truck 85mm sensor
12-05-2006, 05:09 PM
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truck 85mm sensor i have a 85mm truck maf....i wanted to use it on my 99 TA...but then i noticed the harness is different. so i called slp to see if they could sell me one of there harness s .. they said not to use that maf ...saying it was calibrated for the truck and could cause engine damage using it on a car...is this crap or what...i thought it did not matter...the truck engine is still an LS style engine..and an OBD 2 computer... does anybody have any input on this? i also called thunder racing and they said it could work but maybe not too... also how can i get this maf apart to get that bar in the center out?
12-05-2006, 07:28 PM
#2
Originally Posted by speedracer1280
i have a 85mm truck maf....i wanted to use it on my 99 TA...but then i noticed the harness is different. so i called slp to see if they could sell me one of there harness s .. they said not to use that maf ...saying it was calibrated for the truck and could cause engine damage using it on a car...is this crap or what...i thought it did not matter...the truck engine is still an LS style engine..and an OBD 2 computer... does anybody have any input on this? i also called thunder racing and they said it could work but maybe not too... also how can i get this maf apart to get that bar in the center out?
If you are still intent on doing it, look to the right at our sponsor list. Casper's electronics is one of them (at least they used to be)...they sell the harness to adapt the 3 wire connector (stock) to the 5-wire 85mm. The 85mm MAF incorporates the inlet air temp sensor in the MAF housing itself (that's where the other two wires come from).
12-05-2006, 07:53 PM
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aight...cool that makes sense to me...i never really consider what those kind of places like slp say cause i feel like they would say what ever just to get me to buy one of theirs.... but now that you say this it totally makes sense...i also asked the guy i got it from and he had it installed while getting a custom tune at futral... thanks for the help
12-06-2006, 10:57 AM
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There's another problem:
The actual unit itself has to be calibrated. I'm talking about the MAF sensor, not the PCM computer in the car, which has to be calibrated also...
But the unit has to be calibrated, otherwise the voltages will not be read correctly, they won't line up. The only place I know of that sells a calibrated MAF unit is PaceParts, which is why you don't read of anyone having problems if they buy their 85mm piece from there.
The actual unit itself has to be calibrated. I'm talking about the MAF sensor, not the PCM computer in the car, which has to be calibrated also...
But the unit has to be calibrated, otherwise the voltages will not be read correctly, they won't line up. The only place I know of that sells a calibrated MAF unit is PaceParts, which is why you don't read of anyone having problems if they buy their 85mm piece from there.
12-06-2006, 01:40 PM
#6
Originally Posted by lsx24
There's another problem:
The actual unit itself has to be calibrated. I'm talking about the MAF sensor, not the PCM computer in the car, which has to be calibrated also...
But the unit has to be calibrated, otherwise the voltages will not be read correctly, they won't line up. The only place I know of that sells a calibrated MAF unit is PaceParts, which is why you don't read of anyone having problems if they buy their 85mm piece from there.
The actual unit itself has to be calibrated. I'm talking about the MAF sensor, not the PCM computer in the car, which has to be calibrated also...
But the unit has to be calibrated, otherwise the voltages will not be read correctly, they won't line up. The only place I know of that sells a calibrated MAF unit is PaceParts, which is why you don't read of anyone having problems if they buy their 85mm piece from there.
Don't buy into the marketing...the calibration lies solely in the PCM.
12-06-2006, 01:47 PM
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Originally Posted by MeentSS02
Don't buy into the marketing...the calibration lies solely in the PCM.
A Vettes 85 MAF sensor puts out voltages through a higher range than a ls1 MAFs. As an arbitrary example (I don't remember the actual numbers) a Vette MAF will go from 0v to 16v, whereas a ls1 sensor will only go from 0v to 13v...
If you just put a Vette MAF sensor on an ls1 it will NOT be calibrated. Regardless of what you do in the PCM...the unit itself will only send out certain voltages. THAT's what the calibration does, modify the MAF itself to send out the correct voltage range.
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12-06-2006, 01:52 PM
#8
Originally Posted by lsx24
I know for a fact this is NOT TRUE...
A Vettes 85 MAF sensor puts out voltages through a higher range than a ls1 MAFs. As an arbitrary example (I don't remember the actual numbers) a Vette MAF will go from 0v to 16v, whereas a ls1 sensor will only go from 0v to 13v...
If you just put a Vette MAF sensor on an ls1 it will NOT be calibrated. Regardless of what you do in the PCM...the unit itself will only send out certain voltages. THAT's what the calibration does, modify the MAF itself to send out the correct voltage range.
A Vettes 85 MAF sensor puts out voltages through a higher range than a ls1 MAFs. As an arbitrary example (I don't remember the actual numbers) a Vette MAF will go from 0v to 16v, whereas a ls1 sensor will only go from 0v to 13v...
If you just put a Vette MAF sensor on an ls1 it will NOT be calibrated. Regardless of what you do in the PCM...the unit itself will only send out certain voltages. THAT's what the calibration does, modify the MAF itself to send out the correct voltage range.
12-06-2006, 02:07 PM
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Originally Posted by MeentSS02
Would you mind providing a link to this information?
