Exchanging comfort for even more power. M52 supercharging.

Few months back i was inspired with the idea of having a forced induction.
This is just sharing piece of know-how and ideas, since i didn’t test the build for much longer than i wish and also i haven’t pass a dyno run (read below). I wouldn’t write a whole essay why i picked up a supercharger instead of a turbo, but let’s just say superchargers are tempting with their simplicity and easy install for almost no time compared with a turbocharger. I didn’t plan to make a post about this, but recently I found a folder on my PC with a lot of pictures of the process and .. what a heck … it’s 3am and im not going to bed any time soon.

I did this on my car, but later the mod was removed because couple of reasons:
– Superchargers are noisy.
– Unexpected expenses ( i had to sell the SC, injectors and the BOV )
( You will see some rough welds and thick piping, but it was just a beta, since i just wanted to figgure out how the whole thing will work, before investing some extra cash in alloy pipes and tig welding consumables )

So long story short if you want to supercharge on a budget your m52 powered BMW, no matter if its on e28 or any other model  and you are ready to sacrifice your A/C compressor for more power, here is basically everything that you need:

–  Eaton m62 unit, suitable for engines up to 3.5 liters. ( We probably could hook you up with one in good condition – drop us an e-mail)

– Oem m52 A/C crank pulley.

– Set of 6  380 cc high impedance fuel injectors. BOSCH # 0 280 150 431

– Tial Q 50 mm blow off valve with required mounting parts and supercharger spring inside.

– Custom made spacers,bolts and pulleys , used for tensioning the supercharger belt. (One of them should be eccentric to allow adjusting )

– m62b44 maf sensor (early year, so it can match the oem m50/2 connector) Part # 13 62 17 02 078

– Spare ECU for m52b28. So you can remap it. (Stock ecus are good and safe up to 0.9 bars (13 psi)

– Boostmeter ( i had cheap one in the garage)

– Belt. Lenght should be consistent with the Eaton bracket
– Custom piping

Optional

– Intercooler. (You better have one)

——

Let’s begin with the supercharger.

It usually comes with electrical clutch pulley. Good news is it allows you to switch on/off the supercharger whenever you need that extra power. Bad news. It’s huge (120mm diameter) and it’s not compatible with the stock 127 mm OEM A/C crank pulley, since the ratio would be almost 1:1 and that wouldn’t make any boost. The cheapest way is what i did. Replacing the clutch with fixed 60mm pulley.

Then comes the bracket.
You could install the supercharger on the place of the A/C compressor, which was my first thought.

So i made up a custom bracket, allowing me to fit it over the a/c bracket and using the A/C tensioner.

But then i decided to move it closer to the throttle body, because i didn’t plan to have intercooler, since i didn’t want to cut a single piece from my chassis to fit it. I modified a bit the already exsisting adaptor and mount the whole thing on the oil filter plate.

Not really on focus, but i hope you will get the idea. Red circles are the two spare and unsed threads on the oil filter housing where i mount the bracket. Then i had to fabricate the piping adapters which had to be bolted straight to the SC and the gaskets between.

Meanwhile received the BOV and the MAF.

The stock maf housing was too long so i had to customize it, extracting the sensor and fixing it on a pipe.

 

I don’t have a picture of that, but imagine the new MAF housing was mounted on the place of the pipe marked in red,

Then made a spacer for the BOV since the KIT one was alloy and my pipes were from steel and probably you know you can’t weld alloy to a steel.

 

Then everything was almost ready and the only thing left i had to do was the SC intake and belt tensioning.

There was a lot of experiments…

And failures …

It basically ended like this since i didn’t had much space left down below the SC.

 

At first i went just with one tensioner.

But after 2k rpm it becomes really loose, so i had to install second one. Solved.

Then came the easiest part. Installing the injectors, boostmeter and the hoses for the BOV.
Everything looked just fine. Achieved 0.6 bar boost. Car takes off really good even with the stock untouched ecu, but i couldn’t stand the wining of the charger. I mean it’s good for a half an hour drive, or a track,  but just imagine if you have to play along with this on  2 hours ( or more ) trip. Awful. ( I have a video of mine, but till i find it, here is a random one from youtube, so you can just get the idea for what im talking about ) https://www.youtube.com/watch?v=zRLcyDdhRZw 

In Conclusion.

Q: Worth it ?
A: Yeah, totally is. You can gain up to 30% of the base power with intercooler. Without – let’s say 20%. M52b28 base power is 193 hp. do the math yourself,

Q : Is it expensive ?
A : There are people and people. Something expensive for one could be cheap for another, You should check i-net for  some pricing for the needed parts i listed above and make your own conclusions. Anyways it’s cheaper than turbo build, especially if you are handy and got the right tools.

Q : Is it time consuming ?
A : Again. It’s up to you. I’ve done it for 3 weekends.

Q : Can i return back to stock ?
A :  This is the main advantage compared with the turbo build. You can do this for ;ess than a hour.

Q : My car is a daily driver. Should i do this ?
A :  Please, check again this LINK and ask yourself if you can handle that noise everyday for few hours.