M50 2.9 Stroker questions... [Archive] - Bimmerforums

brew

07-30-2005, 02:09 AM

Currently in the process of acquiring parts to build a 2.9 stroker. My power goal is somewhere in the neighborhood of 230whp.

From my research so far, it seems as though the non-vanos M50 is the best platform for this.

I picked up a non-vanos short block and wiring harness this week. I'll be getting a non-vanos head next week from a co-worker and rebuilding it with some sort of cam setup (suggestions welcome). I'm also looking for a good deal on a S50 crank and rods. I've read that the S52 crank is much lighter, but is difficult to retrofit to the OBD1 block/ head/ timing chain assembly. Anyone have any more info on that?

Also, is the compression ratio raised when this is all bolted together, and if so, is 93 octane sufficient?:
N/V M50 block, S50 crank and rods, N/V M50 pistons, N/V M50 head

I've read all the threads about this topic that I could find... just trying to get some solid answers to the few questions I still have.

Thanks in advance.

(BTW this is a cross post from the E36 forum- didn't get much response over there and I figure this is where all the NA engine builders hang out.)

Steve J.

07-30-2005, 02:21 AM

I think you could aim a bit higher then 230whp, thats about what a normal 2.5L semi-built motor puts out. 2.9L stroker M50 is putting out about 265whp for a full race motor.

How much are you looking to spend?

Is this for DM?

brew

07-30-2005, 02:31 AM

I should have clarified myself better- this is going to be in a street car, my e30, I just posted in this forum because I know you guys have the most experience in building NA engines.

buldogge

07-30-2005, 11:46 AM

E30 Stu

07-31-2005, 11:55 AM

Brew, you really need to get all the displacement you can. Yes, you can bolt together a 3liter crank/rods and 86mm pistons with no modification other than a 2mm overbore...but 3.2 is the way to go. It won't be as cost efficient as the 3liter, as it's hard to find a used 3.2 crank...and machining the pistons is necessary, but it will make more of everything you want in your street motor.
3.2 crank
stock 135mm rods
3.0 pistons (will need to me machined slightly to bring c/r down to desired (11:1 for a street motor, if you get 93-octane where you live)
This setup makes 250whp in my brothers E30.

brew

07-31-2005, 12:07 PM

Thanks for the very informative replies guys.

Buldogge, do you have the S50 rods as well? Shoot me a PM with pricing/shipping.

Stu, what does your brother do for software? Is his motor Vanos? I'd like to keep mine non-vanos, and I'm not aware of any software for a non-vanos 3.2.
There also is the budget factor, too. Boring, machining pistons, etc is going to add a lot of cost to this.
I'm not dead set on the 2.9, but it seems like a great, cost effective way to make S50 power.
Also, can you clarify if there are any issues running the S52 crank in the M50 block? I read that some custom work is needed for the crank ref. sensor to read correctly.

like2short

07-31-2005, 01:56 PM

brew

08-01-2005, 10:47 AM

why not just an S52 3.2L and be done with it?

or get an S50, wich is a bored and stroked M50?

If you are BMW club racing and trying to stay in in DMOD, your strategy makes sense, but for a hot street car, go for the extra displacment.

I think my route will be less expensive, plus I really want to build a motor myself from top to bottom and I think this will be a good experience.

I appreciate your input though, thanks.

like2short

08-01-2005, 11:30 AM

E30 Stu

08-01-2005, 01:08 PM

You are neglecting something very important in your cost analysis....

what piston do you plan on running?

The stock M50 bore at 2.5L is 84.0mm, with a 75mm stroke. Ok, so you put in the S50 crank at 86.0mm, now what are you going to do for a piston?

The S50 bore is 86.00mm, I've heard you can bore the M50 block out 2mm to 86.00m, which would allow you to use a used S50 piston, but you have to pay for machine work and I'd double check if you can safley over bore .080" or 2mm.

JL

You just answered your own question. Bore the block to 86mm, run 3liter M3 pistons.

Non-VANOS blocks can be bored to 86mm without problems. They are thick blocks since they are early production and have plenty of space for boring.

Edit: Brew, I really admire what you're doing. I would love to build a custom M50 variant of some sort, later down the road. I've got a few ideas using all factory parts.

like2short

08-01-2005, 02:14 PM

You just answered your own question. Bore the block to 86mm, run 3liter M3 pistons.

