My quest for an engine conversion, bye bye 320i!!

[Rosc0PColtrane]

I currently drive a 320i cab. I love it to bits. The engine has recently tripped 80,000 miles, car has been solid and reliable, turning heads from 8 to 80. I love the noise the 6 pot makes.

However, I am bored with the power output. It's not quick enough!! Especially with the fecking boy racers running round in twin cam rovers giving me grief!!!

My pipe dream is to take my 320i cab off the road next autumn and look to replace the engine.

Am undecided which route to go. Obviously I'm going to see a big power gain whichever route I go down as I'm replaceing a 2ltr lump. However, as this will be my daily driver, it needs to be completely reliable but able to put a bigger smile on my face. I also have to consider which is the most cost effective route along with ease to build/obtain parts.

So should it be a 2.7? A standard 2.5? A newer 2.5 vanos? 2.5 turbo? A non vanos 2.5 M50? (think thats right?)A M502.8?

Suggestions and advice please!!!

Here are some replies I've seen to my questions immediately:

Stevin wrote:

2.5 lt M50

Most reliable, cause it's stock and will make some decent power 2... plus u can do the cams branches... etc leaving it still reliable, with a little more go. IMO

M5pilot wrote:

M52 2.8 engine is the best budget solution by far.

Its much nicer as an engine than the M20 2.7, much more economical. It sounds better and goes aswell in stock form.

With some light mods you'll see a realistic 220-230bhp. A 2.7 putting out that power will idle like a pig and drink like a fish.

Doing an M52/M50 conversion is actually easier than doing a 2.7. Its a different type of job. In both ways your removing an engine and replacing an engine. the difference here is that rather than are farting about rebuilding an engine your using time doing wiring on the 24V units. Getting them into the engine bay is easy and mounts are reasily available.

The one ONE problem with the conversion is the exhaust manifold and it is here that everyone gets stuck. This is one the main reasons people dont go down this route because the manifold costs so much money.

Ste is doing an m52 conversion and we are looking to develop a manifold which is of the BTB style. the standard M50 M52 manifold is really not good at all for performance. If we can make something like the BTB for these engines then I can alot more people ditching the M20 altogether.

2.7's are really a total and utter waste of time when we can use much better engines.

One thing I'm going to re highlight to the power freaks - M20 putting out lots of power idles crap and drinks whereas an m52 modded still drives perfect, gives a much better torque spread and fuel economy.

24v vs 12V........no competition!

[M5pilot]

Looks like you done my reply for me!..LOL

Just want to add that the M52 is lighter than the M20 aswell.

I've driven Will's old car which had an M50 24v engine with no mods excpet a BMC airbox.

It was only a little slower than Karan's monster 2.7 so defo worth doing.

Now if you want to know the difference between an M52 and an M50 then I have a kind of a way to explain.

I used to have an M50 non Vanos Auto 525i Touring

I know someone who has an E39 528i Auto Touring.

Both around the same weight and similar gearing.

At the lights on take off the E39 totally spanks the M50 engined E34. Infact the M52 engined E39 just leaves the M50 E34 in any situation.

M52 over M50 all day. M50 still a brilliant brilliant engine and if someone finds one cheap then no reason not to throw it in. They respond to light tuning very well.

[Turbo-Brown]

Go turbo dude!

Forget all this N/A stuff, the looks you get from people when you breese past them, dump valve hissing is priceless!

Makes me smile every time anyway

That said, if I ever do another conversion in an E30 I'd probably stick an S50 or S54 in, but then I just can't live without throttle bodies! I also can't be arsed fiddling about with getting the standard ECUs to work as I just don't think they're all that suitable for transplants me-self, but the ECU I've got to control my S50 did cost well over a grand!

[dan_emaps]

M52 here chap.

I had a 328i sport last year which uses that engine and loved it, nice and torquey stock with lots of performance options so you can upgrade along the way!

M50 inlet manifold, bbtb, remap and induction saw mine at 233bhp on the rollers, but the run was done in 4th, if it was done in 5th which it should have been really, i imagine your looking at about 240bhp.

Then you have us spec m3 cams, underdrive pulleys, exhaust... still more options to push the power on.

besides the e36 was quick enough, 230+ in a e30 would be awesome, and bags of torque, but still perfectly smooth

Sold it to you yet? lol!

Its what id do if i had the money to attempt a conversion on the touring

[Turbo-Brown]

Why would the gear the power run's done in make any difference?!

