Cliffnotes: This 1988 BMW 325is will be a part of my college Senior Project at Trine University and entered in the $2012 and/or $2013 Challenge.
Ever since reading about the $20xx challenge in Grassroots Motorsports I’ve dreamed about entering the competition myself. And as a mechanical engineering student I am required to do a capstone project my senior year. I decided that I might be able to combine the two; but I needed to do some research/checking first.
First, I determined that I wanted to see the Challenge first hand and see how well it was run and if it would be worth competing in. So my Dad and I drove a little more than 1000 miles from northeast Indiana to Gainesville for the $2011 Challenge. I did little more planning than booking a hotel room nearby, printing off the schedule, and mixing up some trail mix.
My Dad and I showed up early to the track on Friday and offered to work corners at the autocross (best seats in the house). We ended up working the course for almost the entire day. (You might remember me as the tall, blond guy working corner 2 at the end of the first slalom.) We came back on Saturday for the drags that were unfortunately rained out. But I had a great time talking with everyone and looking over the cars. And I learned a lot about what it takes to have a competitive car.
Oh, and I got this cool little crocheted cone from someone on the team that brought the blue Camaro. Sorry, I forget your name, but I love it.
Now that I’d determined that the Challenge was worthwhile, I needed to get the senior project portion approved. After going back and forth with the head of the Mechanical Engineering Department we came up with something that works. The two or three other guys on my team and I would design and build a suspension for a car to compete in the challenge. This will include everything from benchmarking the stock suspension to computer modeling and FEA on prototypes. But there were a few conditions: the car must be rear-wheel drive to begin with, an independent rear suspension is preferred, and no crazy engine swaps because senior year and job hunting is difficult and time consuming enough.
Naturally, I didn’t want to build a suspension for someone else’s race car, so I needed to get my own. I immediately started browsing CraigsList, ebay, and anywhere else I could think of for a car. I wanted something small, lightweight, rear-wheel drive, independent rear suspension, and preferably a manual transmission. And one of my teammates wanted an I-6 engine if possible.
Eventually I came across this BMW. The seller listed it as a 1989 325i that needed work, a water pump, and a noise in the suspension fixed. I show up and look the car over and it turns out to be a 1988 325is automatic that is in pretty good shape, already has lowering springs installed, and comes with a bunch of spare parts. I knew that the car had been overheated some so my Dad helped me check the compression to ensure that major damage hadn’t been done; 120-130psi in all cylinders, yes! Good news.
I ended up buying the car for $500, which fits well into the Challenge budget. We had a little difficulty loading the car on the trailer. It almost stalled a couple of times, and we scraped part of the exhaust off the center of the car. Exhaust had leaks anyways, so no worries.
We got the car home and off the trailer and I started to really look the car over to see what I’d gotten. The body only has a couple of dents; one in each rear quarter panel, one in the trunk, and a repaired keying on the driver’s door. And the only rust on the body is on one of the quarter panel dents and on some rock chips on the hood. The clear coat on the roof, trunk, and hood had burned off like all 3-series from the era. And the passenger side of the front bumper was bent up like it had been in a minor collision. But other than that the body is straight and the trim is in good shape.
All four wheels and tires matched and had like-new tread depth. Car needs a new battery or charging system, but the electric windows and sunroof worked. Gauge cluster and odometer seem to be broken (reads 189,000 miles), so I need to fix those. The car has an aftermarket head unit and speakers that aren’t working at the moment. I’ve discovered a number of non-OEM looking wiring throughout the car, so I’m going to have to dig through that at some point. The hood release handle in the interior is broken and needs fixed. And there is some cheap window tinting on the rear windows that needs to be taken out too.
As far as the driveline goes; the engine needs a water pump and timing belt, there is an oil leak to be discovered, the valves adjusted, and really just a general tune up is needed. The automatic transmission has worked the little that I’ve driven it, but I need to look at the release button on the shifter; it seems to be broken. And I need to find out if I got a limited-slip differential or not. That will come when I get a chance to look under the car (hopefully this weekend).
The suspension still needs to be looked over. But I do know that at least one ball joint in the right front of the car is shot; I hear a nasty CLUNK on hard braking.
As for those spare parts, there are a lot. I think I’ve got a good chance of recouping almost all of the $500 back into the budget -14” euro-weave wheel with new tire -14” bottlecap wheel with new tire (sticker still on it) -a car cover designed to fit the car -spare center console (the part that goes around the shifter) -gasket kit for the bottom end of the engine -air intake/filter box -Mass airflow sensor assembly
Plans for the car: -get it running -get a starting weight and then start it on a weight-loss program -find some way to add power (shooting for 300+ hp) -fix dents and rust, then repaint car -sell spare parts -get some good tires for current wheels or buy some other wheels and get tires for them -Compete in $2012 Challenge -design, test, and build suspension as senior project -maybe modify paint/livery/theme -Compete in $2013 Challenge
As I’m at school and the car is at home an hour away I’ll really only work on the car on weekends and breaks. But I’ll do my best to keep this updated as things progress.
I figured that cleaning the car was a good enough place to start. With my fiancé’s help we emptied the car of everything, vacuumed the interior and the trunk, and wiped down the interior with soapy water. While we cleaned, we discovered nearly $0.70 in change; horary for money back into the budget. When vacuuming the trunk we discovered this mess in the well behind the driver’s side rear tire
I fidgeted with the wire under the seat trying to adjust it correctly and it eventually broke like an old paperclip. So I dug out some wire and made a new one. Works like a charm.
I did have some issues putting the seat back into the car, mainly due to the fact that the brackets are homemade and not particularly well designed (seats are not original to the car). I think I can also lower the seats some too. So I’m adding re-doing the seat brackets to my ever-growing To-Do list.
