Theoretical question re: Motronic

[tim]

I was fooling around trying to figure out the fuel injection maps or something, and I came upon a tidbit; namely that on my e39 with the m62, when the system detects full throttle, it converts from the MAF mixture map, to using engine RPM to control mixture. Cool. I'm wondering whether we could mess with it. The idea would be to have this mixture control kick in at a lower throttle. My guess is that the car will go faster. Am I right? Can it be done? On an e34? (isn't the chip non-programmable).

[Robin-535im]

I was fooling around trying to figure out the fuel injection maps or something, and I came upon a tidbit; namely that on my e39 with the m62, when the system detects full throttle, it converts from the MAF mixture map, to using engine RPM to control mixture. Cool. I'm wondering whether we could mess with it. The idea would be to have this mixture control kick in at a lower throttle. My guess is that the car will go faster. Am I right? Can it be done? On an e34? (isn't the chip non-programmable).

At WOT (~3/4 pedal) the DME uses just the RPM to control the fuel pulse duration (the timing is hardwired by smart engineers or smart chip reprogrammers). It is set at ~10% richer than the "learned" fuel trim map, which is what is used at mid throttle. The "learning" is that the fuel map is trimmed to get 14.7 A/F ratio at all the different RPM / air flow combinations, so you have optimum power/economy settings all the time. Now when you go WOT, only the RPM is used to look up the fuel duration, and it is set 10% richer to give you ~13 A/F ratio, which is worse for emissions but optmium for power.

I think if you adjusted the WOT switch to come on earlier, you would hit the richer A/F ratio sooner and drive at max power more often... the problem is you need to learn the correct ratio at mid throttle before the A/F is set to "max power" when you floor it. I.e., you can't over do it because you'll need to leave *some* mid throttle range so the fuel trim map can learn the car's settings.

At the end of the day, I think it would probably be the same except you'd feel the power come on sooner in the pedal. Same power as flooring it, just with less pedal... car wouldn't really be faster... But adjusting the WOT switch would be fun anyway just to see.

[632 Regal]

making it richer at a lower peddle doesnt mean necessarily less mileage just means at load its making more power. back in the carburetor days I could change springs for the fuel map to come in sooner and there would be an increase of power where we wouldnt have to floor it to get the same results as half throttle...I like Tims thinking here!

[tim]

I first noticed the difference when I got the wife the 99 540it. The m62 map seems to really come on about mid pedal and I really haven't had the guts yet to floor it. In my e34 540i, I can get it to the kickdown switch before it really comes on cam. I'm not talking really about a difference in HP, just a difference in setup. On the wifes, it feels like rpm takes over mixture (purely hypothetically) at about 3500 rpm.

Can we really just adjust the TPS to fool motronic, or are we talking Mark D type stuff?

[Robin-535im]

The TPS may not be adjustable in range, just in offset... so if you make WOT happen earlier, the idle switch won't kick in, and you'll idle poorly. Might have to jigger some kind of thing to chage the WOT instead of just rotating the switch position.

Check to make sure the WOT is triggering at all first, some people have bad ones at this age.

Let us know how it works!

[tim]

Well, the floor switch works, as many the unwary mustang can attest. I forgot what the TPS looks like, but if it's a pot, we could rotate it, and if its a sensor, we could slide it. I'm going to check out the ETK for a bit. I think it's worth doing if we could get our m60's (and others) to act more like the m62. Our m62 has two distinct feels- the low throttle just cruising around mode, and the OMFG mode. Problem is, as you said, how much does the TPS affect mixture at idle? I have an EAT chip and my idle is glassy.

[winfred]

all of the later cars (m50 and newer) run a variable tps with no real on or off position, it adjusts the voltage sent to it from the computer, besides the tranny uses it for shift points as well (notice the kick down cable has dissappered)

[winfred]

the m62 just has more ass due to more displacement and newer computer programing, our 95 740il (m60) chirps the tires and our 98 740il (m62) will do a 25' smokey and i didn't get the chence to play with the 01 740il we just got before the boss sent it to his brother but with it's vanos motor (m62tu?) it really hauled ass


I think it's worth doing if we could get our m60's (and others) to act more like the m62.

[632 Regal]

alterating the fuel and spark advance curve definetly can get positive **** to happen, as for the 530 auto cars the chip and motronic is directly involved with the transmission...thats why Marks chips chose to react adversly with the 530ia transmissions. I pulled mine on the second day but im sure that it took a dramatic toll on the longevity of my trans.

