N52 Swap Discussion

[hubcapboy]

Nando I'll borrow a set from you if you have them kicking around. It'll be a miracle if they work.

I'm pretty sure my engine position is nailed down. The brackets are not even tacked together, but when they are it'll be using the current engine position as my reference. Any rearward movement is going to compromise the heater hose attachments here:



CWLO didn't have that problem because his intake manifold doesn't drop down that far... honestly he might not even have a heater connection if it's just his autocross car. There's no way I'm not connecting the heater... and honestly keeping the 3-stage intake was one of my stated goals for the swap. We know the power output of this engine with the single stage and 3 stage n52 intakes... we don't know what the curve looks like with the N54 intake.



There's definitely room a the back of the engine, but the only two reasons I can think of to push it back are for weight distribution (an inch might matter, but not much) and for fan space (I'll get to that in a minute). when I moved the engine back much further the trans was hitting the tunnel, which meant it needed to drop lower. Clearance to the subframe was already a problem, so that would have meant adding tilt because there's no room to shift the whole engine down. I didn't know this while I had the full engine/trans package in there, but my alignment ended up pretty ok:



This is bore-sighted through the empty block towards the CSB. It's not aligned any more than me holding my phone in front of the engine... but it doesn't encourage me to tilt the engine further. I measured the declination of the M20 in my other car at 3.5 degrees, and this is currently at 3 degrees, so it's pretty dang close.

Part of the work that I tested but didn't share because it didn't work out was trying to get the entire Z4 radiator and puller fan package to fit in front of the engine:


If I thought I was only 3/4" away from making this work I'd definitely think about moving the engine back. As it stands it interferes by at least an inch. There's three inches and change to bearing seat on the front of the block from the face of the radiator (protected with cardboard) and probably two and a half clear to the crank pulley. The z4 fan shroud and motor is about 4 1/2" at this point, which is a shame. in addition to that, there's a significant amount of tank you have to shave off the passenger side (you can see near the low rad hose connection) that would have to be patched back up. The "thin" z4 core with the z4 fan is probably a nonstarter regardless of engine position. I considered a "thin" z3 core and trying to get a pull fan to fit, but I'm now leaning towards a 3-core with a push fan. Plenty of people do that... it doesn't seem like many of them retain air conditioning. I'm actually curious to see how much air the aux fan can push. I expect I"ll see how things work out with the thicker and more efficient radiator with just the aux fan before I solve the push-fan problem.

[LukeJ]

Maybe that half a degree of tilt is the difference between hitting the tunnel or not when the engine is moved back further?

Just know that whatever comments I make are intended to be helpful and not discouraging. If I can add data, then maybe you can make your best decision.

One main difference, is that I plan to use the N54 manifold. Using the 3-stage adds other complications as you've pointed out.

Is it possible to move the condenser forward a bit and make room for a pusher between it and the radiator? Is this a dumb question?

[LukeJ]

Has anyone ever brazed/soldered elbows on the heater inlet/outlets?

I wonder if it would be just as simple as sweat soldering copper pipe.

[nando]

I would just use a pusher fan. There's lots of room to fit a high flow, 16" fan up front, and it will work just fine - I ran one for years, but went back to a clutch fan for simplicity. Even the stock AC fan will work. Obviously, the N52 never had a mechanical fan.

I can't really compare the ix directly because I believe the engine position is very different from the RWD cars. But when I was measuring space, I was pretty sure even if the engine was basically touching the firewall, I wouldn't be able to fit a fan between the radiator and pulleys.

[hubcapboy]

Nando’s recollection matches my recent experience. I appreciate anything you have to add, LukeJ. I’m not trying to dispute anything... I just have photos relevant to your thought experiment ;)

Using the N54 manifold cures that issue among others... and I’m sure modifying the heater core stubs would be straightforward, but I can’t come up with a reason the engine needs to be nudged back from where I have it. It adds shifter carrier modification and the heater core issue and only gets me an inch of mass moved back. If there’s other reasons we think it needs to be further back, start listing them before I start welding!

BMW rates the 3 liter N52 at 268hp with the three stage and 228 hp with the N52 single stage. I’d be shocked if the N54 manifold is an improvement on that. I expect that it’s a compromise that’s compensated for with the forced induction (ie bmw figured the intake was less critical when they could just cram air into it anyway). If the design between the two N52 intakes is 40hp, the N54 intake could easily be a 10-20hp loss. That’s just speculation. It solves a ton of interference problems, but might not see a huge power gain over a much easier M54 swap. We haven’t seen a chassis dyno of one of the cars swapped with the N54 intake to know. Hoveringuy has a dyno of his well-tuned megasquirt M54 waiting to compare.

If I get to the end of this and he and I dyno on the same day and this engine doesn’t smoke him, there’s really no reason for anyone else to keep trying... just stick with the m54.

[hoveringuy]

I was really hoping Cwlo would (will...) dyno his engine. I'd not only like to see peek power but what the curve looks like. Maybe it's a monster, I don't know, but if it is the N54 manifold would solve a lot of issues.

[LukeJ]

Even if the dyno results are a wash, there's still a weight difference right? N52 vs M54.....

I guess I'm less concerned with where the actual hp and torque numbers end up.

With headers, MILVs, and N54 manifold, I'm thinking/guessing I'll end up with about 100 horses more on my butt dyno than my M20 is currently producing.

In a 2800lb car, that should be 'plenty of fun' for me as a daily driven street car.

