Air Temp sensor Relocation Questions

[bruce]

Tip-in timing retard is known as Burst Knock Retard or BKR. You can see the parameters for its operation starting at $3384.

$3384 BRR active time (the active time in a stock chip is .1 sec)
$3385 TPS delta threshold to activate BKR (this is 9.8%)
$3386 BKR retard for active mode (this is set to 7 degrees)
$3387 if coolant less than 40 C skip BKR
$3388 if MPH > 50 skip BKR

The code to process this starts at $E5C3

HTH

Wayne

Your right, my bad.

 

[bruce]

Tip-in timing retard is strictly a function of delta TPS threshold.

You got it right in your explaination.

Once you enable all the perimeters, it's executed.

 

[bruce]

Ive continued to look around on the net for some sort of strategy like this on older GM cars, and it seems like everywhere I look, they mention some means of pulling timing based on temperature.

What *needs* done, is put the IAT in the upper plenum, and then use the IAT timing table. Just like they did with the Syclones. Yes, there are various heat related timing corrections, and as mentioned BKR.

The trouble with any IAT strategy is that it gives you info that's less then accurate. If you want the ecm to do it's best, then you want to tell it about he air characteristics of the air going past the intake valve (ie why MAP, and MATs are such a good idea).

 

[bruce]

Bruce- its possible that there are some aspects of EFI tuning that you havent seen firsthand.

Because you havent seen some particular ECM strategy, it doesnt mean it doesnt exist.

Yep. Happens all the time, and by golly I can even make a mistake from time to time.

BUT, this is a TR Board, and the original guestion was about where to locate the IAT. Just how badly does the original guestion need to be hijacked?.

 

[vader87]

Now I am confused! Not hard to do! So where is the best place to put it? By the filter or in the plenum? If in the plenum how and where is the best place to mount it? Thanks!

 

[scottyb]

Now I am confused! Not hard to do! So where is the best place to put it? By the filter or in the plenum? If in the plenum how and where is the best place to mount it? Thanks!

Well, if my understanding is correct (see above), then I would think that you would not want to move the temp sensor away fron the area of the MAF. Placing it in the up-pipe or intake would cause it to make incorrect adjustments to the MAF readings because of the higher temperatures, especially under boost.

 

[bruce]

Now I am confused! Not hard to do! So where is the best place to put it? By the filter or in the plenum? If in the plenum how and where is the best place to mount it? Thanks!

Anywhere in the upper plenum is fine.
The sensor is well isolated from the base, so as long as it's in the air flow, your OK.

The *best* thing to do is go with a Translator, since the newer MAFs are so much more accurate, and have their own built in temp compensation. With the MAF having it's own correction, then you can have your chip guy *0* out the MAF fueling correcctions, and install the IAT Timing Offset, and IAT timing table.

One step better then doing all that is installing the late MAF (translaotr setup) in the up pipe, so the ecm gets the most accuarate read of what's actually going into the engine.

Relocating the IAT to the plenum, induces a slight fueling error, but having the correct timing / MAT temp is a huge benefit.

 

[bruce]

Well, if my understanding is correct (see above), then I would think that you would not want to move the temp sensor away fron the area of the MAF. Placing it in the up-pipe or intake would cause it to make incorrect adjustments to the MAF readings because of the higher temperatures, especially under boost.

BUT, filling in the IAT info., and having the timing *right* more then makes up for the error.

Placing it in the up pipe, means using a Translator, and late MAF, since the early MAFs don't hold up in boost. (See my last post for all the details).