R3VLimited Forums

Go Back   R3VLimited Forums > E30 Technical Forums > 24V Engine Swaps

Reply
 
Thread Tools Search this Thread
Old 11-15-2018, 11:04 PM   #1
Striebels
Noobie
 
Join Date: Nov 2018
Location: Orange County California
Posts: 7
M50 stroker help

Hello everyone,
So I just got a M50tu and an m52b28 crankshaft for pretty much free and would like to build a 2.8 stroker. I’ve been seeing tons of write ups on the m54 rotating assembly but not too much on the 2.8 setup unless it’s on the non Vanos motor which I believe has different cams and pistons. Can someone please help me figure out what combination of rods, pistons, and cams to use for something that will still run fine on pump gas. Motor will be going into my hennarot 318 ��
Striebels is offline   Reply With Quote
Old 11-19-2018, 10:40 AM   #2
CMBusch
Advanced Member
 
CMBusch's Avatar
 
Join Date: Aug 2016
Location: Philly
Posts: 151
I recently got my E30 back on the road after a complete refresh of the car and M50 stoker build/rebuild/swap. My setup used exactly the same parts as what you have now. You can look on my profile to see the threads I've started for more information. The basic recipe uses M52B28 crank and rods + M50TUB25 pistons. The block and head are normal single vanos M50 parts and I ended up doing a full rebuild with S52 Cams. The end result is a 2.8L with a 11.2~11.3:1 compression ratio.

What you want are 135mm rods (M52B28 and other engines). The 84mm bore is shared between multiple engines, but the bump in compression over a stock M52B28 rotating assembly comes down to the wrist pin height in relation to the top of the piston. The M50TUB25 piston has the largest distance between the wrist pin and top of the piston.

This website will be useful:
https://www.e30zone.net/e30wiki/index.php?title=M5x
CMBusch is offline   Reply With Quote
Old 11-20-2018, 08:59 PM   #3
Striebels
Noobie
 
Join Date: Nov 2018
Location: Orange County California
Posts: 7
Thanks for the help. Iíve read a little bit about that setup before. How do you like it overall? Oh and lastly how do you think stock cams will feel on that setup. Cheers!
Striebels is offline   Reply With Quote
Old 11-28-2018, 08:38 PM   #4
CMBusch
Advanced Member
 
CMBusch's Avatar
 
Join Date: Aug 2016
Location: Philly
Posts: 151
I can't really say I have enough experience to come to a definite conclusion since I have less than 200 miles on it, I've yet to go full throttle, and I haven't revved it past 5500 rpm. I'm just trying to break it in with the tune I have now before I get it on the dyno in the spring.
However, it has plenty of torque down low, even at quarter throttle. It has more low end torque than a standard 2.5, which isn't a surprise with a longer stroke and higher compression. With the cams, it pulls harder and harder as the revs climb. Regarding using the stock cams, I don't think it'll be a problem since the cam profiles are the same for 2.5s and 2.8s. You may have less top end power, and more low end power than m3 cams, but that's just the standard effects of stock cams vs. upgraded cams. Again, I have custom software, but I think the dyno time in the spring may net me more low end power. I would recommend getting some sort of custom software regardless.

All in all, if you have the parts lying around and you're rebuilding a M50 anyway, I see no reason why you shouldn't do it. A lot of people say "jUsT dO a S50 sWaP," but this is arguably cooler and you have a fresh engine for much less than the price of a S50 with 150k miles.
CMBusch is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -7. The time now is 08:56 PM.


Powered by vBulletin® Version 3.8.10
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Copyright 2004 - 2020 R3VLimited LLC