M30 3.5 vs M50 2.8

[MarkF]

Hi guys, i have been thinking for a long while about what my next engine should be. I am currently running an M20 B25, which is great, but im craving more grunt!

I have done alot of research into the M30 swap and this is my most likely option. I love the thought of a big power, big cc engine! But after recently reading that the M50 B28 can reach 220bhp easily, i am wondering if it is worth considering this as an option?

Deep down i prefer the thought of the big, basic, old skool, grunty M30 but cant dismiss the option of an upto date, efficient and smooth engine with better economy and reliability etc.

I am comparing as many aspects as possible, such as, easiest to convert, power/torque, weight, cost, reliability, economy, iron vs ally engine, sourcing engine/parts etc.

Basically any info, opinions and experiences would be appreciated!

Looking forward to your views

Cheers, Mark

[andrews]

I see you have leanred this question yourself very well. So just make a choice what will be better for you: oldschool, simple and reliable as a sledgehammer m30 or modern, more silent and advanced m50. I don't know what I would prefer.

[mrLEE30]

The M52 B2.8 (M50 was only the 2litre engine IIRC) will always be the better engine in terms of fuel economy parts etc etc, but the downside is the fact that due to a more advance engine management system they may be harder to fit,where as the M30 is not so different from what you already have.

the M30 3.5 makes 218hp (book value) on a very good day but more realistically 190-210 today depending on its condition

the M52B28 makes 193 hp and is more likely to make this figure today, but with a 325 throttle body and a chip remap/replace 210-220 is acheivable

there is a slight difference in torque, the bigger engine will produce more torque (310Nm v 280Nm)

so when you look at cold hard figures the M30 is better, when you look at longterm/livability i would opt for the M52 swap

[town325i]

imo i would choose the 24valve engine any day they are just a better engine than the m30 and the m30 is a big old lump of iron to stick in an e30 compaired to the m52b28

[Bob_S]

I'd be going for the M52 if it were me.
They are so easy to install, cheap to get hold of and just as good as the big ol' six.
The m30 has a massive iron block M52 has a nice light small ally block, I'd think the weight difference would counter any advantages that the m30 would have really. Remember an e30 isnt that heavy so with torque figures so close I dont think it would make much difference

[jaistanley]

The M52B28 (the M52B20 is 2.0 litre!) is MUCH easier to install. Fuel economy is light years ahead. It is much lighter. Requires pretty much 0 custom parts to install. Is likely to be more reliable due to cooling issues with M30's in E30's.

There is simply no way I could advocate fitting the 3.5 boat anchor over a 24v lump....

[Jhonno]

24v = Win

[E30BeemerLad]

M52 would be the better all rounder, main hassles will be EWS wiring and then the exhaust manifold modification.

But with the M30 swap you are into custom propshaft and other gubbins to contend with. So neither are pure "plug & play"

If the M52 was a good one, then I'd probably go with that over the M30.

[jaffro]

ive had both lol. a the m50 was far easier a quicker a cheaper to do and a much better all round lump. now bk to the m20

[tristan325]

(M50 was only the 2litre engine IIRC)

M50 was 2 litre and 2.5 litre iron block.

[Jon_Bmw]

All cars need 4 valves per cylinder tbh.

[mattster]

Not than i no much but i did have an e36 328is and the engine pulled like a train...if i money to put one in my cabby i would defo!

[jaistanley]

You can get away without re-fabricating the exhaust manifold by making a narrow steering column adaptor from E34 parts I believe. I think someone has done this recently. Either way, it's not a huge ammount of work compared to fabricating engine mounts, shortening a propshaft, bashing the bulkhead and squeezing a radiator big enough in...

M52 FTW

[Ziggy]

Don't know much about the M52 swap tbh! But I'm guessing you won't find many m52s for a couple of hundred quid? £100 for M30 mounts is all the effort you need there, bulkhead mods aren't always needed (& I can't see them being difficult anyway!) & an E28 rad is a straight fit, as is an E30 M3 prop or a simple swap of flanges to allow the standard M20 prop to stay...

I'd go with an M52 if it was for a daily driver, but my car sits in the garage most of the time so I don't really care about economy! & I would expect an m52 swap to cost significantly more than m30 - especially by the time you've factored in the inlet mods & remap.

[Jon_Bmw]

I would expect an m52 swap to cost significantly more than m30 - especially by the time you've factored in the inlet mods & remap.

This is true, I wouldn't expect much change out of a grand(if any) for the whole thing to be making a proper 215bhp+ But that is plenty in a car like the e30. Trailing arms ftw!

[Jhonno]

to be making a proper 215bhp+ But that is plenty in a car like the e30. Trailing arms ftw!

E30 chassis easily copes with 200bhp imo, could do with more

[Fushion_Julz]

All cars need 4 valves per cylinder tbh.

Dodge obviously forgot to consult you when they built, designed and raced the Viper

[Jon_Bmw]

All cars need 4 valves per cylinder tbh.

Dodge obviously forgot to consult you when they built, designed and raced the Viper

They missed out! They got lambo instead:

"Some within Lamborghini felt the pushrod two-valve design was unsuitable for a performance car and suggested a more comprehensive redesign which would have included four valves per cylinder. However, Chrysler was uncertain about the Viper's production costs and sales potential and so declined to provide the budget for the modification, though Lamborghini was still very active in the creation of the original engine."


I'm sure it was to do with performance and not budget Not! Ever wondered why powerful 2valve per cylinder happen to have MASSIVE capacity. Its the only way they can make comparable power to a smaller more compact 4v engine.

