E28: Eggenberger Group A E28 Tribute Build Thread

[jpod999]

Your builds are always top notch Mike.

[SpasticDwarf]

I didn't realize how much work, and how many specialized parts went into this build. I thought it was just an E28 with a wrap, and an S38. Pretty cool. I agree with ShockWave that your taste seems to be maturing, which is good to see. Also nice to see at least one of your E28s on a track ;)

I gotta hand it to you though, it's impressive how you've built a brand and business for yourself. I remember you posting something on TDF (remember that site?) maybe 10 years ago about how you were going to do an S54 swap in your E36, and thinking no way this kid is gonna do such an involved swap. Well done.

BTW, what other Land Cruiser do you have? I thought you sold the FJ40 recently.

That's part of why I wanted to make a build thread. I'm sure appears to most as it did to you, however, it's absolutely been a build of love and attention to detail. While I don't have the means to build a true replica, I did my best to build a worthy homage to the cars that mean the most to me.

Things have come a long way since TDF. I appreciate the kind words. :)

And you're impressively keen. I didn't think anyone would pick up on that. I bought an FJ60 after my 62 got hit. Here in the next few weeks I'm hoping to get started on what I think will be a very cool build.

[SpasticDwarf]

Your builds are always top notch Mike.

Hugely appreciated.

[SpasticDwarf]

I've really grown to enjoy the ins and outs of roll cage and chassis design, and while I am very far from a pro, I'm happy with the outcome on the E28. It's one of the places I took some creative liberties from the original Group A cars, all in the name of safety. The Eggenberger E28s all ran bolt-in roll cages, and while they can be safe, I prefer something that is safe. However, I did source a copy of the 1985 FIA Group A rulebook, and built the cage to spec, preserving some sense of authenticity.





Inarguably, the most important aspect of cage design is strength and integrity, and while there's an immense amount of wonderful rollcage fabrication out there (and all far better than mine, no doubt), it's the place I see skimped out on most often as I peruse threads and facebook groups. More often than not, "cage builders" seem to skip building proper nodes - where tubes meet - in favor of quicker fabrication. Is it safe? Yeah, probably. But is it right? No, not by my book at least. It doesn't mean you or your cage is wrong, it's just not how I like to work.

An example of what I'm talking about (seen on an E36 sedan, from google images). None of the tubes "intersect." The door bar is below the belt bar, the diagonal misses the rear braces, etc, as does the a-pillar bar. Each of these tubes dead-ends into another perpendicular tube.



You'll see none of the tubes actually meet each other. It's quicker to build this way, but it provides poor load paths in the event of an accident. It also doesn't look very nice. The photo below is one of the few reference photos I have of the actual E28 Group A roll cage - bolted together, and also not incredibly well designed.



You can see in this picture, of my cage, a general idea of my layout and noding. Every tube meets another, "noding" correctly. Again, it may not be important to others, but it was to me, so I spent a lot of time getting it right.



I wish I had taken more photos of stripping the interior itself, but I didn't. It was, by far, the most laborious part of the whole build. Removing the sound deadener and the adhesive for it was a monumental task that took several long nights of scrubbing - the best chemical I found for it was Xylene, which is an adhesive dissolver. It took a few of us to get the job done. The common "dry ice" trick does not work at all on E28s, and I'd imagine it goes for other BMWs as well. Good luck to you if you decide to strip your interior and repaint it. It was an awful job, and probably a month long from start to finish, including the cage build too.

For my roll cage, I opted to build atop plinth boxes, which are a bit stronger than attaching directly to the floor, and they allow the cage to be dropped away from the roof for final welding. Here's a bit of before and after for a front and rear plinth box.



Here's one in place - this one's on the driver's rear. All four plinth boxes are slightly different due to asymmetry in the floor pan. For the finished cage, there is a base plate to each plinth box - it is not welded directly to the floor. This was just mockup purposes. You can also see the adhesive I was dealing with. It covered every inch of the interior. It haunts me to this day.



More adhesive. In some instances and places in the car, it was a few milimeters thick. We had to remove ALL of it to ensure a good finish on the floor pan.



