$2012/$2013 Trine University Challenge Build 1988 BMW 325is

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

Yuck. It seems that someone spilt an entire bag of sand into the trunk and most of it ended up here along with the jack and other tire removal tools and a small quantity of water that was nearly frozen. So, out comes the wet/dry shop vac and we got most of it cleaned up. Results of cleaning interior, much better

I’d noticed during the test drive that the driver’s seat didn’t slide forward and back like it should. I unbolted the front seat and set it on the garage floor to see if I could figure out what was wrong with it. It turns out that the wire connecting the release handle on one side to the release on the other was loose and in the wrong location to work properly.

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.

Sweet, another college team!

welcome aboard. see you in gainesville

hit me up if you need any challenge-price-friendly parts. I have a decent stash of stuff (from an early 318i), and am also willing to trade for stuff to keep you in budget. Interested to watch this build, as I'm working on a budget e30 build as well (albeit not quite as low a budget as you are).

Josh

Needs moar 302/T5 even if it is against the rules....

I shagged cones with your dad for most of the afternoon. Good luck with the build, see you again in Gainesville in the fall!

Great to see another university joining. See you at next competition!

Thank you everyone for the warm welcome.

And thanks irish, we may take you up on that later.

Next up on the agenda was to replace the leaky water pump and inspect the timing belt. So this past weekend I did just that with my fiancé’s help. This whole process starts with removing the hood; because while the forward opening hood looks cool, it is right in my way when I’m working on the front of the engine. We had some issues getting the coolant drained. The radiator drain plug was stripped and the block drain was stuck tight; but we eventually got it done. And we had to run to Harbor Freight to get a 32mm wrench to get the mechanical fan off. Other than that everything went pretty smooth and we got down to the water pump and timing belt.

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. Since the car was up in the air, I gave the front suspension a look-over to see if I could find the source of the clunk under braking. Source discovered:

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.

While I was out and about I ran through a couple of the local junkyards to see if they had any BMWs in the yard. I found an ’87 325is and grabbed the hood release handle from it since mine is broken. Walked out to pay for my part and the guy at the counter just waved me away; free part. Nice. But now I need to establish FMV. I’m thinking $1 is reasonable, what do you guys think? Next up is replacing the lower control arm bushings, adjusting the valves, and getting the interior heat to work. Then I should be able to plate the car and drive it around this winter.

Nice job. And yes, hope to see you in Gainesville this fall.

Chocoholic wrote: I found an ’87 325is and grabbed the hood release handle from it since mine is broken. Walked out to pay for my part and the guy at the counter just waved me away; free part. Nice. But now I need to establish FMV. I’m thinking $1 is reasonable, what do you guys think?

FMV is $0.00 for that part. Because it was a public junkyard, we can assume that he would've done that for anyone who approached the counter with only that part. That is the dollar that will change your entire project. You can thank me later, with a beer.

Legit, following the build.

Chocoholic wrote: Next up is replacing the lower control arm bushings, adjusting the valves, and getting the interior heat to work. Then I should be able to plate the car and drive it around this winter.

do the M3 LCA bushings. They dont' cost much more than the regular ones and they add caster and camber.

If you have to replace balljoints on the LCAs, there are Moog pieces available for the application - let me know if you need the part numbers. Cheaper than getting new LCAs by about half.

Welcome to the family.

I went home this weekend to work on the car. I wanted to replace both broken front control arm bushings, adjust the valves, and maybe work in a test drive greater than 5 mph. I started by removing the old control arm bushings as they were well beyond gone. One of these is not like the other:

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. While we were waiting for the dish soap to dry my Dad and I adjusted the valves. While doing this we noticed that there were markings scratched into the rockers to indicate their position (I6, E6, I5, etc.). That combined with the F and R scratched on the 2 pieces of the exhaust manifold, the really good compression (120psi+) on all 6 cylinders, and the timing belt in good shape leads us to believe that this engine has been rebuilt in the recent past. Score!

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. One of my teammates for the senior project portion of this project came over just in time to ride along with me on a test drive around the block. Good news; the transmission shifts great, the new control arm bushings fixed the clunk on braking, and there were no other noises or vibrations. Bad news; the engine still stumbles a bit off idle. I’ll run some injector cleaner through it once I start driving the car and see if that helps. Next up on the agenda is getting the heat to work, checking over the rear end, replace the fluids in the transmission and differential, and getting the windshield wipers to work. Then I can get license plates for it and drive it some.

I got some more work accomplished on the car this past weekend. I started by removing the gauge cluster and checking on a threaded stud behind the temperature gauge. I read online that there is a nut on there that needs to be tight to ensure a proper ground for the gauge. I discovered that I didn’t even have this nut, so I picked one up from the salvage yard and put it on.

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.

While the car was up on jacks to drain the coolant I greased the other ball joint and decided to replace the transmission fluid. I also dropped the pan on the transmission and cleaned it out and replaced the strainer o-ring. Put it all back together and filled it up with new ATF. New fluid may cost me some of the budget, but I’d rather have the peace of mind knowing that the fluid is fresh. I had noticed earlier that when I turned the car off there was this electric motor sound that would happen for about 5 seconds. I had assumed that this was just the fuel pump or something, but I eventually figured out that it was the motor for the motorized antenna (that no longer exists). So I unplugged the motor and the sound disappeared. Problem solved. Also fixed some of the worst rust (on the rear quarter panel) and filled in the open radio antenna hole with gasket sealer for the time being. Because the paint I used has a flat finish it looks like I just slapped some electrical tape over the rust.

