Best M42 Mods

[M3Philipp]

super easy to do. pull valve cover. loosen cam gears on desired cam to advance. rotate clockwise till you reach your desired advance. clockwise when standing directly in front of your car.

Anyone did that?
How many degrees would you turn intakecam, and would you adjust outake aswell?

[goinstrong]

While my M42 is in an E21, (and the space in the E30 may not allow this),
I have an E21 323i flywheel installed. It REALLY helps on the low end, and revs up and down very quickly. I recommend it!

Tim

Anyone have feedback on the performance chips? I don't normally wind it out all the way, so something that improves the low and midrange area would be best for mine, since it is a DD. Thanks.

[MF DOOM]

^MarkD chip, Coil-on-plug kit, lighter FW. Not crazy light, makes it a bit trickier to drive. I have a 19lb non-ac FW & clutch on my M42.

Ive got a 11lb flywheel on my car and learning to drive it sucked.. so embarrassing. Killing my car in the middle of huge intersections (never empty intersections) and sweating everytime i see a yellow light ahead of me. its such a gnar transition, from 28lb to 11lb.



Protection:alcohol induced post.

w'sup den?

[sc318]

Is the transition from the stock flywheel to a significantly lighter one really that bad? I was considering something in the 9-11lb range.

[1Bad67]

Really?


My 318i didn't have AC...interesting.

Your not in the US. Several other Canooks have reported having the Non AC flywheels too.

[bmwman91]

Based on my experience, the only "easy" M42 power mods worth a damn are a chip and a lighter flywheel. I have tried all of the other things listed in this thread over the last 12 years, and with the exception of the two things that I mentioned, they are useless. The stock air intake is great and won't be beaten by some cone filter, the COP conversion (which I invented BTW) is great for cleaning up the engine bay but makes no more power, advancing the intake cam moves the power band but causes bad mileage and an uneasy idle since the ECU's chip is programmed for a different intake profile and 4-pintle Mustang injectors don't really do anything and don't actually fit 100% properly (~2mm too short). Take it from me, I have tried it all and ended up back with a stock setup for the most part (kept the COP conversion since it is a 1-way road there lol).

Someone mentioned a DASC. That will work great. It is not quite a bolt-on, but it may well be the cheapest and easiest way to make REAL power gains. Other than that, a turbo setup is a good bet. If you want to stay NA, your only options are to bore, stroke, increase compression and put hotter cams in. All of the aforementioned options require a custom chip or a stand-alone ECU and dyno time.

An internally stock M42 will not make more than 160HP at the crank with any amount of bolt-ons. I know that a lot of guys look at boring out the throttle body, putting cone filters on and grinding the intake manifolds to mate evenly, but it all does basically nothing. Stock, the M42 pulls plenty of air and there is almost no restriction seen before the intake valves. The intake ports are a little bit of a bottleneck, but opening those up is not something that any Joe Blow with a Dremel can do, and opening them up too much will start hurting the mid-range power band.

Anyway, this is my take on it after 12 years of owning & screwing around with M42 engines. I founded M42Club and still love the engine (even more now that I have a ~205BHP 2.1L NA M42!), but you have to be realistic about it. It is a good little engine (actually, it is pretty freaking big for a 4-banger) that pulls hard, sounds cool and really eggs the driver into driving the shit out of it. With the exception of a few major mechanical flaws (fairly easily to correct), it should provide years and years of fun driving while still being out-run by newer mini-vans lol.

[RAYREY]

12 years of experience I can respect

[quote=bmwman91;3418488]Based on my experience, the only "easy" M42 power mods worth a damn are a chip and a lighter flywheel. I have tried all of the other things listed in this thread over the last 12 years, and with the exception of the two things that I mentioned, they are useless. The stock air intake is great and won't be beaten by some cone filter, the COP conversion (which I invented BTW) is great for cleaning up the engine bay but makes no more power, advancing the intake cam moves the power band but causes bad mileage and an uneasy idle since the ECU's chip is programmed for a different intake profile and 4-pintle Mustang injectors don't really do anything and don't actually fit 100% properly (~2mm too short). Take it from me, I have tried it all and ended up back with a stock setup for the most part (kept the COP conversion since it is a 1-way road there lol).


I have always been a fan of dasc bit also of Turbo...I know I will end up with a Turbos set up! It;'s very timely that i have been looking into and reading into cop kit coz my plug wires just crapped out... Im doing a cop kit soon in prep for my Turbo project any suggestions on cop kits ( I see several here)? Thanks

[unevolved]

HQ Autosport.

[RAYREY]

hq's cop kit

HQ Autosport.

Thanks for the lead (unevolved) I started looking into HQ cop kit already! I also saw Bav Auto has one but states its not a cop kit!

[jrobie79]

ssk and clutch stop

[djmossm42]

CAI does nothing and advancing the intake cam only moved the powerband up higher, really stupid to do if you use it as a street car.

CAIs work as long as it's designed right and it actually gets colder air than whats in the engine bay. Most of the CAIs out there put the inlet in the hottest locations under the hood unless you build a good shield. Others introduce bends which create too much resistance (some resistance in the system is good though). In my previous cars I've always had good luck with a drop in filter and modifying the stock setup.

So I decided to do the same with my E30. I noticed the airfilter box has a 3" to 2.5" inlet tube coming out of it pointing toward the hole in the back of the headlight cover. I just connected the dots and there is a definite difference.