Non-VANOS blocks can be bored to 86mm without problems. They are thick blocks since they are early production and have plenty of space for boring.

Edit: Brew, I really admire what you're doing. I would love to build a custom M50 variant of some sort, later down the road. I've got a few ideas using all factory parts.

Yeah, I race with a guy that build an 86mmx84mm setup, by overboring a 2.8L M52 Block....

Do you know if the crank from a M54 3.0L would work....i believe that has 84mm bore with an 89.6mm crank.....hmmmmmmmmm.......this could be another interesting way to go.

odortiz

08-01-2005, 04:22 PM

You can overbore the block to 86mm as well (S50 pistons).

There should be no problem running 93. Run the piston 0 deck or maybe -.015/.020 (.5mm)...std headgasket or MLS at std thickness (.071).

If you are in need of some custom cams contact Jim Rowe at Metric Mechanic www.metricmechanic.com

Alternatively, you move the intake cam to the exhuast and buy a Schrick for the intake.

BTW...I have an S50 crank for sale if you're interested.

Good luck...

does that work? have you personally done it? that seems like a great cost savings. where can i get just a Schrick intake cam?
how about schrick intake and stock exhaust on the exhaust side. i figure the reduced lift will give you a better margin for an overrev in case you float a valve.

buldogge

08-01-2005, 04:50 PM

does that work? have you personally done it? that seems like a great cost savings. where can i get just a Schrick intake cam?
how about schrick intake and stock exhaust on the exhaust side. i figure the reduced lift will give you a better margin for an overrev in case you float a valve.

It's a common mod for non-vanos 2.5l motors...and makes for a slightly hotter cam set-up, much like the vanos motor Schricks.

Any Schrick dealer can get you the non-vanos 2.5l intake cam.

E30 Stu

08-01-2005, 05:44 PM

Yeah, I race with a guy that build an 86mmx84mm setup, by overboring a 2.8L M52 Block....

Do you know if the crank from a M54 3.0L would work....i believe that has 84mm bore with an 89.6mm crank.....hmmmmmmmmm.......this could be another interesting way to go.

The M54 3.0 does in fact use the same crank as 3.2L E36 M3's, 89.6 stroke.

My dad ran a 86mm stroke, 84 bore alloy M52 with 11:1...it hauled butt for an otherwise stock E30 M3. The 3.2 crank would just make it all the more powerful down low. :D

like2short

08-01-2005, 05:55 PM

another place where BMW got cheap with us... the Euro 3.2L has a 91mm stroke, instead of the 89.6mm....BMW must have been planing on the M54 to be at 3.0L and hence the goofy stroke length at 89.6mm....why not just make it 90mm....

Stu: Do you guys have any experience doing offset grinds on cranks to change the stroke? maybe an offset grind 89.6mm crank could be fun to make it a bit logner....

putnampunk

08-02-2005, 12:30 AM

It's a common mod for non-vanos 2.5l motors...and makes for a slightly hotter cam set-up, much like the vanos motor Schricks.

Any Schrick dealer can get you the non-vanos 2.5l intake cam.
http://www.europeancarweb.com/tech/techletters/0000ec_techletters02_d/

M3 Cams in 325is
I have a 1992 325is with the non-VANOS engine. I've asked some people this question and everyone seems to give me a different answer. I want to put in M3 cams but because my car is non-VANOS I don't think it will work. Some people said. "yes," some said. "no," and some said. "only if the cams are from a 1995 M3." Turner Motorsport sells a M3 cam set for 1993-95 325is. Is the lack of VANOS going to prevent me from upgrading my engine with M3 parts? If I can't put these cams in what could I use from an M3 to give me some more horsepower?
Dave
via the Internet

We consulted BMW engine builder and parts swap specialist Pete McHenry of Precision Performance in Winston-Salem, N. Ca. His reply: "You can install an intake cam from a 1992 M50 on the exhaust side. Check the beginning of valve lift of the stock cam, then set the timing so that the swapped cam has the same starting point. This will give you a 240-degree cam with 9.7 lift vs. 9.0. Buy a Schrick non-VANOS 252 for the intake and you'll have the same timing as an M3."

