14 years - 1991 325ix, Stroker/5-Speed (N52 swap?)

[stonea]

yeah I think the hubs stick out an extra 1/2" on the ix. so you would need a 12mm spacer in the rear to equalize that out.

Ironically I have all of the measurements for the RWD hub and rotor written down for comparison somewhere, I just never thought about actually using it.

I want more power out of my ix but I really don't want to go turbo. Really never liked the turbo thing on my cars. Just a personal preference. So that leaves one hell of an m20 build or swap.

I'm leaning more to a swap cause it's more power, fuel economy, no timing belt worry, and not a whole lot of extra weight.

As someone who has looked into this swap quiet a bit I would suggest stroking. I looked into the M54, S54, Euro S50, S52, S38, M30 and in the end I'm probably going to stick with the M20, why? Mostly costs and time. Personally I've put a lot of money into the M20 set up in the past year (new sensors, new AC compressor, Alternator, PS pump, half shafts) but on top of that the money it would take to swap it didn't make sense to me. I could finish up my exterior and interior and more projects for what I was budgeting for the swap (and you always go over budget on these projects). If I get a decent job and 10-20 years down the line my stroker still isn't enough power then I'll revisit the situation. But if you're still serious read the 24v swap knowledge thread back to front several times. I think I've read it close to 15 times by now. Its definitely not for the faint of heart or budget friendly. Even when its all said and done the only person we know of that has successfully done the swap not using the frakenpan is Nisse.

As for your reasons for swapping it; you'll never make the money back off of fuel economy from the amount its going to cost to do this swap. I get 21 mpg in my ix and I get 26 mpg in my M54 Z3. I've never understood the timing belt thing. After you do it twice it doesn't take long to do it. Also every 100,000 miles you have to change the water pump anyways so you'll be inconvenienced for an afternoon every 50,000 miles. Also the M20 is the lightest 6 cylinder engine you can get except for the M54 or N52. Even then I've heard the M54's weight savings isn't crazy over the M20. Everyone is so quick to swap the engine to make power, but you can get a decent amount of fun and power out of these old M20's.

[nando]

You've probably already covered this, but how are you going to account for the 10 degree offset with the 24v bellhousing vs the non offset ix pan/diff/driveshaft?

I don't have to. The transmission is already set up for it. The oil pan will be customized and will be set up for the 30 degree angle.

[nando]

Ironically I have all of the measurements for the RWD hub and rotor written down for comparison somewhere, I just never thought about actually using it.



As someone who has looked into this swap quiet a bit I would suggest stroking. I looked into the M54, S54, Euro S50, S52, S38, M30 and in the end I'm probably going to stick with the M20, why? Mostly costs and time. Personally I've put a lot of money into the M20 set up in the past year (new sensors, new AC compressor, Alternator, PS pump, half shafts) but on top of that the money it would take to swap it didn't make sense to me. I could finish up my exterior and interior and more projects for what I was budgeting for the swap (and you always go over budget on these projects). If I get a decent job and 10-20 years down the line my stroker still isn't enough power then I'll revisit the situation. But if you're still serious read the 24v swap knowledge thread back to front several times. I think I've read it close to 15 times by now. Its definitely not for the faint of heart or budget friendly. Even when its all said and done the only person we know of that has successfully done the swap not using the frakenpan is Nisse.

As for your reasons for swapping it; you'll never make the money back off of fuel economy from the amount its going to cost to do this swap. I get 21 mpg in my ix and I get 26 mpg in my M54 Z3. I've never understood the timing belt thing. After you do it twice it doesn't take long to do it. Also every 100,000 miles you have to change the water pump anyways so you'll be inconvenienced for an afternoon every 50,000 miles. Also the M20 is the lightest 6 cylinder engine you can get except for the M54 or N52. Even then I've heard the M54's weight savings isn't crazy over the M20. Everyone is so quick to swap the engine to make power, but you can get a decent amount of fun and power out of these old M20's.

Thats basically where I'm at - i built my stroker 10 years ago and I'm bored. I could build another, but it wouldn't be cheap and its still an M20. I'd do it again for sure if i hadn't already done it all before.