[maxfield]

It shouldn't make a difference should it

[Turbo-Brown]

No, it shouldn't.

Power is a function of torque and speed.

Use 5th gear instead of 4th and you'll end up with less torque at the wheel but more speed, for a given power output.

[dan_emaps]

eek you'll lose me on the technical side to this guys, i just remember on e36coupe 5th gear was supposed to be used as it gives 1:1, and running the car in 4th apposed to fifth would actually give slighty less power?

[Turbo-Brown]

If we ignored the slightly different losses each gear would experience, you could do a power run in 1st and still get exactly the same power figures.

However, if the E36 had a 1:1 5th gear it'd likely unload all the gears on the layshaft which would give rise to a slightly lower loss compared to 4th and a slightly higher at the wheels figure I guess.

Not a gain in the real sense though!

[Rosc0PColtrane]

Thanks for the input guys. I'd love to go turbo, Turbo-Brown but there's no point turboing the 2ltr lump so feel the outlay for getting the right 2.5 and turbo would start getting expensive!! Plus would it not raise doubts about reliability? However the sound of darth vader eminating from my engine bay does please me! Would this not be expensive mate?

Dan, you certainly have sewn the seed mate. Sounds about right. Something relatively straight-forward with opportunity to improve it when I get more cash!!!

Am I right in thinking there ase issues with eithe the inlet or exhaust manifold fitting and needing a custom job, on the m50/m52?

What sort of money we talking about to do this?


Cheers M5pilot, so an m50 is worth considering then eh? Is that the 24v lump from a 5 series? Are the later vanos jobs worth considering too? Or am I talking bollocks?

I really hope this thread can continue, from my pots, it's easy to see I am a novice by my "green" questions!! Hopefully this will enable me to learn more, plus build a car based on Zone opinions and experiences entirely!!!

Ha ha ha just got to make sure booty doesn't start talking me into big reigfer body kits though!!!

Once again, thanks!! keep the input coming

[dan_emaps]

yes mate your correct on the exhaust manifold i think, i belive it needs modding, tho i think its only one section, we have a member called DanThe iirc, who seems to be handy at doing this! would be worth speaking to him if you went the m50/52 route

[fowler]

hello mate got to a 325 M20 because you mwill love the extra bhp from the 320 but go for early high comp lump put a nice mild cam in it then maf it
goo for aboyt 185 bhp save a few quid then get yourself a eta crank and some post 88 pistons then you have a lovely 2.7 torque monster
and it won't cost the earth
regards
Ben
p.s do you still want all the guts out of a drivers door for your cab ??? as i never got back to you apologies

[bmwmaniac]

In Finland the law's are pretty tight considering the engine swaps.
So i had to modify my m20 320i to run like hell, with a little changes..
I put the crankshaft and pistons from the 323 bmw. Changed the intake manifold and throttle housing assy from the m20b25 engine. And tighter camshaft. Also the exhaust system was rebuilt, and i lifted fuel pressures . And i got 163hp out from the engine.

I sold the car and the guy who ows it now, has put the turbo in it. And i've heard that he has taken 280hp out from it. Using 0,8bar pressure.

[Dr Firefly]

hello mate got to a 325 M20 because you mwill love the extra bhp from the 320 but go for early high comp lump put a nice mild cam in it then maf it
goo for aboyt 185 bhp save a few quid then get yourself a eta crank and some post 88 pistons then you have a lovely 2.7 torque monster
and it won't cost the earth
regards
Ben
p.s do you still want all the guts out of a drivers door for your cab ??? as i never got back to you apologies

How reliable are these in the long run? I know the 6 pot 2.0l M20's good for about 300k, but would the life be shortened a lot by the high performance mods? It's just I'd have thought BMW would have done it themselves if it didn't harm the life of the engine. Cheers, it's just this is the conversion I'm eyeing up myself longterm. Would the 2.7 compare to the M3's engine performancewise?

[fowler]

First what M3 engine E36 or e30 ?
The 2.7 is good for 200k easily if its looked after
performannce of a 2.7 is a low down gutsy car with more torque than you can shake a stick at. but with a couple of modes it can be as punchy as you like
thats just my personal opinion

[Rosc0PColtrane]

hello mate got to a 325 M20 because you mwill love the extra bhp from the 320 but go for early high comp lump put a nice mild cam in it then maf it
goo for aboyt 185 bhp save a few quid then get yourself a eta crank and some post 88 pistons then you have a lovely 2.7 torque monster
and it won't cost the earth
regards
Ben
p.s do you still want all the guts out of a drivers door for your cab ??? as i never got back to you apologies

Thanks, seems quite a sensible option. A two stage job was something I had in my mind as alot of this will be finance driven.

