Mark D and 19# on stock car?

[squidmaster]

and it's like a 5% at most different.

either I misread your original post or it was changed, but I thought you said that the o2 is always read.

and either way, LTFT didn't even exist until the very end of e30 production. Both STFT and LTFT are cleared once the car is turned off, too, not permanently stored. It's stored to RAM, after-all, which only holds its gates open/shut with the addition of current.

You're going to go from a 154cc/min single pintle injectors to nearly 200cc/min quad-pintle injectors and think everything is going to work fine? That's a 20% difference and a change in flow and your dme can only account for 5% of that and can't even account for the lag, pulse change, opening per volt, etc.

[Mr. Burns]

your car will be fine!!! it will have better throttle response, give a small bit more power, and run smoother, before i turbo charged my car i had this set up

$40 eBay performance chip

19lb injectors

3.73 lsd

headers with custom exhaust all the way back, no cat

cold air intake

short shifter

the stock n/a e30 had 170 hp right? my car had 202 hp to the wheel on the dyno after i did all this

:drink:

thats an awfully generous claim for j/yard mods and straigh back exhaust.
my appologies if this infact true...but holy cow.

[squidmaster]

Why did you put "fuel dribbling out" in quotation marks? It hasn't even been said in this thread.

[nando]

and it's like a 5% at most different.

either I misread your original post or it was changed, but I thought you said that the o2 is always read.

and either way, LTFT didn't even exist until the very end of e30 production. Both STFT and LTFT are cleared once the car is turned off, too, not permanently stored. It's stored to RAM, after-all, which only holds its gates open/shut with the addition of current.

You're going to go from a 154cc/min single pintle injectors to nearly 200cc/min quad-pintle injectors and think everything is going to work fine? That's a 20% difference and a change in flow and your dme can only account for 5% of that and can't even account for the lag, pulse change, opening per volt, etc.

the DME always has power. the long term trim isn't erased until you disconnect the battery.

motronic 1.1 came out in like 1987.. it's basically the same as 1.3 except the hardware is way more complicated (double boards). That's a lot longer than "the end of E30 production".

your 5% number is pulled out of thin air. There is a limit but it's certainly more than 5%. If it wasn't then my mileage would have dropped from 21mpg to like 16, but it didn't. it stayed the same.

[nando]

Why did you put "fuel dribbling out" in quotation marks? It hasn't even been said in this thread.

I was paraphrasing. you said it would be a "stream" because the pressure is too low. except the 19# injectors are rated at 3 bars, which is exactly what the E30 uses.

[squidmaster]

the DME always has power. the long term trim isn't erased until you disconnect the battery.

motronic 1.1 came out in like 1987.. it's basically the same as 1.3 except the hardware is way more complicated (double boards). That's a lot longer than "the end of E30 production".

your 5% number is pulled out of thin air. There is a limit but it's certainly more than 5%. If it wasn't then my mileage would have dropped from 21mpg to like 16, but it didn't. it stayed the same.

I've not one seen a 5% change. Maybe it is, but when my ecu needed a 20% change, it only gave me ~5%.

LFTF wasn't introduced until 1.3. Look at the Porsche guys running 1.1 and 1.2. No LFTF.

As is my understanding, of putting a multimeter against my dme, that the dme does not have power after the key is removed.

I was paraphrasing. you said it would be a "stream" because the pressure is too low. except the 19# injectors are rated at 3 bars, which is exactly what the E30 uses.

paraphrasing? stream is the most apt word.

the pressure in the lines may be the same but putting 42psi of pressure through a 15# hole is a LOT different than putting a static 42psi through a 19# hole. Go turn on your hose. Your house has a static water pressure in it. Let it flow out freely. Then put your thumb on the nozzle and restrict it a bit. Does it look the same? No, because pressure is only one step in how the liquid exits.

[jlevie]

I've not one seen a 5% change. Maybe it is, but when my ecu needed a 20% change, it only gave me ~5%.

LFTF wasn't introduced until 1.3. Look at the Porsche guys running 1.1 and 1.2. No LFTF.

As is my understanding, of putting a multimeter against my dme, that the dme does not have power after the key is removed.

Un-switched power is on pin 18 of the DME connector.

When I built my first Spec E30 it had a 153 DME (Motronic 1.1). When I took it to the dyno it had been driven on the street to/from HPDE events quite a bit. We made a couple of pulls for a baseline, then disconnected and reconnected the DME to do a reset, and then another pull. A comparison of the AFR trace showed a noticeable difference. So I'd have to say the the DME was storing a long term fuel trim. For grins I've also tried this with a 173 (Motronic 1.3) DME and seen exactly the same affect.

[squidmaster]

Everything I've read says ltft didn't come around until 1.3. Unless Porsche got a different 1.1 than BMW. same for 1.2. Did you do consecutive runs for each before/after resets? Any dyno sheets I can study about this? Since this is different than what I've been doing, I'd like to learn more about it.

[squidmaster]

I'm testing my pin 18 to pin 19 and I've got nothing. Maybe this is why I've never had correction maps carry over.

[squidmaster]

Power under key turn, but it drains after I take out the keys. Weird. Just watched it drain from 45mV to 0mV

Sorry to threadjack.

[nando]

Everything I've read says ltft didn't come around until 1.3. Unless Porsche got a different 1.1 than BMW. same for 1.2. Did you do consecutive runs for each before/after resets? Any dyno sheets I can study about this? Since this is different than what I've been doing, I'd like to learn more about it.

1.1 and 1.3 are functionally indentical. The major difference is in error codes (1.3 has more) and the hardware on 1.3 is much simpler.

[squidmaster]

So you're saying Porsche got a different moronic 1.1 than BMW did? If you find those documents you were talking about, I'd like to read them.

[nando]

or the porsche site you've referenced, while informative, isn't neccesarily 100% accurate.

[squidmaster]

Well, I'm still waiting on your sources to see what's actually going on in that glovebox.

[Wild Ride]

Sounds like the simplest answer is to get 17.5lb injectors as 19lb seems to be a debatable grey area. That's the setup I'm running on my stock motor.