SD tune: Bad for extreme climates?
06-13-2006, 12:14 AM
#1
SD tune: Bad for extreme climates? Been doing alot of research on the whole SD v. MAF junk, and I'm somewhat torn (which probably means I should just stick w/ the MAF), but none the less, I need some advice. Living in Texas means we see 100* days for 3 months straight, then down to 32* in the winter. I know this screws with the SD tune, but if I don't have any tuning software, meaning I'll get tuned once and be stuck with it, will SD be too much of a PITA for me?
I'm wanting to get my tune pretty soon, so since it will more than likely be 100* outside when I do it, will I run extremely lean in winter when the air is more dense? In my searches, I've found people saying the opposite, that they run lean in the summer, which doesn't make much sense. Either way, should I stick with the MAF or does weather play less of a role than I'm making it out to be?
Mods are H/C, 4600 stall. 90% street car.
I'm wanting to get my tune pretty soon, so since it will more than likely be 100* outside when I do it, will I run extremely lean in winter when the air is more dense? In my searches, I've found people saying the opposite, that they run lean in the summer, which doesn't make much sense. Either way, should I stick with the MAF or does weather play less of a role than I'm making it out to be?
Mods are H/C, 4600 stall. 90% street car.
06-13-2006, 04:16 AM
#2
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Stock 75mm will be a restriction with your H/C. A good SD tune will adjust for temps no problem. efi has a special table to deal specifically with this. Also the stock PCM takes into consideration IAT and ECT when determining air volume, so this extra table is to fine tune things.
Just make sure you get a tune from someone who knows SD tuning and it will be fine in all climates.
Just make sure you get a tune from someone who knows SD tuning and it will be fine in all climates.
06-13-2006, 09:04 AM
#3
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Eh, 75mm might be a slight restriction. But, not much if you ask me. Any filter you run will be more of a restriction. Besides, they put the stock MAF on the 600hp ZL1 Camaros built by Berger/GMMG, didn't they? IMO, SD will get you close. SD tuning plus a recalibrated MAF will keep you close. It's not just temperature that plays a part in the accuracy of the tune. There's also atmospheric pressure, humidity, etc.
06-13-2006, 11:05 AM
#4
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Originally Posted by BADFNZ
Been doing alot of research on the whole SD v. MAF junk, and I'm somewhat torn (which probably means I should just stick w/ the MAF), but none the less, I need some advice. Living in Texas means we see 100* days for 3 months straight, then down to 32* in the winter. I know this screws with the SD tune, but if I don't have any tuning software, meaning I'll get tuned once and be stuck with it, will SD be too much of a PITA for me?
I'm wanting to get my tune pretty soon, so since it will more than likely be 100* outside when I do it, will I run extremely lean in winter when the air is more dense? In my searches, I've found people saying the opposite, that they run lean in the summer, which doesn't make much sense. Either way, should I stick with the MAF or does weather play less of a role than I'm making it out to be?
Mods are H/C, 4600 stall. 90% street car.
I'm wanting to get my tune pretty soon, so since it will more than likely be 100* outside when I do it, will I run extremely lean in winter when the air is more dense? In my searches, I've found people saying the opposite, that they run lean in the summer, which doesn't make much sense. Either way, should I stick with the MAF or does weather play less of a role than I'm making it out to be?
Mods are H/C, 4600 stall. 90% street car.
06-13-2006, 04:10 PM
#5
Originally Posted by txhorns281
Danny, I'd go whichever way your tuner feels more comfortable with. If you were doing it yourself, I'd say to follow whichever method seems most intuitive to you during the tuning process. The problem is not the MAF being a restriction, it is more a question of can your tuner nail whichever method accurately. In my experience, MAF mode has been more stable in large climate disparities, but either way does a well enough job to handle a pretty good swing in conditions. Talk to Shaun, I've had him in SD mode since March or so, but mainly b/c he went to a 90/90 setup, and didn't want to deal with different sized bellows. Last I talked to him, his car was running well. Up to that point he was always running MAF, car ran strong as well.
06-13-2006, 04:19 PM
#6
Let me add that not only am I wanting to go SD to eliminate the restriction of the MAF, but also because ever since I've 1st put a cam in my car (~2002), I've had idle surging issues. Three reputable tuners in the DFW area haven't figured out why or how to fix it. They've all said they've never seen a car act like mine. Even with a little TR224, I was having major idle surge in P and in gear, and if I drove it before letting it warm up for 2 minutes, it'd die when I came to a stop. I figured if I eliminated the MAF, it's one less variable that could be causing my idle problems. It may not be correct, but it makes sense in my head.
