N52 Swap Discussion

[nando]

Yeah, TBH you and Steve have done a lot already. IMO - if we just had some kits, or even CAD files - people can figure it out from there (or hire somebody who can weld, which I'll probably do, lol). If you try to make these to sell as whole kits, that's a whole different nightmare that I doubt would ever pay off. I seem to spend most of my time working on other people's projects, which is part of why I haven't really done anything for my own E30 since swapping to Megasquirt 3 in 2011.

[hubcapboy]

So, when are you gents gonna offer a mount and oil pan set up for us... less able persons? ;]

I have Habla lined up as the next guinea pig because he's local and has been following along, but we haven't nailed down when he actually needs pieces and how much fabrication he'll need to do. If/when we go through with that I'll show off what changes hands and how it gets delivered. I've been leaning towards a "u-weld-it" kit where everything comes bent and tacked so the geometry is locked down, but details like the drain plugs and dipstick aren't included, and the finish welding will need to be done.

If you hadn't noticed from the timeline and Steve pulling ahead, I've got a job and kids that are really stretching this process out, so I'm not going to be going into production in the back yard.

[Bored]

So, when are you gents gonna offer a mount and oil pan set up for us... less able persons? ;]

[hubcapboy]

Is the fitment really that bad? nah. but the connections are pointed in the wrong direction. There's plenty of room to "do a thing." Even if that was a tight formed 90 off the existing hoses it would probably fit, but it would be close. (There's two hoses, one above the other, where you see the hose clamps behind the C101)

I'm not concerned about the core age, but I am concerned about the life expectancy of my control valve and I don't think the pricey e30 replacement is expensive because of some superior design. Swapping to a Z3 core looks like the easiest way of attaching some standard hose to a core.

Regarding abandoning the 3-stage... Power between 2200 and 6900 is exactly what I want, and 250 whp sounds dandy. If there were zero fitment issues I would probably pick this intake over power above 7000 rpm. That combined with the possibility of having an A/B dyno between my car and Steve's on the same day with the only real difference being the intake is very intriguing.

[nando]

I have a few irons in the fire but nothing to report back with conclusions on... So I've moved back to research. I have a problem to solve related to the location that the heater core pipes pass through the firewall. This shows up in post #96 on page... 7. It wouldn't be impossible to put elbows on the end of the existing lines (I don't think) but I've started thinking about the age of the heater core and heater control valve. Heater control valves are a limited commodity and are prone to leaking and heater cores have finite lives, but the only reason we're bound to these parts is they physically fit and the connections work with the other parts in the chassis.

This is the heater core from a Mitsubishi Montero:

I don't have this or an e30 core in my hands, but from dimensions I can find online I believe this will fit in the heater box with a modified cover on the drivers side (it should be slightly smaller and can be padded out with foam and aluminum tape). This would give us hose fittings to run out through the firewall and locate a heater control valve under the hood. The operation of the e30 one doesn't seem to be magical... it's just an NO solenoid valve that closes if your temperature knob is below 20 degrees rotation.

Even if the new valve leaks... it wouldn't be on your foot?

FRUSTRATED EDIT:

https://www.pelicanparts.com/BMW/tec...eplacement.htm

40 min of scrolling through heater core specs to find that one, and 5 min after posting this looking for a photo of how the heater core inserts for people who might not know I learned that the Z3 setup is EXACTLY like this and has the heater control valve under the hood. I can't find dimensions for the Z3 core, but it looks like the coverplate layout is the same as the e30... I really, really wonder if it even points the hose quick-connects to the same firewall penetration

I still have the original heater core in my E30. If a new replacement lasts just as long, I'll probably be dead, or unable to drive my E30 any longer, before it needs replaced again.

Is fitment it really that bad with the 3-stage? It's a great feature to have on the N52, as you know, my DD is a 330i - and it's fun even at 3400lbs! But honestly, I'm not sure it's worth the hassle in an E30. You get more peak torque and sooner, but the E30 is a good 800lbs lighter than the 330i or 328i. It gets worse as you add AWD, automatics, and convertibles. Even with the N54 manifold, which is hardly optimized at all and basically just happens to bolt in - you only lose maybe 10 ft/lb of torque. It's still way over what any stock E30 powerplant put out, and it can actually make more power at higher RPM.

