Picked up an E30 roller chassis on my birthday as my next project now that I'm done racing for a while. Chassis is an 1987 325e with 114,000 on the clock. It seems pretty clean all around, doors, fenders, and trunk area is rust free. PO parked it and stole the drive train for another car after hitting a raccoon or something. That's why the front end is missing and the rear aftermarket bumper is cracked.
Plan is to put my Chump Chevette drivetrain in it, a 4G63 converted to rear wheel drive using a world class T5 from a Mustang, and drive it on the street as a fun weekend car. I hope to test fit the motor soon and see how many problems I'll have to solve on this swap. It'll be a different build mindset for me as well as I've never done a weekend car before. Previously it's either been DD builds or full track car builds.
Finished up the motor mounts last night. Happy with how the motor is sitting but I may have to shim up the driver side as the pan is a little closer to the rack than I prefer. It'll knock the motor off level but that's not super critical. Next hurdle is the trans mount and I'm not quite sure how I'll make that yet. The BMW mount is quite a ways rearward of the T5 rubber mount. I may use the mount on the tail shaft but am not sure how I will retain a rubber mount yet.
Completed the transmission mount tonight. There were some weird angles on the crossmember but I used a piece of angle iron bolted with suspension bushings from Oriellys on the cross member and then welded square tubing to that. That allowed me to offset the angle and get the square tubing perpendicular to the ground. The transmission side was also angle iron bolted to a boss on the tail shaft. It's not ideal but it gets the job done and should provide the needed flex to keep the steering wheel from shaking like crazy.
Started mocking up the engine bay to see where things will fit and what needs to change. The downpipe is too close to the firewall near the transmission, it doesn't quite touch the heat shield on the insulation but it's too close. It also runs too close to the floor where it ends. I cobbled the downpipe together at 2am with scrap tubing for the racecar, so I've been meaning to make a new downpipe for a while. The intake also needs to be adjusted but the pipe that's on there has been cut apart multiple times so I will also need to start fresh there. I plan on running the air filter behind the headlights but want to hook up the oil cooler to check how fits with everything.
I took some time to prep the interior for cutting the new shifter hole location on the tunnel. I removed the center console and removed the carpet in the approximate location for the T5 shifter. I also traced the shifter mount under the car to give myself a template for cutting. Luckily I'm running a short shifter, it will be close but it should clear the dash when shifting into third.
Cut a new hole in the tunnel and clearanced the console for the T5 shifter. My hand doesn't hit the dash in 1, 3, or 5. Now I just need to figure out a shift boot, shifter knob, and what to do with the patch panel over the stock shifter hole.
Stripped the Chevette of the parts I want to use on the BMW. I'm doubtful I'll run the surge tank as I don't want to deal with the routing for it and the low pressure pump is on its way out. I'll run the rest of the -6 lines from the tank to the rail though. Brakes are Corrado rotors with a Wilwood Dynalite calipers, they should come in handy to slow things down after I get into the boost.
The best and worst part of building a car, doing the research. Figured out what I need for my front brake lines and the fitting for the clutch master line. Pegasus racing has everything required at the best price and I don't even need to make any AN lines. I have a pretty good system down for AN but the hose with a lining is still not my favorite.
Worked on making the main exhaust for the downpipe today. 2.5" tubing, nothing too crazy but the smaller size helps with clearance underneath and my power goals are minimal. It seems like it follows the contours of the chassis and transmission well. I'm pretty happy with it aside from finish welding it right before a guy offered to tig it together for me. Nobody will really see the crappy welds but I'll know they're there and could have been better.
Intake manifold arrived today. It seems like a pretty good value for $250, the flange in pretty thick and the welds look decent. The "velocity stacks" made me chuckle at how pitiful they are, luckily I'm not super concerned about airflow. Now I just need to cut it in half and have it welded back up.
Ran into the first problem with this janky ebay intake manifold, the throttle body doesn't clear the plenum. If you mount it upside down though, it does clear except for the throttle cable linkage. I will be running it that way, so I did dodge a bullet there but I'm curious how many other issues will show up.
Worked on the car for a couple hours today, sadly it was mostly pointless and I didn't make much progress. I tried modifying the fuel pump hanger for a Walbro 255 I had left over from the Galant but that wasn't possible. I tried a couple configurations but couldn't find a workable solution that would fit into the gas tank. Lost a couple hours on that and ended up just putting the old BMW pump back in, I'll just mount a 255 inline and draw through the stock pump.
I did cut the intake pipe and get the MAF mounted. Not very exciting but it is a little progress.
Removed the factory fuel pump and test fit the high flow one from the Chevette. I'll have to mount a plate to the factory fuel pump mount but I should be able to use the factory feed line and wiring pigtail. Good news is that a 90° off of the fuel pump should work fine going to the fuel rail.