In other words, forget about M3 parts, Dave--you don't have an M3. But what you do have is a very cool high-revving engine that will never need a replacement VANOS unit. In addition to McHenry's sage advice, you should consider a performance exhaust system and a performance computer chip, although neither is necessary to make the cam job work. There are lots of go-fast parts available for this engine. Just check out the ads in european car and start visiting Web sites.

oh yeah. insert "hehehe", someone's dad.

bgcabrio

08-02-2005, 09:45 AM

Its ironic that this is getting some attention. I am slowly putting the parts together for this build as well. I am planning to use a stock bore m50 block and pistons, and S50 crank (knife edged), s50 rods, and an s50 top end. I already have the top end and a source for the crank. I am estimating it will cost me roughly $1000 in parts for everything.

So far my bigget question is if I need to do anything special to drop the compression. It will be a mostly street car, but 93 octane is all I run normally anyway.

brew

08-03-2005, 12:05 AM

Lots of great info here guys!

I really appreciate all the input, especially since this is one of the 'lesser-known' engine builds.

Like2short, I'm planning to use m50b25 pistons, but depending on what comes up for sale, I might bore the block and go with the s50 ones.

Still wondering about software and approximate compression ratio of the 2.9 if anyone has any insight...

like2short

08-03-2005, 02:47 AM

how can you use the m50b25 pistons with a longer crank and keep it from popping out above the block? Do you plan on finding shorter rods? or do you plan on making the pistons shorter?

Lots of great info here guys!

I really appreciate all the input, especially since this is one of the 'lesser-known' engine builds.

Like2short, I'm planning to use m50b25 pistons, but depending on what comes up for sale, I might bore the block and go with the s50 ones.

Still wondering about software and approximate compression ratio of the 2.9 if anyone has any insight...

bgcabrio

08-03-2005, 07:45 AM

You need s50 rods.

E30 Stu

08-03-2005, 10:53 AM

The pistons are machined down to desired compression (11:1 works great on the street for these motors)

bgcabrio

08-03-2005, 11:36 AM

Do you happen to know what that spec would be (how much you have to shave off the top of the piston)? Say I am using an S50 crank and rods with m50 pistons. Could you get the same effect with a thicker headgasket? VAC sells a .140 thick HG.
Does anyone have a link to a page that might help me see the steps for calculating BMW Specific compression ratios. Seems like you would just calculate the volume of the cylinder at full stroke compared to the volume at TDC. Its the void space at TDC that I guess I need specs on.

The pistons are machined down to desired compression (11:1 works great on the street for these motors)

Thin Air

08-03-2005, 02:41 PM

Are there any options like this for the 2.8L M52?? I've been considering building a stroker for the longest time.

JasonH

08-03-2005, 05:15 PM

Are there any options like this for the 2.8L M52?? I've been considering building a stroker for the longest time.

My dad ran a 86mm stroke, 84 bore alloy M52 with 11:1...

:)
Edit: I suppose the advantage in Pete's case, is the the bump in compression. How much of an advantage would a 2mm increase in stroke create?

putnampunk

08-03-2005, 05:20 PM

I think the real advantage was it was an aluminum m52 stroker in a e30 m3 :eek:

:buttrock

(and probably head work, and the compression)

like2short

08-06-2005, 09:50 PM

$1000? I know somebody selling (may have been sold by now) a 1995 S50B30 US for $1,000 but it does need a rebuild. email him at peter@guagenti.com

Its ironic that this is getting some attention. I am slowly putting the parts together for this build as well. I am planning to use a stock bore m50 block and pistons, and S50 crank (knife edged), s50 rods, and an s50 top end. I already have the top end and a source for the crank. I am estimating it will cost me roughly $1000 in parts for everything.

So far my bigget question is if I need to do anything special to drop the compression. It will be a mostly street car, but 93 octane is all I run normally anyway.

like2short

08-06-2005, 09:51 PM

Yeah, it's called S52 or M54 3.0L, both have a 89.6mm crank....the 3.0L has the same 84mm bore as your M52.

Are there any options like this for the 2.8L M52?? I've been considering building a stroker for the longest time.

bgcabrio

08-06-2005, 09:59 PM

If he is is cali the shipping cost would likely be killer.

$1000? I know somebody selling (may have been sold by now) a 1995 S50B30 US for $1,000 but it does need a rebuild. email him at peter@guagenti.com

Thin Air

08-06-2005, 10:41 PM

Yeah, it's called S52 or M54 3.0L, both have a 89.6mm crank....the 3.0L has the same 84mm bore as your M52.

