Bash-e30

Hi guys, just started researching things for a project I’m thinking of doing.
I have a bmw e30 1.8, I want to make it drive a little more modern so I’m going to do an engine swap. I think I’ve pretty much settled on an MX5 engine as it’s RWD to start with but also because I found on here that people like to fit the bmw box which means the adaptor is available so I can run that engine.

ive pm’d a guy on here about the bmw conversion. Are there any other companies that offer it?

and lastly I will be going for the 1.8 MX5 engine and putting a turbo on too. Does it matter if I go for the VVT engine or not?

hope that isn’t too long. Thanks for reading.(I’m in U.K.)

Dyladjent

Welcome. Before you jump into putting the poorly flowing bp into your e30 check out the guys at Kpower Industries. That link is to a full e30 K swap kit that will bolt up to your transmission. The K series is a much better starting point and they've already figured out all of the little things for you. Unless you are doing 100% of the fabrication and wiring and already have all of the tools to do it, I think it would be cheaper in the long run to go with a K24. After physically making the mounts and installing the miata 1.8 you are going to have to work out how to integrate the electronics into the BMW stuff. Even if you managed to get the engine in and running and communicating with the BMW cluster a stock 1.8 bp will be limited to 150ish NA horsepower without big $$$ and tons of work or about 250HP with a FI setup. A junkyard K will give you an easy 250 NA or 400+ FI with no major work. You are looking at 5K+ into a bp before all of the fab work just to make 250 HP and to many of us here it's not worth it when you have other options available.

I don't know how available K24s or k20s are in the UK but you would be taking a step back by putting a Miata BP, VVT or otherwise, opposed to anything else that would fit. There is nothing modern about the design of the 1.8 in the miata it was designed in the 80s and remained basically unchanged between 1989 and 2005.

I'm by no means trying to scare you away from doing whatever and using the Kpower BMW to BP adapter plate would probably make it "easy" to physically fit the 1.8 into the BMW engine bay assuming it was far enough forward to clear the firewall. I just don't think it would be worth it to put the time and money into putting a 700$ boat anchor in your E30 when there are other options available.

Bash-e30

Hi, thanks for your reply.

I’m pretty sure we don’t have the 2.4 K over here and to get a good K20 is such a lot of money.

As you say, I know it isn’t modern tech but I can buy a whole miata for £500 and then sell the parts I don’t need to basically get a free engine. I’m lucky that I can make all the mounts myself and my brother will help with wiring. I’ve turbo’d a few cars I’ve owned so I’m lucky that I have a little knowledge.

I do really appreciate what you’re saying.

Bash-e30

Edit. We do have the K24. Sorry

Dyladjent

If you are 100% set on it then that's fine. The knowledge here will 100% apply to boosting a bp regardless of what it's in. Just remember a free bp still needs a full rods build to make any more than 250 at the wheels and at that point a k might not be so expensive. A standalone + turbo + manifold + clutch will already be upwards of 3-5k depending on what you get. And I don't know what you are looking at for adapter plates for the bp but everything I've looked at has been 1500$ + for just bolting the trans to the engine.

With my current setup on my car I know that figuring out how to make cheap parts work can be more expensive in the end just to end up with a suboptimal system. Just make sure you look at all of your options before diving in on a setup where you are going to have to compromise everywhere to make it work. With a car that old 9 times out of 10 if it was worth doing it would already be done and documented.

technicalninja

I have an E36 M3 and I've decided to stay BMW.
The car will hold it's value better if I don't cross-pollinate. I was really heading to the GM 3rd gen small block (LS4) and T56.
The stock S52 can easily make 500+ hp boosted (some are above 700) and I stay "stock".
If I had a nice E30 (E30 are appreciating right now) I'd try to stay BMW (a six cylinder) boost that and live with the results (which will be great).
My M3 is nice enough that I'm not planning to drill a single hole in the unibody to retain "stock value" down the road.
I'm also keeping all of the stock stuff that I am removing, packaged up nicely and stored for the future.

