Early e34 535's

[ScD 0]

I'm looking at exhaust and a couple of other options for gaining a few extra hp from my e34 535, NZ delivered, build date 6/88. When I check the VIN number here I'm told I have a catalytic converted installed. From what I've read in other forums, I don't think that's true, and when I changed the oil yesterday, I had a good look under the car and couldn't tell.

The other odd thing is the DME number of the ECU does not match that of other early 535's over seas. The DME numbers match the last of the 635's and early 735's. This lead me to think that we got a more basic version of the Motronic (v1.1 instead of the standard v1.3) for use without O2 sensors and cat's.

I've spoken to Brent a little about this, but I'd love to hear others thoughts.

Thoughts?

[kiwi535 538]

you are right,at least about the cat.The vin decoder also tells me i have a cat,but i dont.I think our cars should be the same as very early UK cars,I cant help you with the ecu number,tho i have always meant to get a chip for mine .Do you need to pull the ecu to bits (as you would when replacing the chip) or is it just a mattter of pulling it out and looking on the cover?From what i have heard you wont gain much from the exhaust,the stock system is heavy but flows well,same as the intake,its well matched to the rest of the engine.Prolly the best thing to do would be to get rid of the butterfly valve in the intake and get a hot wire systemMAF vsMAS or something....

I tink brents car is a uk import is his ecu no the same as yours,i will look at mine too!

Edited May 1, 2005 by kiwi535

[ScD 0]

You can find the DME number by taking the cover off the black box on the drivers side on the engine bay, removing the harness and pulling the DME out. The number is on a Bosh sticker on the box. A better descriptions is here

I actually ordered an EAT chip, but didn't know to check the DME numbers and so have the wrong one. I've been looking for a v1.3 motronic from a later 535 for a month or so, but haven't found one cheap enough. From what I've read, using a later DME without an O2 probe will cause the unit to run in an open loop, telling the DME that the 02 is perfect all the time, causing it to run a little rich.

I'd be really interested to know what your DME number is.

[CaM 0]

From what i have heard you wont gain much from the exhaust,the stock system is heavy but flows well,same as the intake,its well matched to the rest of the engine.Prolly the best thing to do would be to get rid of the butterfly valve in the intake and get a hot wire systemMAF vsMAS or something....

I've always read differently about the stock system, plus the middle muffler, apparently, has a tendency to collapse internally (baffles dislodge) which block them up like nobody's business.... when sparkle did his exhaus it made a huge difference... when you get the factory mufflers off you see exactly how sh*t they are.

Personally I'd rip the factory ecu out, not bothering with chipping or hotwire afm conversions...

Link ecus have had a price reduction of late, should be able to pick up a whole setup for around $1200 i'm told, then you run MAP sensor instead of afm, fully tuneable rom... with a chip you're fairly set in the ways of the manufacturer of that particular chip's specs, with a link you have full tuneability, and extra bits and pieces like electric fan controls, shift lights and that sorta thing if you should feel it neccessary.. sure you have to run it up and tune it on a dyno, but then again, you really have to do the same for a chip, and then to get the real benefit you still have to do the big afm change (moving vane are so restrictive) which woulld tip you well over the price of the link, and without the same potential power still...

my 2 cents

[CaM 0]

You can find the DME number by taking the cover off the black box on the drivers side on the engine bay, removing the harness and pulling the DME out. The number is on a Bosh sticker on the box. A better descriptions is here

I actually ordered an EAT chip, but didn't know to check the DME numbers and so have the wrong one. I've been looking for a v1.3 motronic from a later 535 for a month or so, but haven't found one cheap enough. From what I've read, using a later DME without an O2 probe will cause the unit to run in an open loop, telling the DME that the 02 is perfect all the time, causing it to run a little rich.

correct, it'll run on like a "limp" mode, which adds more fuel..... shouldn't be too much of a job to install and wire up an O2 sensor... get a lead safe one then you can runs avgas :pimp: :bounce: :bowdown:

[kiwi535 538]

i am sure that if you emailed mark at eat chips he would do a swap.I have talked to him about this and he reckons that he could do a chip for our "open loop" cars

ScD are you interested in my dme #?

