The Official OBD1 vs OBD2 argument thread.

[nmlss2006]

Well, it looks like we are, indeed, in agreement. Even on this final point, that is, on the fact that you can have fun even when the car is out of tune. I will, however, take exception with the fact that one won't feel the difference with the typical exhaust and intake that I see installed: there are measurable, BIG power gains and losses, in a site where people discuss underdrive pulleys to gain 5HP in transitories maybe, one would think it would have more importance, but as you said, maybe the fun part is good enough for most. I just wish, in that case, that people were more aware of what they're throwing away before going into exotic projects for the lost 0.25HP.
To finish, Vinnie and etxxs, I agree with both of you on the probable determination about the best route being based on what parts you have. Today, it's probably the most realistic for a 'fun' (as opposed to most powerful) swap. And yes, I have a swapped car in the garage right now - not the first one, it's loads of fun, I just wish it were the same as the E36 it came from from a reliability standpoint, but I'm working towards that end.
And again, because I'm a pain in the ass, I have the correct exhaust for it and the KAmotors intake which is possibly the best compromise given the limited airbox space we have, unless one wants to build an expensive custom mould.
Sorry about being abrasive. It's just that the thread had started out about OBD II being so great for reasons that weren't really supported. I don't like that, you've noticed.

One last note for everyone in this thread. Earlier, the red/yellow ABS pin *for late cars* is discussed. The conclusions in the thread don't match the ETM: there needs to be power from the main relais, there, as per factory wiring. Otherwise, ABS will never work.

[etxxz]

I'm really not trying to battle with you. The only thing i wanted to convey was that you have two choices. OBD1 and OBD2. If you have the option of OBD2 is because your engine is a 2.8 or a 3.2. So why would YOU go with OBD1 or OBD2?

Forget this data you're looking for, I'll tell you logistically why you should make that decision - if you can get the OBD2 bits with the engine then you'll save a LOT of money and effort. The difference in performance is null granted you use the OBD1 intake manifold.

If you don't have access to the OBD2 bits then don't source them. Go to a junkyard and get some OBD1 bits and a TRM chip. Boom, end of thread.

even the difference between a crappy intake and exhaust one won't "feel the difference" - maybe it'll sound like crap, but will probably perform the similarly. At the track its a driver thing so why worry about data so much. Go with what i said above. You'd be surprised how "out of spec" you can go and still be so fun you won't give a damn.

i sold my track s52 e30 with e36m3 brakes 1.5weeks ago. Funnest toy i've ever had. It was a beast holy crap that thing moved and braked like few others could and i have the times to prove it. It didn't run like a stock e36 did, but it ran good that was *enough*.

[VinniE30]

I'm doing a swap soon and it just looks like keeping it OBD2 is way easier. Most people get the engine with everything on it, at least I will be.. And it looks like most people buy engines like this. All the ones i've seen for sale on CL or even in junkyards come with everything accessories, harness, sensors, etc included.
So why take a bunch of stuff off and then buy all the obd1 stuff to OBD1 convert it when you can just keep it the way it is and send the ECU to delete stuff not necessary like EWS, evap stuff, air pump stuff, etc... That makes it just as "simple" as OBD1. If you were running an S52 on an OBD1 ecu would you need a correctly tuned chip anyway.

The people arguing for OBD1 aren't actually listing any advantages of OBD1, just arguing that OBD2 doesn't offer much advantage over it, which is somewhat true, there aren't any huge advantages to OBD2, it's just easier and the way I see it, and the right, proper way to do it. OBD1 on an M52/S52 looks like more work and headache for no advantage.(if anything, arguably disadvantages)

[nmlss2006]

I think you have misconstrued my reply entirely: what I was trying to communicate was precisely what you were saying, that is, among other things, that a hotter engine with a better exhaust does, indeed, give more power.
What I was trying to add is that *conversely* a cooler engine with crappy intakes and exhausts like 95% of the swaps out there may very well run worse with the OBD 2 setup, because it's running significantly out of original spec. Do we know for sure? No, apparently we do not, therefore 'go OBD2 because it's better' doesn't hold water.
And incidentally, I even agree with you about the fact that the definition of 'better' can vary a lot, but with the parameters you've given, it seems that a) OBD I has fit the bill for a lot of people b) we don't have hard data on the actual differences or improvements that OBD 2 can offer in this context.
Therefore I will not trouble you for your data - it seems that we are in agreement and I have given up on arguing on forums, mostly - and I will remain of the opinion that there isn't enough data to support the unconditional argument that OBDII S52 swaps in E30 work better than OBD I.
With this said, folks, have a ball. It would seem that this has become a vendor forum and honestly, I'll pick my battles.

