Mass Air vs Speed Density
02-07-2010, 02:33 PM
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Mass Air vs Speed Density I know that guys prefer SD over MA for more aggressive FI setups.
The Mustang and GN guys make impressive power with MA.
I’ve seen GN’s using LT1 meters with translators so why are LT1 and LS1
guys going to SD?
A MA car’s drivability is very smooth, it seams to me that it would be preferred over SD on a street car.
The Mustang and GN guys make impressive power with MA.
I’ve seen GN’s using LT1 meters with translators so why are LT1 and LS1
guys going to SD?
A MA car’s drivability is very smooth, it seams to me that it would be preferred over SD on a street car.
02-07-2010, 06:46 PM
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Speed Density closed loop is also very smooth. look at the size comparisons... 78mm....85mm....100mm....102mm
100mm I think will max out around 600HP or so (power adder)
It really doesn't matter as long as you can get a proper tune that gives you the results & has the engine running great.
Once you exceed the MAF you have to alter other tables to "add" in more fuel as otherwise the car would lean out
100mm I think will max out around 600HP or so (power adder)
It really doesn't matter as long as you can get a proper tune that gives you the results & has the engine running great.
Once you exceed the MAF you have to alter other tables to "add" in more fuel as otherwise the car would lean out
02-07-2010, 07:34 PM
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For instance, find out your air density based on altitude....there are online tables for that via google.... then you can take 512g/s and convert it to LB/min
and use the density multiplier to get your airflow result.
generally, around 67.73 LB/min you will max out the MAF....this is somewhat a generalized statement as its all "relative". depends on other factors, MAF size....etc
why SD is looked down upon...well how may ways can you skin a cat?
Speed Density Closed Loop still uses fuel trim feedback
Speed Density Open Loop does not use fuel trims....for a daily driver & living in an area with forever changing temperature & humidity good luck tuning it right.
I could see how people smack talk SD OL....as it is a nightmare to tune for all the changes that happen from day to day or seasonal. I have seen it, and they switched back to SD CL
and use the density multiplier to get your airflow result.
generally, around 67.73 LB/min you will max out the MAF....this is somewhat a generalized statement as its all "relative". depends on other factors, MAF size....etc
why SD is looked down upon...well how may ways can you skin a cat?
Speed Density Closed Loop still uses fuel trim feedback
Speed Density Open Loop does not use fuel trims....for a daily driver & living in an area with forever changing temperature & humidity good luck tuning it right.
I could see how people smack talk SD OL....as it is a nightmare to tune for all the changes that happen from day to day or seasonal. I have seen it, and they switched back to SD CL
02-07-2010, 11:39 PM
#5
I run OLSD on all my vehicles, they run great. Never touch the driveability portion of my VE. They will run a little leaner on an ice cold night as opposed to a hot humid day, but not enough to notice without the wideband. I will tweak the wot if I am going from 2000 to 9000 DA or something drastic like that.
02-08-2010, 02:27 AM
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MAF in my experience tends to be smoother and much faster to tune, but unless you know how to modulate certain tables, SD tends to have crisper throttle response. However, on the opposite side, if you don't know how to modulate certain other tables, SD tends to follow temperature and altitude less efficiently.
In the end, however, if all things are lined out, the end results should be identical. I tend to like GM's hybrid system.
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02-08-2010, 06:24 AM
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oh btw my s/n on efilive.com is whytryz06...
03-02-2010, 11:34 AM
#12
how does SDCL do in changing conditions.
lets say for instance, i tune my car here in Ohio in SDCL, and i drive it to Idaho to see my family, will i have to take the laptop with me to change things to make it run to its potential driving through higher altitudes and God knows how many different weather changes? BTW i have a 98.
i like all the advantages of SDCL (no 02's no intake restriction...etc) but i dont want to have to tune it everytime the weather changes.
i want to be able to tune it here and drive it cross country and have no problems and have it run just as good there as here.
is this possible?
lets say for instance, i tune my car here in Ohio in SDCL, and i drive it to Idaho to see my family, will i have to take the laptop with me to change things to make it run to its potential driving through higher altitudes and God knows how many different weather changes? BTW i have a 98.
i like all the advantages of SDCL (no 02's no intake restriction...etc) but i dont want to have to tune it everytime the weather changes.
i want to be able to tune it here and drive it cross country and have no problems and have it run just as good there as here.
is this possible?
03-02-2010, 02:18 PM
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03-02-2010, 03:02 PM
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i guess ill start looking into SD tune.
can anyone reccomend a tuner in or around ohio? someone who wont have a problem tuning a 98. the last guy charged me 500 bucks to do a dyno tune and the car never has run right. even after taking it back to him twice.
can anyone reccomend a tuner in or around ohio? someone who wont have a problem tuning a 98. the last guy charged me 500 bucks to do a dyno tune and the car never has run right. even after taking it back to him twice.
03-02-2010, 03:15 PM
#17
Send it to Frost. Discuss what you're looking for & you'll be OK. BTW, I run OL MAF very near you, without issue. IMO, you'll be OK w/ a CLSD if year round driven. If only from April through October/November, then OLSD. Good-luck
03-02-2010, 04:26 PM
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Really, there should never be a 'vs' debate.
Depending on your power goals, you can do either. Especially, if you are running closed-loop. Sometimes Trims actually line up better with CLSD, but ultimately if you are getting the AFR you want (both stoich and PE), you do not need to pit the two against each other.
Tune both properly and you will be happy. You will have proper transitional fueling and in the event your MAF fails, life will be good. MAF may require a little more work (resolution-wise), but it does not have to be a 'one or the other mentality'.
Depending on your power goals, you can do either. Especially, if you are running closed-loop. Sometimes Trims actually line up better with CLSD, but ultimately if you are getting the AFR you want (both stoich and PE), you do not need to pit the two against each other.
Tune both properly and you will be happy. You will have proper transitional fueling and in the event your MAF fails, life will be good. MAF may require a little more work (resolution-wise), but it does not have to be a 'one or the other mentality'.
03-02-2010, 04:42 PM
#20