Ultimate M20

[Dr Firefly]

I know I've asked a lot of questions about different engine mods over the last year, but I think I'm finally coming close to a decision for when I graduate as a doctor next year and finally get earning decent money...

Kept a 320i limping along on a student budget and got very fond of it, so it'll be time to blow a couple of grand on it then.

What's the ultimate that people can do with an M20 engine these days? Don't want to do a conversion to a newer engine, as I want to maintain the weight balance of the car. However I know there's only so much you can do with an old single cam two valved engine.

I was thinking a 2.8 conversion, and then turbo it. What sort of power would that produce? And would it be reliable? And what sort of fuel consumption as an everyday car would I get?

Now I know this might sound really newbie-ish, but I don't know much about turboes. Would it be possible to install a turbo that you could turn on when you wanted? Like with a subtle switch on the dashboard. So when you're doing a constant speed on the motorway, or a normal about town drive, you could turn it off so that you're not using a massive amount of fuel?

My long-term plan for this car is - mod the engine to a good 270bhp (or something - don't know how much is realistic), get it into perfect condition as regards interior and chassis, uprate the brakes and suspension, and run her forever. So any help would be appreciated.

Here's a thread with photos of the car when some numpty of a teenage girl ran into it at about 40mph and wrote off her brand new Peugeot (£10k) 206. Everything's fixed now, and went on a 2000 mile road trip, which I'll post about properly shortly. But this car's been amazing, and I can't wait to get it in perfect nick once I've got the money in a year's time. Just trying to get a definite plan of action together at the moment though.

http://www.e30zone.net/modules.php?name ... ce+opinion

[Kos]

turbos run off exhaust manifold gasses, to you cant turn it on or off, superchargers are belt driven and are always "on"

however you can dive off boost , just dont go over a certain RPM with a turbo

what you need to know is what your budget is, and see if you can stick to it. normally they end up doubling !!!

your target of 270ish bhp is achivable, 250 bhp with similar torque will be plent quick in an e30.

[Dr Firefly]

Do turbos significantly reduce fuel economy then or not? Thanks for the info so far Kos, that's useful knowledge....

I'm also thinking I'll need an M3 diff and prop in good nick too to take the power, as well as the brakes and suspension improvements to control that kind of power?

[Kos]

Do turbos significantly reduce fuel economy then or not? Thanks for the info so far Kos, that's useful knowledge....

I'm also thinking I'll need an M3 diff and prop in good nick too to take the power, as well as the brakes and suspension improvements to control that kind of power?

a "larger" e30 LSD diff ( as found on any sport and M3 ) will easily take 300bhp IF respected. as for you prop, that should be fine.

brakes, for street use, a basic upgrade of good pads and disks, decent brake fluid should be fine

a good thought would be for you to re build your suspension, change all the bushings and prop doughnut etc before you start with power upgrades.

fuel economy, when driven off boost, the car used no more fuel, actually less than when it was non turbo ( thats on a long run ) around town it will be a little less.

[Turbo-Brown]

Sounds like your aims aren't too different from what mine were when I started my last project Firefly

You can get 270bhp from a 2.5 engine which would make the conversion cheaper I guess.

I can get 28mpg or so out of my car on a mixture of motorway and town driving. Depends largely on the traffic though as it drops to 23mpg if you're forced to just sit in a jam

[FormerMember]

If you want to be different supercharge it! Gives lots of torque all the time and ~300bhp is quite easily achieved. Turbo with 0,75 bar boost is the same thing but "everyone" has turbo.
No need to stroke the engine if you boost it but of course if you have extra money then more cubic inches are sensible

You could get ~250bhp NA but it'd be expensive, easiest and cheapest is turbo.

[oakey]

See if you can get near 250hp naturally aspirated

[Morat]

I think your most realistic option is to roll it down to Ant's place and ask for a low pressure conversion. Should be in the £3-4k region all done and running as opposed to several months of fettling in your spare time - which you're not going to have a lot of as a junior doctor - the golfing comes later in your career

[Dr Firefly]

Well this is going to be a long-term project, so to some extent, cost isn't too much of an issue. Just want a totally reliable engine that will beat pretty much anything I meet on the roads, and still maintains the lovely handling characteristics. I'm guessing Ant is still the best person to do all this?

Kos: After the accident, had totally new rear end suspension (upgraded to disc brakes too) including rear beam, trailing arms, new subframe bushes, and new shocks and springs all round. Was doing it all on economy though, so next year I'll be uprating all the shocks and springs and any bushes that haven't been replaced recently. The engine's going to be the last thing I sort - I think the car will be in my local garage every weekend for a couple of months first to get it back into top notch condition. No point putting a powerful engine in a tired old car. Replaced the rubber doughnut too recently, and that was amazing! Cut out so much slack in the drivetrain.

I think I'll be sticking to a turboed 2.8 as my basic plan, though I've heard negative things about it being an unbalanced engine in comparison to the 2.5 - that it revs high and doesn't have much low down torque? But with it being larger cc, it must develop more power at any given revs than a 2.5, surely? Do people have info on the exact specs Hartage or Alpina used when they modified the engines? Because it would be kind of good to tread where good tuning companies have gone before in building a better N/A engine, and then turbo it...

One question though.... has anyone blown up their M20 by doing too much to it in terms of turboing and mods? I want a useable everyday car at the end of this, not a fussy prima donna that breaks down all the time.

[FormerMember]

Do people have info on the exact specs Hartage or Alpina used when they modified the engines? Because it would be kind of good to tread where good tuning companies have gone before in building a better N/A engine, and then turbo it...

On M20 Hartge / AC Schnitzer / Alpina basically made same things; diesel-crank (=> 2,7l), some head-work, wilder cam, good exhaust + manifold and some ECU-remapping. They all made ~200-220hp.

One question though.... has anyone blown up their M20 by doing too much to it in terms of turboing and mods? I want a useable everyday car at the end of this, not a fussy prima donna that breaks down all the time.

Buy good, well known parts, they are maybe not the cheapest but you have to pay for quality. In Sweden there are few 800-950hp M20 turbos so even 1000hp is reachable.
What i'm trying to say is that 250-300 hp is "nothing" in M20, it can take it easily and so can gearbox, diff etc etc. So don't worry Just use good parts, well mapped injection / ignition -system is really important.

[e30_Turbo]

From what I've been told, heard and read the M20 in it's stock form has a power limit around the 500bhp area.

The main reson for this is the bottom end will come apart, usually ending in a hole in the block, there are M20's running more, I doubt 1000bhp but atleast 700/800 but the work needed to get that in vast and expensive, IIRC PPF would sell you a engine ready for boost for around £8 or £9k.

You need to see BMW BY RONTA's vid too see what 600bhp does to a e30, it's just insane!

has anyone blown up their M20

Yes, me but that's due too being too boost happy and not having the right parts in the right places, now it's all sorted and I have a limit to work too I doubt I'll be having another issue like that, although I do plan to have one last 'pop' before the new lump goes in.

You could just bolt on a reasonable sized blower to a stock lump and see 300bhp with ease, but you really need to set a plan and work to it, my first conversion with a T3 produced a 0-100 warrior with huge torque and excellent low down acceleration ( spooled @ 2k ) but with the truck turbo it's all 3k plus, bit of lag before hitting warp speed all the way to redline!

I know what I prefer and am happy with the end results but there are some people out there who want both ( Alex) and go for twin turbo's!

Re the M52 Turbo, search out BMWSOB on e30tech as he's finishing off his at the mo....... and I expect some really good results from his project as his M20 Turbo managed a 11.6 @ 120 mph quarter mile.

HTH, Mark