Engine conversion?

Post Mon Feb 07, 2005 10:44 pm

Hya everyone.I am currently in the process of modifying my 318i(M40 engine),and have just got hold of 1990 320i se.Is it a straight forwaed conversion to swap over to 2lt,or do I have to change full wiring loom etc?Any info or links would be great,thanks

Post Mon Feb 07, 2005 10:51 pm

Don't do it, the M42 318iS engine is loads better than the M20 320 engine.

The 320 engine is the worst of the bunch with very poor fuel economy and not much power for 6 cylinders, stick with your M42 and fit a zone BBTB and chip.

IF you're gonna swap an M20 into it then stick the 2.5 lump in, otherwise it's just not worth it.

Post Mon Feb 07, 2005 10:56 pm

He could use the 320i as a donor to make a 2.7... 525e bottom end with the rest of the 320 bits to finish... then it'll be worth it! (on the cheapy cheap cheap of course)

Post Mon Feb 07, 2005 10:59 pm

stick with your M42 and fit a zone BBTB and chip

surely he said m40 318i ?

Post Mon Feb 07, 2005 11:01 pm

Toby_Unna wrote:
stick with your M42 and fit a zone BBTB and chip
surely he said m40 318i ?

Oh yeah, my bad

I still wouldn't bother with the 320 though, it's trully awful.

Post Mon Feb 07, 2005 11:02 pm

sorry I did mean M40 ,its not 16v

Post Mon Feb 07, 2005 11:05 pm

To convert the M40 properly you'll need:

Engine
Wiring Loom
ECU
Cooling System
Gearbox
Propshaft
Diff
Suspension
Brakes (possibly)

Post Mon Feb 07, 2005 11:09 pm

Looks like I may stick to what Ive got!Thanks all for the advice

Post Mon Feb 07, 2005 11:12 pm

E30Adam wrote:To convert the M40 properly you'll need:

Engine
Wiring Loom
ECU
Cooling System
Gearbox
Propshaft
Diff
Suspension
Brakes (possibly)

320's run on drums anyways at the rear

Post Mon Feb 07, 2005 11:27 pm

Richy325iTouring wrote:
E30Adam wrote:To convert the M40 properly you'll need:

Engine
Wiring Loom
ECU
Cooling System
Gearbox
Propshaft
Diff
Suspension
Brakes (possibly)
320's run on drums anyways at the rear

Yeah I know but what I meant was if he was going to go the 325 route he'd definately need an upgrade but not for a 320.

I know one crazy kid who's got a 3.5 with rear drums :lol:

Post Mon Feb 07, 2005 11:28 pm

tahts not the one that had knackered 316 suspension is it

Post Mon Feb 07, 2005 11:35 pm

Not any more it's not,Toby has fitted rear discs, M-tec suspension and he's soon to put on some Spax springs.

Post Mon Feb 07, 2005 11:39 pm

my old 316 had rear discs apex susspension drilled front disc and i only went from 1800 carb to injection lol

Post Tue Feb 08, 2005 10:05 pm

adam do you think all 320 beemers are trully awful??

Post Tue Feb 08, 2005 10:07 pm

johnl320 wrote:adam do you think all 320 beemers are trully awful??

I didn't say 320 beemers, I said the M20B20 engines. Crap for power and poor fuel consumption, I can't think of anything good about them.

Post Tue Feb 08, 2005 10:10 pm

do you think 316/318 m10/m40 engines are crap??

Post Tue Feb 08, 2005 10:12 pm

johnl320 wrote:do you think 316/318 m10/m40 engines are crap??

No, the M10 is a great little engine and the M40 is also good unless it's a high miler in which case will most likely be riddled with problems.

Post Tue Feb 08, 2005 10:16 pm

so what would you prefer M20B20 ,m10 or m40??

Post Tue Feb 08, 2005 10:22 pm

johnl320 wrote:so what would you prefer M20B20 ,m10 or m40??

If all in equal good condition, an M40 if I had to choose one out of the 3 or an M10 if I was going to tune it. None would be my choice if the options were open.