What would be the cost outlays, a rough gestimate would be helpful!!! I know alot of it is driven by sourcing parts etc.

I'm really confused about my cental locking. Inspite of the bits "floating" around in the door, it has started working perfectly!! Think moisture must be getting in to the servo where the boot caps for the connectors weren't replaced correctly when the alarm was fitted.

A friend of mine knows a chap who is breaking a 320i three door and said I can have a poke around for nothing and take whatever I need, thanks for remembering though!!

Apologies to all for slow replies, have been ill and not near a pc!! Will respond to all now, thanks again guys. I hope this comes off. A car completely built on zone opinions sounds cool. I hope I can make some cash!!

[Rosc0PColtrane]

In Finland the law's are pretty tight considering the engine swaps.
So i had to modify my m20 320i to run like hell, with a little changes..
I put the crankshaft and pistons from the 323 bmw. Changed the intake manifold and throttle housing assy from the m20b25 engine. And tighter camshaft. Also the exhaust system was rebuilt, and i lifted fuel pressures . And i got 163hp out from the engine.

I sold the car and the guy who ows it now, has put the turbo in it. And i've heard that he has taken 280hp out from it. Using 0,8bar pressure.

That's a wicked effort for the 320. I think I could source a 2.5 lump more easily than following your idea. Nice to know the 2.0 isn't entirely a lost cause!!!

Really would like to be as close to plug and play as possible, like I said previously, if I could do it in two stages, ie revisit the engine at a later date for further mods when the money builds up, I think would be the best option?

Plus dropping a straight 2.5 in give me something with a better stock bhp figure to start with

Remember to include costs as they will be a driving factor!!

Thanks!!

Nathan

[jmc330i]

A much as I like the 2.5 M20, I really think you should look at a 2.5 M50/2.8 M52 conversion.

Would be a great conversion in a Cab and realistically is a better/easier and possibly cheaper way of getting 190bhp+ in an E30.

As has been said, the 2.8 M52 is good for a decent 220bhp with some easy mods and will still be reliable and easy to drive.
The conversion isnt hard if its planned for in advance and as M5pilot says the only real pain is the exhaust manifold, but now a few have be done, it shouldnt be a huge problem anymore.

[Rosc0PColtrane]

A much as I like the 2.5 M20, I really think you should look at a 2.5 M50/2.8 M52 conversion.

Would be a great conversion in a Cab and realistically is a better/easier and possibly cheaper way of getting 190bhp+ in an E30.

As has been said, the 2.8 M52 is good for a decent 220bhp with some easy mods and will still be reliable and easy to drive.
The conversion isnt hard if its planned for in advance and as M5pilot says the only real pain is the exhaust manifold, but now a few have be done, it shouldnt be a huge problem anymore.

That's what I'm thinking.

So I'm looking for e24 525's and 528's? Or e36's??

I guess the next thing to consider is brake and suspension upgrades, bushes too?

Exhaust system?

This is all good stuff guys thanks!!!!!

[jmc330i]

E34 5 series is the best bet.
The engines are likely to have had an easier life than that of an E36 and the 5 series engine has the correct sump for fitting in the E30. Other than that, I believe the engines are pretty much the same.

Brakes and suspension I would just uprate the E30 stuff, the M50/M52 engines arent that big a jump over the M20. An E30 325i exhaust should be fine for either the M50 or M52 or you could fit an E30 M3 exhaust if you want slightly bigger bore pipes. A little bit of work will see them matched up to the M5* downpipes no problem.

[FormerMember]

M30 is a great engine too, cheap, bullet-proof, easy to fit engine. Lots of torque and that lovely big-six sound

M52 is good option too but costs a lot... and if you want lots of power then you should go S50 way.

All of those are stock engines so they are really reliable (if only the swap is done correctly) so it's only up to budget which one to pick

Just my 2 cents

[Rosc0PColtrane]

E34 5 series is the best bet.
The engines are likely to have had an easier life than that of an E36 and the 5 series engine has the correct sump for fitting in the E30. Other than that, I believe the engines are pretty much the same.

Brakes and suspension I would just uprate the E30 stuff, the M50/M52 engines arent that big a jump over the M20. An E30 325i exhaust should be fine for either the M50 or M52 or you could fit an E30 M3 exhaust if you want slightly bigger bore pipes. A little bit of work will see them matched up to the M5* downpipes no problem.

