N52 Swap Discussion

[hoveringuy]

Would it continue to make power until an 8k redline? .

Yeah, this Dyno has 400 lb rollers so it accelerates quicker than it usually would, like 2nd gear on the street.

My understanding of the N52 soft limiter is that it's predictive so if revs are increasing quickly it will pull back earlier. Rev limit was set to 7750 here and it was pulling power starting at 7100-7200.
On a few pulls where we bumped the limit way up it carried power all the way through.
There wasn't ever a defined peak, just plateaued.

[hoveringuy]

The winner of track event #4 was the towing service. First session was 2 laps under yellow per standard practice, then green. 1 1/2 laps into green a Mustang GT-350R blew its (newish) engine. Black flag, all cars left the track.
Second session, an hour later. Green from the git-go, 2 1/2 laps in an e30 spun into the berm. Black flag, all cars left the track...
Third session, I actually did 11 contiguous laps! Lots of traffic so no new "best" laps although I did get an improved top speed commensurate with the boost in power.

The take-away from the day is that the car is reliable and fast. I got lots of questions in the paddocks from Porsche owners and even an M2 guy that struggled to keep up "what motor is in your car...?" The M2 guy did pass me but says he worked the hardest to pass me, so there's that.

I got some good measurements of the the PS temps and they're up around 275F.

I will focus on the "reduce heat" side of the equation before trying to install a cooler.

The N52 PS pulley is only 116mm compared to 135mm on most of our other cars, so it spins faster. Swapping to a 135mm pulley will reduce the speed by 16% and hopefully heat input.

The Luk LF-30 pump is rated for 135bar in the E90s compared to only 120bar in most previous cars, so I'm working to figure-out the pressure regulator to drop the pressure or possibly drop in the pump from a Cayman which is only 100bar.



Pictured below are the 116mm E90 pulley, a 135mm E36 pulley, and a 143mm Turner underdrive pulley for E36. The N52, M54 and M50 motors all have different back-spacing on the pulleys so they are not directly interchangeable.

[LukeJ]

The take-away from the day is that the car is reliable and fast. I got lots of questions in the paddocks from Porsche owners and even an M2 guy that struggled to keep up "what motor is in your car...?" The M2 guy did pass me but says he worked the hardest to pass me, so there's that.


Loving it! All good stuff here. Congrats!!

[hoveringuy]

I've been focusing on optimizing the power steering and have a small update. Props to LukeJ for fabricating an amazing PS pulley and shipping it to me so quickly! It is truly a work of art and I am very grateful.

This picture shows the original configuration of the power steering pulley and idler pulley, it's a 116mm PS pulley and 80mm deflection pulley. There's only about 10mm between the deflection and the PS pulley, so the deflection needs to get smaller in order for the PS pulley to get larger, so...



There are 70mm deflection pulleys. I ordered P/N 11-28-7-790-44, but it had a different arbor size in the bearing for an m8 bolt instead of m10, so I needed to swap the bearing with a press, no bigee.



With the smaller 70mm deflection, there's now enough room for a a larger PS pulley. This one is 135mm so it matches the e36 motors and spins 16% slower. Heat is very proportional to motor rpm so I should see a decent reduction in temps, and that's not including the fact that this pulley has a fan built in. Yes! The holes are canted and they blow air on the pump. I tested it with some dog hair, naturally.

The belt is now 1 1/4 inches longer, a Master Pro P/N K060507 works perfectly, it's a 6PK1290 with 1300mm OC.




I will update temps the next chance I get to flog the car.

I will also mention that hubcapboy turned a beautiful adapter that lets any e36 PS pulley be spaced to properly fit the N52, so there are several ways to do this.

[hoveringuy]

My other initiative is that I've been looking at how to reduce the 135bar pressure of my pump. My initial guess was that I would need a stiffer spring, but after collecting a variety of LUK pumps I discovered that they all had the exact same 9lb spring. They also had the exact same seat depth for the spring, pressure and vent port spacing and everything. I was kinda stumped on how they actually changed pressure between pumps until I got the 100bar Porsche Cayman pump in the mail. Same, exact LUK LF-30 pump that we used with some slight changes in pulley depth, but otherwise identical.

