Why do people seem so interested in the M20? To me it seems to be a dead end in terms of performance. I guess I'm just wondering if I'm missing something about my m20b25...

 

Tons of cheap parts. U pull has engines.
Turbo kits on Ebay for 999.. They are not the best but do the job.

But you are right. they are limited.. Best bang for the buck is a M50 conversion.

 

I guess that makes sense. Parts for them are cheap, but I thought ebay turbo kits can't handle much boost.

EDIT: Wow, I just realized what I said. Not trying to start the "to Ebay, or not to Ebay" debate. I'm just genuinely curious about it. Most people I've heard from have said Ebay kits are crap, but I haven't heard anyone speak from personal experience. Are there any issues from using such a kit as a starting point and then moving up from there (ie better turbo and manifold, BOV, etc)?

 

the m20 is great to build because if youve had one for years you already know the ins and outs of it. 24v swaps will net you more HP for money than modding an m20, but 24v swaps require lots of non-e30 parts and work to get the engine tranny and driveshaft all where they need to be. and youre still left with a non-rebuilt motor. i have friends with 24v swaps and i have an m50 i could have swapped, yet ive chosen twice to keep working with the m20.

 

A chipped IS engine is OK hp..
I like the durability.. You always hear about these engines going 300k. So a 150k car is cheap.. and you can easily covert it for a track or auto X car. with the Spec e30 class there are even good guidelines on how to set up a car.

If you dont do a ETA IS engine combo or put in a thick head gasket. You really dont run much boost any way . So the cheap kits are OK.. But I agree that you get what you pay for.

I just pulled apart a turboed m20 I am guessing they were running 15lbs plus boost.. All the crank bearing surfaces were badly worn. And 4 of the connecting rods bent. So even with forged rods I dont think the engine has a large enough bearing surface to handle a great deal of boost.
Example the 80's Vovlos use a engine derived from the truck engine, So the bearing surfaces are over engineered. This they can handle the load a turbo puts on the bottom end.

B

 

So what you're suggesting is that an m20 shouldn't be run with over 15psi with forged internals and maybe half that without?
What do you mean by the ETA IS combo? ETA bottom with an I head?

I've done some research on the swaps you've mentioned and they seem relatively costly and in-depth, which makes me wonder... Despite their more substantial horsepower (compared to the stock m20b25), how realistic is such a conversion is compared to a forced induction setup?

 

Yes if you use a ETA bottom end with the flat pistons and the I head that is made for domed pistons.. I have read that it drops the compression about 1.. I have never tested so I am only going by what is on the net.
I am sure there is more data out there.

Turbo sites. There are some really fast Turboed M20 cars over in Sweden. Also Germany.- Europe. I didnt really follow these sites because I wasnt going to build a turboed m20.

You can get M50 engines cheap. You can get a whole 525 parts car for $700 if you look around. The engine will bolt up to the e30 trans.

The M50 engines go over 200k miles easy. The head gaskets can go or the head will crack. From my experiences its a 50-50 chance. RE gasket vs crack. If the fan clutches are good and the radiator good then the head should be fine. My 5 series has 214k miles and runs well. It has had the head redone. It was purchased as a blown headgasket. Turned out was a cracked head.

I just found a 525 at LKQ last week. The intake was gone. I grabbed the ECu. you can get an engine from the yard for $250. ish. Of course its a crap shoot if its good.
The swap is welding a trans bracket, shift linkage. 5 series engine mounts and trans mounts. E21 brake booster. and a very few wires need to be spliced.
Its all on the web. If you are mechanically inclined I dont think it is a huge project once you have all the parts.

A weekend to do the swap OR a weekend to bolt on a Turbo, drill and tap the oil pan. swap out injectors. Then there is the whole issue about remapping the ECU,etc. If you are running high boost fuel will need to be addressed.
I would say they are about the same time investment. And close to the same amount of $$. IF you can do them yourself.

But I have not done either. So I am only going off data.
I will be doing a m52 swap into a 318ti soon Ill let you know how that goes.

B

 

I just like m20's because basically i know the ins and outs of it like posted above. I think they generate a decent ammount of hp stock and its just fun to see how quick that little motor goes. The m50 is a bad ass swap don't get me wrong but i'd just way rather spend my money on my m20 and do her up the way i would like.

By the way if your gonna do an m50 swap or any swap at all I would love to take that m20 off your hands if your willing to sell for a decent price. Just let me know. Thanks.