The Honda K series is the "best" 4 cylinder ever produced by anyone IMO.
It is a stellar platform to work with with huge potential both NA and boosted.
It's the "go to" platform IMO for high output 4 cylinders for anything, Miata's included.
It's so good that it requires BMW transmissions be cross-pollinated into Miatas as the stock drive trains abilities can be exceeded easily by the K24 in ultimate NA form. (K24 block,K20 head, big cams. ITBs)
Boost that K24 (even a bone stock one) and you need to upgrade EVERYTHING behind the engine in a Miata.

Even still I would first try to stay "German" on a German car. You can easily fit a six into that E30 and BMW hotrod stuff is easily available.
I might go K series if the car was a "beater" and the K24 was super available (it is here in the USA) this would be BAD-ASSED but...
You will anger the BMW gods and enthusiasts, It will probably NOT retain value over a proper BMW swap, and you will be treated like a step-child on the BMW forums/ BMW events even if you're substantially quicker than everyone else.
You might get banned from participating in events as the "BMW snobs" do not want to be beaten by a Japanese "wanna-be".
I don't agree with this trend but I realize it's out there.

I would NOT put a Miata engine in one...
I'm planning to stay with all Mazda parts in my 2001 SE but limiting my build to under 300lbs/ft of torque to allow use of a "standard drivetrain".
A Miata with 300 lbs /ft of torque makes for a very quick street car.

Newaza

If thats the m10 based engine I would turbo the heck out that thing and make it fly. Factory forged crank and cast iron closed deck block. It would need forged pistons and maybe rods for strength. Also an aftermarket ecu, fuel system and of course turbo setup. Slap a big turbo with some man boost on that old school bad boy to make some serious power.... Unless Im wrong I believe the very early m10 based block was the bases for the development around the bmw f1 program of the early 80's

technicalninja

This is a better suggestion than what I advised!
I didn't even think about modding the original engine...
Bad Ninja, BAD BAD Ninja...

He's RIGHT!

One of my mentors, Corky Bell built a turbo system for the e30 (320i) in the early 80s with a not perfect sized turbo and "blow through" Mikuni Carbs (another limiting factor).
It was A2W intercooled and "state of the art" in 1983. He made close to 220 hp out of it with a bone stock engine. It was a HOOT to drive!

With the current crop of go fast stuff (4 decades of improvement!) I would think 350 is a conservative boosted HP level now for this engine. I'm not an M10 expert but I know these guys exist.
Find one and ask him for power suggestions with the stock motor.
When I say "stock" it just means the "family" of engines, it does not mean stock rods, pistons, or anything that can be easily changed. It means original style block that can be easily bolted up to stock mount points and transmission.

If you really have the original block in your car it might be better to mod up another and keep the original engine stock in storage. It all depends on the "niceness" of the car you own.
My M3 has just enough "damage" to the unibody to no longer classify as "Mint". If it was truly "perfect" I'd not modify it.
I'm still not going to "damage" it any further because it took me 6 months searching to find a car that was "clean enough" for me...
Always remember, the E30 M3 at one time was an unwanted, hard to drive (for a non-enthusiast, too much "feedback"), low torque cast-a-way. I remember lots of them below 5K.
Now, a crappy one is worth 25K and super nice ones can hit 6 figures!
Don't devaluate something that might triple in value over the next 10 years if you can

This way saves big money as well...