Finalized the fuel pump mount after removing the oem rubber mounts and bolting in an aluminum plate. The location is close enough to utilize the factory wiring as well, so the wiring is nice and tidy with a grommeted pass through in the floor. I did screw up the preparation for the fuel pump rewire by not thinking things through and cutting both the power and ground in the body harness. I only needed to cut the power wire to tie into the relay. Not a terrible mistake but the final result won't be as clean as it could have been. I also ran the -6AN feed line into the engine bay to prep for the fuel pressure regulator installation.
After an Alaskan vacation sidetracked my progress I was able to get back at it and work on the intake manifold. I had an old racing buddy shorten up the runners by one inch and rotate the plenum 180°. Today, I clearanced the plenum for the brake master cylinder and vacuum booster. I didn't have to take much out, which I was happy with as I was concerned with starving cylinder 4. I'll have it finish welded and then figure out the cold side piping as the throttle body elbow dumps out pretty near the radiator.
Bent up some steel tubing last night so I could plumb the engine into the heater core. I deleted all the heater core stuff on the racecar, so I'm having to add it back in for the BMW. I should be able to find a heater hose at the parts store to cut apart and complete the connections with the correct bends.
Got my 11" rotors back from a machinist friend, had to open up the hub bore 1mm to fit. I also ordered all of the -3an lines and necessary adapters from Pegasus racing to fit the wilwood calipers. Only thing left is to get bar stock for the caliper mounting bracket and I can get the front brake upgrade sorted.
Made a caliper bracket for one side of the car using 1/4" plate last night. The caliper lined up really nicely with the caliper carrier mounts on the strut so I didn't have to step the plate at all, just kept it flat and drilled some holes. I had to drill out the holes on the chassis to pass through the bolt I wanted to use but aside from that it was pretty straight forward. I also taped two washers under the caliper with the orange duct tape to ensure radial clearance to the rotor. Aside from that it was just spending time with a sawzall, bench grinder, and the drill press. Wheel in the final picture is 17x7. Only thing left to do is remove the excess on the bracket and smooth out any rough edges.
After a sad realization that I won't be driving this car before the snow flies, I haven't worked on the BMW in a while. I got back to it today and pulled the motor so that I could paint up the engine mounts, install the power steering delete block, and clearance the core support for the intercooler piping.
I tried cutting the passenger side of the core support with the motor in the car and basically made a mess of things. Once I had space to work without the motor in the way, things went much more smoothly. I don't think the 2G throttle body elbow will work with my setup though, it dumps right into the radiator fan. I think the best thing to do will be to make a TB flange out of mild steel plate and then I can weld piping to whatever angle I need as the cold side piping is so short.
Made up a throttle body flange which will make the cold side intercooler piping easier to route. I can weld the piping directly to the plate at the exact angle I need, which is crucial since the distance between the intercooler and throttle body is so short.
Got started on the intercooler piping tonight. I was extremely happy with how the cold side turned out, the angles didn't work out as well as I had planned on the hot side. I said fuck it and ground down the welds to make things look a bit better, I don't normally do that but it bugged me on the piping. I'm undecided on running a hump hose on the hot side, I'm not sure if I need them on both sides? I also still need to plumb the bov in yet, I need to mount up the intake piping and see where it makes the most sense to put it.
Made a cover up panel for the oem shifter location and a spot for the new shifter boot to mount to. I'll have to remake it, but I wanted to rough out my ideas to see if the end result worked. It doesn't fit the coin tray as snug as I wanted, the bends aren't exactly where I need them, and I misjudged the shifter location by 3/8", all easily remedied on the next one.
This turned into a huge information dump, so it's really wordy.
I didn't do anything too exciting to the car this week, it was all finishing up little things on the car. I installed the clutch slave, bent the hard line to clear the motor mount, and bled the air from the system. I also installed the final fitting I omitted from the original order for the front brake and then bled the front calipers. The pedal feel was good, I was unsure how the master cylinder would react to the different calipers so I'm happy that turned out well. I also remade the shifter patch panel but left it in primer until I decide whether to put a gauge or a push button start in the center. That decision hinges upon me figuring out why the starter signal wire is showing 12 volts in both the start and run key positions. I found a heater hose at the parts store that had the bends I needed for both hoses once I cut it in the right spot. Intercooler piping got painted but I screwed up on that one by primering the hot side pipe before installing the blow off valve flange, whoops. The fuel pump hanger got reinstalled and I got the wiring for the inline Walbro 255 run into the trunk where I'll put a relay wired up to the battery.
I made up an ecu mount today. I was unable to fit the ecu plugs through the hole in the firewall so I couldn't mount the ecu above the glovebox like I had originally planned. This spot by the power distribution block was the next best thing so I made up a mount to bolt it in place. Welding it was a pain in the butt because I couldn't do it with the ecu in place for fear of damaging it with the welding current, so it had to mark where I wanted to bolts really well then tack it and then check the fitment.
