8hp45

[hoveringuy]

I've gone down the 8HP45 rabbit hole and purchased one...

One of the nice things about having the N52 is that the swap should be mechanically trivial; anything from an N55 or N20 engine is a direct fit. I purchased a 40,000 mile box that came from an F30 328i (N20 engine) for $350.

I'm not sure exactly where I'm going with this, but I'll probably integrate it electronically using a CAN TCU controller and then have either paddle shifters or a sequential shifter (or both?). The weight appears to be about 45lbs more than my GS6-17 or 25 more than a GS6-37.

This won't be the first E30 application, that's been done a bunch already so I know it will fit.

Timeline is that I'll finish my last track events in September and then put the car on jacks, should have it driving again by the end of the year. Next year will be evaluation on the track!

[hoveringuy]

Reserved for eventual TLDR summary.

[DesertBMW]

I am sure it is too wide on the bottom to fit E30 tunnel.

[TobyB]

Oh, ha- 'me too!' But I want to put it in the E39 wagon, behind an N52, and then play with tuning the transmission
controller so that it doesn't behave like the current GM slushbox that's in there now (and that I find so hateful)

So I'm in- there was one in a 528 at the Lake Stevens yard, and given that the engine was pretty well locked up,
I figure it's at least good enough to do development work on. (that car kicked my butt. I'm getting old.)
It's not a very big transmission- if it hits an E30 tunnel, it won't be by much.

What I'm trying to figure out- WHICH currently available controller gives you the most control over the transmission?
There's CANECU, MaxxECU, and the original... Turbolamik?

this is very much a 'back burner' project here, so I'll just shut up now and follow along...

t

[hoveringuy]

I am sure it is too wide on the bottom to fit E30 tunnel.

The top of the transmission isn't that big, it's the very bottom that's wide. I've seen plenty of examples of E30's with these now, so I know it will fit. I think the fat bottom part ends-up being a little below the tunnel (but still above the exhaust and the frame rails....)

So, updates...

first, I assembled my spray pup-tent, bought 5lbs of #10 glass bead media and went to town. Sealed every orifice carefully.

I cut-off/ground-off a few of the bigger tabs on top that are only used for production handling and were more likely to interfere with the top of the tunnel.





much-more better!




mocked-up some mounting plates and ordered this one in stainless. May not have perfect geometry but I need something to just get it mounted so I can see how far I'm off.




Best I can tell, the centerline will be about where the red line is. My current cross bar won't work anymore.



So I ordered P/N 24711129346 from an '84 318is which spans the two slots on the left side and then one on the right. I like this design because it clears the exhaust on the right side much better (and I don't want one of the mounting nuts UNDER the exhaust...)

This may also not be perfect but at least I'll have some geometry to start with.

[Caperix]

Do you think this will require a controller for the transmission or can MSV70/80 talk to it correctly. 8HP's were installed behind N52's in early F10's & & F25's but they all used a continental DME.

[hoveringuy]

Do you think this will require a controller for the transmission or can MSV70/80 talk to it correctly. 8HP's were installed behind N52's in early F10's & & F25's but they all used a continental DME.

I think its possible for direct ECU control if the mechatronics is out of an E-series, but mine is out of F-series and I'm not even trying. My default plan is to use the CAN TCU bridge. The most I will need is to code my ECU from "manual" to "automatic" so it responds to torque cut for upshifting and blips for down...

[hoveringuy]

I finished the "version1.0" design of my mount. The transmission plate has already been on-order for 3-D printing out of stainless in China, the crossbar is being done by SendCutSend, because that's relatively cheap for a prototype. Final version may also be 3-d printed in aluminum, but I could just stick with this concept and weld vertical stiffeners underneath.

The centerline of the of the mounting studs is forward of the normal slots and aligned with rear set of slots that's normally used for automatic transmissions. I'd like to keep using the forward slots as much as possible because they're much easier to access, particularly on the driver side. My rear slot on the passenger side is where my exhaust routes, and while exhaust can be moved, I'm lazy (for now...).

I can probably reduce the amount of the cantilever once everything has been test-fit.

I'm also pretty sure that I won't have interference installing the plug but that also needs to be verified.

[Caperix]

E46 guys are using the transmission mount off an e84 x1. Rumor is that makes a 8hp bolt into that chassis, may be worth looking into as well.

[hoveringuy]

More "little things" progress before I physically swap in a few days...


The 3D printed mounting flange came back. Fits great! If the geometry works I'll revise a little bit to add some stiffening ribs.



This is meant to be "good enough to hang". I'll make any adjustments and verify geometry when it's installed.



One thing about the 8HP is that while it can be shifted into Neutral without the engine running, it can't be released from Park; it takes hydraulic pressure from the transmission pump to release the park prawl.

That means if the engine shits itself at the track the car will be stuck in "park" and can't be pulled off.

Some cars have an emergency over-ride lever and some cars just have a screw on the transmission that can get turned-in to release the park prawls. No way in hell I'm getting under the car to do that....

There's a kit that adds a cable-actuated lever to this transmission. I modified it a bit by welding an actual flange to one of the bosses.



Prototype in PLA for now. Aluminum printed one in a few weeks.



Adapter for the factory oil lines to 18mm ORB. I'll probably use my M2 PS cooler but I'll tackle that later.

[hoveringuy]

The manual box is out. Super-easy!

Here are some size comparisons and intallation notes.

Note that I have the GS6-16 from the 328 and not the bigger GS6-37 from the 330 which is longer and about 20lbs heavier.





It's known that the 8HP45 won't fit directly on the N52 without some slight massaging. The one top hole need to be drilled to 13mm. The other one needs to be oblonged about 3mm. Use the sheet metal cover a guide and a reemer or a burr tool.

Weird to me that the top one is off by 3mm, BMW is great about standardizing that kind of stuff between motors....

[hoveringuy]

Final weight tally.

164lbs for the 8HP45 without 6 qts of fluid.

115 for the GS6-17.

50lbs difference, not counting fluid in the autobox.

[hoveringuy]

Well, it fits...

There's a few places where there's not a ton of clearance but 16lb clearance tool was not required. The geometry on my bracket was PERFECT. The output points exactly where it needs to, smack in the middle of the center bearing.

It looks really low until the exhaust is next to it and then it's just... low. It's not lower than the exhaust, but it's about 1 1/2 inches lower than the frame rails. Not horrible.

Lots of clearance to access the coolant lines. NO clearance for the parking unlock lever, I'll need to design one that's E30 specific.

To do: Need to fabricate a new front driveshaft section. Finish bolting up the starter, torque converter and such. The exhaust will eventually need some slight re-routing but fine for now.

Also, order the TCUCAN interface!



Exhaust will need some slight re-routing.



Mount geometry is spot-on.



It looks really low until the exhaust is next to it.

[DesertBMW]

it fits with zero clearance issues? Not touching the tunnel at all?

[hoveringuy]

it fits with zero clearance issues? Not touching the tunnel at all?

Nope... My N52 is moved back 15mm from the "stock" location so I'm even in the narrower part of the tunnel. There's a rib of sorts in the tunnel that's about 10mm from where the plug is, and that's the closest potential interference. Everything else is cool!

There's room to move it up a tad, but the output shaft is perfectly aligned as-is.

I was NOT able to include the lever on the pawl release.