[rThor432]

^^Like you said, I could care less if I'm running OBD1 or 2 as long as the thing runs right. I had OBD1 on my last S52 and it never missed a beat. Very simple setup. I'm running OBD2 on my new S52 because 1- Some tuners (read: the one I'm using) prefer the extent of some adjustments vs OBD1 and 2- I prefer the diagnostic interface that ISTA/D gives with OBD2 vs. OBD1.

Maybe I'll read through this thread and be convinced otherwise. Haven't hooked everything up yet and I've got OBD1 and OBD2 setups in my parts department.

[etxxz]

well here the big facts. OBD2 was introduced for emissions regulations. The OBD1 engines could not make the same power so BMW bumped up the displacements and restricted intakes to make up for this. So, as an already engineer that designs engines for a living you're gonna have to research on your own to compare the obd2 Siemens MS (41.0?) vs the obd1 Bosch unit. You can surely find online are dyno #s from multiple bimmerforums and r3v members. The bigger intake and less restrictive the exhaust, as idiotic as you think that is, also make big difference.. a hotter engine will typically make more power and run more efficiently than cooler one. I have extremely accurate data from many many engines with so many sensors it takes a whole day to connect everything and no you can't have it.

The thing is, define "worse" - more emissions, less power, higher cov, combustion instability, higher bsfc's?

Some, ie track junkies like me, could care less about these parameters as long as my car 1) ran well and 2) was faster than it was before. Ofcourse you ask me during work hours and i will answer differently.

[nmlss2006]

As an engineer by training, 'different' and 'much more data' will not encourage me to make claims about 'better' especially when coupled with 'we'll never understand'.
I don't mean to sound snarky, it's a statement of fact: if we're going to state that A works better than B, we should be able to give reasons and numbers. Or at least reasonable predictions for numbers. Because it may very well be that the 'different' is actually working worse when it has the typical idiotic intake, the typical idiotic exhaust, is running 10C cooler than it should, again typically etc - and it may very well be that the more advanced electronics cope less well with having out of spec conditions. This would actually be fairly realistic. So far, it's all speculation and I'll take it as such - with no offense intended.

[etxxz]

The computer itself is different, it processes much more data and i'm sure the bmw engineers took advantage of that capability to refine things. What - i probably will never know and we'll never understand. There's a lot more to just running than knock sensing and idle control. I work in a company that designs and tests motorcycle engines. You'd be surprised the endless amount of parameters we have to deal with to run a tiny itty bit better than a previous test.

^You can run a OBD2 fuel rail on the OBD1 manifold easily...

I second this. Its very easy (AND CHEAP) to DIY your own kit. OBD2 with M/S50 manifold. No problem. This where all if not most of the gains of the "obd1" swap come from anyways.


on a bad side of things. I have sold all my e30s. i'm out of the e30 world. will probably move onto e46 fanatics... If anyone should need obd2 support or wiring schematics pm me. I tend to receive emails on that ; | happy moddin to all.

[nmlss2006]

Two O2 sensors, OK, how is the adaptation different and how is the idle control and the knock sensing smarter? Genuine question, mind, because as far as I know the differences are not material except in an emissions sense and then only if you use everything that was supposed to be there, but we're all here to learn.

[cmeptb13]

That's good to know. Thanks. So is the OBD1 rail simply for the use with the plastic cover then? Is there any reason at all why you'd need OBD1 fuel rail?

[328ijunkie]

^You can run a OBD2 fuel rail on the OBD1 manifold easily...

[cmeptb13]

Why do you need an OBDI fuel rail? I'm running the OBDII rail on mine along with the FPR that was under the car on the e36.

You're right. The only reason you would need OBD1 fuel rail is if you're doing the m50 intake manifold swap. That's why it's offered with the m50 manifold swap kit.

[328ijunkie]

2 bank o2 sensors. Short and long term adaptation for each bank. Smarter idle control and knock detection...

[nmlss2006]

In all of this I have not yet seen hard data on how the OBD II ECU would be 'smarter' or 'cleaner', when you remove the air pump, the tank pressure sensor etc. You do have the more immediate diagnostics advantage, coupled with the more substantial advantage of not having to convert the engine IF you can get it with all the parts, certainly, but you have to weigh that against the fact that the swap is a lot less documented and supported by vendors.
By the by, the OBD I Bosch is certainly not 1980s technology as some poster up here has offered, perhaps some research is warranted.

[metris228]

Is it as simple as this with the M54 engine and MS43 ecu?
Just flash out a heaps of options from the ecu?
Am I able to buy a harness adapter for this?

I already have a 330i wreck so already have everything I need... and I have no issues with mounting and running the drive-by-wire throttle.