Post Tue Feb 08, 2005 10:27 pm

Sorry for picking your brain but why did BMW produce the M20B20 if it is so poor compared to say the m10??

Post Tue Feb 08, 2005 10:40 pm

johnl320 wrote:Sorry for picking your brain but why did BMW produce the M20B20 if it is so poor compared to say the m10??

They're completely different engines, the M10 is a 4 cylinder engine and was tuned up to silly figures by race teams. In stock form it only produces about 110bhp which works out at about 27.5bhp per cylinder.

On the other hand, take the 320, it's about 140bhp for a 6 cyliner engine, this works out at only 23bhp per cyliner.

The M20B20 doesn't produce a lot of power so labours a lot which is what causes the poor fuel economy. I'm not 100% on the above stock power figures but I think I'm in the right ball park and you probably get the idea.

Post Tue Feb 08, 2005 11:02 pm

Adam, you can probably tell i like the M20b20 lump , i certainly wouldn't say the engine labours, yes i agree on that the gearing is such that the revs seem high even at 75 mph which is why i'm changing diff ratio (slightly) and to get any real fun out of it you have to wring its neck but its still a super strong unstressed engine that it silky smooth has a great exhaust note and is capable of gallactic mileage. You are obviously a man of great experience when it comes to E30s and a lot of people on the zone respect your opinion , including myself which is probably why i am writing this , i think you saying that the engine in the 320 is awful will hurt the feelings of a lot of people here and surely every e30 has its place in history and more importantly on the zone. I'm not some wet blanket that is going to burst into tears with every comment against my car
Saying that the M20B20 is the worst chioce for any conversion!! i've done one!!

Post Tue Feb 08, 2005 11:05 pm

I have grown to like my 2.0 engine. Although I am going 2.5 because I crave the extra power.

The 2.0 is ok, as mentioned above, if you really go for it, it does shift, and is not 'loads' slower than a 2.5

But I do agree with if you are gonna go 6 pot from 4 pot, it's worth going 2.5.

Depends what you want.

Post Tue Feb 08, 2005 11:12 pm

davetouring wrote:
But I do agree with if you are gonna go 6 pot from 4 pot, it's worth going 2.5.

Depends what you want.

Spot on mate,it's a bit like me doing my M30 swap and using a 2.8 ltr or 3.0 ltr M30 instead of my 3.5 ltr

Got to make use of the extra capacity in the type of engine your swapping.

Post Tue Feb 08, 2005 11:53 pm

Don't get me wrong John, the M20B20 isn't by any means a bad engine, I probably (well did) phrase it wrong.

I guess what I was trying to say was if you were thinking about converting an engine then the 2.0L wouldn't be a good choice. It's ny own opinion but I think it's probably the worst engine that came in an E30.

I think Andy sums it up well with his example.

Post Wed Feb 09, 2005 12:27 am

Hmmm... not the best engine, but compared to a m40?!

Surely the sound's enough?!

Post Wed Feb 09, 2005 12:31 am

Hmmm... not the best engine, but compared to a m40?!

Surely the sound's enough?!

lovely short stroke straight six, don't know what all the fuss is about, they sound lovely!

Post Wed Feb 09, 2005 12:38 am

Sound isn't really an important factor when selecting an engine though is it

Post Wed Feb 09, 2005 12:57 am

speak for yourself adam, it certainly is for me.

as important as the power it makes as far as i'm concerned

Post Wed Feb 09, 2005 1:05 am

I think it is important, but power for me is more important.

To have a great sound with big power is a bonus.

Post Wed Feb 09, 2005 1:10 am

Adam ,

Youre out of order , I think the 320 engine is great if you havent got a 325? Same sound but a bit slower , We are purists us 320 owners dont you know?? :lol:

If youve got a 320 why would you want a 325 anyway

Post Wed Feb 09, 2005 1:11 am

I don't think Adam was caning the two litre engine, just saying that if you're gonna convert from 4 pot to 6 pot, you may as well go for the 2.5 for 40bhp more. With the prices the engines are now, it wouldn't even cost more.

I like my 2.0!!

But I need more power.