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.

In reply to Chocoholic:

Wow you are making some progress Following your build as well good luck

Good luck with the build and the challenge!

I'm in my last semester now and I talked with some department heads to get into a automotive related project too, EcoCar. Its a ton of work but rewarding in the end.

Success!! The car has officially reached daily driver status. The main thing holding it back was that the interior heat was not working. We had already checked the heater control valve and the heater core. Both appeared to be working properly and flowing well. And since the car wasn’t overheating the radiator and thermostat were working fine. But we decided to check the thermostat anyways since it is right there on top. We got it removed and heated it on the stove. It opened right where the book said it should.

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.

We got the rear of the car on jacks so that we could look over the rear end and get the parking brake adjusted. All the suspension bushings looked good and we found that the lowering springs are from Bavarian Autosport and the shocks are Bilstein HDs. Having never adjusted a BMW parking brake before, I wasn’t quite sure which way to turn the adjusting screw to expand the shoes to the drum. And we didn’t know the condition of the pads. So we pulled the rotors off to inspect everything. This went very smoothly; it appears that the last person to work on the brakes put some anti-seize compound on the screw that holds the rotor in place when the wheel is removed. All of the pads looked great so we adjusted the parking brake and put it all back together.

It had just recently snowed so, naturally I had to take the car outside and test the limited-slip differential. It works; I never knew that power oversteer was so much fun .

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. So for the next couple of months I’ll use the car as a daily driver and work out the bugs. Things like the tachometer not working, the coolant temp gauge being glitch, and removing excess wiring. We’ll also start researching ways to add power; likely a turbo or supercharger. And we’ll look into Mega-Squirt as we’ll probably need that to run the forced induction properly.

Spring break was last week so we made some more progress. The button on the shifter was not springing back into place after being depressed. It turns out that the spring is just a block of high density foam. It had just deteriorated over time. We picked up a new one from the salvage yard.

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 decided to start the car on its weight loss program. We removed the carpet (other than the dead pedal), the loose sound deadening, the trunk lock, the motorized radio antenna, the A/C compressor (that thing is heavy), and the easy to remove A/C plumbing. Ensuing pile of E30 parts:

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. We also removed the old window tinting from the back windows. Clear is so much better than purple. In progress:

Completed:

We only damaged one of the defroster lines; we may try to fix that later. While the car was sitting in the garage I noticed that there was oil slowly dripping from the drain plug. I had trouble getting the plug in when we changed the oil due to the heli-coil that one of the previous owners had installed: time to take that out and replace it with something better. What was in there:

We got a replacement plug at the parts store to fit the oil pan (M14). Hopefully this fixes the problem. Most of these are minor items, but I’m using the car as a daily driver. We’ll take the car off the road in early May. In the meantime we are doing research on the rest of the project. Things like MegaSquirt, turbo-charging, roll cages, and the like.

for the tach issue, most gauge cluster problems are a result of the circuit board batteries going dead. They're in a little "pocket" of sorts under the circuit board below the gauges. They're "not replaceable" but plenty of people replace them, you just need to un-solder them and re-solder them in. Check the forums for a write-up.

Is is a motometer or VDO gauge cluster?

EDIT noticed that you already checked that - nevermind!

Also think about deleting the IACV system. It'll only save you a pound, but it will clear out some plumbing and crap from under the hood. One you delete and block off the ends, just set the TB idle screw to open the butterfly a bit (e.g. controlling the idle with the TB rather than the IACV that is finicky). Only issue with this is on cold starts you have to give the car a bit of gas manually via the pedal or it will stall. Once a bit warmed up it will idle fine, at whatever rpm you set. Because the IACV is notorious for causing 2k-3k idle speeds, which really sucks.

Also if you haven't already, look for manual window cranks - replacing the electric windows/motors/relays/controller will get rid of 5lbs or so. I think there's someone on here who has a set of spare manual crank windows (look in my build thread, he posted in there yesterday). The cranks are hard to find (I got mine from Malaysia), but you could just improv something pretty easily/free.

also check that hose comign into the TB on the left side of your "gunk" pic. I think that's the coolant line, and it looks to be cracked/brittle. i would replace!

In reply to irish44j: Thanks for the tips. It's good to know that the IACV can be removed easily. And that cracked hose is just the air vent hose from the valve cover. So I'm not too worried about it being cracked.

This makes me wish I would have gone with an e30 instead of my e36 for just a general dd/autox project lol.Great progress! Ill be following from now on.

Update time. I got this strange package in the mail. I’m sure I didn’t order mail-order waffles.

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. These two transistors were in the correct places, but they were put in backwards. The curve of the narrow sides is supposed to follow the silkscreened curve on the PCB.

After ten minutes with a soldering iron, solder wick, and a pair of pliers the problem is solved. 

While driving the car I noticed that the ABS warning light wasn’t coming on when it should (while starting the car) and the ABS wasn’t working. So I pulled the gauge cluster and replaced the bulb. Wouldn’t you know it, ABS light comes on and stays on.

So it seems that the previous owner(s) had left the ABS broken so long that the warning light actually burned out, nice. I did a couple of hours of research on the internet for why the ABS wasn’t working. It turns out that there is a fusible link in the ABS relay under the dashboard breaks after someone jump starts the car backwards. I pulled the relay apart and found this:

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. Yesterday was the first autocross of the season in my region so naturally I had to go.

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. In two weeks the car gets its daily-driver privileges revoked and we can finally really start digging into it. I can’t wait.