1984 318i - school me please: Grassroots Motorsports forum: Grassroots Motorsports Magazine

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May 22, 2011 8:48 a.m. mthomson22 New Reader

I just picked up 84 e30 318i. I know I'll never make monster power out of the M10, heck not even modest power. I intend to autocross and trackday it and am fishing for suggestions on how to make the most out the platform I have to work with. Preliminary thoughts are header and exhaust, cold air intake, shock/spring upgrade, some light 15" wheels, and new rotors/pads on the front.

I'm open to any insight as this is a different animal than my current 91 Miata.

I should point out that the 318 is an automatic also.

thanks, mark
May 22, 2011 9:25 a.m. SlickDizzy SuperDork

Beware of the transmission; they are NOT robust and tend to fail quickly under stress. You will probably lose power with a header and exhaust due to the backpressure drop, unless you get a nasty cam for it and port the head. CAI will do nothing but make a cool "whoosh" sound. The ONLY way to get power out of the M10 is a serious cam and head job, or FI. Suspension-wise, it is an E30, how far you want to go solely depends on the size of your wallet.

A buddy of mine in high school had one of these with a 5-speed. It was remarkably slow. You already have the Miata, why this? If automatic is a must, I'd try to find something that will hold up better to track duty. The ancient 3-speed mated to an 80-some HP engine that needs to be revved to go anywhere is a pretty bad combo.
May 22, 2011 9:48 a.m. Luke SuperDork

Was fuel injection not the norm for US 318i's?

I test-drove a 318i manual, once. It was obviously underpowered, but peppy enough. Lots of gear shifting required to keep the engine on the boil. So, I'd be looking at a manual swap, if anything.
May 22, 2011 9:50 a.m. SlickDizzy SuperDork

Luke wrote:

Was fuel injection not the norm for US 318i's?

I test-drove a 318i manual, once. It was obviously underpowered, but peppy enough. Lots of gear shifting required to keep the engine on the boil. So, I'd be looking at a manual swap, if anything.

I meant Forced Induction, not Fuel Injection.
May 22, 2011 9:56 a.m. WilberM3 HalfDork

you could swap a later 24-valve M50/M52 engine with its likely stronger transmission for both more power and presumably more durable, but to be honest i dont know exactly how strong either stock trans is.
the nice thing is that an 84 318 is the lightest e30 built.

any e30 will respond nicely to the mods youve listed, but i'd also carefully inspect the rear brake hard lines as by now they may really need replacing, along with rear subframe bushings and possibly fuel tank. i'd add SS braided brake hoses to the list too.

are there any shift kits available for german automatics? i dont recall if a 318 has a trans cooler, but i'd see about adding one if it doesnt.
May 22, 2011 10:05 a.m. SlickDizzy SuperDork

Okay, I just found your other thread and can offer a few suggestions...

These websites are going to be your friend for race parts: Ireland Engineering Turner Motorsport Pelican Parts

Any BMW owner needs this site bookmarked for the awesome diagrams and part # cross-referencing: Real OEM BMW

If $5k is your budget, you have some room to play. Try to find a later M40 (16v I4) or M50 (24v I6) engine with the later 4-speed auto attached. Like Wilber, I have no idea if it will be any stronger, but at least you'd get an extra gear. Either way, add a heavy duty trans cooler, and put some Redline synthetic fluid in it right away, and it might go the distance for you. I don't know of any shift kits available out there, but they could exist.

Do all the suspension bushings (pick your favorite material, it's out there for the E30), then drive it and tune from there. As said above, SS lines are always a good investment. Maybe convert to rear disc brakes? I would do wheels and tires before any other suspension stuff, E30's are pretty tossable and neutral from the factory when everything is fresh.

If you really want to stick with the M10, or just have a boner for the "old-school way" like I do (I'm currently building an antiquated Subaru EA82 to period WRC spec with a bunch of rare low-production parts) there is power to be had, but it won't be cheap. Look into Schrick cams, and send the head off for a major work-over. Get some 9.5:1 compression pistons, then slap it together and make the next big decision - you could run carbs, ITBs, or even standalone EFI at this point. THEN a header, full exhaust, and good intake will make a hell of a difference. It will sound totally awesome too. This setup will net you somewhere around 170HP, and be period correct. Not your only option, but certainly one way to go.

Good luck with the project, now that I've seen your other thread everything makes a lot more sense to me.
May 22, 2011 11:00 a.m. Joshua Reader

The 'i' on BMW's means fuel injection.

One of the BMW magazines did an article a few years ago on the 318, it's supposed to be very easy to turbo and make decent power. I think the magazine was Performance BMW but I could be wrong.
May 22, 2011 11:12 a.m. mthomson22 New Reader

Thank you Slick, that's exactly the type of info I'm looking for!!! I do like old school, and for whatever bizarre reason do love small underpowered cars...maybe my inner John Morton shining through

I'm pretty excited about tinkering with this, and trying a track day after some initial messing about with it.

The carb/itb route sounds interesting but for now I'll stick with the injection until motor rebuild time.

For now I'll concentrate on adding lightness and handling.

Any specific exhaust recommendations? I like reasonably loud

mark
May 22, 2011 11:26 a.m. SlickDizzy SuperDork

I don't think anyone makes an aftermarket exhaust for the M10 318. There are options for the M40 318 that MAY fit, but that's a crapshoot. If you want to see some performance increase right away, I would get the Schrick 284 cam and match that with a header (I think Ireland has them, Schrick used to make really nice ones but they are rare) and a custom 2.5" exhaust (find someone locally that can do mandrel bending). Even with the stock fuel injection and low compression pistons, this should bump you over 100HP and give you a much better soundtrack.

If you do some searching around the good BMW forums (E30tech, r3vlimited, Bimmerforums, Pelican) for "M10 performance" or "M10 upgrades" etc etc you will find everything from mild bolt-on builds to near F1-spec 800HP turbo monsters. The M10 has been around since man discovered fire, and there are newer, cheaper ways to go fast, but due to its history there is a lot of good info out there if you look for it.
May 22, 2011 11:48 a.m. z31maniac SuperDork

You'll want to convert to a later style rear trailing arm with disc brakes on the rear, and get newer strut housings as well as they are larger, and have many more suspension options.
May 22, 2011 11:53 a.m. carzan HalfDork

The M10 is good for 400+ HP when properly boosted. The autotragic ain't gonna handle it, though..

http://cgi.ebay.com/ebaymotors/BMW-M10-Stainless-Turbo-Header-Manifold-T3-BMW-2002...

Just sayin'
May 22, 2011 12:06 p.m. carzan HalfDork

Also:

http://home.mchsi.com/~jroal/

Click on "Cars" button on the top left. Then click on "1984 BMW 318i Turbo" on the bottom right. Good info with before and after videos.

Have fun!
May 22, 2011 12:30 p.m. BoxheadTim SuperDork

First thing I'd check is the state of the cam, at least in Europe the 318 has a reputation for wearing cams if the oil change intervals have been stretched out a little too far.