N52 Swap Discussion

[Caperix]

I will be interested to see how your n52 dct works our, that is what I am leaning towards for my car. Staying with the factory modules would be nice, the standalone dct controllers need alot of time tuning from what I have read. Like nando said there are no documented n52 dct swaps so its unknown how msv70/80 will work with it. You will also probably need a compatible abs system, and the factory software will set errors if the rear end ratio is to far from what it was designed for, 2.78 for the standard, 3.08 for the gts I think.
If you are not going to use valvetronic what about putting a n54 head on it & using msd80 with a n53 map? You will have to use direct injection so a n54 vacuum pump and high pressure pump would be needed, but msd80 does work with duct.

[nando]

I mean, MSV70 is pretty easy to work with. And it definitely reports the values over CAN that would be needed. My only hesitation is have never seen a factory DCT car with an N52, but I know they exist (just not in the US). So I have never messed with any of those parameters. Manual is easy because the driver does the shifting and you don't need to care about it while tuning, lol.

You could mechanically lock the Valvetronic to full lift and use a normal throttle of course, which a few people have done. You definitely can't control it like it was a throttle body, there's no linear relationship between pedal input and valve lift.

I don't think you're going to get any standalone that is going to control it properly either - the factory software is insanely complex, especially because it has to be 100% safe to avoid uncontrolled throttle output. Even if somebody advertises Valvetronic support I'd be extremely skeptical.

I'm not sure how locking it affects the torque curve, but one of the advantages is you control lift so you can keep intake port velocity high at all times. I assume WOT power would be the same but you might give up low end torque, which is maybe less important on a race car.

Are you using a standalone box to control the DCT?

[MWC]

Well my buddy and I are officially aboard the train. Picked up 2 N52ks and 2 DCTs this weekend.

With how affordable standalones have become in recent years and the fact that these are race cars with no need to integrate with anything factory at all we're thinking its going to be best to go that route. Hopefully anything we learn with respect to making power and keeping the engines reliable on track will be relevant to others in this thread.

As far as the timing is concerned we're likely going to key the crank hub like Nando suggested. It seems like the most foolproof solution and I'll be sure to get some pics when we get there.

The only thing I'm hung up on with respect to standalones is I'm not sure I'm going to be able to run valvetronic. The other N52 race engines I've been able to find on the internet have all locked the valvetronic at max lift and either used an N54 manifold and throttle body or ITBs adapted from a euro S50 or S54. Are there any performance losses by not using valvetronic? I think the system is really cool and it kind of makes me squirm to think about bypassing it, but it's beginning to look like a standalone with DCT or valvetronic with MSV70 and we're committed to getting the DCT to work. It's going to be absolutely amazing in the race cars.

How is the stepper motor that controls valvetronic functionally different than a normal TBW throttle body like in an M54 for example? Looking at how valvetronic works it seems to me it should be similar.

[nando]

Well, I'm 99% sure I'm going to drill a hole and dowel mine, lol. I pretty much want to rebuild the entire engine anyway.

Anyway, even if this was a serious issue - and I'm not convinced of that - N52s are so cheap/common. It would be more of an annoyance, not a huge setback like losing $20k repairing an ugly, 4000lb F30 "M3". My N52 was literally hundreds of dollars, lol. I think you could do even better now..

[Caperix]

I don't have the part number for the friction ring, realoem shows it as grayed out, I wonder if BMW started etching the oil pump gear at some point like they started on the n20 to serve the same purpose.

[moatilliatta]

I see timing slip more when the exhaust cam housing seizes up. - N52

Probably promoted more from poor oil service…

You can look up S55 fixes for the crank hub.

[nando]

Do you have a part #? my DD is a 6mt N52, but the engine I have on a stand is an auto.. I'd bet 95% of N52s sourced from a yard are going to be automatics as well.

I actually always wondered why you couldn't just key the crank hub. Cam timing is completely independent of the crank sprocket, so the clocking of that isn't important during assembly - I feel like you could just drill a hole and put in a dowel pin pretty easy.