When we were tuning my car for the 85mm sensor, we noticed it put out voltages that were correct for ls1...compared to the PCM table they were spot on, compared to the voltages that are hard-coded into the PCM. We tested this by downloading a Z06 PCM file and reading the MAF voltages in the tune, and they had a range that was higher than the ls1 went to. So a Z06's PCM file expects voltage ranges that are outside the range of an ls1 MAF sensor, as they are hard-coded into the PCM file to read a specific range.
Therefore, without calibration, it's pointless to run a 85 mm MAF on a ls1 car, because it won't be reading the correct voltages from the MAF unit itself.
Also, that's what SLP tries to do with their "resistor" mod...it tricks the MAF unit to put out a different voltage range than normal, simple electronics using a resistor, technically should work just as good, but in reality DOESN'T work just as good as the calibrated unit from PACE.
12-06-2006, 05:29 PM
#10
For those that like to exercise their brain, this has been continued over in the PCM section here:
https://ls1tech.com/forums/pcm-diagnostics-tuning/620036-trying-find-info-voltage-differences-z06-85mm-maf-sensor.html
Maybe that's why I don't like 85mm MAF sensors. Too much thought required
https://ls1tech.com/forums/pcm-diagnostics-tuning/620036-trying-find-info-voltage-differences-z06-85mm-maf-sensor.html
Maybe that's why I don't like 85mm MAF sensors. Too much thought required
12-07-2006, 08:31 AM
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Lol there's varying opinion in that discussion as well...the mistake I made above was referencing voltage, when I should be talking about frequency...but I stand by my theory being correct.
12-07-2006, 01:02 PM
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Originally Posted by lsx24
Sorry I don't have a link...there just isn't enough information on MAFs around...But I saw it with my own eyes with my tuner, Jeff Creech from Carolina Automasters:
When we were tuning my car for the 85mm sensor, we noticed it put out voltages that were correct for ls1...compared to the PCM table they were spot on, compared to the voltages that are hard-coded into the PCM. We tested this by downloading a Z06 PCM file and reading the MAF voltages in the tune, and they had a range that was higher than the ls1 went to. So a Z06's PCM file expects voltage ranges that are outside the range of an ls1 MAF sensor, as they are hard-coded into the PCM file to read a specific range.
Therefore, without calibration, it's pointless to run a 85 mm MAF on a ls1 car, because it won't be reading the correct voltages from the MAF unit itself.
Also, that's what SLP tries to do with their "resistor" mod...it tricks the MAF unit to put out a different voltage range than normal, simple electronics using a resistor, technically should work just as good, but in reality DOESN'T work just as good as the calibrated unit from PACE.
When we were tuning my car for the 85mm sensor, we noticed it put out voltages that were correct for ls1...compared to the PCM table they were spot on, compared to the voltages that are hard-coded into the PCM. We tested this by downloading a Z06 PCM file and reading the MAF voltages in the tune, and they had a range that was higher than the ls1 went to. So a Z06's PCM file expects voltage ranges that are outside the range of an ls1 MAF sensor, as they are hard-coded into the PCM file to read a specific range.
Therefore, without calibration, it's pointless to run a 85 mm MAF on a ls1 car, because it won't be reading the correct voltages from the MAF unit itself.
Also, that's what SLP tries to do with their "resistor" mod...it tricks the MAF unit to put out a different voltage range than normal, simple electronics using a resistor, technically should work just as good, but in reality DOESN'T work just as good as the calibrated unit from PACE.
12-07-2006, 01:30 PM
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Originally Posted by dummer
The PACE 85mm MAF is no better than the SLP. I bought one, and found that it uses the same "trick". There is a resisitor solder to two legs of the MAF sensor. It is just hidden in the side of the MAF, and covered with what appeared to be, some sort of epoxy, which I dug out and uncovered the resistor. 1.5K Ohms, I think was the value of it don't remember for sure. Calibrated MAF my ***!
12-07-2006, 10:40 PM
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I realize that, but a resistor is a linear device, and it is going to simply shift the entire MAF response curve up or down.
That may actually get the calibration close to the stock MAF, but it just seems to me that some frequency ranges may need more adjustment than others to match the stock MAF (the 85mm MAF may be further off from the stock MAF in the lower frequncy range, say 8% then may only measure 5% different in the upper frequencies, for example) the resistor is going to adjust the MAF's entire out range up or down an equal amount.
That may actually get the calibration close to the stock MAF, but it just seems to me that some frequency ranges may need more adjustment than others to match the stock MAF (the 85mm MAF may be further off from the stock MAF in the lower frequncy range, say 8% then may only measure 5% different in the upper frequencies, for example) the resistor is going to adjust the MAF's entire out range up or down an equal amount.
12-08-2006, 09:59 AM
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I see what you're saying, it makes sense that it would be a total or complete shift, rather than piece-meal type shift. There just isn't enough information on MAF sensors to go around, SLP and PACE use different resistors for seemingly the same effect, and whos to say that's the best way of calibrating it anyway. However for what it is the PACE unit seems to work well. I have not heard of anyone having a problem with it, UNLIKE the SLP units which are constantly having problems....when I had one on my car it worked flawlessly and was easy to tune.