Are chips worth the money

[Farrierman]

Hi don't no any thing about chips on bmw e30 ,I have had loads of remaps done on new cars ....any ideas Alex

[Brianmoooore]

BMW have to design their cars to cope with extremes of temperature, low air pressure at high altitudes, and dubious fuel qualities, as well as for low emmisions. If you live in a country such as the UK, where the fuel is of a high quality, temperatures don't go to extremes, and you're unlikely to drive at an altitude of more than 400m, then certain compromises can be programmed out of the timing and fuel maps, releasing a very few BHP and MPG.
Claims of releasing the order of 10 BHP or more without over fuelling are ludicrous, unless the programmer relies on the assumption that the injectors on the recipient vehicle are clapped out, in which case the money would be better spent in first having them rebuilt.

[aimlessrock]

A chip in a well maintained engine will give you a little more mid range grunt and a few more mpg's but it is not a substitute for proper maintenance.

A mild chip in my cabby made it a little more responsive and a tad more economical and worth the small investment.

[Farrierman]

Thanks, have a 1991 325 touring looking for a few more horses is it a good idea to remove to cat to increase performance any other cheep tunning mods thanks Alex

[Brianmoooore]

Cats. on a M20B25 don't have much effect on power, but do have a noticeable effect on fuel consumption (42.8 MPG down to 40.1 at a constant 56 MPH, according to BMWs own figures).
As long as the car's build date or date of first use is before August '92, you can remove the cat.
BMW didn't skimp on these engines, so there's nothing simple that will massively improve performance on the cheap.
The best advice is to get it running as it left the factory, starting with rebuilt injectors - see traders' forum.

[DHFiS]

Have you had it on the dyno so you know what power is it making at the now?

[Farrierman]

No have it up on the ramp doings it's mot work and thought might squeeze some more bhp out of it what should it have ?

[aimlessrock]

No have it up on the ramp doings it's mot work and thought might squeeze some more bhp out of it what should it have ?

unless they have been overhauled in the last few years make the injectors your first port of call.

[HairyScreech]

The mapping on the stock ECU is not actually very good, I have been working hard to understand the E30 and E36 fueling strategy and Cat cars seem to be more concerned with keeping the cat happy than the driver.

The lambda forces the fueling to a false/detected lambda=1 all the time even when the engine would like more fuel, even at WOT the fueling and timing is very conservative, I have some race maps I was given for stock engines there is so much extra ignition timing at some point I was amazed.

If you have a pre 92 cat car then you can drop the cat and ditch the lambda sensor too, then once chipped you will see the biggest benefit.
If you have a pre-cat car but still have the lambda sensor then ditch it.

The E30 ECU hardware is actually pretty good, better than Vauxhall/alfa and volvo stuff from the late 90s! but they were programmed for a very specific task from the factory.

[bosers]

I felt like the 'mild' chip I bought for my 325i touring gave a bit of mid range grunt and i was pleased with it. Never had it dynoed though so can't give any evidence I'm afraid. I had the injectors rebuilt and had done all gaskets, seals etc. before fitting the chip

[Brianmoooore]

I felt like the 'mild' chip I bought for my 325i touring gave a bit of mid range grunt and i was pleased with it. Never had it dynoed though so can't give any evidence I'm afraid. I had the injectors rebuilt and had done all gaskets, seals etc. before fitting the chip

That about sums it up nicely. Worth doing, as long as you don't expect miracles

[Farrierman]

Thanks it's a j reg , is there a cat replacement part you can buy or do I make one up ?

[bosers]

Mines a j reg and was registered just before cats became mandatory, can't remember exact date though. A pre cat exhaust section can be bolted up I believe.

[reggid]

The mapping on the stock ECU is not actually very good, I have been working hard to understand the E30 and E36 fueling strategy and Cat cars seem to be more concerned with keeping the cat happy than the driver.