What are some expected power numbers like?? Any dyno plots available? What rods would need to be used and what would the compression be like?

Thanks in advance.

like2short

08-07-2005, 02:29 AM

Peter is in CA, but you'd be surprised how reasonable it can be to ship an engine via truck....way cheaper than UPS.

If he is is cali the shipping cost would likely be killer.

like2short

08-07-2005, 07:36 PM

DEPENDS if you want to build a street motor or race motor..

What are some expected power numbers like?? Any dyno plots available? What rods would need to be used and what would the compression be like?

Thanks in advance.

Thin Air

08-07-2005, 07:38 PM

DEPENDS if you want to build a street motor or race motor..

Definately street, all I do is auto-x (maybe like 10/year) and a couple track days per year.....for now anyway.

karl hugh

08-07-2005, 08:00 PM

What are some expected power numbers like?? Any dyno plots available? What rods would need to be used and what would the compression be like?

Thanks in advance.

I have tons of information on this 2.9L set up, dyno information, AFR, all sorts of combinations from 220 rwhp on a Mustang MD250 dyno to 245 rwhp on the same dyno ~~~ 260rwhp on a dynojet 248C.All running on 93 octane fuel, crazy power for a NA motor. One of these motors already has over 80,000 miles on it and still running strong.

Please do not PM me, I never check my PM's, too busy, email me direct at kh@ilcs.net

e36'n

08-07-2005, 08:00 PM

Do you happen to know what that spec would be (how much you have to shave off the top of the piston)? Say I am using an S50 crank and rods with m50 pistons. Could you get the same effect with a thicker headgasket? VAC sells a .140 thick HG.
Does anyone have a link to a page that might help me see the steps for calculating BMW Specific compression ratios.

I need to know the same information. I have a s50 crank and would like to use the stock 84mm pistons, but I can't put it in until I know how much to shave off the tops for 11:1 (I only have access to 91 octane, so maybe 10.8:1 or so).

like2short

08-07-2005, 10:45 PM

Ok....so you wanna hot street motor....with a lotta torque, and long term reliability....easy solution....get an S52, put a the sunbelt or schrick cams in it, and get 240-260 rwhp. The factory did all the work for you 86.4mm bore 89.6mm stroke....done...

Definately street, all I do is auto-x (maybe like 10/year) and a couple track days per year.....for now anyway.

Thin Air

08-07-2005, 11:21 PM

Ok....so you wanna hot street motor....with a lotta torque, and long term reliability....easy solution....get an S52, put a the sunbelt or schrick cams in it, and get 240-260 rwhp. The factory did all the work for you 86.4mm bore 89.6mm stroke....done...

I was hoping to use an aluminium M52B28 block. I don't know if it can be bored to 86.4mm....

I've thought of the M52B32 swap many times, maybe even trying to get my hands on a real S50B32, or an S54B32. There are a couple local guys here what have swapped the S54B32 into their e36's while using retaining the motronix ECU that came with it.

It all comes to budget. If I went the M52B32 route like you suggested, it'd still have a stock engine with cams, if I went the stroked 2.8, I could at least work on the internals while I have it apart.

like2short

08-08-2005, 12:29 AM

Good question on the Alum block overbore....maybe just find an M54 3.0L and use the shortblock? I think the biggest issue your probalby going to have once you build the engine, is tuning the thing. As you know tuning an OBD 2 Simens computer is not going to be easy.

I was hoping to use an aluminium M52B28 block. I don't know if it can be bored to 86.4mm....

I've thought of the M52B32 swap many times, maybe even trying to get my hands on a real S50B32, or an S54B32. There are a couple local guys here what have swapped the S54B32 into their e36's while using retaining the motronix ECU that came with it.

It all comes to budget. If I went the M52B32 route like you suggested, it'd still have a stock engine with cams, if I went the stroked 2.8, I could at least work on the internals while I have it apart.

bgcabrio

08-08-2005, 09:49 AM

Karl from AA right? I thought you were on vacation.

I sent you an email last week about SW for my OBDI S50 M3. I would like to talk to you about the stroker and associated software for it as well.

I will send an email with my #.