[rThor234]

The M52B28 (the M52B20 is 2.0 litre!) is MUCH easier to install. Fuel economy is light years ahead. It is much lighter. Requires pretty much 0 custom parts to install. Is likely to be more reliable due to cooling issues with M30's in E30's.

There is simply no way I could advocate fitting the 3.5 boat anchor over a 24v lump....

I agree with your entire post. Couldnt have stated my opinion any better.

How about a 3.0 or 3.2 litre M50? I'd call that a winner.. Should be about the same cost as getting the M30 shoe-horned into the little car.

[e30bmlover]

b28 ftw!!! 24v's.......... yummy yummy!!

[Rosc0PColtrane]

The M52B28 (the M52B20 is 2.0 litre!) is MUCH easier to install. Fuel economy is light years ahead. It is much lighter. Requires pretty much 0 custom parts to install. Is likely to be more reliable due to cooling issues with M30's in E30's.

There is simply no way I could advocate fitting the 3.5 boat anchor over a 24v lump....

Custom parts? I thought a custom fanimold was needed

[gooner1]

The M52B28 (the M52B20 is 2.0 litre!) is MUCH easier to install. Fuel economy is light years ahead. It is much lighter. Requires pretty much 0 custom parts to install. Is likely to be more reliable due to cooling issues with M30's in E30's.

There is simply no way I could advocate fitting the 3.5 boat anchor over a 24v lump....

Custom parts? I thought a custom fanimold was needed

jaistanley Posted: Wed Nov 05, 2008 11:59 pm Post subject: Re: M30 3.5 vs M50 2.8

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You can get away without re-fabricating the exhaust manifold by making a narrow steering column adaptor from E34 parts I believe.

[MarkF]

Well by the looks of things the M52 (not M50-my mistake) is the way to go! Is the wiring particularly difficult? Modifying the exhausts are a problem for me so may have to look down this route!

I was always led to believe that there was alot more involved with the 24V conversion?

Thanks for the suggestions/help guys

[Bob_S]

my m50 swop cost me nothing and that includes a pair of schrick cams I think maybe I should of put my m52 in though.. mehhh bugger it lol

[bss325i]

If i had a chrome turd i would be inclined to put an M30 in it as its more "period" and would suit the style of the car better i feel.

If its a plastic bumper car the with out a shadow of a doubt the far superior M52 would be going in!

[E30BeemerLad]

b28 ftw!!! 24v's.......... yummy yummy!!

why you throwing dollars at your m20 spunk box then mate?

[mrLEE30]

(M50 was only the 2litre engine IIRC)

M50 was 2 litre and 2.5 litre iron block.

sorry I could be right, been lookin a bit more and M50 is only 1991cc 24V built from 91-96

M51 is diesel lump

M52 is 24V 1991-2793cc built 1995-2000 single VANOS
and M54 is 2171-2979 built from 2001 double VANOS


all according to Tony Lewin's book anyway

mrlee

[Brianmoooore]

Don't know who Tony Lewin is, but I should give him his book back!
M50 came in 2.0 and 2.5 variants, both with and without single vanos.
M52 came with both single and double (late versions) vanos.

[mrLEE30]

Tony Lewin wrote ''The complete book of BMW'' and this is the info i found in the Appendix B showing all engine codes from the M10 to the W17

its quite specific in that the M20 produced from 1991 is 1991 cc and that 1,068,844 were produced, but then again there appears to be a 4 year gap in the production of the 2.5 motor from end of M20 to M52 so probably a typo.

Stand up and be corrected mr lee!!

mrlee

[jaistanley]

Aaaah. Zone expertise.

I know of an M52 going into an E28. Thats a cool project! I think it's prety much time to retire M30's, unless you are going for massive turbo power in which case they are a nice cheap starting point.

[DieselMeister]

M50B25 or M52B28 has to be the optimum donk swap for an E30, weighing costs (obtaining, fitting and running) against performance gains unless you're any of the following:

- a traditionalist (stroked / boosted M20 - very tasty)
- a power-crazed boost junky (as above but including your choice of FI applications / engine combos - tastier still)
- richer than you are sane (V12, S62, biturbo etc. - lotto?)
- blessed with access to an S50 plus necessary parts and time / skill / funds to fit it for enhanced "///M-powerment" (the grail imo - will cost you to become immortal though...)

[Andyboy]

ive had both lol. a the m50 was far easier a quicker a cheaper to do and a much better all round lump. now bk to the m20

Not as easy as replying to PM's though Pal.......

[Andyboy]

M52's are okay but they're old now and if the head gasket goes, the engine is scrap. EWS is a pain in the rectum and complication you don't need. I would always fit an M50 non EWS E34 loom - and guess what. I've got one for £60 with the ECU.

Jon B has got a really nice mega low mileage M30 3.5 for peanuts. The 3.5 has still got a lot to offer - it's got loads of grunt (more than a 2. and is capable of decent economy in a light E30. I'd be surprised if you didn't get 30+ on a run.

[Theo]

I've driven an m50 e30 and it really is nothing like as fun as an m30 transplant. Further positives to the m30 include it's ability to withstand untold abuse, a really lovely exhaust sound, cheap parts, cheap engine, only custom part needed to fit to an e30 are the engine mounts, very simple conversion.

Stick a turbo on an m30 and you are going seriously quick, I still laugh when I think how rapid Toby's was.

[DieselMeister]

I in no way meant to demean the M30 - if you can find one they are the good bang per buck, relatively easy to fit and sound gorgeous. I have fond memories of passengering a 535i some years back - was rapid and sonorous as a bimmer should be. loads of nice engine options for E30s!