Bash-e30

Honestly, the K swap would be the dream. I’d get the same BHP but get to keep it N/A and it would be amazing. 5k for the fitting kit plus another 1500 for the engine it then starts to be expensive. And as much as I’d like to say cost doesn’t matter I don’t have an endless pit. It also isn't the cleanest of examples so again doing a few little jobs like this doesn’t worry me. Was owned by a little old lady for 15 years but unfortunately kept outside so I had to do a little work to get it through the MOT.

it probably hasn’t been done because it would be a lot of work to gain 8 valves over the engine already. The bmw 6 pots are great but they are so heavy. I’m on very friendly terms with a bmw breakers who have offered me the full swap for not much money at all but even though it isn’t the best example it does drive well and putting an anchor up front I think would ruin it. If it was an M3, even a poor one I wouldn’t even consider it.

deep down we all enjoy upsetting the purists don’t we? a good friend of mine put a Vauxhall engine in his VW and that didn’t go down well at all. He also attempted to put an MR2 engine in the back of another vw but unfortunately it didn’t get finished.

m10 is famous for the being the turbocharged F1 engine isn’t it? But I’ve looked around and the kits are so rare. Not to mention management, fuel, ignition, etc. And if I have issues I would have spent a lot of money and be stuck with it. Just to find forged pistons is hard enough.

which is why I settled on the miata engine just purely for availability and also a little for cost.

im gonna go away and look in to a K24 though, I just don’t know it I could afford it.

thanks very much for the replies so far. You’ve been super helpful.

Newaza

That stock bmw engine may hold more than you think.

If were me I would still lean heavily towards boosting that rather than swap. I don't know your skill level for fabricating but its really not hard to diy a turbo setup. Don't be scared of ebay turbos and intercoolers if you are on a budget. After turbo system is done you just need a way to add fuel and retard timing. Again its really not that hard to make existing stuff work with a little modifying or adding to. Most on here would call doing stuff like that band aids and dinosaur caveman mods, but I've successfully band aided several turbo setups for very little money. Stand alone ecu with modern fueling would be best, but not absolutely necessary.

I will give you a quick example of my first successful turbo build. This was back around 1988-89. It was a small block chevy in an old firebird. I used stock cast iron manifolds with the normal oulets cut off and capped with a steel plates welded in. New outlets were added facing forwards as the turbos (there were two) were located at the front of the engine. The cast manifolds and steel tubing were stick welded with nirods by yours truly and didnt fall off LOL... . All the remainder of the exhaust was fabbed with 2 1/2 exhaust off each turbo. If I remeber right the turbos were garret t04 with v trim compressors. There was no intercooler. It was blow through a holley 700 double pumper with most of the mods you see people doing to them now for blow through, not all of them though. Some of the mods guys do for blow through carb now I didn't know back then. No internet in those days so I had to figure out what was needed. The fuel pump was a boost referenced mechanical pump along with a holley blue pump at back of car behind the tank that activated only in boost through a hobbs switch.. To retard the timing I opened up the vacuum advance canister and moved the spring to other side of diaphragm to make it essentially a boost retard canister. Doing all this that cobbled together piece of crap probably made over 500hp on pump premium. I've succesfully cobbled together several other pos builds on the cheap since then. It would be a surprise to most on here how well they worked. In fact my current play toy is a cobbled together pos miata done with some good parts, but also a lot of ebay junk as well. You can see in my sig how well junk can work with a little imagination and planning.

I only say all this to show as an example what is possible to do on a budget. It doesn't necessarily take a lot of money, but it does take time, imagination, learning some fabrication skills, and learning how your car is fueled and ignition so you can work out the necessary mods. Just remember if you do go this route, your first time in boost you want super rich fueling and low timing. You basically want first boost to look like you're coal rolling lol.. You wont make any power but you'll be safe. You get the power slowly by carefully leaning fuel and adding timing in small steps and testing each small step..

Anyways with all that said it is your car so you can build or swap as you see fit, but I for one hope to see you on here in the future with a turboed, old school m10 monster!!

Zed.

There’s a guy (in Australia iirc?) fitting a Mazda 1.8 cylinder head on a BMW m10 cylinder block....

some interesting ideas out there.....



to CONUS based members, MX5’s are cheaper over this side of the pond, $2-300 can buy a car and if you’re lucky it’s not just spare parts!
go-faster parts are expensive though

Rich.

Dyladjent

@Zed. and you could probably find a briggs and stratton lawn mower engine for 20$ but that doesn't mean I want to put it in my car.