N52 Swap Discussion

[nando]

MMMmmm, hot air intake! :p

I have a KAmotors intake on my M20. Ehhh.. we can figure out something better than that. But it at least shields the filter I guess. I think most people though, just run an open filter. Heck, amost 99% of N54/N55s I see with mods have the open filters right on top of the engine.

If you could get that elbow/filter a little higher and closer to the headlight, it wouldn't be too hard to form something with a sheet of ABS or something, at least to shield it from direct airflow off the radiator.

[Victell]

This is a 3.25" MAF to match the N54 throttle body... What are the cool kids with ABS doing for cold air?

If you dont mind stepping down to 3" then it looks like the Kamotors intake kit would fit.

[nick496]

No that I've purchased, but you'd probably want something like this: https://castromotorsport.bigcartel.c...ce-air-box-e30
Which puts the filter almost above the ABS unit, and boxes it in there.

I'm sure you'd be able to make something similar like this guy: https://www.bimmerforums.com/forum/s...34#post9817834

[hoveringuy]

"Cause if you liked it than you should have put a MAF on it..."

or something like that.

Yes, the consensus was that I needed a MAF to go from engine model inferred airflow to measured airflow, and what a difference! Whereas before it was rough, hesitated, had flat spots and was no fun to drive around town, the MAF made it perfectly happy pulling from 1000rpm in 5th gear.

This is a 3.25" MAF to match the N54 throttle body.

HELP NEEDED. My intake temps are awful with my hot air intake. What are the cool kids with ABS doing for cold air?

[Bored]

also looking at N55 rockers for the exhaust, should be a similar bump in lift on the exhaust cam (different rocker ratios). I have them on hand, going to stick them on a head and measure the change in lift directly.

So MILVs for the intake, and N55 exhaust rockers? Sounds rad.

[LukeJ]

Your bracket assembly for the DME and IVM is well executed. Thanks for posting it up.

Engine bay looks clean too.... Very nice.

[nando]

also looking at N55 rockers for the exhaust, should be a similar bump in lift on the exhaust cam (different rocker ratios). I have them on hand, going to stick them on a head and measure the change in lift directly.

[hoveringuy]

ok, that just got my attention.

Especially given how much the N52 doesn't weigh...

t
now buying up wrecked E90's...

That's on a motor with stock internals! No Schrick cam, porting, pistons, etc.
There's a bolt on mod for the N52 called MILV (Modified Intake Valve Lift) that increases max lift by 1mm by changing the shim on the eccentric shaft. Takes it from 9.7mm to 10.7mm.

It's making that with 0.5mm less lift than a stock S52.

[TobyB]

with 288hp at 7500rpm,

ok, that just got my attention.

Especially given how much the N52 doesn't weigh...

t
now buying up wrecked E90's...

[hoveringuy]

I'm pleased with how the engine bay looks, it's come a long way from the wiring shit-show when I first had it running! This is using a Z4 harness. I highly recommend Z4 as the base harness because of the IVM, which replaces a tangle of plugs, fuse boxes and relays with one simple, svelte little box. It combines all the relays, fuses and plugs and makes things a lot easier.

Now, the drivers side of the Z4 harness is too short to reach the glovebox, but the e90 harness is perfect, so I swapped all the wires on that side from Z4 to E90. It's simple, trust me, only takes an hour or two. On the passenger side, the Z4 harness is 2 1/2 ft too LONG, but there's not nearly as many wires and they're quite simple to shorten.

Pictures with and without the M3 beauty cover.

[hoveringuy]

Small update just to show how I ended-up mounting the ECU and IVM. It will be even neater once I'm done optimizing the wiring and zip-tying. I'll have a separate post on what I used for the wiring harness later.

[nando]

Yeah, I still believe no-MAF is the way to go - but with the changes in your engine, especially the headers - I think the fuel model is too far off for it to work correctly. Normally, you just set the AF target, the DME matches it, and you carry on with your day. As you know, it's not happening like that with your car for whatever reason. But at least with the MAF, it should be easier to get running properly even if you lose a few HP.

I thought about it this afternoon, and actually I wonder if there is more from the S54 calibration of MSS70 we can copy to your DME (MSS70 and MSV70 are 98% identical - MSS70 even has valvetronic maps, although they're calibrated for full lift). I only ever tried transferring the wideband feedback loop (although, I think on your current tune - it doesn't even have that). I never tried copying the base fuel maps or any other parameters. Since you're making similar power to a stock S54. that actually might work as a better baseline.

There's no reason this won't be a hell of a lot faster, and definitely smoother, once the bugs are worked out. I really appreciate your feedback and patience on getting this sorted - because I really want to do this conversion myself!

[hoveringuy]

N52 track day #2. Good day, learned some more stuff.

1) Nando had previously raised the minimum operating speed of the water pump to ensure that sufficient coolant made it through the core for heat. Possibly related to that I found that on the drive to the track the temperature was oscillating wildly. It would get to 1/2 on the gauge, about 205F, and then plunge down to just above the blue. It would slowly creep back up to 205 and then repeat.

I think what's happening is that the MAP thermostat is being activated. The heated wax melts and expands, which opens the thermostat some more. It gets a rush of extra coolant which cools the engine down until the wax shrinks and the cycle continues.

I pulled the electrical plug from the thermostat and the motor was rock-steady at 205F/96C for the rest of the day.

2) The car definitely has more power, but it's not usable. At WOT it absolutely runs like a beast and my top speed on the straight increased from 126 to 131, but the 95% of the time that I needed part throttle modulation it didn't do very well. So maintenance throttle in the corner was hard to get right and I was timid rolling on the gas coming out of the corner because it was moist asphalt and I didn't feel confident that power would be smooth.

So, even though the M54 had less power, I put down faster lap times with it because it was smooth, sharp and completely predicable.

I'm not running a MAF because the newer N52's infer airflow from their engine model and then fine-tune with 02 sensor feedback. I no longer have a valid engine model; with the intake and the headers I haven't just bent it, I've completely broken it.

So, the plan is to put a MAF on to have measured airflow instead of inferred.

[hubcapboy]

Speaking of, are you still planning on using the Tesla booster?

It's sitting on the floor in the garage waiting for a rod length adjustment.

[hubcapboy]

Looking forward to how your lap times improve as you get everything worked out.

I did learn something new about n52 AC compressors by getting an incorrect part today. Apparently some 2011/12 e92 328's got an AC compressor with a clutch. The part number is 64 52 6 918 749, the car I was working on had the standard clutch less compressor so I do not know if there are any climate control differences.

This is something I found and came to conclusions about... but can't reproduce them. The difference is shown here: https://www.realoem.com/bmw/enUS/sho...94#64526918749



These are labeled as with magnetic clutch, and without magnetic clutch... and boy does the diagram look like that's the case. The reason I didn't pursue this is that there's no difference in the wiring on these cars, so the part that I cared about (how to activate the compressor when I wanted A/C) was still an issue. I *believe* that this was a late hardware revision to the compressor to save wear on the bearings during periods without A/C demand, which was a shortcoming of the original design, and this was done by having the pump itself activate and deactivate the freewheel clutch with its own internal (well, external) wiring.

I believe these are both variable rate compressors and thus...

The signal *to* the compressor is the same - probably PWM - signal for either unit, as is the plug. We could wire the compressor clutch directly (probably) and engage it with the e30 body harness, but the variable pump would be in whatever it's resting state is, which I believe is 0%, resulting in a very confusing installation where the system charges and the pump cycles on but there's no pressure change from the compressor.

For people who are reading this for the first time, the M73 compressor shows up on page 20 of this thread.