MAF failed in exactly the same way as we do it and on a stock os without all the advantages that we have today.
Old 12-26-2008, 04:06 PM
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Originally Posted by CALL911
It does not compensate for it in the same way that MAF cars do. If Bryan Herter from PCM's for less, one of the best tuners in the country, who Mario Andretti himself only trusts to do a tune on his Corvette's feels that MAF is the only way to tune to a point he won't even do SD tunes, it is good enough to back MAF tunes IMO.
i've seen a few pcm for less tunes and they look like ****.....the sd tune up still have correction for air temp and density. see what happends is some people run sp open loop. then there is no fuel correction only what is commanded. in closed loop then u get fuel correction. doesn't matter if its maf or sd if its in closed loop then its always try to get back to 14.7 a/f. if u have it in open loop then u can richen up the a/f and put a another degree or 2 of timing and the car will be much more responsive.
Old 12-26-2008, 04:22 PM
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does anyone make a smooth bellow fromt the TB to the intake box?
Old 12-29-2008, 04:20 PM
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Originally Posted by nemss1
i read some info in a thread on here and one of the cons to SD was if u had an auto tranny because an auto relies on the MAF. could someone explain this and if i could switch to SD with an auto???
The '98 pcm commands full line-pressure constantly if it thinks the maf has a problem. This is bad for the transmission. It makes all gear changes harsh, and the car jerks hard when putting it into gear initially.

So you can't just remove/fail the maf, you also have to disable 3 maf codes to avoid getting the full line-pressure mode. That's the only tie-in with the auto tranny that I can think of.



In general, SD can account for air temps. The trick is to get the IAT / ECT blending table set up right. Too little emphasis on IAT and it doesn't adequately cover the change in air density. Too much emphasis on IAT and it over-corrects. This is one I'm still figuring out...
Old 12-29-2008, 08:05 PM
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Originally Posted by John_D.
The '98 pcm commands full line-pressure constantly if it thinks the maf has a problem. This is bad for the transmission. It makes all gear changes harsh, and the car jerks hard when putting it into gear initially.

So you can't just remove/fail the maf, you also have to disable 3 maf codes to avoid getting the full line-pressure mode. That's the only tie-in with the auto tranny that I can think of.



In general, SD can account for air temps. The trick is to get the IAT / ECT blending table set up right. Too little emphasis on IAT and it doesn't adequately cover the change in air density. Too much emphasis on IAT and it over-corrects. This is one I'm still figuring out...
thanx for this clearup in my head!
Old 12-30-2008, 04:46 PM
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http://www.carcraft.com/techarticles...ion/index.html

Basic article on Mass Flow vs Speed Density for those wondering
Old 12-30-2008, 05:17 PM
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Originally Posted by nemss1
i have an auto. doesnt the maf play a role in auto trannys?
could i still switch to SD and recalibrate the tranny to work like it should?
The trans function relies on calculated torque which comes from cylinder airmass which comes from either of the VE or the MAF...

So if you're SD, then the trans is fine as long as your VE is good and not under.

As Macca said, you will be fine... especially the F-bodies (in the US) since thier VE table is close from the factory.

As Jonh_D said, you have to disable the trans failsafes for the 3 MAF DTC's.


Last edited by joecar; 12-30-2008 at 05:28 PM.
Old 12-30-2008, 07:32 PM
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ok thanx. that all makes sense

anyone make MAF delete bellows???




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