Building the best non-vanos M50

[1990m3]

sounds like an interesting plan. what is the benefit from running the non vanos head with the m3 cams?

I have an identical brilliantrot 318is I'm doing an S50 swap into right now. I'm sticking with the s50 + ltw flywheel, ltw pullies, 540i HFM, conforti chip, and that's about it. I'm hoping to stay around 2600lbs as I've got a full interior. Keep us posted on your specs and how the swap goes. Post some pics too, I keep forgetting to take pics of mine where it's at. I'll start snapping some photos next week before parts start going back on the car...finally!

[Brew]

sounds like an interesting plan. what is the benefit from running the non vanos head with the m3 cams?

Well, I already had the cammed non-vanos head and complete wiring harness so it just seems like the most cost effective thing to do. Plus, no vanos unit to fail, and the better non-vanos valvetrain. When I get the motronic dyno tuned I'll probably have them raise the redline to 7300 or so.

[Budget Beater]

you can make S50 numbers out of a M50 (especially the non-vanos), it just requires some mods. Hope that helps.

[Charlie]

you can make S50 numbers out of a M50 (especially the non-vanos), it just requires some mods. Hope that helps.

That wins the "duh" statement of the year. Granted, we're only the second day in, but still. Of course you can make S50 level numbers out of an m50 based powerplant - basically by running all S50 parts. When you're finished, based on the cost of parts and time spent (big issue there), you're just as well off having started with an s50.

-Charlie

[rwh11385]

That wins the "duh" statement of the year. Granted, we're only the second day in, but still. Of course you can make S50 level numbers out of an m50 based powerplant - basically by running all S50 parts. When you're finished, based on the cost of parts and time spent (big issue there), you're just as well off having started with an s50.

-Charlie

bumbners?

[Bimmerfanatik]

Well, I already had the cammed non-vanos head and complete wiring harness so it just seems like the most cost effective thing to do. Plus, no vanos unit to fail, and the better non-vanos valvetrain. When I get the motronic dyno tuned I'll probably have them raise the redline to 7300 or so.

Where are you in this Brew?

This was a list of reasonable parts listed on the bf.c post, curious if anyone ever tried it:

92 non-vanos m50b25
s50 crank
s50 conrods (are the non vanos rods the same? both are 135 mm...
a choice of using m50b25 pistons or boring and going with the s50 pistons for a full 3.0L non-vanos motor.
swapping the intake cam to the exhaust side and buying a schrick cam for the intake
Add on a euro HFM and 24# injectors

[Brew]

Ended up getting an s50 head.

Just putting together a plain old s50 now, with a 3.5" hfm, and 24# injectors and conforti software.

The non-vanos would be cool, but it would have been a major pain in the ass to tune, and I just don't have the time or the patience.

[Bimmerfanatik]

Ended up getting an s50 head.

Just putting together a plain old s50 now, with a 3.5" hfm, and 24# injectors and conforti software.

The non-vanos would be cool, but it would have been a major pain in the ass to tune, and I just don't have the time or the patience.

plain old. lol.

So if I put a non-vanos head on a non vanos block, bored out and fitted with s50 crank, rods and pistons - what issues will I run into?

[Brew]

plain old. lol.

So if I put a non-vanos head on a non vanos block, bored out and fitted with s50 crank, rods and pistons - what issues will I run into?

Mechanically there will be no issues. The tricky part is tuning-- you will either need to dyno-tune the motronic, or get a piggyback(i.e. SMT-6) or standalone engine management system and a wideband setup. Obviously bigger injectors, I'd say 21.5#. The other possible issue is the hot-wire MAF, which I've been told has a lower max air mass reading threshold than the hot-film MAFs.

[Bimmerfanatik]

Mechanically there will be no issues. The tricky part is tuning-- you will either need to dyno-tune the motronic, or get a piggyback(i.e. SMT-6) or standalone engine management system and a wideband setup. Obviously bigger injectors, I'd say 21.5#. The other possible issue is the hot-wire MAF, which I've been told has a lower max air mass reading threshold than the hot-film MAFs.