Most of the guys at the bimmer info e 34 forum seem to think the exhaust and intake arent too bad for the stock engine...dont get an increase rpm limit for the old m30

[ScD 0]

ScD are you interested in my dme

Yeah, I would be interested to know if its the same as mine. I suspect it will be.

i am sure that if you emailed mark at eat chips he would do a swap. I have talked to him about this and he reckons that he could do a chip for our "open loop" cars

I emailed Mark when I first got the wrong chip and told him about the version mismatch. He scratched his head a little, because his data on the motronic says that the e34 never had the older v1.1 DME. My guess is that NZ and possibly Oz were special cases; we would have been some of the only countries to not get cats. He did say he could make a chip for the older DME, but he thought it would be better if i could find a more advanced motronic first.

Tonight I'll pull my DME out and get one of the propeller heads here at work to copy the EPROM chip and send it to Mark so he can have a play..

:bounce:

[kiwi535 538]

I am sure he would be able to do something,as i say i have talked (emailed) himabout it and told him obout our non cat non o2 cars.His website has chips for early m30s doesnt it...Wait for my dme # till you send it off to mark and we'll see if he will do two for a bit cheaper!!!!

[ScD 0]

Have you managed to check your DME number yet kiwi?

[ScD 0]

So I finally got around to pulling my DME out and had the eprom copied by the techs at work without any problems. I've emailed the code to Mark at EAT and hes working on a chip for our non-cat, non 02 cars! I should have the results by middle of next week. :mosh:

[kiwi535 538]

no sorry scd with my little rear end accident ,new job and bad weather(and a bimmersport run) I havent,,I have to tidy the car uo tho so i will have a look this coming weekend....

[bezzal 1]

Scd,

Did you ever get the Chip back? Have you installed it? results? would you like my DME #

Richard.

[rxsumo 33]

I'm a little late with this thread, but the cat/no cat mystery might be answered by something that happened to a friend of mine.

A mate of mine owned the NZ demo E34 M5 (3.6 I think). When he got the car it idled roughly and generally didnt do things quite as nice as it should fuelling wise.

While the car was still under the warranty, he did so reasearch and found that the car was an Aussie spec car (ie should have a cat), but the car didnt.

On further research, he found that the car was shipped from Germany with a new front pipe sitting in the boot and that BMW NZ swapped the front pipe on arrival (no other changes) and ditched the cat ....because we werent lead free at that stage.

The only hitch of course...ECU is expecting a cat....no cat...ECU runs those sensors in limp home mode, hence fuelling at idle and slow running all up the creek.

BMW NZ eventually swapped the ECU for a South African one at their cost....funny enough the car came right....idles nice....fuel economy increased.

Perhaps the cars actually need the cat in place....havent actually checked our one but that could explain the intermittent fuelling issue that you have on startup Paul.....

[bezzal 1]

My DME # is 0 261 200 179

That is interesting RXSUMO. Sounds like BMW did a bit of a Half Job on the import of that M5 car anyway. They could well have done the same with ours!

Richard.

[kiwi535 538]

might also explain the less than spectacular fuel economy

[kiwi535 538]

so a later ecu plus oxygen sensor,the cat itself isnt required is it???

[bezzal 1]

I'm pretty keen to find out the full story on our ECU no Cat situation.

When you had you car on a Dyno Paul did they monitor your fuel/air ratio? (I gather from previuos posts that you have done this) That I would have thought would have indicated if the ECU doing anything out of the ordinary.

Also I guess if the ECU thinks it has a cat to warm up to temp asap it will be doing things that aren't required for our cars.

Richard.

