N52 Swap Discussion

[D_Eclipse9916]

Looking at planning and sourcing parts soon, any suggestions for engine + transmission sources other than ebay? I'll start searching locally too.

Where are you located? I have a spare engine and six speed transmission, but only makes sense if local because of weight.

I found my multiples on ebay/facebook, as dismantlers do business on ebay its better than private. The engines are so cheap, private sellers think they are worth far more.

[DEV0 E30]

Looking at planning and sourcing parts soon, any suggestions for engine + transmission sources other than ebay? I'll start searching locally too.

[D_Eclipse9916]

It's interesting to me that the factory tuning for valvetronic is so complicated. I could see how the MSV70 could be programmed to take a lot of extra variables into consideration if the goal was the perfect fuel mixture and optimal fuel economy, but based on how it works mechanically I don't see how it wouldn't be possible to set up some kind of simplified relationship between the valvetronic position and pedal position.

I have been trying to find which models came with an N52 and DCT but I'm actually think there weren't any at this point. All models on realoem that came with an N52 do not list the DCT as a transmission options no matter which region I select. If there was one that would be great but it may not solve all my problems. Caperix mentions differential ratios being a problem. If that's the case I will definitely run into that because I'm going to be running a 3.91 or something even higher. The classes I run in are based around power to weight, so running shorter gears is a big advantage. The higher redline potential of the N52 was one of the biggest draws for me in the first place for this reason. ABS is simple as the MK60 is amazing and a fully standalone system on it's own.


I do believe the DCT works by sending power cut and blip requests to the ECU when you call for a shift. At least that is how the major GCUs/standalones on the market operate. Right now if I do go with a standalone I'm leading toward the Maxxecu. They are the only standalone manufacturer I've seen that can integrate with the factory DCT TCU which to me is a big advantage. At least one VSS is required, but I'd have to dig into the pinouts on the DCT connector to see if it's getting VSS directly in the factory application. You can read more about the Maxxecu DCT stuff here if you're curious: https://www.maxxecu.com/webhelp/advanced-bmw_dct.html.

You guys have already shown that the MSV70 can make great power in a track car application and for racers just looking to run an N52 with a manual there's certainly no reason not to use it. It looks like there are still hurdles to overcome with the tuning side of things, but I'm sure that will come in time. For me and my buddy the challenge is the DCT. He's all in on the standalone because they've already made it work at Maxxecu and they are easier to tune, but I would have a hard time ditching the MSV70 if it meant I could run valvetronic and have my cake too. I also think it would make this conversion more accessible for people who are turned off by a standalone. I have a lot more research to do but I appreciate this thread and the discussion here.

You make any progress?
I have a N52 with HTG GCU controlling the ZF 8 speed. With their new closed loop tuning and DBW mod, I am running it off a stock ECU (and works awesome).

In fact the only issue I have right now is the ECU is stuck in limp mode, hoping Nando can help out with that. But the HTG GCU is running it perfectly, you just have to intercept the 2x pedal signal wiring so the GCU can control blips and cuts. The closed loop mode works fantastic right out of the box, once I got full throttle; just need to adjust a couple parameters for feel out on track.

[DEV0 E30]

Plus we have smaller wheels so it ends up being shorter.

I have the 3.15 Torsen and it's great. 3.25 was good, too. 3.73 was fun but annoying on the highway. With a 6 speed there's no reason not to have civilized highway gearing

Good to know.

[hoveringuy]

the 330i 6mt came with a 3.15 stock. it's pretty perfect for that car, even though it's way heavier than any E30.

Some guys like to put in the 3.73 from the xi/auto, but I don't really see the point.

Plus we have smaller wheels so it ends up being shorter.

I have the 3.15 Torsen and it's great. 3.25 was good, too. 3.73 was fun but annoying on the highway. With a 6 speed there's no reason not to have civilized highway gearing

[nando]

the 330i 6mt came with a 3.15 stock. it's pretty perfect for that car, even though it's way heavier than any E30.

Some guys like to put in the 3.73 from the xi/auto, but I don't really see the point.

[DEV0 E30]

I'm running the 3.15 Torsen.

4th gear, 6000 rpm = 110mph.

6th gear, 2900 rpm = 80mph

Around town I'm in either 4th or 5th for 45mph. Which is between 2k and 2500 rpms.

EndTuning - Gear Speed Calculator

This sounds like my jam.

[LukeJ]

I'm running the 3.15 Torsen.

4th gear, 6000 rpm = 110mph.

6th gear, 2900 rpm = 80mph

Around town I'm in either 4th or 5th for 45mph. Which is between 2k and 2500 rpms.

EndTuning - Gear Speed Calculator

[DEV0 E30]

I'm curious too, but if a stock N52 can easily do 280whp as hoveringuy said, I think that is plenty for the street in a lightweight chassis - I'd be fine with 250whp+ honestly.

I thought S50s were pretty much perfect for daily needs like 15 years ago.

If the N52 + 6 speed can be had cheaper and with the help from hoveringuy, nando, and others in here to make it actually work... as soon as it cools down I really want to do this.

Questions:

What differential are you guys running?
Assuming you are running the 6 speed, anyone have a shorthand on what you get to in each gear?
What RPM are you at 65/80mph, etc?

I'd love for 6th to be the "activate better than any previous e30 mpg" gear.

[moatilliatta]

I wonder what the highest HP stock N52 is minus Milv mod.

[DEV0 E30]

I'm not too familiar with the S54, but the difference between an M54 and N52 is huge. LOTS of room for porting in the M54 because the exhaust port is small and everything is rough cast. Parting lines and all

N52 is completely CNC machined and is a jewel in comparison.

S54 has 7% more displacement so makes sense that the valves are bigger.

The N52 can flow plenty on a stock head without even MILV to make upwards of 280whp when intake and exhaust are optimized.

You're basically making me want to buy an N52 off of ebay today and throw caution to the wind.

[hoveringuy]

I'm not too familiar with the S54, but the difference between an M54 and N52 is huge. LOTS of room for porting in the M54 because the exhaust port is small and everything is rough cast. Parting lines and all

N52 is completely CNC machined and is a jewel in comparison.

S54 has 7% more displacement so makes sense that the valves are bigger.

The N52 can flow plenty on a stock head without even MILV to make upwards of 280whp when intake and exhaust are optimized.

[nando]

the design is basically the same, but the S54 has bigger ports, bigger valves, and a bigger cam. Basically everything is 10-20% more on the S54. Part of the manifold is cast into the N52 head so it appears that the ports are really long in comparison, but if you measure from on the injector location to the back of the valve they aren't that different there either.

[MWC]

Has anyone here had the opportunity to compare an S54 and N52 head? I'm curious what the differences are as I'm interested in doing a mild port and polish on an N52 head when I build my next engine. I know bigger isn't necessarily better so I'm curious if there are any significant differences between the intake/exhaust ports, short radii, etc. that I can take something away from.

[HCMW Adam]

Unless you're body swapping the entire harness and all of the modules, there's not really any way to make it work properly without modifying the DME. For example, making the VSS input work properly without the DSC unit, adjusting the water pump speed to work without the radiator temp sensor input, etc. There were a lot of little things we tweaked on hoveringuy 's car to make everything work properly. Having the CAS might be fun for starting without a key (or retrofitting comfort access) but I don't see much point in doing that.

I'm picking up what you're putting down. I now know I must have the ECM modified and that will define some of my other considerations.