LIFE WITH SIRS

[dj10]

John, I am not gonna quote any rules here but I think anywhere the stock portion of the loom can plug in would be OK. I had thought of the possibility of running a hose across the front tof the engine and back to the stock location and putting the MAF on the end. I think the tubing is free these days and the additional length may alllow the MAF to work correctly with the SIR. This is just a thought but the proven (dynoed)deal is Airfilter====MAF====SIR===TB... [/b]

Joe, in your opinion, doesn't it seem logicial that with the SIR the engine should run rich since the AFM is reading good volume and clean air but the SIR is shutting down the air, thus the computer is throwing more fuel into what is actually less air? Am I looking at this correctly?
Thanks
dj

[mlytle]

Joe, in your opinion, doesn't it seem logicial that with the SIR the engine should run rich since the AFM is reading good volume and clean air but the SIR is shutting down the air, thus the computer is throwing more fuel into what is actually less air? Am I looking at this correctly?
Thanks
dj
[/b]

if the sir is shutting down the air, then the air will stop going through the maf and it will read the correct amount of air. air has to go somewhere...if it can't get through the sir, then is won't get past the maf either, even if the maf is in front of the sir. it is a "sealed" system.

in theory....

[dj10]

if the sir is shutting down the air, then the air will stop going through the maf and it will read the correct amount of air. air has to go somewhere...if it can't get through the sir, then is won't get past the maf either, even if the maf is in front of the sir. it is a "sealed" system.
in theory.... [/b]

So if I read you correctly, if the maf is reading less air then it is telling the computer to put less fuel to the engine thus creating a lean condition? Does this sound right? If this is correct then engine should start going lean from about 3500- 4000 rpm up.

[mlytle]

So if I read you correctly, if the maf is reading less air then it is telling the computer to put less fuel to the engine thus creating a lean condition? Does this sound right? If this is correct then engine should start going lean from about 3500- 4000 rpm up.
[/b]

not really. maf is reading less air because less air is going into the engine through the sir. this leads to computer putting less fuel in to try to keep the mixture at the correct ratio based on the maps in the computer. this is where the custom chip is critcal and just playing with an adjustable fpr isn't very effective.

of course, i am not a professional engine tuner, but i hung out with one during several tuning sessions on my car last year....

[dj10]

not really. maf is reading less air because less air is going into the engine through the sir. this leads to computer putting less fuel in to try to keep the mixture at the correct ratio based on the maps in the computer. this is where the custom chip is critcal and just playing with an adjustable fpr isn't very effective.

of course, i am not a professional engine tuner, but i hung out with one during several tuning sessions on my car last year....
[/b]

I wonder who that might be? I think I'm understanding this a little better. From what I've heard your enginer tuner/ builder should get his 29 mm SIR this week. I had him burn me 2 chips last year and only 1 will be any good (the one without the FPR) lol. Damn is that a long day for me if I have to go to his dyno again to get another chip burnt (620 miles round trip). He's such a unique and likable guy would be worth it if I had too.

I may be incorrect, but, I don't believe that the MAF will read correctly because it was designed to work in the 4 inch(or so) air intake system, calculate velocity, and determine volume with respect to that area. With the velocity being considerably greater due to the restriction readings will have to be adjusted accordingly.
That is why the MAF doesn't want the SIR in front of it, as it will direct the airstream only on the middle of the wire. Causing way out readings.
This is just a SWAG(Scientific Wild Ass Guess). I pick up my E36 this coming weekend and am looking to learn all I can, and help where ever possible.
Thanks--------------------
Chris Leone
E36 ITS underconstruction
Remember half of the people you call friends are considered below average.

SWAG--------Good one Chris! Man did you pick a good time to do a E36 .
This is a reason maybe not to mount the SIR to close to the MAF but not to close the TB either. I know there is only a limited amout of space to mount everything needed.