There are some downsides to the 3-stage that I don't think many realize - aside from cost, complexity and fitment, you're limited to the exact powerband that it's tuned for - ~2200 to 6900rpm. You're *never* going to break ~250whp with the 3-stage manifold. It's not physically possible. The "3 stage" name comes from the 3 resonance frequencies it's tuned for, which are activated at different RPM by the DISA flaps (~1700-3200rpm, 3200-4500, 4500-redline). But unfortunately, after the 3rd stage, this highly tuned manifold cause a *negative* resonance. Torque drops off like a cliff above 6900rpm, making it pointless to rev higher (even if you can make the rest of the engine breathe, which you can). It's frustrating and basically insurmountable (and I've tried everything).

The irony is the N52 actually loves to rev and has a head design bested only by the S motors. All those light parts, tight tolerances, and a free flowing head based on the S54.. stuck at 7000rpm or less. :( Remove that bottleneck, I don't see any reason why 300bhp isn't possible - it just takes more revs than you can get with the 3-stage manifold.

And even if you don't want an 8000rpm screamer, is it worth the 10 ft/lbs to reinvent the wheel on heater core replacements? I'm not sure. There are other considerations, such as the external CCV used with the earlier motors (not sure how that works with the N54 or other custom manifolds?).

I don't want to change your mind at all, I've gone back and forth on this myself and still am not totally decided. Just something to consider - and you've actually driven Steve's car (which isn't fully optimized yet!).

I still want to make my S54 ITBs work though. I actually made progress on my adapter, then I got busy, and then my 3D printer died.. lol

[Habla]

I’m getting all kinds of wild ideas now, since I have the entire car. Do I keep the whole heater box? Blower motor changes from under the glovebox? Yes please. Hell, dashboards are so expensive now, ive even considered whittling down the e90 one and put that in there with the cluster 😅

If the aux fan was a pusher, I would use it as is, but I could at least use the controller setup with a spal fan in front.

Excited to cart the pos into the shop and start harvesting.

[hubcapboy]

I have a few irons in the fire but nothing to report back with conclusions on... So I've moved back to research. I have a problem to solve related to the location that the heater core pipes pass through the firewall. This shows up in post #96 on page... 7. It wouldn't be impossible to put elbows on the end of the existing lines (I don't think) but I've started thinking about the age of the heater core and heater control valve. Heater control valves are a limited commodity and are prone to leaking and heater cores have finite lives, but the only reason we're bound to these parts is they physically fit and the connections work with the other parts in the chassis.

This is the heater core from a Mitsubishi Montero:



I don't have this or an e30 core in my hands, but from dimensions I can find online I believe this will fit in the heater box with a modified cover on the drivers side (it should be slightly smaller and can be padded out with foam and aluminum tape). This would give us hose fittings to run out through the firewall and locate a heater control valve under the hood. The operation of the e30 one doesn't seem to be magical... it's just an NO solenoid valve that closes if your temperature knob is below 20 degrees rotation.

Even if the new valve leaks... it wouldn't be on your foot?

FRUSTRATED EDIT:

https://www.pelicanparts.com/BMW/techarticles/BMW-Z3/105-WATER-Heater_Core_Replacement/105-WATER-Heater_Core_Replacement.htm

40 min of scrolling through heater core specs to find that one, and 5 min after posting this looking for a photo of how the heater core inserts for people who might not know I learned that the Z3 setup is EXACTLY like this and has the heater control valve under the hood. I can't find dimensions for the Z3 core, but it looks like the coverplate layout is the same as the e30... I really, really wonder if it even points the hose quick-connects to the same firewall penetration

[hoveringuy]

On cooling...

So on my M54, as it was on the M20, I had a fixed 80C thermostat, which means my coolant temps ran somewhere around 90C/195F and my radiator outlet temps were around 82C. I had the standard 91C/99C aux fan thermostat switch and a SPAL pusher fan.

In normal driving the temp gauge was somewhere just to the left of 1/2 and if I was in slow traffic or at a light it would creep above 1/2 and trigger the aux fan low speed. All was good. (BTW, I never, ever had an issue cooling the M54 with the stock radiator, even tracking on hot days...)