I have tons of information on this 2.9L set up, dyno information, AFR, all sorts of combinations from 220 rwhp on a Mustang MD250 dyno to 245 rwhp on the same dyno ~~~ 260rwhp on a dynojet 248C.All running on 93 octane fuel, crazy power for a NA motor. One of these motors already has over 80,000 miles on it and still running strong.

Please do not PM me, I never check my PM's, too busy, email me direct at kh@ilcs.net

bgcabrio

08-18-2005, 06:01 PM

Well I now have a core 325 motor, over reved S50 topend, and S50 crank. A set of S50 rods and pistons should be on the way. (I haven't decided if I will have the block bored to accept the bigger pistons yet.)

My donor M50 motor had 110k miles. Realistically if I can get about 40k miles out the reassembled motor I would be happy if I was making good power. I am tempted to just throw the S50 crank, rods, and cams in with a new head gasket and head bolts. I am shooting to have a strong street car that I can autox if I don't want to run my 3.2L M3. I will be doing all the assembly and installation and my real goal is to get comfortable (and have fun) tearing into these motors. I have rebuilt a few small engines (1-2 cylinders) in the past, but this will be my first real car engine.

Money wise so far I am out of pocket about $800. My next decision is how much I really want to spend on this thing. As far as wearing internals, what is everyones opinion on replacements. If I decide to go all out, does anyone have a good source for rebuild kits other than Bavauto?

like2short

08-18-2005, 06:11 PM

I would try a dealer for the parts....look for somebody that gives discounts to club memebers.

Well I now have a core 325 motor, over reved S50 topend, and S50 crank. A set of S50 rods and pistons should be on the way. (I haven't decided if I will have the block bored to accept the bigger pistons yet.)

My donor M50 motor had 110k miles. Realistically if I can get about 40k miles out the reassembled motor I would be happy if I was making good power. I am tempted to just throw the S50 crank, rods, and cams in with a new head gasket and head bolts. I am shooting to have a strong street car that I can autox if I don't want to run my 3.2L M3. I will be doing all the assembly and installation and my real goal is to get comfortable (and have fun) tearing into these motors. I have rebuilt a few small engines (1-2 cylinders) in the past, but this will be my first real car engine.

Money wise so far I am out of pocket about $800. My next decision is how much I really want to spend on this thing. As far as wearing internals, what is everyones opinion on replacements. If I decide to go all out, does anyone have a good source for rebuild kits other than Bavauto?

bgcabrio

09-14-2005, 07:48 PM

Would anyone care to comment on the potential pos/neg for using the non-vanos M50 pistons in a vanos m50 stroker? I thought they were the same, but they have different part numbers.

I may have found a cheap source for the pre '93 pieces.

bgcabrio

09-16-2005, 07:30 PM

bump for feedback

Would anyone care to comment on the potential pos/neg for using the non-vanos M50 pistons in a vanos m50 stroker? I thought they were the same, but they have different part numbers.

I may have found a cheap source for the pre '93 pieces.

325iklu

09-16-2005, 07:48 PM

Im in the process of doing this too, but whan it comes to cams and tuning im stumped??

brew

09-16-2005, 08:01 PM

bump for feedback

I would guess that the non-vanos pistons have a slightly different face design that produces the 10:1 compression instead of the 10.5:1 of the vanos motor.

325iklu: There are a few options for cams, but I think the most cost effective option is to get S50 cams reground to work without vanos. I bought a set off of a Bimmerforums member a few weeks ago.

Tuning: AA makes a chip for the 2.9.

bgcabrio

09-17-2005, 09:05 AM

brew, I forgot about the diff compression. I think that would be a good thing for my setup. This will wind up as a street motor with the occasional autox.

M52 POWER!

09-17-2005, 08:32 PM

So the max a M52 can go is 3.0 liters? Ive read just using a S52 crank on a M52 would stroke it farther creating 2.97 liters?

325racer

09-18-2005, 12:52 AM

Just dynoed my basic 92 325is, Non Vanos car yesterday, in plans of building a custom exhaust for it.

Current mods are Conforti chip and Intake, stock exhaust, 180K+ miles, about 1600 miles into an oil change that has seen about 400 of that on the track.

167.7hp @ 6200
154.1 lb/ft @ 4800

I'd like to see 180 @ the wheels in "Stock" configuration, but we'll see what happens.

The next plan is to go straight to the 2.8L as it's legal in many of the classes I currently am running and plan to run in, in the future.