With a 100bar, 120bar, and 135bar pumps laid-out, I could finally see that the regulation happened in the throat of the outlet. The black cylinder is balanced by PS fluid on each side, but the side on the spring is static and the side towards the outlet sees the output pressure.

The higher the rated pump pressure, the smaller the shaft that sits in the outlet orifice. Since it's the backpressure of fluid exiting the orifice that drives the cylinder into the spring to unseat the vent port, the smallest shaft has the highest pressure.

Conversely, the 100bar pump has the largest shaft on the plunger, it's the quickest to create backpressure that vents the fluid.

The pump uses the dynamic interaction of moving fluid to regulate the pressure, the upshot is that any of these regulators are interchangeable, I can drop the 100bar assembly into my 135bar pump to make a 100bar pump!

My limited understanding of power steering is that at idle the pressure is only around 140psi as fluid easily slips through the steering rack rotary valve, and my presumption is that pressure increases with rpms until hitting rated pressure. The other way to get full pressure is to try to turn your wheels when they're blocked from moving, like against a curb.

I will measure the temperature change from the pulley alone and then swap the regulator to measure it independently.

I'm definitely excited about being able to tune my steering and reduce heat.

[nando]

That's cool. will the Porsche pump bolt in place? or can we get the regulators separately?

BMWs tend to have overboosted steering anyway, so I doubt the pressure loss will be a big deal.

[hoveringuy]

That's cool. will the Porsche pump bolt in place? or can we get the regulators separately?

BMWs tend to have overboosted steering anyway, so I doubt the pressure loss will be a big deal.

The Porsche pump would bolt into place perfectly, but the shaft to the pulley flange is 10mm shorter so it would need a spacer. The regulator will just swap over, so no need...

I found that as a car gets heavier, it gets a smaller pulley (more volume) and higher pressure. Makes sense that the Cayman has low pressure and a big pulley.

The cool thing is that this works on any 120bar Luk pump for other BMW engines.

As an aside, the one on the far right looks different but works the same. I think is has the square seat so that when you disconnect the HP hose all the fluid doesn't drain out. At rest, the spring pushes the seat against the outlet, blocking it.

[matt]

That PS pulley is beautiful. Can I buy one?

[MWC]

Awesome thread! It's a rare treat to read through a build thread that follows through, and with dyno plots to boot! Holy...

A friend and I are trying to build two N52 powered race cars, one E36 and one E46. This forum has the most comprehensive information on swapping these motors that I can find, so while I wish there was an N52 subforum to post this in, this thread seems like the next best option. I've read through the entire thing a few times now and have a few questions:

• In a race car it would be ideal to have the fuel pump hot wired to it's own switch. Is the EKP necessary under these circumstances? I.e. does the ECU need the EKP present to function properly?
• The E36 and E46 ECU location is similar in distance from the motor as an E30. Is the E90 harness with X3 injector harness still the way to go? or would it make more sense now to look for a full Z4 harness? Seems like there's more work involved in adapting the Z4 injector harness to clean up the engine bay. It may be easier to just stick with an X3 to start.
• This ones for Nando .Can the MSV70 speak to a DCT? We're buying two of those as well and are going to try and make them work. It would be sweet to use the original TCU but I'm not sure if anyone's mapped those yet. There are aftermarket controllers like an HTG unit we look into, but considering the DCT is a BMW product originally installed along side a BMW ECU it would be nice to be able to use a tuned version of the stock TCU setup.
  
  In the event that that isn't possible, is the MSV70 capable of sending CAN information to an aftermarket TCU? The signals needed are things like TPS, RPM, Temps, and the ability to receive cut and blip requests. I have no idea if these are a possibility, but again considering the DCT was originally installed in these cars with an N54/N55 I have to believe that it's possible.