[kiwi535 538]

I did an air fuel ratio.On this excel version of my run I show the plot,i will see if i can find the original for the actual numbers

[nath 129]

I see little point with any of you guys changing chips in your DME or fitting aftermarket control units unless you start changing the internals of your engine.A chip or a LINK system may sound great if your a sucker and listen to the sales pitch but all its doing is throwing in more fuel into a engine with standard cams and compression and maybe advancing your ignition timing slightly which is not great when using crap NZ pump gas.

[rxsumo 33]

I see little point with any of you guys changing chips in your DME or fitting aftermarket control units unless you start changing the internals of your engine.A chip or a LINK system may sound great if your a sucker and listen to the sales pitch but all its doing is throwing in more fuel into a engine with standard cams and compression and maybe advancing your ignition timing slightly which is not great when using crap NZ pump gas.

A mate of mine had an issue with the standard computer, and didnt want to splash out the $4K for a genuine BMW replacement, not too sure if it was a 525 or 535 manual, and installed a Link to run the car.

On the un-modified internally car, the power increase was said to be significant and noticable.

Only hiccup is that the Link wont run all the other stuff that the standard E34 computer does....like the dash etc etc.

[Guest Andrew]

I see little point with any of you guys changing chips in your DME or fitting aftermarket control units unless you start changing the internals of your engine.A chip or a LINK system may sound great if your a sucker and listen to the sales pitch but all its doing is throwing in more fuel into a engine with standard cams and compression and maybe advancing your ignition timing slightly which is not great when using crap NZ pump gas.

Link gains are huge over stock engine management -

Having said that on my modified motor i got massive gains

[nath 129]

I would interested to hear anybodys thoughts on just how a control unit upgrade on a standard engine would give noticable gains.Has anybody seen actual results on a dyno?

[bezzal 1]

From what I have gathered, the ecu is set up on std cars to get good economy, and if fitted with a catalytic converter to keep the gas that is passing into it at the optimal range so as to allow it to perform. Which is an air fuel ratio of approx 14:1. All of the above is to pass emissions test.

The car manufactures have std tests that they do for economy runs etc. It is set up to optimise that as well.

None of the above conditions are for good power!

I've had a bit of a play with a S13 CA18DET engine. There were big hollowsand lumps in the fuel maps. With the aid of a wideband O2 sensor to check what was happening, we leaned it out in a few places and enriched it in others. the car was noticably more responsive and felt faster. Not scientific but the is my 2cents worth.

I know it is a turbo so probably the differences were more pronounced. But heh why not have you car optimised and doing things as well as it can.

[Guest Andrew]

I would interested to hear anybodys thoughts on just how a control unit upgrade on a standard engine would give noticable gains.Has anybody seen actual results on a dyno?

Nearly 30 hp on another one that was done at Bob Homewood - the main thing is the AFM is removed - that thing is hugely restrictive and you can run poo loads of timing advance.

[ScD 0]

Long time to reply...

AFIK: Late 80's and early 90's cars wont have a catalyic converter, nor will they have an oxygen snesor. Since we used leaded fuel, had next to no environmental laws, and fuel was cheap, fitting a cat and oxygen sensor would have been a waste. The DME in these cars can only use engine speed and AFM to control spark and injection, it gets no readout on what happens after combustion, so cannot fine tune air-fuel ratio. I know for a fact that my m30 535i is NZ new, has no cat or oxygen sensor, and has a .150 DME fitted.

My guess is that most imported cars and maybe some later model NZ new cars will have cats and oxygen sensors fitted. Because of the oxygen sensor, the DME can find the optimum air-fuel ratio by reading the exhaust gas. My guess is that most of the m30 535i will have a .179 DME with oxygen sensor and cat.

If you pull the cat in these cars, provided the oxygen sensor is before the cat, there should be no effect on performance. If you pull the oxygen sensor out, the DME will go into closed loop mode, running exactly like the DME in a non-cat, non-oxy car.

I have an EAT chip designed for the .179 DME fro a m30 535, but at the moment, it is of no use to me. Mark D from EAT has had a copy of the eprom from my .150 dme for he past 6 months, but is either ignoring me, or too busy to reply.