06-13-2006, 05:19 PM
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That surge is probably all in the idle base running airflow,
idle spark advance and maybe some throttle cracker
(which on some models is just plain ugly). The MAF is
pretty much ignored at and about idle. A descreened
unit is a negligible restriction, except maybe for the
folks who've gone to 90mm TB and intake with the
cam, heads and exhaust to back it up.
Take a look at (BARO-MAP)/BARO at the top of gear
as a percentage; that's the percentage you stand
to gain, at best, from an infinite sized MAF, TB and
intake orifice as the engine stands today.
idle spark advance and maybe some throttle cracker
(which on some models is just plain ugly). The MAF is
pretty much ignored at and about idle. A descreened
unit is a negligible restriction, except maybe for the
folks who've gone to 90mm TB and intake with the
cam, heads and exhaust to back it up.
Take a look at (BARO-MAP)/BARO at the top of gear
as a percentage; that's the percentage you stand
to gain, at best, from an infinite sized MAF, TB and
intake orifice as the engine stands today.
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06-13-2006, 06:29 PM
#8
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Originally Posted by jimmyblue
That surge is probably all in the idle base running airflow,
idle spark advance and maybe some throttle cracker
(which on some models is just plain ugly)..
idle spark advance and maybe some throttle cracker
(which on some models is just plain ugly)..
Unless there is something physically wrong with the car, I cannot fathom how an experienced tuner cannot tame a small cam like yours, or mine. It almost runs properly on a stock tune... I had my TSP224R 112lsa idling @ 550rpm the other day on a stock tune, just messing around.
06-13-2006, 07:12 PM
#9
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I think you should better yet talk about SD tuning in the light of open loop or closed loop. If you are in open loop, then yes you have some concerns. You can still do a SD tune and keep it in closed loop as well if you are worried about climate. thats another way of looking at it.
Rick
Rick
06-13-2006, 07:41 PM
#10
You will want to go MAF. An SD tune will make OVER corrections. That is why it does not seem normal. It shoudl richen up in the summer time but infact it leans out. What happens is the SD airmass calculation sucks. When it is hot out it will calculate the airflow being too low which means it will fuel less. This is the main issue with SD, between that and improper VE table for cooler coolant temps (which can be "fixed" with the OLFA table).
Personally, I have something in the car now which will allow me to adjust the IAT reading which in the end will give my car the correct fueling and limit what the computer makes as a correction. Works quite well.
Personally, I have something in the car now which will allow me to adjust the IAT reading which in the end will give my car the correct fueling and limit what the computer makes as a correction. Works quite well.
06-13-2006, 07:44 PM
#11
Originally Posted by BADFNZ
Let me add that not only am I wanting to go SD to eliminate the restriction of the MAF, but also because ever since I've 1st put a cam in my car (~2002), I've had idle surging issues. Three reputable tuners in the DFW area haven't figured out why or how to fix it. They've all said they've never seen a car act like mine. Even with a little TR224, I was having major idle surge in P and in gear, and if I drove it before letting it warm up for 2 minutes, it'd die when I came to a stop. I figured if I eliminated the MAF, it's one less variable that could be causing my idle problems. It may not be correct, but it makes sense in my head.
06-13-2006, 07:51 PM
#12
Out of curiousity, do you have a ported throttle body? If so, was the IAC area filled with epoxy and left just a small passage through for it?
I personally had a throttle body that was filled and smoothed as such, and I could not get the car to idle properly for the life of me... (nor could several other reputable houston area tuners) I finally broke out the dremel and took out all the epoxy and BOOM, it idled great afterwards.
Also, do you have a hole drilled in the throttle body?
Just some things to look at.
I personally had a throttle body that was filled and smoothed as such, and I could not get the car to idle properly for the life of me... (nor could several other reputable houston area tuners) I finally broke out the dremel and took out all the epoxy and BOOM, it idled great afterwards.
Also, do you have a hole drilled in the throttle body?
Just some things to look at.
06-13-2006, 08:00 PM
#13
That is a good point, a lot of the epoxy filled TB's can screw with the idle, esp if it has trouble on a cold start. Either way, tuning the idle airflow will fix that granted the IAC position isnt very high at hot idle.
As far as drilling a hole, dont even mess with that. With a small cam like that there should be no issues. Plus you really need to know what you are doing and how to fix the tune before doing that. It can make things even worse.
