N52 Swap Discussion

[hoveringuy]

I have a small but important technical update.

One of the features of the N52 is that the alternator is controlled by the DME through CAN. This means that it can shed that load under WOT which is pretty sweet. The issue is that there is no longer a separate blue wire with it's own alternator field windings to connect to the alternator warning light, so there's no way of knowing that the alternator is actually charging... Plus, there's no longer that satisfying dimming of the lights as everything comes on-line.

I finally got around to creating the circuit to resolve it, it's a simple voltage divider that biases the B-E junction of an NPN transistor which then feeds another NPN that sinks the cluster current at the C101 pin 1 (blue wire). The lights will be on anywhere below around 12.6V and off above 13.5V, adjustable, of course. The interesting thing is that the ABS, brake fluid and parking brake lights are all tied into the alternator output. I don't know why... If the alternator in an e30 fails I think you'll get the parking brake, brake fluid and alt lights all at the same time. There also seems to be a 6 second delay between the engine starting and the alternator turning on. Another N52 design feature?

https://www.youtube.com/shorts/W27SWoJkaMQ

[Cdmef]

Awesome, thanks a lot! I’m hoping to get into it later in the summer, I have a demanding workload to get through and then I can start digging in.

[nando]

Just send me a PM when you're ready here. I don't really have time to do much with Bimmerlabs these days, unfortunately.

[Cdmef]

Yeah I’ve decided not to do the 2.5, I just wanted to make sure someone with experience agreed it wasn’t worth it. Yes there are a lot of 3.0 cars out there, I have been holding out for an actual 330 setup for the better transmission for one thing. One reason is that down the line if I wanted to upgrade the transmission I would also need to figure out the driveshaft and the 330 trans into e36 has already been sorted. And of course I would prefer to do it right the first time haha! If I don’t find a 330 I’ll do a 328, they are abundant and I have a line on one from a friend.

when I’m ready to get the ecu flashed should I pm you nando, or get in touch on bimmerlabs? You mentioned hooking up with cobra Marty, as I am in near Toronto too

[nando]

I don't think the 2.5l is worth it, no. Not only does it weigh about the same - it makes less power - and the 2.5 liter engines have issues with rings and burning oil. I'd imagine the swap costs/work will be pretty much the same as well. you want the 3 liter if you're doing an E30, otherwise do one of the older swaps (M52/M54). Or just build an M20.

Maybe you could get a 2.5l block and punch it out to 3.0 liter, but it's probably cheaper to just get the 3.0- to begin with. They're super common in North America - everything got them regardless if it was badged a 325i or a 330i. they also came in the Z4, X3, X5, 5 series, and 7 series. The only 2.5 liters in North America are the 323i cars, but those were only sold in Canada. So anything in Canada that isn't a 323i (or 523i? I have never seen one of those) is going to have the N52B30.

My 2012 X3 28i has the same basic engine (N52B30) as my 2006 330i and my old 2006 325xi wagon. Not sure why they marketed the 325i with a 3 liter engine, but at least it made for an cheap/easy upgrade. 2 out of the 3 N52B30 powered cars I have owned came from Canada, so I don't think they are that rare.

[Cdmef]

That’s why I would wonder if the 2.5L n52b25 would be worth the work, the dynos running full bolt ons seem to only be about 200 whp. I have been looking for the full 330 setup but they have become pretty pricey and rarely up for sale here in Canada.

[nando]

That looks like it was a blast!

I have an opportunity to get an 06 323, 2.5L for next to nothing. I’m thinking of grabbing this and figuring the swap kinks out, I know it’s only good for about 200hp maybe a bit more with n54 mani, and driveshaft will be different once I go for a 330 and matching tranny… thoughts? Would I be wasting my time?

200hp? the stock N52B30OL makes ~260bhp/220whp from the factory with stock cats, a stock tune and the 3 stage manifold. Maybe the nerf-tuned 328i with an AT struggles to hit 200whp, but nobody is going to swap an N52 in an E30 and leave the tune stock (that's impossible anyway).

[wazzu70]

I always love the 3a/3b configuration on the downhill!

[Cdmef]

That looks like it was a blast!

I have an opportunity to get an 06 323, 2.5L for next to nothing. I’m thinking of grabbing this and figuring the swap kinks out, I know it’s only good for about 200hp maybe a bit more with n54 mani, and driveshaft will be different once I go for a 330 and matching tranny… thoughts? Would I be wasting my time?

[moatilliatta]

Beautiful track!

[LukeJ]

Awesome video once again Steve!

Looking forward to when I'll be able to take my car for a trip around the block. Still waiting....

[hoveringuy]

Who needs aero and downforce when you've got DRAG!


https://m.youtube.com/watch?v=xU7-LC-gPU8

[hoveringuy]

For sure. In my case it’s an e36 but I agree it shouldn’t be too bad once I get my head in it. It will help having all the pieces to go through in person too.

On the modern cars everything is inter-related. The ECU knows when you lock a door or adjust the volume and it makes adjustments. On the e30/e36 the interface between the engine and body-side electrics is almost completely what's in the C101 or X20 plugs. RPM, IGN, starter, oil press, etc. Pretty simple.

[Cdmef]

For sure. In my case it’s an e36 but I agree it shouldn’t be too bad once I get my head in it. It will help having all the pieces to go through in person too.

[nando]

yeah, you don't need any of that. Honestly, Hoveringuy did a pretty good job documenting what he did. There are various parts of the wiring that can be modularized to basically plug into the E30. I don't think it's really going to be a big deal - the E30 wiring is quite primitive compared to an E90, and you don't even need a lot of the modules that the E90 has. Pretty much you need the DME, power block/relays, the EKP, and you probably also want a fan controller (any PWM fan controller will do). The rest of the CAN bus is irrelevant because it can all be turned off.