[hoveringuy]

All I know is that when I was developing my M54 swap in 2009 I spent a lot of time at the dyno. I learned that exhaust cam retard doesn't do anything for power and I still have my exhaust cam solenoid disconnected to this day.

I also learned that DISA works. Amazingly so...

The difference in the curves between having DISA connected and not connected is eye-opening. I can only imagine how well the newer 3-stage N52 DISA works.

I think the N54 manifold is probably fine, as well.

I currently have the M50 manifold on my M54 for simplicity and am happy with it, although I do miss some of the torque.

[hubcapboy]

Presumably interesting news. This is the fully dressed weight of the engine and transmission. No fluids. Tared to exclude the weight of the balance arm. No headers, no engine arms. Everything else ready to run. 462 lbs.

[nando]

The only issue with the 3-stage is it's tuned to specific frequencies. So basically, it limits the maximum potential of the engine to frequencies that fall into those ranges. Anything above ~6900rpm is pretty much pointless, and that's where the potential is for more power (without internal mods). It's already been proven that the N52 can rev significantly higher than stock. All the lightweight components are a huge benefit there. But if you dig that torque curve, it's definitely really good, even in a heavy ass E90.

The N54 manifold definitely isn't optimal (you need to at least line up the ports better for one), but by eliminating the factory tuned frequencies, you can unlock that potential. The cost is some low end torque - but the E30 is so light, I feel like it wouldn't matter too much, especially with shorter gearing (I could at best, put in a 3.64).

What we have never actually seen, except some guy's expensive race engine built years ago - is what an optimized manifold could do. Think of the N54 manifold like being the dbilas ITB kit (which is crap), vs the RHD kit which makes significantly more power even on otherwise stock engines.

FWIW, my 330i put down 225whp totally stock. Torque starts at like 2000rpm and goes close to redline. There's no other BMW N/A 6 like it really - except maybe the M engines, but they all have high weight penalties.

[nando]

Presumably interesting news. This is the fully dressed weight of the engine and transmission. No fluids. Tared to exclude the weight of the balance arm. No headers, no engine arms. Everything else ready to run. 462 lbs.

I'd like to see a weight without the transmission, since not everyone will use the same one. I'm almost certain the 6 speed is heavier than the Getrag 260, for example. My flywheel weighs like ~6 lbs.

Does that include the AC compressor as well?

[nando]

BTW..


And that's with the much lighter Getrag 240. The N52 is missing the manifolds, but they are actually really light.

[cwlo]

I really don't see much advantage with the 3 stage intake for an e30 installation. I've also never dynoed my car because it wouldn't really provide much info in isolation. Now Bob at StageFP back in the day dynoed the N54 and N52 3 stage intake with tune, and they were pretty darn close, with the N54 having more top end at the expense of some torque mid-range compared to the 3 stage. In additon, the N54 manifold has a smoother curve, without the disa flaps. I do have my heater hoses connected, and I think the hp/torque in the e30 is about perfect. I did have the 3.0 M54 in the car before the N52, and while the M54 is a nice setup for a street car, anything over 4500 rpm was unbalanced, and weak.

https://www.1addicts.com/forums/show....php?t=1451616

https://www.e90post.com/forums/showthread.php?t=1267573

[nando]

The EKT says the GS6-37BZ weighs 99lbs. The pressure plate is 16lbs, the clutch is 2.4 and the fork is 1.7. the dual mass flywheel is 22.7lbs. Put that all together (without fasteners) and you have 141.8lbs for the full 6 speed assembly (in your pic, there's no shifter, so I'm not counting that).

The front manifold with cat is 10.8lbs, The rear is 8lbs. Call it 20 total (gaskets, bolts, etc). Aftermarket will probably be lighter, with no cats.

So 462 + 20 - 141.8 = 340.2lbs, and that's with the AC compressor. Nice.

I won't be running A/C,, so subtract another 12lbs for 328, fully dressed. That really closely matches the weight listed in this thread, 326lbs (must be without CATs and A/C). https://www.r3vlimited.com/board/for...-weights-guide

FWIW, a full M20B25 is almost 400lbs. http://www.r3vlimited.com/board/showthread.php?t=99913

I alrready don't have A/C, so I stand to lose a good 50lbs over the front wheels. :)

[hubcapboy]

AC compressor is included... it's sitting right there above the water pump (I still can't believe that's the water pump). I'd be happy to weigh it without the trans but... I'm not even going to separate them. I don't need to upgrade the clutch and if it needs clutch or flywheel work I'll just yank it again. It's not like I won't have practice.

I have absolutely no doubt that there's more high end power to be found in the engine, and that it'll keep turning past its redline, and that the intake to accommodate that higher end is shorter and maybe even resembles the N54 manifold. I'm used to driving this car at a 4700 rpm redline. 7000 is already going to feel like a party trick.

A few years before my e30 was my daily driver, I had a 2nd gen Honda S2000. Between that and the e30, I commuted on a BMW motorcycle every day. I'm going to disappoint you all when I say that I'm planning on keeping my 3.07 torsen rear end and don't plan on shortening the gearing...

I fell in love with the eta m20 and the effortless grunt it put out low down. I'm never going to win the all-out e30 power war... I hope for this to be a daily driver, and I need usable torque when I put my foot down (and for the AC to work). In the high end power vs available torque at 2500rpm trade-off, I want the torque... no question.

My ambition for weight was 4 cylinder weight. It looks like we're within 30-40 lbs of an M42. I'll take it. That means we're probably on-par with an S14 as well. If you don't need AC, you're there.