Jump to content

14th Annual SoCal Vintage BMW Meet 2021! “All couped up”

Registration is still open. Rally from NorCal is scheduled for Friday. Post your event photos.

SoCal Vintage is Here! 

Post your photos!

M10 stroker turbo


Recommended Posts

I have a m10 and am interested in stroking and turbocharging it. I am wondering if anyone has done this before and if so if they have any advise as far as where to get parts and what parts to use. I would like to build a motor that gets 250+ hp but is still very drivable on the street. Thanks

Link to comment
Share on other sites

You won't need a stroker to hit 250hp. Mine was making stupid high HP with a Garret GT3071 dual ball bearing turbo before I bought it. Now it will have a smaller GT28 size T04E turbo and make a little less power, but the power will come on sooner and still be able to overwhelm the drivetrain.

From what I've gathered 250whp is approaching the limit of the stock diff, especially if you are hard on it. The guy I got my motor from blew a stock diff up in less than a week but swapped it out for an E30 medium case diff(because he had an '84 318i).

S14 crank + a slight overbore will get 2.3L but it's way more work than necessary if you *only* want 250-300. You're going to need stand alone management like megasquirt or SDS(?, something others on this board have used)

Don't forget these cars are light and old, with that much power you'll start breaking stuff and the car may end up very hard to control.

Just search the build blogs, there's lots of info there. The stock bottom end will easily hold 250 if tuned correctly. Also, these are not like honda's, you don't just buy a kit off ebay and slap it on. It's hard to really answer your question with absolutely no knowledge of your background. However, the standard question "I want X hp by turbo'ing the motor what do I need to buy to do that" usually means you're getting in over your head.

Link to comment
Share on other sites

Over my head is something I am fine with. I have a fair amount of experience and am currently studying automotive engineering, so I have access to some great resources and people. I also understand that with such a small and light car like the 2002 I really don't need a whole lot to have something quick. I am just trying to figure out a combination that will give me enough power to make it really fun and fast but to still have something that will be reliable and drivable. I would really prefer not to just go the rout of the turbo to get the power because I don't like the idea of having too much lag or having to deal with the high boost pressure. I will be able to do almost all of my own machining, ie the exhaust manifold, port match and polish and possibly the over bore and will also do all of the labor myself. I am really looking to make the m10 powerful yet really responsive.

Link to comment
Share on other sites

OK then, read up on some of the project blogs.

You'll have an extremely hard time making over 180 with out forced induction, an M20 swap, or an S14 swap.

Turbos can be responsive, just don't put too large of one on. Most agree the Garrett GT28RS "disco potato" is the best match for most 1.8-2.3L 4cyl motors. I'm a fan of turbo's, they are fun!

An M20 can be built to a 2.7L stroker easily and with a cam, chip, exhaust/intake attention can be brought to over 200 crank easily. That's probably the cheapest way to get to 200, but it does add some weight to the front axle.

S14 conversions give you a nice 192+ if you mod it, but they cost a lot of money.

If you really want 250ish hp(I'm shooting for 230 to start and 300+ once i get my custom rear end figured out) then go megasquirt II, 84-85 318i intake, 88-91 325i throttle body, ebay turbo manifold + intercooler and piping, 2.5" exhaust, E21LSD, stock bottom end, ported head, and an E21 5spd just because it's nice to have over drive. If you've never tuned megasquirt before and you don't have any friends who've done it use a stock headgasket since it will blow before you cause any block damage.

I meant no offense by my prior comment, but we get that a lot. "I just bought one of these and I want to smoke my friends STI" or recently "what do I need to do to get 500hp?" <---...facepalm.

And seriously, use the forum search (make sure to check the "search for all terms" box) because there is a lot of info on here which might help you narrow down what you want before asking a lot of questions.

Edit: I love seeing turbo projects so if you've got the drive and funds do it! Also, I knew barely above jack shit when I got my first 2002 5 years ago when I was 18. I purposely try to get myself in over my head with projects because I find great satisfaction in figuring out the solution. That's kinda where my turbo project has gone, but I've learned a lot and had a least some fun doing it(much more once it's running). I think that comes with being a hands on person and studying engineer.

Link to comment
Share on other sites

Don't worry I wasn't offended by your comment. I too know that there are a lot of people who post on forums seeking an answer to a question that they will have a hard time turning into a reality. That info is exactly what I was looking for. Do you know what the compression ratio will be if I use the s14 crank pistons and rods in the m10 with a 75 2.0L head?

Link to comment
Share on other sites

250hp at the crank is no big deal at all as long you have someone to tune it you could go with totaly stock engine. If you have budget for a camshaft look for 292 or 304gr shrick (but then you will get more than 250 depends on boost but the rpm register will be better), build an nice twinentry exhaust and use original m10 (518 e28) intake L-Jetronic.

My old winter car had about 400hp @ the crank. 2L stock engine with ported head and cumbustionchambers, 304gr camshaft, vems management system. GT40 Truckturbo 56mm in 0.96A/R



Its all about using the right parts and manage to tune it right. For 250hp i would use a total stock engine and consentrate on the parts around it, exhaust, injectionsystem, turbo (i would go for somthing in the range of td0416t or simular)

Link to comment
Share on other sites

Do you know what the compression ratio will be if I use the s14 crank pistons and rods in the m10 with a 75 2.0L head?


You can't safely run the 93.4 mm S14 pistons in a M10 block. There is just not enough meat in the cylinder walls to overbore them by 4 MM. You can run a M10 head on a S14 block with a bit of modification to the front timing cover. You will need to use a Cometic headgasket (don't use a S14 gasket the water passages run the water the wrong way through the head and it WILL overheat)

I have built a number of M10's with S14 cranks (84 mm stroke) and 92 mm bores (2233 cc) but only after sonic checking the blocks to make sure there is enough wall thickness to hold up. About 1 in 4 blocks I have checked will not take that much overbore.

If you run a flat top piston with a 0.00" deck height at 92 mm bore and 84 mm stroke with a cometic gasket and a e21 2.0 head you will have a compression ratio of 9.0:1. If you use a E12 head it will be 8.6:1

Link to comment
Share on other sites

  • 2 weeks later...
  • 1 month later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...