Just got my motor! Now some questions. OBDI or OBDII, eh?

[PiercedE30]

Its when forced induction comes into play where the OBD1 conversion has its merits in terms of cash and and availability.

Yea, too bad the OBDI ECU can only support 65lb injectors and roughly 600 horses.

[BigD]

Yea, too bad the OBDI ECU can only support 65lb injectors and roughly 600 horses.

How does having a different computer affect how much power an engine can make or what injectors you use? The ECU opens injectors for a given duration. It may have a limited pulse width upperbound but then you just get a bigger injector.

[e30s52]

or just go MS.

[PiercedE30]

How does having a different computer affect how much power an engine can make or what injectors you use? The ECU opens injectors for a given duration. It may have a limited pulse width upperbound but then you just get a bigger injector.

You can only make as much power as your injectors can flow, fuel wise. The OBDI ECU can only go as high as 65 lb injectors due to the injector scaling. I don't know why, it just is. Matt can confirm this.

[BigD]

You can only make as much power as your injectors can flow, fuel wise. The OBDI ECU can only go as high as 65 lb injectors due to the injector scaling. I don't know why, it just is. Matt can confirm this.

Cool, just doesn't make sense to me. As far as the ECU goes it's just a solenoid that it opens for some period of time, what does it care if the solenoid happens to open a valve which flows 1 lb or 1000.

[Charlie]

Cool, just doesn't make sense to me. As far as the ECU goes it's just a solenoid that it opens for some period of time, what does it care if the solenoid happens to open a valve which flows 1 lb or 1000.

Umm..

You might want to read up a little more.

-Charlie

[BigD]

Umm..

You might want to read up a little more.

-Charlie

If someone wants to write out why, I'll read, otherwise I don't really care.

[mattdk318i]

for the record im staying all OBD2. Ive been reading up on it and it seems the logical decision for ME. fortunatly i have all of the nessasary parts and wiring for the swap
There are a few things that i will most likely do, like the secondary air pump delete.
Id like to see where this thread goes. Im at the same stage as the OP, but with a FULL donor car.

[MIKe30]

for the record im staying all OBD2. Ive been reading up on it and it seems the logical decision for ME. fortunatly i have all of the nessasary parts and wiring for the swap
There are a few things that i will most likely do, like the secondary air pump delete.
Id like to see where this thread goes. Im at the same stage as the OP, but with a FULL donor car.

Interesting. I just keep trying to read and read. I asked the e36 guys on bf.c last night what they thought - haven't checked it yet as i've been reading the links that came up with my search.

Anyway, it is nice that you have the full donor car. I have what i think is all necessary accessories and wiring, and I believe I'm going to stay obd2. Most likely deleting the air pump, and 2 o2 sensors. I believe I will try to keep the ews functional as long as i can get my hands on a second chip for it, putting the chips in my e30 keys if i can. If not, i'll just delete it.

We'll see where this goes. I hope you make a progress thread, I'd like to stay up with it.

-mike

[etxxz]

in my case it was cheaper to stay obd2 so i went that route and added the M50 manifold for extra hp. Its likely that you can squish a couple more hp from the OBDI s52 tunes (see racersmarket.net) but as i came to find out, them an extra 100hp was enough.

read this:

http://www.r3vlimited.com/board/showthread.php?t=100950

[MIKe30]

in my case it was cheaper to stay obd2 so i went that route and added the M50 manifold for extra hp. Its likely that you can squish a couple more hp from the OBDI s52 tunes (see racersmarket.net) but as i came to find out, them an extra 100hp was enough.

read this:
http://www.r3vlimited.com/board/showthread.php?t=100950

That link is already added to my favorites on my laptop :p thanks for the write-up.

I think I'll stay obd2. I can always convert to obd1 down the line if i feel 2 isn't doing enough for me. What kind of numbers were you putting down in your e30?

[PiercedE30]

I have a COMPLETE OBDII wiring set up if anyone needs it. Everything from the keys to the EWS module to the ECU from a 98 328.

[MIKe30]

I have a COMPLETE OBDII wiring set up if anyone needs it. Everything from the keys to the EWS module to the ECU from a 98 328.

shameless plug eh? you might as well post a price, forum rules :mrgreen:

[SpecM]

If someone wants to write out why, I'll read, otherwise I don't really care.

I'll take a stab at it:

-Big injectors flow more, right? At any given duty rate (1-100%) they will flow more than their little brothers. At WOT that's OK, you want more fuel.
-But lets saw with stock injectors the duty cycle's at 2% max flow at a slow, hot idle (fake numbers btw). What if you quadrulple (still fake!) the flow rate? Then at idle the injector duty cycle must be 1/2% so the engine wouldn't idle too rich.
-Apperantly, ODB 1 computers can't compute a "1/2%" duty cylce, they just defalt to 1% (remember, made-up numbers!). So the engine idles so rich (double the fuel!), it may not run at all!
-OBD II uses more advanced computers and can calculate duty cycles more effectivly. Think of it as if OBD I has to compute in intervals of 1%, but OBD II can compute in intervals of 0.1%

[BigD]

I'll take a stab at it:

-Big injectors flow more, right? At any given duty rate (1-100%) they will flow more than their little brothers. At WOT that's OK, you want more fuel.
-But lets saw with stock injectors the duty cycle's at 2% max flow at a slow, hot idle (fake numbers btw). What if you quadrulple (still fake!) the flow rate? Then at idle the injector duty cycle must be 1/2% so the engine wouldn't idle too rich.
-Apperantly, ODB 1 computers can't compute a "1/2%" duty cylce, they just defalt to 1% (remember, made-up numbers!). So the engine idles so rich (double the fuel!), it may not run at all!
-OBD II uses more advanced computers and can calculate duty cycles more effectivly. Think of it as if OBD I has to compute in intervals of 1%, but OBD II can compute in intervals of 0.1%

Ah ok, cool, thanks dude. I was only considering what would happen at WOT.