[tim]

Winfred- I really assumed they were more or less equivalent, but the m62 has much more ass.
( One thing I sort of hate is that we have the steptronic, and the shifter goes the wrong way for my taste- forward for upshift and back for down, while my left motorcyle toe is doing the opposite. It's like patting your head and rubbing your stomach)
I'm never getting rid of the e34 though, which brings it to the logical conclusion. The m60/m62 swap is quite do-able. Certain things are problematic for a drop in fit, but nothing a few brackets, hoses and clamps won't fix. This mech I know in dallas, Sergei, claims he does a swap where he pulls engine and tranny together, uses a different output shaft coupler, and custom routes the updated cat, resonator, muffler setup. He uses the new harness from the engine to the dme, but uses the old for accessory and subsystem wiring. It great ********ting material, but man, I'd love to see one. Can you imagine my e34 540 lurking around with that!!! Talk about a sleeper. I think I'd take my 1/4 mi from 16+ to 14ish. On my 15" basketweaves.
(And I have seen the 550 that's around but the m62 would beat it no prob, IMHO.)

[tim]

I pulled mine before that happened but sure that it took a dramatic toll on the longevity of my trans.

I didn't know about this. Do you have the ZF? I love my EAT chip, but in my review on the old board, the first thing I noticed about it was how it changed my shiftpoints for the better. Many people debated me as to how that was possible, not really understanding the full motronic picture. I didn't know there was a price to this improvement.

[winfred]

**** find one of those 4.6 alpina motors from a automatic z8 or the x5 with it's almost 350 hp in the same general package


Talk about a sleeper. I think I'd take my 1/4 mi from 16+ to 14ish. On my 15" basketweaves.
(And I have seen the 550 that's around but the m62 would beat it no prob, IMHO.)

[632 Regal]

the 540 has a stronger trans than mine.


I didn't know about this. Do you have the ZF? I love my EAT chip, but in my review on the old board, the first thing I noticed about it was how it changed my shiftpoints for the better. Many people debated me as to how that was possible, not really understanding the full motronic picture. I didn't know there was a price to this improvement.

[granit_silber]

the 540 has a stronger trans than mine.

Jeff,

Are you saying that Mark's chip damages the tranny? Crap! I wanted one of those!!

-ashley

[MarkD]

I didn't know about this. Do you have the ZF? I love my EAT chip, but in my review on the old board, the first thing I noticed about it was how it changed my shiftpoints for the better. Many people debated me as to how that was possible, not really understanding the full motronic picture. I didn't know there was a price to this improvement.


There is no problem with the 540 chip. And Jeff is refering to a problem with the first version of 530iA chip, which only 4 people had. Two people sold their cars soon after, but I did ship a new version to 2 or 3 others and it worked fine. Jeff had asked for a refund, and so was eliminated from the field test and did not get the next update.
MarkD

[tim]

Hey,

It's my thread and I say no bickering, especially between two of my favorite people. Mark, you got a right to back yourself up, and Jeff, you have a right to say what you want- But I have a right to say case closed as far as this thread goes.

Meanwhile,

Mark, what do think about this whole throttle position thing on a 540i. Can we do it, and do you think its worthwhile?

[632 Regal]

Mark,
I still promote you chips for all cars except the 530ia, my reference to "blow trans" was my term of the inevetable if I would have left the chip in. I talked with a few people regarding the cause including Kirt Kohller and they all said that there is a definite link between the chip and the transmission which you even said that you saw hidden in the chip last time we chatted. I also was not the only person with problems with the 530 chip. The chip was only in my car 2 days before I pulled it and the problem went away.

My response to Achre was posted above his post for whatever reason making it look like I'm leading people to think that theres a problem with all of your chips, which is not true.

As for the refund I requested several times you made it clear that I should wait months for some sort of "fix" and that you had NO money to refund me. Yes I was mad for being a paying ginuea pig, I'm sure if things were reversed you would have felt the same.

Also before the refund and the last time we chatted (a month ago?) I made it clear to you that I would send you my stock chip, the JC chip and read or whatever when the reader comes this way, how is this being malicious? I was still willing to help you with the developement of this chip which has a pretty high demand this last year. I just didnt have a very positive experience with the 530 chip. Thats it! I was also willing to pay you and give whatever chip you finally finished another try.

I will edit my above post to reflect just the 530 chips as that was not intentional.