The nice thing with race cars is that we don't need AC or HVAC etc. We'll both probably run an AIM dash as well so no need to make the original clusters work either. We just need to make the motors work, and a DCT!

[nando]

I think you need the EKP, but it just triggers the ground for the pump I'm pretty sure - in any case, you can still wire a shut off switch to the pump's power supply.

MSV70 can talk to DCT, they even came with them from the factory on some models (in europe?) - I have zero experience with tuning for those, but all the parameters for DCT are present in every DME. In any case, it can definitely send data over CAN, either the CAN11h mode like the E46 or BN2000 like newer cars, it also supports K-line.

Funny enough, the E46 would be the easiest swap electronically. Other than adapting the wiring harness, it'd just work - Z4 mounts should bolt up, stock oil pan, 6 speed would fit. I'm pretty sure all of the CAN signals are the same. The cluster and HVAC would work, and I think you could even make EWS work (as long as you knew the original ISN from the stock DME). I realize you're talking race cars here, but I always thought it'd be an interesting swap for a daily driver.

[hoveringuy]

[LIST][*]In a race car it would be ideal to have the fuel pump hot wired to it's own switch. Is the EKP necessary under these circumstances? I.e. does the ECU need the EKP present to function properly?
!

It couldn't care less about the EKP, the command to turn on the fuel pump is sent "in the blind" (ECU never gets an acknowledgement).

[hoveringuy]

Update! The track event last month was a complete cluster-fuck. I couldn't get more than a few laps without someone blowing an engine or spinning into the berm to bring out the black flag. Nothing worthwhile came from it.

Today, however, was awesome!

First, the larger PS pulley and 100bar regulator are clear winners! After several 30 minute floggings the PS temps were well below the 275 temps I saw earlier in the season, all the way down to 215. A cooler won't even be necessary.
Best of all, steering feel is much improved, great feedback in the corners now. Highly, highly recommend. I will call this sorted.

It was essentially an open track day, running port and starboard 30 minute sessions. I got over 100 miles in before lunch over several long sessions and the motor was flawless. No hiccups, burps leaks. Nothing.

I had also upgraded to a 3.25LSD with a 3-disc clutch pack and it was A-Ok. Great fun to play with exiting the corners, and what surprised me the most is how much better the braking became. No more dancing around under heavy braking, it tracks straight and true now even when braking hard on uneven pavement. Nice!

Unfortunately, I needed to limp home after lunch because of a cracked brake rotor.

Coupla good stretches where I'm drag racing an E46 M3 here.... https://www.youtube.com/watch?v=dvRmVAqjZ14

[moatilliatta]

hoveringuy, what are you running for tire/ oil pressure monitoring?

I see rabid racing development is in the works for S54 Itb kit on an n52.

What do we think these will dyno?

I almost want to scrap my S54 iteration 2 motor in my E30…
be nice to cancel out 75lbs ~

[hoveringuy]

hoveringuy, what are you running for tire/ oil pressure monitoring?

I see rabid racing development is in the works for S54 Itb kit on an n52.

What do we think these will dyno?

I almost want to scrap my S54 iteration 2 motor in my E30…
be nice to cancel out 75lbs ~

I don't have a TPMS. I'm typically 29psi cold and 35hot. Oil pressures? If the light stays off I'm happy. (hasn't ever flickered even a bit)

I'm not sure an ITB would dyno anymore than the N54 intake, not even sure they would really work right unless you locked the Valvetronic to full lift. N52 already has ITB of sorts in the valve lift.

[moatilliatta]

I don't have a TPMS. I'm typically 29psi cold and 35hot. Oil pressures? If the light stays off I'm happy. (hasn't ever flickered even a bit)

I'm not sure an ITB would dyno anymore than the N54 intake, not even sure they would really work right unless you locked the Valvetronic to full lift. N52 already has ITB of sorts in the valve lift.

Sorry. Which tires are you running. What are you doing for oil pressure monitoring?

If only direct injected… ITB - Valve lift..

But throttles have faster response than the valvetronic?