Nice thinking!!! This is really good input. E34's are cheap as chips, reckon this will be a splendin idea! 325 Exhausts are cheap enough, even from Eurocarparts.

What brakes and suspension would you go for?

[Rosc0PColtrane]

M30 is a great engine too, cheap, bullet-proof, easy to fit engine. Lots of torque and that lovely big-six sound

M52 is good option too but costs a lot... and if you want lots of power then you should go S50 way.

All of those are stock engines so they are really reliable (if only the swap is done correctly) so it's only up to budget which one to pick

Just my 2 cents

Thanks for your 2 cents!! Budget will be tight, What does an M30 come from?

M52 is the later engine that went into the e34, post 1992(ish) right?

[jmc330i]

M30 is the 'big six', the 2.5 M20s big brother. Either 3.0 or 3.5, from the 535i, 730i, 735i etc.

The M50/M52s are the more modern engines.


For the brakes, I would go for uprated E30 stuff, like the ATE Powerdiscs, some decent pads and fluid.
For the suspension, have a look in the Zone Shop. The H&R stuff is rated by most people, I would think the -35mm kit would be fine.

[Rosc0PColtrane]

Excellent info.

Lets starting talking prices. My bro is a mechanic so no massive worries about labour costs.

Anything I need to watch out for, difficult to fiind bits as well as hints and tips with the build and obvious errors I am prone and likely to make?

Currently running 205's. Would wider wheels be advisable (I'd say so!!)??

Keep the advice coming guys!!

[Jhonno]

How reliable are these in the long run? I know the 6 pot 2.0l M20's good for about 300k, but would the life be shortened a lot by the high performance mods? It's just I'd have thought BMW would have done it themselves if it didn't harm the life of the engine. Cheers, it's just this is the conversion I'm eyeing up myself longterm. Would the 2.7 compare to the M3's engine performancewise?

they did do a 2.7 for the South African market i think..

also alpina and hartge did them and they are manufactures themselves so wouldnt want to compromise reliability

[jmc330i]

Guessing youre thinking about the M50 conversion, have a read through this thread - click me
Theres quite a bit of waffling, but it should tell you everything you need to know.

Also this one (start on page 4) - click me

That way you can get an idea of whats needed and then ask about the bits youre not sure on.
If we both make it to the Poole meet, we can talk then.

[Rosc0PColtrane]

Guessing youre thinking about the M50 conversion, have a read through this thread - click me
Theres quite a bit of waffling, but it should tell you everything you need to know.

Also this one (start on page 4) - click me

That way you can get an idea of whats needed and then ask about the bits youre not sure on.
If we both make it to the Poole meet, we can talk then.

Thanks mate, haven't got a reason not to make next Sunday. Look forward to seeing you then!

[Rosc0PColtrane]

A couple more questions, firstly if anyone can band about ball park figures that this will cost me to do, that would be a big help.

Secondly, what would I need to do about an ecu? Keep the existing? (Which I doubt!!), Use the donor ecu or use an after market job like MS???

Thanks for all the help and advice!!!

[jmc330i]

Cost is really down to how much work you do yourself and how cheap you can get the parts needed. If you or someone you know can do the bulk of the work (for some beer tokens) then thats half the battle won.

You will need the ECU from the donor vehicle, or at least one for the type of engine (M50).
If you get an M52 2.8 then it will probably have the EWS security system - you must get the matching ECU, ignition key and EWS module, or the engine will not start.
These do not need to be from the original vehicle or match to the engine, but they must all be from the same vehicle.

[Rosc0PColtrane]

Thanks for the heads up. Have thought of another issue. I have a clifford alarm. I know they have immobiliser that immobilise on three points, just cant remember were, I knw one is on the fuel line. Think I may take advice on that nearer the time.

Also thinking about brake set ups and suspension set ups too

[jmc330i]

AFAIK most alarm/immobilizers wont be wired into the engine loom of the car, which is the bit you will be changing. The wiring is all done under the dash on the 'car loom' so you wont be playing with that.

I didnt touch my alarm/immob wiring when doing my conversion, even when I wired in the EWS system.

[Rosc0PColtrane]

Thanks again mate!!!

Are you going to any of the southern meets?

[jmc330i]

I shall be at the one this Sunday - Upton Country Park or whatever its called.

[Rosc0PColtrane]

see you there mate. Watch out for a lost looking red heard in a black cab!!!