Here's the front two plinth boxes (and base plates) mocked into position. I'm no pro welder, so affixing my base plate material to the floor, effecitvely, was hard. Strong? Yes. Pretty? Eh, not so much. Sorry, professionals out there.





From there, I moved on to cage construction, of which I didn't take too many photos.



My position for the rear bars is a bit atypical. Normally, E28 cages head straight to the wheel well arch, forward of the strut tower. It's very easy to access and mount to, and it's very strong. I wanted to attach directly to the strut tower, and thus had to remove a sement of the rear bulkhead on each side. The sheet metal is in the way, normally. On the to-do list, to this day, is to rivet in some nice aluminum covers to seal it back off. It's the only part of the car I feel is "unfinished" in its current state.







My good friend Riley Stair joined in for the weekend to help knock out the cage, since my SEMA clock was ticking.

Following the cage build, and a WHOLE lot more interior cleanup, we were finally ready to prep and paint the interior of the car. A few of us did prep work, but it was my good friend Cory Hutchison that did the paintwork itself, and the outcome is honestly better than I ever expected. Masking took an impressively long time, with lots of paper, tape, and foil used to keep everything clean. We had to paint in stages, masking the floor off first to paint the cage, and then the cage to paint the floor, all in an effort to prevent overspray problems and to ensure a factory-like finish.



Here you can see the cage dropped down, so that the top could be painted. This was another reason for painting the floor separately - I had to lift the cage back into place, and weld it up.







Here's where things finally started to come together. Also in the mix was dying the headliner to black, to keep things true to the "M5" theme. I also, after everything was said and done, took the time to re-wrap the whole harness with black cloth tape, to clean up the inside of the car.







And a few final photos:







I wish I had a good photo to show off the paintwork on the floor, but it really did come out beautifully. I feel bad trampling all over it when I get in and out of the car. Overall, aside from a couple small details, the interior is really where I want it to be. I'll add another short post about my choice of interior amenities.

[Powling]

Great build! Just curious how long the entire build took from car purchase to track ready?

[SpasticDwarf]

Great build! Just curious how long the entire build took from car purchase to track ready?

4 months to the day, exactly. It was an after-hours and weekend project only.

[UNHCLL]

For our hub, we did add some lightening holes (as also used on the original hub I own, but not as seen on the Gr. A E28s in the pic above), however, they do use the drive pins to affix to the car - they’re not a dual-bolt style “adapter”. It’s as close to the factory centerlock hubs as we could venture.

Mike,

Having just gone through this, with a car weighing less than your E28, I can tell you with 100% assurance that using the drive pins to hold those front hub adapters to the hub will result in failure.
The front wheel hubs are NOT strong enough to support the load of the wheel under actual track use/racing conditions. It will pull the drive pins from the aluminum of the hub.

The "vendor" who sold us the identical setup to what you have created claimed the same. Just bolt them on using drive pins. It doesn't work.
Been there, tried that.

If you plan on using the car any more than just a nice show piece for parade laps, you need to revisit the front spindle connection method.

Also, you might want to check your driveshaft angle on that wrap! ;)

-Chris

[SpasticDwarf]

Mike,

Having just gone through this, with a car weighing less than your E28, I can tell you with 100% assurance that using the drive pins to hold those front hub adapters to the hub will result in failure.
The front wheel hubs are NOT strong enough to support the load of the wheel under actual track use/racing conditions. It will pull the drive pins from the aluminum of the hub.

The "vendor" who sold us the identical setup to what you have created claimed the same. Just bolt them on using drive pins. It doesn't work.
Been there, tried that.

If you plan on using the car any more than just a nice show piece for parade laps, you need to revisit the front spindle connection method.

Also, you might want to check your driveshaft angle on that wrap! ;)

-Chris

Chris,

With all due respect, your setup can not be "identical" because mine is not from a vendor, but instead was designed specifically for this project by an aerospace mechanical engineer using FEA software to establish a safety factor of 2.5 using the dynamic loads from a respected name in the wheel industry. My components are also made from 7075 aircraft alloy, which is about 60% stronger than 6061 T6 forged aluminum; if you used an aluminum part, it was made from that. My pins are built to Grade 8 specifications.

