JP's E21 DD

[Hermes]

Ordered straps and tilt knobs today, $85 after tax and shipping

[PKR]

I'm really enjoying your project ... it takes me back to one of my most beloved BMWs: a gray-market E21 I imported back in the mid-80s. My '81 323i came from Switzerland, via a dealer I already knew. When traded in there it needed a new head so I arranged for a new Hartge head/cam to be installed before shipping it to the US. One of the most balanced cars I've ever owned. You'll enjoy yours, I'm sure.

[Hermes]

Nice 323! Is that a Zender spoiler you had on it? I'm definitely going to put a 6 cylinder in at some point, but still debating which engine. Although I know M20 is the easy choice because that's what the 323 had, I really don't want an iron block engine. I'm thinking probably M52B28 all alloy from a 97-99 Z3, but possibly a M54. Honestly I would prefer a non-VANOS engine but they all have iron blocks

[PKR]

Thanks ... and yes, it was a Zender rear lip. In addition it also had Bilstein/springs/bars, 14" replica Style 32s (15s were way too $$ back then!), a Recaro drivers seat (which I kept when I sold the car - nope, its not for sale), Stahl header, LSD (OEM, though built up to a 40% lock from the standard 25%), and an Alpina auxiliary fuel tank . "Stupid" is the only word for my decision to sell it.
As to which Six to use I'd only say that with the M20 this car had Perfect Balance ... consider that when you're investigating the choices. Others might make it quicker but .... . If I were to replicate this car I'd stay with the M20 but it'd be balanced, have a sweet head/cam/valves, lightweight flywheel, and more up-to-date fuel injection than the E21 had. Having driven a couple of other 323s back in the day I can say that the Hartge head/cam is what really woke this car up, though without the better breathing header it would have suffered.

[Hermes]

Beautiful car! Do I see the stops for headlight wipers (can't actually see the wipers)? I'm currently running Bilstein struts/shocks w/Suspension Technique springs and bars (25mm front/19mm rear).

I know what you're saying about the M20 being the great fit, especially if you upgrade to Motronic vs Jetronic, but my main issues are:

1 - iron block vs alloy block

2 - SOHC/12 valve vs DOHC/24 valve

3 - weight distribution due to that heavy lump in front. It's already nose heavy with the M10, M20 won't help anything in that regards.

I have a friend here in town with a 1978 320 w/M50B25 (he bought it that way, he would've done a different swap) and it's a beast at autocross. We keep planning together what we are going to do with our cars. His is gutted and on coilovers, while mine is still a daily so our goals are not exactly the same but many things are shared between what we want to accomplish.

The main problem is what can I legally accomplish in with the Air Resources Board hovering over my shoulder. Whatever I decide to do I have to swap everything from the air filter to the tailpipe to comply with the car that the engine is coming from. I will then be required to pass smog for whatever car the engine is from (so if I decide to go the Z3 route, I will have to pass smog for a 97-99 Z3).

Main problem is weight. M20 short engine weighs 117kg dry, M52 alloy version weighs 118kg dry.

dressed engines on the other hand weigh quite a bit more

M20 - 180kg


M52 alloy - 149kg


mine would actually weigh less because I would delete the AC and power steering, so maybe 130-140 kg?

The problem I see with the M20 is how much will it cost me to build and engine with comparable performance on top of the fact that it weighs more. With the M52 I can swap in S52 parts to get bigger displacement for cheap, M20 is much more expensive to match power levels.

Anyways, this is all still in the planning stages. Right now I just need to put my car back together and drive it some more.


EDIT: M10 is around 85kg, so nothing else is gonna be that light

...maybe a M42/M44 but I want more cylinders

[PKR]

Hmmm... complicated issues. Certainly more complicated than I had to deal with back then! But I'm afraid that I'm utterly unfamiliar with ARB issues.
Have you driven an E30-M20 or an E30-M52? If not then that's where to start. But drive it the way you'll use yours. Power solves alot of problems in an autocross setting - but only if you're a genuinely competent driver, since (usually) the car's limits are higher than the driver's. On the other hand for a DD the extra power in the lower RPMs would be fun - and actually practical! Either way good luck with the project ... I'll be enjoying it along with you.
Oh, and yes, my car did have headlight wipers ... until I removed 'em - too much hassle.

[Hermes]

Thanks! Yeah, the California Air Resource Board is a huge pain to deal with. Even after I do all my swap I have to take it to a "referee" to then approve my swap before I'm given what they call a BAR tag basically stating that it's a legal swap.

I have in fact driven many M20 E30's, specifically I love my buddy's 2.7 stroker


His car is pushing around 200hp, but his engine probably cost him over $4k to build. The M52 comes out of the box at 189hp and I can probably make that difference up significantly cheaper

I've never driven a M52 E30, but Ryan's car approximates it close enough I think.

My thinking is the extra power will be nice at autocross, but mainly it will help just driving around town. I'm currently getting 27mpg and hopefully with that much extra power in such a light shell (around 2300lbs) I can be easy on the gas and get into the 30-40mpg range

[Hermes]

Well, I have come to the conclusion that the original owner must have rear ended somebody over his 30 year period with the car. Decided to pull the hood off and do some persuasion to the core support



You just need the right tools and anything is possible

[derbo]

Brute persuasion seem to fair well all the time

[Hermes]

So Matt and I did some brainstorming last night and have come up with an idea for solving out terrible suspension/low strength diff/general driveline stuff.

E28 rear and and E36 front end swap. We're thinking about using a 3.25 medium case LSD rated at 440 ft/lbs vs our current small case 3.91 at 240 ft/lbs.

He already has a ZF 5 speed from an E36 M3 in his '78 M50 non-VANOS swapped car, but we're thinking of maybe doing a Getrag 420G 6 speed (368 ft/lbs)... but supposedly can handle more torque than that