M50 2.8 stroker conversion

[alexbaby88]

Has anyone done a stroker conversion on their M50 engines taking displacement from 2.5L to 2.8L?

I was reading a post by Andyboy recently on this which involves swapping the crank, con rods and cams from the M52 B28.

The boys in the US with access to the US S50/S52 engines are doing 2.9L and higher stroker conversions using the S50/S52 parts.

Has anyone on this board done this? What compression ratio do you end up with and is there a need for a remap / rechip?

Perhaps Andrew can chip in.

Cheers

[m-dtech]

check out this

http://www.e30zone.net/modules.php?name ... hlight=m50

remap = yes
compression ratio 11.25.1

[Motorhole]

Just a thought...would this work on an M50B20 too!??

[jaistanley]

Think you have to have it (M50B20) re-bored to match the pistons you'll need (M50B25/M52). Not a problem, about £15 a bore.

Jai

[m-dtech]

http://www.bmwworld.com/engines/m50.htm - gives you the bores and strokes etc
http://www.bmwworld.com/engines/m52.htm - as above but for m52

[Motorhole]

Cheers Chaps!

[DanThe]

This is what im doing at the moment, im using an M50B25 block and head (non vanos) with the M52B28 crank, rods and pistons.
The c/r will be higher than standard by using the N/V head due to smaller combustion chambers, this is one of the reasons I opted for the N/V head, but also the valve train altogether is better I belive, double springs, higher lift cams etc.

[m-dtech]

i want to do this to my m50b25, how do you think i can get the compression lower ??

the 2.5 has an 84mm bore, same as m20.

so,

flat top pistons from a 2.0 ??

[WillG]

arent b20 pistons 80mm?, look at some M42 pistons, if they worked in M20B25 they should work in M50

[alexbaby88]

This is what im doing at the moment, im using an M50B25 block and head (non vanos) with the M52B28 crank, rods and pistons.
The c/r will be higher than standard by using the N/V head due to smaller combustion chambers, this is one of the reasons I opted for the N/V head, but also the valve train altogether is better I belive, double springs, higher lift cams etc.

Dan

What are you doing for software? Who would be able to supply a chip for a M50 2.8L stroker?

[jaistanley]

Someone seriously needs to build a vanos controller for megasquirt....

Jai

[DanThe]

Standard M50 loom should be able to handle it, I hope..........

Andy did a similar thing with an M52B28, using an M52B25 loom and ECU, I know he had problems with the mixture getting rich high up in the RPM but he didnt have an O2 sensor. I have a viper2 chip in my ECU so hopefully it will be fine

[ste]

The M54B30 crank also fits....

[DanThe]

The M54B30 crank also fits....

And will be finding its way into one of my lumps if I ever find one at a 'proper' price

[DanThe]

What about this?

http://cgi.ebay.co.uk/BMW-E36-M3-3-0-Cr ... dZViewItem

[jaistanley]

I don't think thatll fit as it's from a Euro M3. I'm not 100% about the 3.0litre but the 3.2 has different sized bearings.

Jai

[DanThe]

So thats why its not as pricey as id imagined

[jaistanley]

If I had the money I'd like to build a supercharged S50 engine and I think I'd use that crank rather than the 3.2. Other than that I cant think what we could use it for. Perhaps you can have the M50 block line-bored to take it??? Anyone?

Jai

[ste]

The M54B30 crank also fits....

And will be finding its way into one of my lumps if I ever find one at a 'proper' price

The engine I'd love to build is an M52B28 (still alu block - you can all slate them but you can't argue with the weight saving ) - M54B30 crank to take it to 3.0litre, custom grind Catcams and an Active Autowerks charger. I think you'd end up with a real 350bhp and as much torque as you'd ever need in an e30.

That's my aim - I have to make myself hold onto the car and get there rather than do my usual thing of selling it when it's 1/2 way finished.

[jaistanley]

The only problem I can see with your idea is the price of Nikasil (well, equivalent) bore linings. A friend looked into having his porsche flat six re-bored and nikasil coated, then promptly bought a next to new block. I don't even think you can re-hone them to take a new set of piston rings, even if the bore is kept the same (does the M54B30 have the same bore as a M52B28?). I suppose you could always have iron liners installed but that's a pain.

Look at this: http://www.pistonheads.com/gassing/topi ... hw=nikasil

It's a guy talking about BMW V8 tuning but has info on Nikasil I beleive.

I can't knock the ally block, you're right about the weight saving. I'm just not sure I could be bothered dealing with the complexities.

Jai

[ste]

What complexities? If the block gets damaged you buy a new one - whole M52s only cost circa £400 (i think I paid £350 for mine with everything attached).

There's no issue at all with having to bore the block, reapply Nikasil or anything similar if you want to fit the M54b30 crank, the crank is just a longer stroke, you just need to take the sump off, crack the bearing caps and swap the cranks over. No re-hone, no new rings etc as you don't even need to remove the pistons from the bores!

Nikasil engines were only a 'problem' because of a few batches of high sulphur fuel in the North West, almost 10 years ago. If your Nikasil block was damaged you'd already know as it would behave more like a kettle than an engine. If you buy an M52 engine that is running well now it's either a Nikasil block and has not been affected, or it's a replacement Alusil block.

[DanThe]

So M54B30 pistons and rods are the same measurements as the M52B28?

[alexbaby88]

M50/52 2.5/2.8 engines had 84mm bores, I'd imagine that the 3.0 has a bigger bore hence the pistons are unlikely to fit unless you rebored the block bigger.

[DanThe]

Just found a bit of info :-

The M54B30 is a 3.0 L (2979 ccm) successor of the 2.8 L BMW M52. Bore remains the same at 84 mm, but stroke is increased 5.6 mm to 89.6 mm. Power is 225 hp (168 kW) while torque is 214 ft.lbf (290 Nm).


So the pistons will travel just 2.8 mm closer to the valves.
I should be able to have about 3 mm removed safley from my 2.8 then

[jaistanley]

I was imagining you having to have an overbore which struck me as complex, or at least expensive..

You'll soon be running a supercharged 3 litre then?

Jai

[alexbaby88]

Just found a bit of info :-

The M54B30 is a 3.0 L (2979 ccm) successor of the 2.8 L BMW M52. Bore remains the same at 84 mm, but stroke is increased 5.6 mm to 89.6 mm. Power is 225 hp (168 kW) while torque is 214 ft.lbf (290 Nm).


So the pistons will travel just 2.8 mm closer to the valves.
I should be able to have about 3 mm removed safley from my 2.8 then

I stand corrected.......

[alexbaby88]

Just wondering how different the M54B30 crank was compared to the S50US B30 crank?

[benjy]

whole M52s only cost circa £400

Where are you finding these?? Everywhere Ive spoken to wants silly money, i.e. 800+

[GrindCulture]

whole M52s only cost circa £400

Where are you finding these?? Everywhere Ive spoken to wants silly money, i.e. 800+

This thread is nearly 2 years old...

[benjy]

Yeah, only noticed that after I posted :doh:

[DanThe]

24 valve engines in general are getting harder to come by at a reasonable price, eBay prices are laughable at the moment, no wonder hardly any are selling