Timing belt was in great shape. Yes! I was not looking forward to removing the crankshaft pulley bolt. We replaced the water pump with a new one and got everything put back together. The cooling system was even fairly easy to bleed. I also changed the oil and filter while I had the car up on jack stands.
Both lower control arm bushings are shot. I also noticed that a couple of the ball joints had broken boots; they’ll get a check when the bushings get replaced.
With my Dad’s help I got the outer portion old bushing removed from the bracket. We took the cut-off wheel to the inner portion of the old bushing that was still on the control arm:
I checked out the inner ball joint that had a busted boot. I couldn’t detect any play so we packed the joint with a thick grease to help delay any further wear. I’m also considering wrapping the joint in saran wrap to keep the grease in, but I’m a little worried about the plastic melting from engine heat. Opinions? Ball joint (before grease packing):
Then we needed to get the new bushing into the bracket. As it’s a tight fit we put the new bushing in the freezer (I got flak from Mom for that) and held the bracket in front of the propane heater:
After they were suitably hot and cold we used a table vise to slide the bushing in as far as possible and got it the rest of the way with a large piece of metal and a sledgehammer. Worked like a charm. We lubed up the control arm and bushing with some dish soap, slid the bushing on, got it bolted down, and got the car on the ground in rapid time.
I also pulled the instrument cluster to check on the batteries in the SI board. ~3V on both and there was no corrosion on the board, so that’s not what is causing the tachometer and the coolant temp gauge to work intermittently. I’ll start looking for bad grounds next time I get to work on the car.
And I pulled out the odometer to see if I could find out why it was not working. One of the gears was completely stripped; no teeth left. I’ll see if I can get a replacement out of a junkyard for cheap.
This seems to have fixed the temperature gauge, but not the tachometer. So I checked on all of the grounds in the car to ensure that they were tightened down. While doing this I found this mess of wires underneath the rear seat. It seems that this car had some subs in the trunk at one point.
Next, I wanted to get the interior heat working as it gets cold here in northern Indiana. I got the car warm and felt the coolant pipes going into the interior. The pipe going into the heater control valve was warm, but the pipe going out wasn’t. I figured that the valve was faulty, so I drained the coolant and removed the valve. I tested it and it seems to work as it is supposed to. Since I was in there I removed and flushed the heater core.
As nothing seemed to be working incorrectly I put it all back together. I think that the problem is that the coolant system wasn’t completely bled after we replaced the water pump. I didn’t have time to finish bleeding the system, I’ll do that next weekend.
I also found a GRM sticker lying around and decided to put it on the car. And I bought some air fresheners to put in the car to help get rid of the cigarette smell.
Next weekend we need to finish bleeding the cooling system, check over the rear end, change the differential fluid, adjust the parking brake, and run the car through a carwash if we get time.
So that only leaves a clog in the plumbing somewhere that could cause the heat not to work. With my Dad’s help we disconnected the hoses and started putting pressure through parts of the system with compressed air. It flowed through the heater core and valve and the hose from the thermostat, but didn’t flow through this:
It turns out that BMW put a secondary thermostat in the cooling system to block coolant from flowing through the heater core until the engine is warm. Unfortunately this one has stopped working. So we replaced it with a simple T fitting from the parts store and got the cooling system back together. And now the heat works.
Just the other day I stopped by the local truck stop and got the starting weight for the car. This is with all of the street equipment and a full tank of gas and without a driver.
2840lbs. Not bad.
While driving the car I noticed that the throttle was a little sticky of idle when the car was cold. So we took apart the intake to see what we could see. This is what we found:
Lots of goop from the valve cover vent. We cleaned all of that out and the throttle works well now. While we were in there we also bypassed the heated intake (you can see the hoses on the left in the above picture).
We’ll get the rest of the sound deadening next time with the assistance of some dry ice. And we’ll get the rest of the A/C system when the car comes off the road and we can remove the dashboard and bumpers.
Completed:
We only damaged one of the defroster lines; we may try to fix that later.
We got a replacement plug at the parts store to fit the oil pan (M14). Hopefully this fixes the problem.
So let’s open it up and see what’s inside.
Ah, yes, that’s right, I bought a MegaSquirt ECU from someone on the GRM board. Also included in the box was a wiring harness and the assembly guide for the ECU. Seeing as there are a few wiring decisions to be made, I decided to go through the build instructions and ensure that everything was in the correct place. Everything was where it needed to be except for two things. Considering how many components are on this thing, that’s pretty darn good.
After ten minutes with a soldering iron, solder wick, and a pair of pliers the problem is solved.
So it seems that the previous owner(s) had left the ABS broken so long that the warning light actually burned out, nice.
The fusible link was broken. The internet also told me that you could solder a couple of wires across the broken fuse with a 7.5-8 amp fuse inline. So I did just that.
Put it back in the car and the ABS light went out and the ABS worked. But I also noticed that the relay was getting very warm while the car was running. So I took the relay apart again and found that one of my solder joints wasn’t connected well. In the process of fixing it I accidentally unsoldered another joint in the relay. It happened to be one end of the coil wire and proved impossible to fix. Next run to the salvage yard I’ll look for a replacement.
It was a lot of fun, but I was reminded how much I hate automatic transmissions in performance applications. I could bump shift it between 1 and 2, but it still felt slow. Overall impressions: the car has lots of body roll, the nearly new all-season tires aren’t very good (to be expected), the limited slip works well, the engine pulls strong (at least compared to my del Sol), and the seat needs to be lowered and/or the sunroof removed.