For about $100 you can go to PepBoys and get the following

K&N drop in filter ~$50

APC 3" extendable tubing $20 (consider getting some clamps)
*I'm now using a piece of PVC and just a small section of the flexible tubing to reduce turbulence in the tube as well as making it less temperature sensitive*

APC 6"- 3" cone inlet $20

Some, or most of you that are running projector style lights may not be able to do this the same way I did. You may have to ditch the cone.

I'll do a proper write up with more pics soon. But it's pretty simple to figure out. Basically replace the stock inlet tube with a 3" straight tube and put a cone on the end between the space behind the headlights and the headlight access cover which acts as a heat shield. It looks stock but sounds and feels good :D

[bmwman91]

CAIs work as long as it's designed right...

"Designed" When I think of that word with respect to an automotive air intake, I think:

What is the helmholtz resonance frequency of the inlet snout / airbox volume (including the impedance presented by the air filter element)? At which RPMs does this result in positive pressure waves impinging on the intake valves, and which RPMs does this leave rarefied waves impinging on them? What is the net gain in volumetric efficiency and energy output when integrating the power curve from min-to-max RPM? What is the net change in temperature for the induced air/fuel charge that is pulled into the combustion chamber? How is the atomization of fuel effected by a change in inlet air temperature?

Home-Depot'ing car mods is fun, no denying that, and it can be a real learning experience. At the end of the day though, you do need to keep in mind that you are trying to improve upon a design that was optimized by a bunch of German PhD's and engineers that probably solve the wave equations* for the optimal air intake on the back of napkins for fun when they are out having bier with their friends. They have already taken into account everything you can imagine, and about 3x as many things that most normal enthusiasts have never even heard of, when designing the air intake system. Messing with it really only makes some aspects of the system different, not better. The whole reason BMWs are "good" cars that carry a big price premium is because they are designed well enough that $30 in parts from Home Depot CANNOT improve them!

With the exception of the stock chip, there is no "free" low-hanging fruit. As far as I can tell, the stock M42 software was severely crippled so that the M42 models would not eat into the more expensive M20 models' sales volumes. A chip is the only power mod worth its price, really. A light flywheel is nice too, but it comes at the expense of a rough idle, slightly degraded driveability and probably reduced transmission life. The heavy flywheel was another case of "the best option with all things considered."

This isn't a personal attack directed at you specifically or anything. It's just my usual tirade about "cold air intakes." I wasted all sorts of time and money on them a decade ago before I knew better too. Hell, I am glad I did. It drove me to study mechanical engineering, which is the only reason that I know better now anyway lol.

*(probably sounds simple...look it up).

[Martin C.]

What about the Dinan chip? AS far as I know they only produced the one with no software updates (I called them).

[getouth]

I agree that the only mods worth it are the flywheel and chip. Mark D or Turner motorsports and I highly recommend removing the fan clutch and installing a 16" spal electric fan! It takes a load off the engine and improve acceleration and economy. I've owned M42's for the last 5 yrs four total. My $0.02

[djmossm42]

"Designed" When I think of that word with respect to an automotive air intake, I think:

What is the helmholtz resonance frequency of the inlet snout / airbox volume (including the impedance presented by the air filter element)? At which RPMs does this result in positive pressure waves impinging on the intake valves, and which RPMs does this leave rarefied waves impinging on them? What is the net gain in volumetric efficiency and energy output when integrating the power curve from min-to-max RPM? What is the net change in temperature for the induced air/fuel charge that is pulled into the combustion chamber? How is the atomization of fuel effected by a change in inlet air temperature?

Home-Depot'ing car mods is fun, no denying that, and it can be a real learning experience. At the end of the day though, you do need to keep in mind that you are trying to improve upon a design that was optimized by a bunch of German PhD's and engineers that probably solve the wave equations* for the optimal air intake on the back of napkins for fun when they are out having bier with their friends. They have already taken into account everything you can imagine, and about 3x as many things that most normal enthusiasts have never even heard of, when designing the air intake system. Messing with it really only makes some aspects of the system different, not better. The whole reason BMWs are "good" cars that carry a big price premium is because they are designed well enough that $30 in parts from Home Depot CANNOT improve them!

With the exception of the stock chip, there is no "free" low-hanging fruit. As far as I can tell, the stock M42 software was severely crippled so that the M42 models would not eat into the more expensive M20 models' sales volumes. A chip is the only power mod worth its price, really. A light flywheel is nice too, but it comes at the expense of a rough idle, slightly degraded driveability and probably reduced transmission life. The heavy flywheel was another case of "the best option with all things considered."

This isn't a personal attack directed at you specifically or anything. It's just my usual tirade about "cold air intakes." I wasted all sorts of time and money on them a decade ago before I knew better too. Hell, I am glad I did. It drove me to study mechanical engineering, which is the only reason that I know better now anyway lol.

*(probably sounds simple...look it up).

I don't take it personal I know this is a controversial subject and I've seen many threads saying the same thing that it doesn't work or not worth it. I don't claim to be a mechanical engineer by any means and pretty much the reason why I've always tweeked what was there on my cars to see if there is something that can be gained. In the case of my 318 I have to agree that BMW did have it pretty much spot on as the difference my mod makes is not drastic but it is noticeable. Whether it's worth the cost is subjective to the person. This has now become an experiment for me and I would like to gather some actual data since my car is basically stock at this point.

I plan on doing 3 tests :

1. Bone stock setup with paper filter
2. Inlet modification with paper filter
3. Inlet modification with K&N filter

Once I have some data I will share with everyone.