[Caperix]

Did you slot the steel inserts in the intake, or did you get offset bored inserts?
The timing slip is not common, I have seen 10 personally. The modded s55 guys have reported slipping at higher power levels but a n52 will never make those numbers. I would install the friction ring if the engine came out of an auto car for peace of mind if it was going to be driven hard

[hoveringuy]

On the n54 manifold, I have read e90 posts that say the port match is not perfect & if you smoke the intake they leak, have you noticed this?

If you just straight-up bolt the N54 manifold on the ports are mis-aligned by about 2.5mm. There is an easy way to shim the the bore for the manifold bolts (they pop out and can be adjusted). Super easy, but yes it can leak if not done

The last S52 was manufactured over 20 years ago now, N52s are falling out of the trees.

They are famous for blowing their tiny little head gaskets. This is what it looks like. .

https://youtu.be/_mEohPpKNlU

(That's back when I had the N54)

[nando]

I've seen a few n52's slip timing, usually due to a locked up AC compressor or a failed tensioner causing the belt to bind. I have never had one suffer engine damage from this though, just replace the crank bolt & re time the engine. Manual transmission cars use an extra friction disc in the front crank hub to help with preventing slip from a rough down shift.
On the n54 manifold, I have read e90 posts that say the port match is not perfect & if you smoke the intake they leak, have you noticed this?

If it happens it has to be exceptionally rare. The crank hub design is the same on the N53, N54, and N55, so a handful out of literally millions of engines.

the ports of the N54 manifold I think is offset a bit but you can adjust it. I don't know exactly what Steve did to his, slot the bolt holes or something? I don't see why it would leak, it uses the same gaskets as the N52 manifold.

Well, this certainly changes things from N52 being a potentially good pipe dream to amazing upgrade and should see a lot more of them, particularly in E36s as S52s dwindle in number and increase in price. N52s can be had for a song and love how low maintenance mine has been.

Yeah, I don't know why you would want an S52 over this, especially for what they cost now. The only thing I can think of is the swap is a bit simpler and doesn't need much fabrication on an E30. But in the E36 it's basically bolt together.

[rwh11385]

The baseline dyno showed that, indeed, it was a bit down on power at only 242hp/ and 227ft-lb. It had made around 270hp with no MAF (and no air filter...) and I expected to to recoup most of that, but expected a penalty for the MAF and the filter.
By playing with the timing and VANOS they were able to get it back up to 268hp and 246ft-lbs. It looks like there's a dip in torque at 2200 and 4000, but I think that the headers are just so strong at 3000 that it only appears that way. Drives great, pulls noticeably harder now and has an amazing amount of torque down low that makes me question why *anybody* would want a DISA intake on the N52.

Well, this certainly changes things from N52 being a potentially good pipe dream to amazing upgrade and should see a lot more of them, particularly in E36s as S52s dwindle in number and increase in price. N52s can be had for a song and love how low maintenance mine has been.

[Caperix]

I've seen a few n52's slip timing, usually due to a locked up AC compressor or a failed tensioner causing the belt to bind. I have never had one suffer engine damage from this though, just replace the crank bolt & re time the engine. Manual transmission cars use an extra friction disc in the front crank hub to help with preventing slip from a rough down shift.
On the n54 manifold, I have read e90 posts that say the port match is not perfect & if you smoke the intake they leak, have you noticed this?

[nando]

I've never heard of that.

[MWC]

Does the N52 have issues with the timing chain on track? I’ve heard the chain can skip if you slightly miss a downshift etc. Is this true?

[nando]

yeah, you're never getting 350whp out of an N52, without boost anyway. I think 285-300 is doable. Is it worth it? I'm not sure. I didn't even bury Steve's car and it was pretty fast for me, lol.

Yeah, sound is definitely part of it too. I'm just saying, the N54 manifold works, but it's not exactly ideal. What it really has going for it is cost, you can get them for like $20. Maybe I'll try that CF Nylon filament and 3D print my own.. lol