I'm hoping for about 50lbs off the front wheels. The cf hood and AC delete made a big difference in how the car felt, so i want more of that. Plus the N52 makes almost 100hp more than the m20 stock.

[litu]

That M54B30 engine in ix would be awesome

[Nisse Järnet]

Hub measurments:

[digger]

Thats basically where I'm at - i built my stroker 10 years ago and I'm bored. I could build another, but it wouldn't be cheap and its still an M20. I'd do it again for sure if i hadn't already done it all before.

I'm hoping for about 50lbs off the front wheels. The cf hood and AC delete made a big difference in how the car felt, so i want more of that. Plus the N52 makes almost 100hp more than the m20 stock.

Knowing what the community knows now about modding the m20 these days a proper 3L with fairly straight right forward recipe is a pretty potent engine. With N52 you'll probably end up with a little more bottom end and fuel economy compared to doing a better m20 build IMO (aside from any weight benefits). Certainly its an interesting project and the journey is half the fun though.....

[nando]

I think the potential in the N52 is just a lot more than the M20. Even if I built up another stroker, there's no guarantee that I would reach even stock N52B30oo power levels.

I agree that there's way better knowledge now than there was 10 years ago though. I've considered the RHD ITBs on my existing motor, but that's money I could spend on completing the N52 build.

[Coupelx]

They can be redone, the main difference is honing.

If my cylinder walls are just glazed over, I can use an aluminum paste & ball hone that exposes fresh silica crystals and I can just re-ring it. If there are any scratches or scores, I'll have to bore it out. Porsche has been using Alusil blocks (and magnesium) since the 1970s, so there's lots of information to be found outside of BMW. here's a good read with lots of details:

http://www.sunnen.com/NewsDetails.aspx?NewsID=11

Supposedly the sillca bores are actually harder than steel bores, so I'm hoping I can just deglaze it. Otherwise, I've got to get aftermarket pistons which will be double what I paid for the whole motor. lol.

here's another discussion on honing alusil bores. it really doesn't sound too bad - you can't really overhone it because you're only removing a small amount of aluminum.
http://forums.pelicanparts.com/porsc...sil-bores.html

Atv's have used plated cylinders for along time (though they are usually nikasil). Short of catastrophic failure, they run for a very long time compared to their steel/iron counterparts. you can usually go though several sets of pistons/rings before the plating needs addressed, even light vertical scoring isnt cause for much concern.

[digger]

I think the potential in the N52 is just a lot more than the M20. Even if I built up another stroker, there's no guarantee that I would reach even stock N52B30oo power levels.

I agree that there's way better knowledge now than there was 10 years ago though. I've considered the RHD ITBs on my existing motor, but that's money I could spend on completing the N52 build.

stock N52B30 make 210-220whp at best and the torque is 200-210wtq from looking at e90 post dyno thread. sure you can mod it but i imagine its more complex than doing the same on a M52 or S52 as it has alot of trickery going on the background. If you were talking s54 potential then hell yeah

Johns 2.8L m20 made 215whp and 200wtq with 170wtq at 2500rpm, thats with a fairly basic 2.8L bottom end and 272 cam, some basic head work in the right areas. A few more , cubes, more compression, slighty more cam and your going to make gains across the board with a hell of a lot less hassle.

i am biast though as thats the route im taking:devil:

[The Dark Side of Will]

Hub measurments:

Which is the front and which is the rear?

[nando]

stock N52B30 make 210-220whp at best and the torque is 200-210wtq from looking at e90 post dyno thread.

yeah, stock. they are doing 240-250 with headers and a different intake setup. still all stock internals. Nobody's even really tried to do anything with them - except one guy in the UK who was making over 300hp.

sure you can mod it but i imagine its more complex than doing the same on a M52 or S52 as it has alot of trickery going on the background. If you were talking s54 potential then hell yeah

This is FUD - the valvetronic mechanism is basically a way to have a variable rocker ratio. It's not any more complicated to mod than any other engine. I suspect you realize that though. The main thing the S54 has in advantage is a more aggressive cam and more displacement - the N52 internals are light, it can definitely rev. it's also significantly lighter than an S54!

the biggest obstacle is lifter bleedout at 8k rpm. 7700-7800 seems relatively safe on the stock valvetrain. FWIW, the S55 uses basically all of the same valvetrain parts. it revs to 7600rpm stock. With a better intake setup there's potential to make power up there, and still have a relatively broad/flat torque curve.

