Worth moving Air Temp sensor?
Thread Starter
Instructor
Joined: Aug 2004
Posts: 109
Likes: 3
From: Just North of Boston Mass
Worth moving Air Temp sensor?
ANyone have any experience with moving the Man air Temp sensor
to the air cleaner base with a rewire kit? Supposed to read cooler temps and make more power.I would think that only
"REAL" cooler temps
would work not just tricking the pcm into thinking the air temp was cooler.
OR:
Is this jist one of those waste of money and time things?
to the air cleaner base with a rewire kit? Supposed to read cooler temps and make more power.I would think that only
"REAL" cooler tempswould work not just tricking the pcm into thinking the air temp was cooler.
OR:
Is this jist one of those waste of money and time things?
Race Director
Joined: Jul 2004
Posts: 16,795
Likes: 62
From: Lake Havasu City, AZ
I don't know. I recently asked whether tricking the computer by putting in a resistor would achieve the same end. ie, to give the computer a lower temperature reading.
The advise was to buy a programmable chip and spend some money where it would do good.
So, I am interested in seeing the answers you get to your question.
The advise was to buy a programmable chip and spend some money where it would do good.
So, I am interested in seeing the answers you get to your question.
Thread Starter
Instructor
Joined: Aug 2004
Posts: 109
Likes: 3
From: Just North of Boston Mass
I Have noticed most all newer cars Do have the sensor in the air inlet tube.
Where most cars from the 80's had it in the intake manifold.
here is an article on mat relocation modification although not a vette same seems to apply.
http://www.gmtips.com/3rd-degree/dox/tips/mat/mat.htm
I have a stock chip and can't see buying someone elses replacement and unless I learn how to program it myself
I got a lot to learn before I can do that!
I'll just keep tinkering to see how far I can go.
Where most cars from the 80's had it in the intake manifold.
here is an article on mat relocation modification although not a vette same seems to apply.
http://www.gmtips.com/3rd-degree/dox/tips/mat/mat.htm
I have a stock chip and can't see buying someone elses replacement and unless I learn how to program it myself
I got a lot to learn before I can do that!
I'll just keep tinkering to see how far I can go.
Instructor
Joined: May 2001
Posts: 186
Likes: 0
From: Midwest
"ANyone have any experience with moving the Man air Temp sensor
to the air cleaner base with a rewire kit? Supposed to read cooler temps and make more power.I would think that only "REAL" cooler temps
would work not just tricking the pcm into thinking the air temp was cooler.
OR:
Is this jist one of those waste of money and time things?"
That is an interesting question because I do not recall ever seeing a table for this in any of the C4 programming that I have ever done - could have just missed it. We also do a lot of Ford PCM programming and we mess with that table alot, especially for boost applications to control timing. Assuming that GM uses the IAT to control timing, giving a cooler reading would increase timing, but can we use more timing? Most of the C4s, especially the modded ones are bumping the knock sensor already. If it is used to control fuel, the stock C4s are already too rich at WOT and the IAT reading cooler would cause it to go more rich robbing power. Wish I knew the answer.
EJ
to the air cleaner base with a rewire kit? Supposed to read cooler temps and make more power.I would think that only "REAL" cooler temps
would work not just tricking the pcm into thinking the air temp was cooler.
OR:
Is this jist one of those waste of money and time things?"
That is an interesting question because I do not recall ever seeing a table for this in any of the C4 programming that I have ever done - could have just missed it. We also do a lot of Ford PCM programming and we mess with that table alot, especially for boost applications to control timing. Assuming that GM uses the IAT to control timing, giving a cooler reading would increase timing, but can we use more timing? Most of the C4s, especially the modded ones are bumping the knock sensor already. If it is used to control fuel, the stock C4s are already too rich at WOT and the IAT reading cooler would cause it to go more rich robbing power. Wish I knew the answer.
EJ
Thread Starter
Instructor
Joined: Aug 2004
Posts: 109
Likes: 3
From: Just North of Boston Mass
Wow!;
Thanks for the info all good food for thought.
