SD tuning vs altitude and temp changes?
SD tuning vs altitude and temp changes? Can anyone comment on how large altitude and/or temperature changes affect SD-tuned cars? It is my understanding that MAF equipped cars are more capable of dealing with large changes in alt. and temp. whereas SD cars don't have the same range of adaptability, which is why most auto mfg's use the MAFs. Any truth to this?
My driving patterns regularly take me from sea-level to 4500ft+ and from 20F to 90F so I don't want to convert to a MAF-less SD tune if it will hurt my driveability in any of these situations.
Thoughts and advice?
Thanks
My driving patterns regularly take me from sea-level to 4500ft+ and from 20F to 90F so I don't want to convert to a MAF-less SD tune if it will hurt my driveability in any of these situations.
Thoughts and advice?
Thanks
TECH Fanatic
Joined: Aug 2005
Posts: 1,691
Likes: 1
From: Sunny London, UK
Plenty in the search man.
<lights touch paper>
Basically no difference. Other than the MAF being a relatively slow sensor restricting airflow as stock.
MAF only requires about 85 values to be close to work properly. Where as SD needs 380 values to be close to work properly.
Also as long as you dont alter the MAF unit itself it will stay pretty accurate independent of engine mods. SD will require all 380 values to be recalculated after each mod in order to remain accurate.
Thats the real reason manufacturers use it. Its cheap and easy.
Altitude and temp are irrelevant.
IAT sensor measures intake temp, MAP and Barometric sensors read altitude/pressure and are used in both calculations.
SD is more responsive and doesn't cause a restriction in flow. Sure you can get a larger MAF sensor to reduce restriction, but why bother wasting the money? Spend it on a nice exhaust, or intake instead of a chunk of crap used by lazy manufacturers.
</lights touch paper>
<lights touch paper>
Basically no difference. Other than the MAF being a relatively slow sensor restricting airflow as stock.
MAF only requires about 85 values to be close to work properly. Where as SD needs 380 values to be close to work properly.
Also as long as you dont alter the MAF unit itself it will stay pretty accurate independent of engine mods. SD will require all 380 values to be recalculated after each mod in order to remain accurate.
Thats the real reason manufacturers use it. Its cheap and easy.
Altitude and temp are irrelevant.
IAT sensor measures intake temp, MAP and Barometric sensors read altitude/pressure and are used in both calculations.
SD is more responsive and doesn't cause a restriction in flow. Sure you can get a larger MAF sensor to reduce restriction, but why bother wasting the money? Spend it on a nice exhaust, or intake instead of a chunk of crap used by lazy manufacturers.
</lights touch paper>
11 Second Club
Joined: Jun 2005
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From: San Diego, Ca.
Originally Posted by ringram
MAF only requires about 85 values to be close to work properly. Where as SD needs 380 values to be close to work properly.
11 Second Club
Joined: Jun 2005
Posts: 287
Likes: 0
From: San Diego, Ca.
Originally Posted by foff667
primary VE table is like 20 cells by 19 cells of 3d resolution=380, whereas maf is only like 85 cells of 2d resolution
11 Second Club
Joined: Jun 2005
Posts: 287
Likes: 0
From: San Diego, Ca.
Originally Posted by foff667
you could go 2 bar but you'd be pushing it, unfortunatly I don't know if hptuners offers a 3 bar for your particular 04 OS if you indeed have the 04 GTO in your sig.
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Originally Posted by foff667
primary VE table is like 20 cells by 19 cells of 3d resolution=380, whereas maf is only like 85 cells of 2d resolution
TECH Fanatic
Joined: Aug 2005
Posts: 1,691
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From: Sunny London, UK
True, Im sure not all MAF cells would get hit either. But likely a lot higher percentage than the VE for sure. However you would be surprised what cells you do hit in ve. Especially on startup and stop. Way in the corners.
Originally Posted by RedHardSupra
that's correct, but theoretical, it would be much more realistic if you actually counted how many cells do you hit in most driving conditions, most cars dont do past 6800rpm, or high pressure/low rpm, or high rpm/low pressure, cammed cars dont get <50kPa, stalled cars dont really do 3000-5000rpm, etc... you get the idea. i'd like to actually see a comparison how many cells are actually used--it's an interesting little tidbit
Originally Posted by ringram
True, Im sure not all MAF cells would get hit either. But likely a lot higher percentage than the VE for sure. However you would be surprised what cells you do hit in ve. Especially on startup and stop. Way in the corners.