It will pull the drive pins from the aluminum of the hub.s

You also mention pulling the pins from the "hub" (I assume you mean the centerlock hub, not the E28 hub itself), which is impossible, because my drive pins do not thread into it. They pass through it.

With all of that said, and considering that's how the Group A cars were run:







And considering they didn't have problems:


I'm going to assume mine will be alright. I have, and will continue inspecting the parts after each track day to confirm integrity. Two track days so far and there's no sign of a problem.

Furthermore, I assume the other setup you are referring to is akin to the steel hub and either steel or titanium drive pins provided by a certain E30 M3 fabricator. The designer of my setup noticed that the hex-key arrangement in the drive pin tips seems to complicate the torquing process of the pins into the hub. The flats designed into my drive pins and many other drive pin setups we have seen (including the GrpA parts) makes torquing the pins to an appropriate value much more consistent and less fraught with error.

As far as driveshaft angles go, someone get BMW on the phone! We've gotta fix their car too :D

[Northern]

I also find your most recent builds more to my taste than the older/slammed cars from before. Not that I dislike the Model A, E9, Rusty(post crash), or the E36, just meat/function is more my style.

Glad to see some of your content on r3v again. It's been too long.

[pandaboo911]

I remember I met you once at Bimmerfest 2009, it's been a mintue. Awesome build!

[UNHCLL]

You also mention pulling the pins from the "hub" (I assume you mean the centerlock hub, not the E28 hub itself), which is impossible, because my drive pins do not thread into it. They pass through it.

Hi Mike,

No, not referring to the center spindle/nut that you had custom machined.
I am referring to the drive pins and their method of attachment to the wheel hub.

Are they through bolted with a nut on the backside of the hub (FAG piece), or simply bolted INTO the existing threads on the wheel hub where you would normally screw in lug bolts (photo of the FAG bearing above)?

If the later, they will fail. What material you had the drive spindle made out of has zero bearing on this.

-Chris

[Sh3rpak!ng]

Nicely done! So damn cool to see such dedication put into making a faithful replica like this. Was there also a motor build to go along with it? I'd love to see that documented too! Also thanks for posting up detailed photos of the cage construction. That tar/adhesive scares me just looking at it.

[theneek]

Hi Mike,

No, not referring to the center spindle/nut that you had custom machined.
I am referring to the drive pins and their method of attachment to the wheel hub.

Are they through bolted with a nut on the backside of the hub (FAG piece), or simply bolted INTO the existing threads on the wheel hub where you would normally screw in lug bolts (photo of the FAG bearing above)?

If the later, they will fail. What material you had the drive spindle made out of has zero bearing on this.

-Chris

Chris, do you have photos of the failed unit(s)? I'm curious to see it. Sounds like a scary situation.

[SpasticDwarf]

Hi Mike,

No, not referring to the center spindle/nut that you had custom machined.
I am referring to the drive pins and their method of attachment to the wheel hub.

Are they through bolted with a nut on the backside of the hub (FAG piece), or simply bolted INTO the existing threads on the wheel hub where you would normally screw in lug bolts (photo of the FAG bearing above)?

If the later, they will fail. What material you had the drive spindle made out of has zero bearing on this.

-Chris

The material the pins are made out of does have an effect, as a stronger material means less flexure, especially within the threads. Also, mechanically, the load on the FAG hub isn't largely different than a wheel mounted with an 18mm spacer and extended lugs. Those aren't tearing off hubs regularly.

With that said, I too would like to see pictures of the failed part, if possible.

Nicely done! So damn cool to see such dedication put into making a faithful replica like this. Was there also a motor build to go along with it? I'd love to see that documented too! Also thanks for posting up detailed photos of the cage construction. That tar/adhesive scares me just looking at it.

Thank you! Yes, there's more posts to come.

[SpasticDwarf]

I also find your most recent builds more to my taste than the older/slammed cars from before. Not that I dislike the Model A, E9, Rusty(post crash), or the E36, just meat/function is more my style.

Glad to see some of your content on r3v again. It's been too long.

I remember I met you once at Bimmerfest 2009, it's been a mintue. Awesome build!

Thank you both!