I definately can't use more timing, I Can only stop audible pinging with Exon 93 Super. So more Timing is out. I do feel as though it is still kicking the timing back [only going by seat of the pants]
I did not Know C4's were too rich at WOT. When I changed to a 180 thermistat the car really perked up and started to fly. So I know coolant temps play a big role.
I'm assuming it goes open loop at WOT and then maybe it would not even look at the MAT. But What about part throttle maybe it would richen it up just enough to combat some of the pinging.AS far as being too rich Would one of the fuel ratio gauges that I see in catalogs be accurate enough to help know what the fuel ratio is? Maybe I could control mixture with coolant temp.
I'm a carb guy from way back. I really am going to have to figure out how to get into programing this thing.
BC
Thanks for the info all good food for thought.
I definately can't use more timing, I Can only stop audible pinging with Exon 93 Super. So more Timing is out. I do feel as though it is still kicking the timing back [only going by seat of the pants]
I did not Know C4's were too rich at WOT. When I changed to a 180 thermistat the car really perked up and started to fly. So I know coolant temps play a big role.
I'm assuming it goes open loop at WOT and then maybe it would not even look at the MAT. But What about part throttle maybe it would richen it up just enough to combat some of the pinging.AS far as being too rich Would one of the fuel ratio gauges that I see in catalogs be accurate enough to help know what the fuel ratio is? Maybe I could control mixture with coolant temp.
I'm a carb guy from way back. I really am going to have to figure out how to get into programing this thing.
BC
Instructor
Joined: May 2001
Posts: 186
Likes: 0
From: Midwest
Keep in mind, at idle and less than WOT you are in closed loop, so within reason, no matter what you do the A/F ratio will be held at 14.7:1. If you mess with certain sensors or fuel pressure you could shift the fuel trims which could affect your WOT A/F ratio. The common narrow band A/F indicator will not read accurately enough to let you know what your A/F ratio is at WOT, it can only indicate if you are at 14.7 or richer or leaner then that. I'm not sure what year Vette you have but the best way to keep your fuel trims (Integrator and Block Learn Multiplier) correct and stable and acheive the best WOT A/F ratio is with an ECM reprogram by a competant tuner with a good wide band A/F indicator.
EJ
EJ
Thread Starter
Instructor
Joined: Aug 2004
Posts: 109
Likes: 3
From: Just North of Boston Mass
Thanks for the info DYNOCAR. I have a 85 with slight mods.
I better not mess with too much until I learn what I'm doing.
It runs well and i can enjoy it the way it is. for now!
but I will make it better!
I better not mess with too much until I learn what I'm doing.
It runs well and i can enjoy it the way it is. for now!
but I will make it better!
Instructor
Joined: May 2004
Posts: 163
Likes: 0
From: machesney park il
the mat sensor does nothing for the AF ratio.it only tells the egr when its warm enough to operate.moving it will do nothing for performance.per the manual on my 85.i fell for that relocate bs also,until i learned what it actually does.save your $$$.
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Thread Starter
Instructor
Joined: Aug 2004
Posts: 109
Likes: 3
From: Just North of Boston Mass
Thanks for the input.
I believe as Dynocar stated the MAT does control timing in addition to
the EGR. It takes timing out as temp increases.
I can't use more timing due to increased compression and poor gas locally. I can already feel loss of power due to timing retard.
I need to get my pinging,knock sensor, timing situation under control
before I go changing MAT.
I believe as Dynocar stated the MAT does control timing in addition to
the EGR. It takes timing out as temp increases.
I can't use more timing due to increased compression and poor gas locally. I can already feel loss of power due to timing retard.
I need to get my pinging,knock sensor, timing situation under control
before I go changing MAT.
Melting Slicks
Joined: Apr 2001
Posts: 2,114
Likes: 220
From: Ca.
On maf cars relocating the mat sensor does nothing....it "regulates" the egr only...on map cars it does have an effect-however you then need to recalibrate the mat tables-that's the Inverse mat term lookup delta multiplier vs airflow table...try 0=1.000; 16=0.805; 32=0.523; 48=0.297 64=0.117 80=0.094 96=0.086 112=0.078 128=0.070 144=0.070.....