The lambda forces the fueling to a false/detected lambda=1 all the time even when the engine would like more fuel, even at WOT the fueling and timing is very conservative, I have some race maps I was given for stock engines there is so much extra ignition timing at some point I was amazed.

If you have a pre 92 cat car then you can drop the cat and ditch the lambda sensor too, then once chipped you will see the biggest benefit.
If you have a pre-cat car but still have the lambda sensor then ditch it.

The E30 ECU hardware is actually pretty good, better than Vauxhall/alfa and volvo stuff from the late 90s! but they were programmed for a very specific task from the factory.

pretty much all modern cars run at stoich at light and medium load when you arent interested in max performance. For sure stoich is used for emissions and cat life but its actually a pretty good AFR to target for most operating points except for high loads and perhaps idle on a cammed engine.

Richening the mixture and running O2 less isnt going to bring much benefit as the power from a slighty rich mix is pretty small but it will eat more fuel.

my stroker used to run that way before i went to bigger and better things, the O2 was disconnected, ECU reset and a "live" chip was made on the RR. i ended up plugging in the O2 sensor and it ran better(more consistent) IMO and used less fuel. personally i would only optimise the advance in those areas for performance.

racemaps with more advance doesnt mean it makes more power, sometimes less is more. I dynoed a couple chips before and they gave more midrange 3500-5500 but no extra peak power, from more recent tuning experience i would say they were over advanced on the ignition side of things. A custom map piggyback on a stock car gave far superior gains and was better money spent but that was 10years ago.

[HairyScreech]

I will have to pass the ecu info I have over to you at some point, I am sure you would be interested. I have to get my head around it a bit further first though really.

Fully agree that 1 is not a bad target and most modern stuff will run towards it but the M20 and M50 seem to want to be leaner and richer at some points than the ECU will allow in its narrow operating range.
Quite a few reports from the tuning guys that are doing their own stuff and keep a WBO2 on all the time that after a while the O2 feedback starts fucking with the tune, It's worth noting that it is common practice to disable it while producing the tune and then re-enable it later or leave it off in the code on the E36.

Also totally true that the ideal is the most power possible with the least advance, that's a sign of a good engine. The closer to TDC you fire the less negative work done.

I have the ability to read, burn and emulate all OBD1 BMW chips now and I'm trying to disassemble the ECU base code for the M1.3 and M3.3, turns some interesting things up when you start looking at the code level.

[reggid]

I will have to pass the ecu info I have over to you at some point, I am sure you would be interested. I have to get my head around it a bit further first though really.

Fully agree that 1 is not a bad target and most modern stuff will run towards it but the M20 and M50 seem to want to be leaner and richer at some points than the ECU will allow in its narrow operating range.
Quite a few reports from the tuning guys that are doing their own stuff and keep a WBO2 on all the time that after a while the O2 feedback starts ******* with the tune, It's worth noting that it is common practice to disable it while producing the tune and then re-enable it later or leave it off in the code on the E36.

Also totally true that the ideal is the most power possible with the least advance, that's a sign of a good engine. The closer to TDC you fire the less negative work done.

I have the ability to read, burn and emulate all OBD1 BMW chips now and I'm trying to disassemble the ECU base code for the M1.3 and M3.3, turns some interesting things up when you start looking at the code level.

if the pulse width stored in the chip is different to the pulse with under operation of closed loop (.e. the o2 is trimming fuel) then the ECU seems to use this data to offset all other maps including WOT as "corrections/learning". so you need to disconnect the sensor when tuning and tune for stoich under the conditions that O2 feedback will be active so the ECu doesnt "learn"

[Speedtouch]

Mild chips are particularly beneficial on the later low compression M20B25 cars, which tend to feel a bit 'flat' in the lower end of the rev range.

Fitting one will make the car feel livelier, with improved bottom end torque and overall driveability (better throttle response, etc.), plus you can expect an average of 2-3 mpg improvement in fuel economy if the car is driven gently.

Well worth the effort of fitting one, even if I may be biased.