Johns 2.8L m20 made 215whp and 200wtq with 170wtq at 2500rpm, thats with a fairly basic 2.8L bottom end and 272 cam, some basic head work in the right areas. A few more , cubes, more compression, slighty more cam and your going to make gains across the board with a hell of a lot less hassle.

i am biast though as thats the route im taking:devil:

well, an engine with vanos is going to make torque across a much wider band - typically it's flat from ~2000rpm to near redline. while the peak number isn't that high, the area under the curve is much broader. I think my N52 made peak torque at like 2200rpm.

as far as hassles - I'm tired of dicking around with standalones. you can't run a wild M20 on the stock computer (well, I wouldn't want to anyway). I don't want to have to dick around with things like cold starts and idle control that are going to work perfectly with the factory DME, even with a modified motor.

I've considered just doing another M20 again and again, and I just don't want to. However I'm looking forward to see what your new engine build does. :)

[digger]

Sure you can do basic bolt ons to give a bit more but of all the 24V engines I cant see there ever being as much aftermarket engine support as for other 24V engines.

Once you’ve found limits of basic bolt ons and look to ported heads and cams I would imagine calibrating, tuning the valvetronic to idle properly might be a bigger challenge than on a regular engine because you get some drastically different flow characteristics happening at low valve lifts. it would also be pretty easy to screw up the combustion characteristics as well with direct injection engine.

IMO the N52 is one of those engines where you dont want to deviate too far from stock otherwise you are a chance of losing the very benefits that make it what it is

[nando]

A) N52 is not direct injection.
B) Sorry but that's just more FUD. There are all kinds of cam & mass flow parameters that can be adjusted for whatever want to do. low valve lift should not be changed with an aftermarket cam. you command it how much you want it to open in a given situation. For the most part it corrects itself as long as it knows the lobe centerline, lift and duration.

I'm not planning on really doing any "bolt-ons". I'm not using the stock intake manifold at all. The only aftermarket part I really need are headers. the wild card is headwork - the heads are CNC'd but they definitely aren't as optimized as they could be. lots of rough edges and sharp corners. The only real issue there is the bolt pattern is different from the standard BMW small six so somebody like ForcedFirebird would have to build a different jig to flowtest it.

I'm not sure what you mean by that last sentence. what characteristics are you going to lose? it's a very light engine that revs well and has good head flow characteristics. I'm not talking about doubling the power output - hell, I'm only talking about ~45hp. I don't believe that to be unrealistic at all. Some of the basic bolt on cars are already close to that.

[Nisse Järnet]

Which is the front and which is the rear?

I think all of them is rear.

[digger]

A) N52 is not direct injection.
B) Sorry but that's just more FUD. There are all kinds of cam & mass flow parameters that can be adjusted for whatever want to do. low valve lift should not be changed with an aftermarket cam. you command it how much you want it to open in a given situation. For the most part it corrects itself as long as it knows the lobe centerline, lift and duration.

I'm not planning on really doing any "bolt-ons". I'm not using the stock intake manifold at all. The only aftermarket part I really need are headers. the wild card is headwork - the heads are CNC'd but they definitely aren't as optimized as they could be. lots of rough edges and sharp corners. The only real issue there is the bolt pattern is different from the standard BMW small six so somebody like ForcedFirebird would have to build a different jig to flowtest it.

I'm not sure what you mean by that last sentence. what characteristics are you going to lose? it's a very light engine that revs well and has good head flow characteristics. I'm not talking about doubling the power output - hell, I'm only talking about ~45hp. I don't believe that to be unrealistic at all. Some of the basic bolt on cars are already close to that.

i confused N53 and N52 so thats a positive that its not DI, the low lift flow can change massively if you do different valve jobs and port work change.

what manifold will you use? you wouldn't want to lose the characteristics of the multi stage tuned intake IMO is what i meant