Installing new booster, replace MC while I'm in there? Which MC should I get?

[E turd]

Hey guys. I am putting in a new brake booster from a Porsche 944 in preparation for my m52 swap and will be doing stainless lines at the same time. My question is should I replace the master cylinder while I am in there? They aren't cheap, but it seems like a good time to do it, especially since I don't know how old my original one is. Also, would it be worth the cost/effort to upgrade to the M3 unit? It's larger than my stock 325i (w/ ABS) unit, but not as large as the popular 750i one that a lot of guys seem to run. I believe it also requires running a different hard line since the M3 MC doesn't have the same size bores, or at least that's what I read.


Thoughts? Suggestions?



TIA

Logan

[RoadHazard]

I'm guessing the Porsche booster is smaller than E30 one. If that is the case, then you'll have to press harder on the pedal. And that will be worse if you change the MC to a larger bore. But the pedal will travel less. If you don't mind this fact then go ahead and change to a larger MC. It is indeed a good time to do it. However, the M3 MC will require one new hard line so I'd go for the E32 one instead and save some trouble but it may be a little overkill. But if you plan to run BBK later on the a larger MC is a good idea because you will need to move a lot of fluid in that case.

[greg1333]

Most people that do a M50/52 swap in to a e30 will use an e21 brake booster, it bolts up and only needs minor modification (shortening threaded shaft to pedal)
I would be interested in seeing what the porsche booster assy looks like.

[RoadHazard]

Went to find some pic. This is from another forum.

the left one is the E30 one at a slight angle, the right one is a porsche 944 turbo one sitting up straight:

[greg1333]

that porsche turbo one looks a lot like a BMW E21 style booster

[E turd]

I researched my options for the booster and chose the 944 unit over the others. It is sitting on a shelf in my workshop now. I'll snap a pic or two to show it for those who want to see it. I had the 25mm MC, but sold it because in some correspondence with Lee (MassiveLee), he was telling me that when upgrading to a BBK, it is not necessary to run a larger MC. He was saying that when using a larger MC, you have one unit doing more work, whereas running multipot calipers distributes this work to each corner. Not sure if it makes sense the way I wrote it, but I got what he was saying. In any case, I figured the M3 unit might be the happy medium both now and later when the BBK gets added.