As far as drilling a hole, dont even mess with that. With a small cam like that there should be no issues. Plus you really need to know what you are doing and how to fix the tune before doing that. It can make things even worse.
06-13-2006, 08:13 PM
#14
I just looked through some of your past posts... are you running a Fast 90 setup? If so, that can lead to be a whole other can of worms when trying to work on the tune. You really need to give us more information on your mods than just H/C & 4600 stall.
06-13-2006, 08:43 PM
#15
Originally Posted by xaon
I just looked through some of your past posts... are you running a Fast 90 setup? If so, that can lead to be a whole other can of worms when trying to work on the tune. You really need to give us more information on your mods than just H/C & 4600 stall.
06-13-2006, 08:58 PM
#16
all cams need a hole to idle properly.even the stock one....thats why theres one on every cable drive care...ETC vehicles actually move the throttle blade top get enough air to idle...but when you do cam and heads and blah blah blah..you need a hole on those guys as well...
in general you want your IAC position down around 60ish on a hot idle with fans off,aC off and your hood open to get away from heatsoak when trying to get this done..on ETC vehicles you want TPS to be around 3-4% in these same conditions....
epoxy filled TB only messes with your stuff when you fill too much or dont have a hole atleast the same size as your IAC pintle motor hole is...
I persoanlly dont epoxy them cause the gains you see from it are just wasted money.....
I mean..cmon..is .25 hp really worth all the $$ and work to epoxy a TB??
I've done back t oback dyno pulls with 4 different TB's and saw no gain from one just ported and polished and one epoxy filed...both done by me
in general you want your IAC position down around 60ish on a hot idle with fans off,aC off and your hood open to get away from heatsoak when trying to get this done..on ETC vehicles you want TPS to be around 3-4% in these same conditions....
epoxy filled TB only messes with your stuff when you fill too much or dont have a hole atleast the same size as your IAC pintle motor hole is...
I persoanlly dont epoxy them cause the gains you see from it are just wasted money.....
I mean..cmon..is .25 hp really worth all the $$ and work to epoxy a TB??
I've done back t oback dyno pulls with 4 different TB's and saw no gain from one just ported and polished and one epoxy filed...both done by me
06-13-2006, 11:31 PM
#17
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Originally Posted by BADFNZ
I think you should make a trip to Dallas to visit Shaun, and if you have time you can squeeze in a tune for me
it will happen sooner or later, the question is, how soon are you looking for tuning? And your setup shouldn't be impossible for these "heralded" tuners, but then again it all comes down to how much time do you want to spend to get it all accurate as can be.
06-13-2006, 11:47 PM
#18
My mods are a mild cam (230ish/.600ish/111), slightly ported heads, 90/90, 4600 stall, stock maf.
When I was running my TR224, which was years ago, the tuner couldn't get it to idle right. After it warms up it's fine, but it takes a couple minutes to get there. I then went to an F13, had a few tweeks to the tune, but same result. I even brought the car to him another time after he got HP Tuners (had LS1 Edit previously) but no change.
Now I have my current cam and got slight tweaks to the tune by a different tuner. It idles better but still has more surge than it should. For some result he could get it to idle easily with the A/C on, but couldn't with the A/C off. After all of this I'm starting to think something must be wrong with a sensor on the car, and figured if I could eliminate the MAF all together, then maybe it would do the trick. But from what ya'll are saying, it shouldn't make a difference.
BTW, the TB is a Nick Williams, no epoxy or fillers involved. My last TB was a Shaner and the IAC area wasn't filled.
Thanks for the help so far.
When I was running my TR224, which was years ago, the tuner couldn't get it to idle right. After it warms up it's fine, but it takes a couple minutes to get there. I then went to an F13, had a few tweeks to the tune, but same result. I even brought the car to him another time after he got HP Tuners (had LS1 Edit previously) but no change.
Now I have my current cam and got slight tweaks to the tune by a different tuner. It idles better but still has more surge than it should. For some result he could get it to idle easily with the A/C on, but couldn't with the A/C off. After all of this I'm starting to think something must be wrong with a sensor on the car, and figured if I could eliminate the MAF all together, then maybe it would do the trick. But from what ya'll are saying, it shouldn't make a difference.
BTW, the TB is a Nick Williams, no epoxy or fillers involved. My last TB was a Shaner and the IAC area wasn't filled.
Thanks for the help so far.