The N52, however, is completely different...

I've had the chance to drive it a bit now and observe its quirks. First, it has a 97C thermostat which means that normal operating temp is around 105C/220F and it can also slip into "eco" mode.at 112C/234F or down to 95C, depending on what I'm doing. So, the gauge can be settled at 1/2 and then spontaneously start moving to the right if I'm not hooning it. it's kind-of disconcerting and probably why the modern temperature gauges just tell you that things are "normal".

Anyway, this means that with an operating temp of 105 my radiator outlet temp is around 95-97C, which clearly triggers the aux fan. Sometimes I even trigger aux "high" at 99C.

What seems to happen is that the aux fan and the ECU end up fighting each other. The aux fan kicks-on to drive down temps, but the ECU is determined to raise them so it just reduces coolant flow. The aux fan ends up running all the time, even at highway speeds.

So, I need the aux fan and the ECU to coordinate with each other. If only there was a way to do that...

To start, I connected C101 pin 14 VSS with 6001 pin 17 speed input and verified that the ECU is registering road speed, I think that's a critical parameter in how it controls the aux fan. I put the car on jackstands and at 40mph the
Geschwindigkeit was 63kph. Sweet!

Next, I need to see about getting an aux fan module and seeing how that integrates with the ECU and the SPAL.

As a final note, early N52's have a radiator outlet temperature sensor, but the later N52K's do not. I think the later motors just assign an outlet temp that's 7.5C lower than inlet. Since my flash isn't necessarily from a late motor, I may or may not need to add the outlet temp sensor to make everything work...

As a final, final note, the cooling parameters have tables and can be mapped like anything else, so there is a degree of software control that's available, but I'm not sure how I would change it.

For documentation, this is the PWM fan signal. It's a 5v signal that's pulled down to ground (open collector), 100Hz. This is 15 percent duty cycle. Some PWM fan controllers are setup for this signal and some are reversed polarity, where duty cycle is time at 5v instead of ground..

[nando]

hours.. there's so much shit in the way. you can't really even fully access the head because the wiring harness runs right over cylinder #5.

[hoveringuy]

It's funny, because in a much smaller car - the engine is actually way more accessible and easier to work on than it was originally.

I can have the valve cover completely off in under 20 minutes (done that 3x now..), or have the electric water pump pulled in about the same.

How long would that take in an E90?

With the N54 intake I'm staring at the starter and the heater core connections are out in space

[nando]

It's funny, because in a much smaller car - the engine is actually way more accessible and easier to work on than it was originally.

[hoveringuy]

See, isn't this better already? That long X3 harness is going to be replaced by one from a Z4, which exits the back of the engine instead of the side. It's going to look great, trust me.

[nando]

The E box is ugly and most of the electronics inside aren't needed, so it would be mostly empty. Seems to make sense to put it in the glovebox like a stock E30. A better grommet would be nice though..

[Habla]

don't ever sell it! We had a 2006 E91 6mt (along with my 2006 330i 6mt). Perfect family car - we also have 2 kids and 2 dogs. We took it on a trip once with 3 adults, 2 kids, bikes and camping gear for 5 days. Drove it across the steepest pass in Canada, which it did no problem at 80mph.

Thanks, high praise! It should stick around for a while. Shes already attached :)

It would be like this, but instead of cheezits it would be your glove box.

Haha, why not both? I'm not into the electrics yet, but maybe I'll consider putting the ebox in the battery tray?

Ive got the core support off the 330 now, and the entire interior is out, even the dash beam. Let me know if there are any in-situ pictures you might want before I start unhooking the engine too quickly and not documenting how it goes together...

Did you know it has a power steering oil cooler??

P

[hubcapboy]

I had an idea for this that I didn't explain very well (I also think it only takes about 10 min to take the sub-connectors out of the black plastic clips and re-assemble them on the other side of the firewall, but hoveringuy REALLY wanted to cut that hole. To cover it back up again you could cut the rim off an air-sealed plastic container, mount/glue/seal it to the firewall, and then use the lid as your pass-through... so that you can "unclip" that part of the firewall and have a larger hole behind it?


It would be like this, but instead of cheezits it would be your glove box.