E30 with M30B35

[schtozo]

My m20 spins 6th and its even an autotragic :pimp: WTF??

Hahaha but seriously i got into the m30 e30 in the video i posted few posts back and it was really fast for being stock and itvreally spinned second gear easily, dont remember third though...

[MR 325]

Yes, the hardest thing about the swap is dropping the engine in! :)

On my buddy;s we used the stock driveshaft, swapped the small flange on to the trans. We used the stock wiring harness from the M20, it was awesome! Very simple swap.

[Lurker27]

A few things. Rebuilt from the bottom up, turbo M30b35 swapped e30 owner here.

1. The M30b35, healthy and with a chip, is a shade above 240bhp, with a monster torque midrange of over 260lb-ft. Because of the shape of the torque curve, they produce more area under the curve than most 24V swaps. S5x swaps are better, particularly when cammed + m50 manifold.

2. In terms of mechanical and electric difficulty, the M30 is probably harder than the m/s5x at this point. You need the right harness and the engine will always fit worse in the bay. You also need more big ticket parts. The M30 engines themselves are slightly cheaper than even m52s, but cost is largely a push at this point.

3. The weight difference is negligible. If you have the lightweight e34 b35 casting, you are losing weight compared to a 24v swap.

4. bashing the firewall is a GOOD THING. Moving the engine further back is a GOOD thing. If you buy mounts that don't require a bashing, you bought the wrong mounts.

5. Feel: The m30b35, with it's slightly-hot 276 cam and "Big typewriter" valves, is the I6 that wants to be a V8. That's how they drive. They're even a little lumpy at idle, but once you're into the glorious midrange powerband, it settles into the BMW I6 smoothness. It really is a glorious engine - if S38 maintenance costs weren't ridiculous I'd kill to own one.

The m52/s52, on the other hand, is buttery smooth and refined through and through.

The M30 is an M20 on steroids. The M50 is the M20 with a college education.

[LJ851]

The M30 is an M20 on steroids. The M50 is the M20 with a college education.

Well spoken, Sir. That is a perfect description.

[Jean]

Yep, M30B35 is just awesome with all of it's torque delivery! I would pick it over any M50 or M50V but not over S52.

[chadthestampede]

1. The M30b35, healthy and with a chip, is a shade above 240bhp, with a monster torque midrange of over 260lb-ft.

As much as I am a fan of the m30, I'd like to see proof of this before I believe it.

[Lurker27]

http://www.r3vlimited.com/board/showthread.php?t=202673

Obviously if your seals are beat to shit, running a bad spark setup and sucking hot air it will be a lot less. For what it's worth i opened up my M30 at 310+k miles and the cylinder cross hatchings were still clearly visible, and the compression was 170-175 (factory) across the board. It pulls idle down below 30kpa (logged using megasquirt). In short, they can stay plenty strong if taken care of. Entire top end was refreshed 70k ago with a valve job, though.

[VinniE30]

This thread made me fall in love with my m30 all over again.:D
Everyone and their mother has a 24v swap. M30 is way more uncommon. Better looking engine IMO too, no cheap looking plastic all over it and looks more period correct.

If you have the lightweight e34 b35 casting...

How is this any different from the e32 b35?

[kronus]

I'm going through an M30 swap right now. It'll be awesome, theoretically, especially since it's going into an e30 pickup truck we're building for the 24 hours of lemons. So far we haven't had a ton of issues, these motors are plentiful from junkyards, and hook right up to e30 electronics and late eta driveshafts.

The only surprise we've had so far is that some M30 cars (like the 635 our motor came from) didn't have traditional vacuum brake boosters, so we need to tap the manifold for a vacuum line to the booster. No big deal.

[slammin.e28]

How is this any different from the e32 b35?

It's not. B35 is B35. Only difference is the early ones (e24/e32 period) had the same oil filter housing as a B34.

[chadthestampede]

It's not. B35 is B35. Only difference is the early ones (e24/e32 period) had the same oil filter housing as a B34.

Not totally true:

If you decide to swap it for a B35 stay away from casting dates newer(later) than 1of 88 . These blocks are a lightweight version of the B35 and not a good turbo platform (decks crack). The only B35 block that I currently use bares a late 87 casting date and is rather hard to find.

[VinniE30]

It's not. B35 is B35. Only difference is the early ones (e24/e32 period) had the same oil filter housing as a B34.

Yea thats what I thought.

Not totally true:
"Originally Posted by paul burke
If you decide to swap it for a B35 stay away from casting dates newer(later) than 1of 88 . These blocks are a lightweight version of the B35 and not a good turbo platform (decks crack). The only B35 block that I currently use bares a late 87 casting date and is rather hard to find."

Hmm, i'll have to look into this...

[slammin.e28]

...learn something new everyday. I respect Paul Burke, but since, in his own words, he said the better block is rare and hard to find (which it is, being that early of a B35) I stand by my statement, as it applies to most of the B35s out there that one is to come across.

[Roysneon]

If you use the correct Alpina mounts, the firewall requires no modification. Oh lol thanks for that :)

I was just going off of the research I did when I was up in the air about doing an M50 or M30 swap.

Honestly, you seem to know a lot, not sure why you made a thread asking such a vague question.

[chadthestampede]

If anyone is interested, this was the whole pm. Some interesting tidbits in here:

Hello Bob, You can stick with your B32 as it is the same stroke and will take a 92mm bore ending up the same dimensionally as the B34. If you decide to swap it for a B35 stay away from casting dates newer(later) than 1of 88 . These blocks are a lightweight version of the B35 and not a good turbo platform (decks crack). The only B35 block that I currently use bares a late 87 casting date and is rather hard to find.

All the B35 heads are the same and have a larger intake port than the B34 which works well when a turbocharging.

If you decide to use the B35 head on the B32/34 short block it will require a custom piston (flat top is approx 9 to 1 ) .

You will pretty much have to commit yourself to a N/A build going any higher than 9 to 1 on a street engine . If you want to gain any worthwhile performance out of the B32/34 (N/A without turbo) it will need to be at least 10 to 1 comp. which will all but rule out adding a turbo.

If you want to combine stock parts and stay normally aspirated for the moment, I would get the B35 short block (has flat top pistons) and use you B34 head (60cc chamber) which will result in a comp. ratio of approx 9.6/7 to 1, combine that with a decent cam and you will have a nice (very cheap) 220hp M30.

There is one draw back however, all the B35 blocks except the 87 date coded ones only have the E32/34 pass. side motor mount provisions so you might have to deal with making a new motor mount bracket.

Paul