Thanks for answering this out here instead of PM - so others can view our intellectually stimulating conversation ;)

It's pretty apparent that the motronic is the weak link, am I correct? So standalone is a better idea altogether...Unfortunately, I know [_] that much about standalone engine management. What I do know is that you gain a world more of tuneability, which is obviously a good thing, and since I have a deep interest in tuning engines and learning how, maybe building a motor like this and experimenting with a standalone system is a good start.

What's the difference in MAF's? Which would be a better one to use for this setup? Forgive me, I'm stuck in SOHC motronic world - this new stuff is, well, new to me :)

Also, what's the difference between megasquirt and SMT-6? Is it like pc vs mac?

[streetknight]

quick questions what would happen if i just put in the s50 crank and keeped the m50 rods and pistons?

[Bimmerfanatik]

quick questions what would happen if i just put in the s50 crank and keeped the m50 rods and pistons?

no such word as keeped ;)

I'm almost certain the rods wouldn't be an issue - I'm told the s50 rods and m50 non-vanos rods are all 135mm. As for the pistons - one of the shmaht kids would have to answer that...thought I've heard of just swapping cranks on the non-vanos and keeping the rest the same...

[FredK]

You'd have to get the M50 pistons milled down. The crank is going to place the pistons 9 mm higher at top dead center. The M50B25 has a 75mm stroke, and the S50 has a 86mm stroke.

How much you need to mill down the pistons to get a reasonable compression ratio, I am not sure...

As for tuning a 3.0L Non Vanos (as I have seriously considered, so much so that I have a Non Vanos engine sitting in my basement, together with S50 pistons and rods), can't you slap your car on a dyno then get a custom chip burned by someone like Chuck Stickley? I think his custom software is like $600, but I am not absolutely sure... I guess that'd mean you'd have to drive to PA, but eh, what's 6 hours in a noisy, stiffly sprung vehicle? :D

Anyway, I'm thinking it'd be easier for me to just get a running S50 and slap it in. I checked at my local engine rebuilder, and to get the M50 Non Vanos bored out 2mm would cost $280. You can sometimes get a bottom end for around $600-800.

[Brew]

Thanks for answering this out here instead of PM - so others can view our intellectually stimulating conversation ;)

It's pretty apparent that the motronic is the weak link, am I correct? So standalone is a better idea altogether...Unfortunately, I know [_] that much about standalone engine management. What I do know is that you gain a world more of tuneability, which is obviously a good thing, and since I have a deep interest in tuning engines and learning how, maybe building a motor like this and experimenting with a standalone system is a good start.

Not necessarily a weak link... the best way to tune the motor would be to have it dyno-tuned by somebody who really know the non-vanos DME- Stickley, Conforti, etc. Obviously that is pricey, and then you are basically stuck with that engine setup/modifications unless you get it retuned.

As far as standalone (megasquirt, tec3r, motec) vs. piggyback (SMT-6, unichip, etc):
Standalone systems are just that- they replace the factory dme and control all engine management. They are difficult to tune because you are basically starting from ground-zero with all the parameters. You need to know a lot about engine management and electronics to even get the car running with one of these.

Piggyback systems like the SMT-6 work in conjunction with the factory DME and adjust tuning by modifying voltage signals before they get to the DME- basically 'tricking' it into changing timing, fuel trim, etc. They are the best option for someone who doesn't know a ton about tuning and who wants to be able to change the tuning themself with a laptop. You would need a wideband 02 sensor to do this so that you can monitor A/F ratios.

What's the difference in MAF's? Which would be a better one to use for this setup? Forgive me, I'm stuck in SOHC motronic world - this new stuff is, well, new to me :)

You need to use the non-vanos MAF if you are sticking with the stock engine management.

[raimo]

Can an aftermarket EMS be put on a vanos engine ? what would control the vanos then or does it work with oil pressure only ?
is vanos worth the extra time & effort in terms of reliability ? i've seen a couple of vanos units to fail