More power, Scotty!

Post Tue Apr 02, 2013 8:29 pm

I'm getting a cheap run about so that I can keep my E30 off the road whilst I get the work done underneath the car. I'm now thinking I can take advantage and sort the engine at the same time. My original plan was a S50B32 swap but ive recently thought of adding a turbo to the M20 instead. Its a 1990 325i sport and I thought it would be better keeping the car closer to it's original condition instead of a swap. I'd assume it would also be a bit more fuel efficient and I can set the amount of power I want (S50 too much really for my needs). Recon I'm heading in the right direction?

Post Tue Apr 02, 2013 8:50 pm

Depends what you want, OEM reliability or Fred in the shed home brew.

I would personally go for m50 turbo, but from the options I would go s50.

And don't go into turboing thinking it will be at all efficient

Post Tue Apr 02, 2013 8:56 pm

Or more realistically if s50 power is too much for you (only 281hp) why don't you throw in a m52 with an m50 inlet and maybe even with the huge money saved over turboing/s50'ing throw in some cams.

Will see you over 220hp, nice N/A power delivery, cheap and reliable.

Post Tue Apr 02, 2013 9:16 pm

Maybe I was thinking too preciously about maintaining the original condition. Considering im doing a 5 stud conversion I'm obviously straying. So an S50 could be back on, just thought they were 300+.

Post Tue Apr 02, 2013 9:21 pm

If original condition is an issue then the best way would be 2.7/2.8/3l m20.

Post Tue Apr 02, 2013 9:31 pm

Not that much of an issue for me. Just thought that the general opinion of a 325i sport was it shouldn't be spoilt too much. Maybe I'm completely wrong and I should lose the M20! Haha

Post Tue Apr 02, 2013 9:31 pm

Craggy73 wrote:Maybe I was thinking too preciously about maintaining the original condition. Considering im doing a 5 stud conversion I'm obviously straying. So an S50 could be back on, just thought they were 300+.

S50B32's make 321hp in LHD form, runoured to make around 300hp in a rhd provided you have a well modified manifold I.E. a BTB.

Don't get me wrong, 281hp is more than you will ever need in the constraints of an e30.

Post Tue Apr 02, 2013 9:36 pm

Yeah! 281 is a nice enough figure for me.

Post Tue Apr 02, 2013 9:41 pm

Just keep the m20 in storage/the garage. That way you can always swap back to keep original value.

Better have deep pockets to do an s50 conversion properly though

Post Tue Apr 02, 2013 9:50 pm

3.0l S50 power curve with a full BTB exhaust system in the link below. The torque that hits at just over 3500 rpm is EPIC and very addictive

http://www.e30zone.net/e30zonewiki/inde ... Graphs#S50

Post Wed Apr 03, 2013 7:29 am

ross_jsy wrote:Just keep the m20 in storage/the garage. That way you can always swap back to keep original value.

Better have deep pockets to do an s50 conversion properly though

Not really got the option of storage. I'd rather sell the engine to contribute (all be it a small amount) to the cost of the conversion.

This is part of the dilema. The cost againt the power gain. I'm sure I'll be more than happy with figures around 250bhp.

Post Wed Apr 03, 2013 9:46 am

I can't see a strong argument against M52 and tweaks for the power levels you're after. If you want a lighter engine you could go M54B30 - but M52 is tried and tested with parts available and the weight of the block is offset by the fact that you can take the head off if you need to. You could buy both and combine them into an M52B30 stroker if you're an engine building hero

Post Wed Apr 03, 2013 12:37 pm

Morat wrote:I can't see a strong argument against M52 and tweaks for the power levels you're after. If you want a lighter engine you could go M54B30 - but M52 is tried and tested with parts available and the weight of the block is offset by the fact that you can take the head off if you need to. You could buy both and combine them into an M52B30 stroker if you're an engine building hero

The M52B28 was the first engine I was looking at for a swap. Might be my best option. I could drop it in them look at mods afterwards to improve power as I see fit. Oh, I'm no engine hero. I'd do as little as possible with the internals myself.

Post Wed Apr 03, 2013 1:53 pm

A m52 is between £1-2k to instal where an s5x conversion will be £6k +. Might influence your decision a bit

Post Wed Apr 03, 2013 2:37 pm

Morat wrote:I can't see a strong argument against M52 and tweaks for the power levels you're after. If you want a lighter engine you could go M54B30 - but M52 is tried and tested with parts available and the weight of the block is offset by the fact that you can take the head off if you need to. You could buy both and combine them into an M52B30 stroker if you're an engine building hero

Would the M54b30 not be a nightmare, electrically speaking, though, to get working in the E30? It's a great engine, but i've not seen many conversions with it in - Not that i've looked, admitedly..

Post Wed Apr 03, 2013 3:06 pm

Yes a lot of work to get one to work, although I think you can get the ecu flashed so it doesn't look for all the sensors. There are a couple of zoners who can do this.

Post Wed Apr 03, 2013 5:19 pm

If you want any kind of fuel efficiency, stay away from anything turbo - it only takes a small tickle of the loud pedal to start using boost and more fuel than is needed for the situation.

The most fuel efficient E30 I've owned was my S50 powered one, all the power and torque meant it just wafted along when driven sensibly. Yes it had a drink problem when used hard, but it was still better than the M20!

I would think the M52 will give similar mpg figures to the S50 with everyday use, and with a bit of cash thrown at it, will be almost as fun as the S50.

I have said a few times now, that I would probably build an M52'd E30 next, rather than another S50, but it's worth noting that while I found an M52'd E30 great when I borrowed one for a few days, it did lack the epic grin factor of the S50 on full chat.

Is the S50 worth the extra £3-4k??? The only thing stopping me building an M52'd E30 is I keep thinking I'll probably wish I'd spent the extra after a month or two!

As for originality, my Sport last had an S50 fitted. If you do it right, it can be done without any mods to the car so it can be put back to standard easily - the same goes with an M50/52 conversion. A turbo build might not be so easily changed back with any mods needed to fit an intercooler or route the pipe work etc etc.

Craggy73 wrote: I'm sure I'll be more than happy with figures around 250bhp.

Never happen. Once you have a little power, you will always want more, especially with a turbo build as its only a small boost tweek for that bit extra - and then the work starts building an engine to cope with more!

billgatese30 wrote:3.0l S50 power curve with a full BTB exhaust system in the link below. The torque that hits at just over 3500 rpm is EPIC and very addictive

http://www.e30zone.net/e30zonewiki/inde ... Graphs#S50

Oh yes, I really really miss mine

Post Wed Apr 03, 2013 5:51 pm

Most of my journeys are short ones just across town but I'd like the power for longer journeys and embarrassing the new cars at the traffic lights now and then, haha. S50 may be too much overall and I think the m52 is enough, for now at least. Will get my car off the road and the jobs done. Hopefully in a month or so I can start engine shopping

Post Wed Apr 03, 2013 6:20 pm

jmc330i wrote: Never happen. Once you have a little power, you will always want more, especially with a turbo build as its only a small boost tweek for that bit extra - and then the work starts building an engine to cope with more!

I'd agree. I was wishing mine had more oomph before I even managed to get as far north as Trowell services (half way home!) the day I picked it up.