E30 Recaro Seats in E21

“We’re going to do what they say can’t be done.” – Jerry Reed, Smokey & The Bandit.

I’m determined to replace my E21 Recaro seats with the Recaro sport seats out of an E30. There’s nothing wrong with my E21 Recaros; they work perfectly fine and are comfortable. But the E30 Recaros are more supportive and comfortable and I’m a little nervous something will happen to the E21 seats (they’re quite valuable).

Lucky for me my car came with a set of original seats with sliders. And I have a set of beat up E30 Recaros to take apart.

From my basic Internet research there is at least one major hurdle to overcome – the E21 floor is uneven thanks to a raised section of raised sheetmetal on the outboard side. There is also an inboard raised section but it’s lower than the outside.

There is a 2″ difference in height between the factory seat rails to level the seat base. The people who have installed E30 seats have cut this sheetmetal section out, then bolted the E30 seat rails to the floor. But I’m not OK with that kind of semi-permanent modification.

Here are the methods I have come up with –

Plan A: install a matching raised section on the inboard side and bolt the E30 seat sliders to each section.

Result: this would make the E30 seat too high. The E30 seat will always sit higher than the E21 because there is a 1.5″ gap between the seat base and the seat rail (the E21 has no gap). I have to keep that in mind with any work I do.

Plan B: bolt the E21 sliders to the E30 seat base.

The E21 slider rails are simply bolted to the metal seat base with small machine screws.

The E30 rails use a combination of large bolts and sheetmetal pins to secure the base to the sliders. The backrest and seat rake adjustments are part of the attachment to the sliders.

Result: the E21 sliders interfere with either the rail for the backrest or the lever for the rake adjustment.

I could install the E21 sliders if I disable one or both seat adjustments. But it will be awkward without them. The goal should be a full install without losing any function.

Also – the width between the E21 seat sliders is 42.5cm (16.75″) and the E30 is 41.7cm (16.4″). So even if the sliders did bolt to the E30 base, they would be too narrow to then fit to the floor.

I really like the idea of using the E21 sliders because they are a direct fit to the floor, solving the biggest problem. So I need to find a way of attaching the E30 seat to the E21 sliders

Plan C: bolt the E21 sliders to the floor as factory, then use a thick steel adapter between the sliders and the E30 seat. If I design the steel plate correctly it will clear the adjusters for the backrest and rake.

Result: TBD

Plan D: use a floor mount (Wedge Engineering or Planted) for a racing seat with the E21 sliders or a set of racing seat sliders. Recaro racing sliders are 16″ wide.

Result: TBD

There’s no deadline for this to work. But I’m determined so check back again for updates.

E30 Recaro Seats in E21

Hazard Switch Blues

The weakest link in the E21 failed on me tonight. A lot of electrical components run through the hazard switch (it has 15 connections on the back). When the switch fails, it’s a brownout for your E21. Luckily I was carrying a spare.

I also have a short somewhere that pops fuse 17 and I don’t know if the failed hazard switch is related to it.

I went to dinner tonight and left the car in reverse when I parked. When I started the car it cranked longer and when it finally started the hazard lights were flashing. My voltage gauge was flickering between 10-14. Now that I think about it, the door buzzer did was not working when I opened the door (run through fuse 17).

With the hazard switch malfunctioning, and fuse 17 blown, I lost the front parking lights, turn signals, instrument cluster lights, digital clock, door buzzer, and interior lights. The headlights and taillights still worked though so I was able to make it home at dusk.

Luckily after reading the frustrations of other E21 owners I bought a cheap replacement switch to carry as a spare. I popped the new switch in and replaced the fuse and all was good. It’s easy to replace the switch from the top. I put the original switch in as a test and the fuse blew again. Problem solved? Was the switch the source of my fuse 17 issue all along?

Hazard Switch Blues

E21 Winter 2016 List

List of things to do this Winter:

Finish garage wall! Can’t do much when I have one of the walls under construction. And I need to plan the layout to allow me to work in the Winter. The original M20B23 engine is on an engine stand and more in the way than I expected. COMPLETE!

Complete the wiring for the M20 swap. It’s all there and connected and everything works. I just have to run the sheath over it and plug the metal connectors into the right places on the fuse box plug and C101 plug. I’m only using 7 pins but there are 20+ connections so I have to get it right the first time. I have a few spare connectors but it still makes me nervous. Then I have to mount the C101 connector on the firewall. COMPLETE!

I also need to connect the VDO oil pressure and oil temp sender. Edit: this is not going to be as simple as screwing it on and plugging in some wires. The owner’s original wiring is incomplete. I’ll have to re-do that too, all the way back to the gauges.

Then install the cowl cover and the engine swap should be 99.9% complete. COMPLETE!

I should set the idle speed to a more normal 750-800 RPM. It’s still up over 1,000 to keep it from stalling, but the O2 sensor seemed to take care of it. I might have to wait for warmer weather to do this though.

The temp gauge only gets to 1/4 on the gauge. I’m running the standard E30 80* thermostat and E21 fan. With a cold temp the DME richens the fuel mixture. I can adjust the fuel map but probably better to have the temp in the right place before I start tuning. First I’ll try removing the fan (done.). If that doesn’t work I’ll install a 88* thermostat. 

Other work on the engine should be: check the bottom end and make sure the rod bolts are tight and there are no spun bearings, and check for any leaks. COMPLETE! Bearings look great. A few small leaks from loose bolts and hose clamps. 

While I am around the subframe I need to replace the tie rod boots because they are ripped (COMPLETE! What a job to get the inner tie rod off!). And finish rust-proofing and painting the frame rails.

On the inside, I have a full Euro non-A/C center console to install. That will mean removing the radio (maybe a new one?) and reinstalling it in the normal horizontal position (COMPLETE! Center console is installed and looks great!). I need to fix or replace the radio antenna. I need to fix a few pieces of the center console before installing it. And I don’t have any hardware for it (COMPLETE! Hardware was sourced from Lowe’s and it looks great). At the same time I need to fix the heater controls because the temp and the vent knobs don’t move. I’m hoping I don’t break anything. And I want to check the hazard light switch because they are a known to be problematic (I bought a backup to have).   

how I want my interior to look

I don’t have the ECU mounted. It’s just dangling on the floor (COMPLETE! Mounted to the firewall. The glovebox closes too. Need to tidy up some other interior pieces and I’ll be ready). I want to try the Ostrich emulator so I can make tuning changes on the fly. And I have to recalibrate the wideband O2 sensor in the Spring (COMPLETE).

Lastly, I need to modify my battery hold-down tray so the Optima battery fits in it. It was supposed to fit but Optima must have changed the case and the battery tray manufacturer didn’t come out with a new one. 


I also installed new hood and trunk BMW emblems (roundels) and new wheel emblems.

Wow that seems like a lot! I’ll probably go down this list in order rather than pick and choose. But it all needs to be done before I can really start driving the car in 2016.

E21 Winter 2016 List