It's been a while since the last update but I've been slowly working on getting the wiring sorted on the car, which isn't very photogenic. I did start getting the wiring harmess laid out in the engine bay, which is a bit of a milestone worth documenting. I'm pretty happy with how the intake side turned out. I orginally laid everything on top of the manifold but no matter how I positioned it I wasn't happy. It took me a bit to realize that I was no longer required to use the factory routing and could run the harness under the intake with the aftermarket manifold. I think it looks much cleaner and turned out nicely. The ecu area needs to have a few final wires for the dash gauges wired up, run the fuel pump signal wire, and then cover it all in loom.
The next hurdles are to figure out where the igniter and coil pack go but I think that will be greatly simplified by just making new brackets for those.
Started work on the water pipe connecting the thermostat housing and radiator. I reused the 180 degree bend from the Chevette but everything else was new metal. It was a big ordeal to wiggle the finished pipe so I wanted to rethink how the support worked on the radiator side of the pipe. I needed something low profile and able to clear the radiator hose, I ended up going with a slip fit tube that bolts to an unused mount on the motor.
Finding all of the required fittings and dealing with the BSPT threads on the Mitsubishi motor has been a bit of a hassle. The intake manifold also has small vacuum ports which made plumbing the vacuum booster for the brakes suck and left me with a less than ideal solution. It should be sufficient for this build but it is by far the jankiest think I've put on this car yet.
Finally, here's how the engine bay is sitting as of today.
Mounted up the fuel pressure regulator this afternoon. I bent up a piece of flat stock aluminum then ran the fuel and vacuum lines after drilling it to bolt up to the intake manifold. The oil cooler was mounted in a similar manner to the core support but due to the lack of clearance between the intercooler and radiator I put cushioning on the oil cooler.
Next steps are to run the -10 lines for the oil cooler and keep making progress on the gauges. I need mounting solutions for the water, oil, and boost gauges, I'm thinking it'll be a dash plate in the radio spot. I'll have to drill and tap the lower thermostat housing for the mechanical water temp sender. I'm also going to convert the boost gauge to runner vacuum line instead of that awful plastic line.
Tied up a few loose ends today that completed work on a few sections of the car. The O2 sensor got mounted in the downpipe which finalizes the work on that, the rest of the exhaust will get run once I get the driveshaft in the car.
After that I drilled and tapped the lower thermostat housing for the water temp sender. I didn't get a picture of it after I cleaned the metal shavings and grime off but it cleaned up well. Once that was mounted on the motor I installed the radiator hoses for what should be the last time. The only thing left after that is to run an overflow tank.
Lastly, I test fit the gauges in the radio spot. Sadly the shifter relocation is where a lot of people run gauges in this chassis so I had to put them elsewhere and I figured the radio is the next best spot. If I get tired of listening to turbo noises I'll just get earbuds for my phone or something. My current plans are to run boost/ vacuum, oil pressure, and water temp in the panel. The panel in the picture is just a crappy parts store one cut to fit, I'll make an entirely new one now that I know the gauges work well there.
Had a frustrating night out in the race shop tonight. I installed the used JM Fab coil relocation bracket I picked up. Due to me running my water pipe under the intake it interfered with where it would put the coil packs so I had to use a BFH to bend it to a position that would clear the water pipe. This worked out fine until I went to run the spark plug wires and only 3 reached the coils. I like how simply it mounted the coil and igniter so I'm going to find longer wires from a used set.
Once I got that installed I moved on to priming the fuel pump system now that it's all plumbed in. I tried priming it a couple weeks ago to no avail, I tried troubleshooting it by hooking it up directly to a fuel hug and running power directly to it but it wouldn't pump anything. I figured running it in the endurance race car for a couple years had killed it through vibration so I ordered up a new replacement. After I put the new pump in it wouldn't prime either, so I got exasperated and hooked the "bad pump" up to a battery and stuck an end in a fuel jug. Now that I was able to see the correct electrical connectors on the pump, lo and behold it pumped gas just fine. I feel dumb now but at least the pump won't need replacing for the foreseeable future.
I also bought some new gauges and a transmission yoke with the fuel pump and coil bracket. Those will get installed after making a new gauge panel to fit in the radio spot on the dash. I also painted the shifter cover up panel and drilled the holes to mount the shifter boot. I'll install that after I wire in the back up lights to the transmission sender.
After fixing the wiring mistake on the fuel pump I pressure tested the system and was happy to see there were no leaks. I also set the base fuel pressure to 37psi with the regulator.
I also started making the gauge panel insert for the radio spot in the dash, I got it shaped to fit and the next step is to cut the gauge holes. I'll be using that crappy parts store gauge panel I test fit previously as a pattern for the gauge holes.
Finished up the gauges today. I used a smaller than needed hole saw to ditch most of the material to be removed, then used a die grinder to get close and finalized the size with a hand file. The weird part was that each gauge was slightly different in diameter, so I had to plan out where I wanted the gauges then fit each one to its respective position. Once they were all in the panel and secured with the backing retainers I tried fitting it in the dash but the plastic retainers wouldn't clear the dash inset. I ended up clipping out the interfering sections and didn't lose any retention to the panel so thought it was a decent compromise. After that I painted the panel and routed the required hoses for each gauge. I also ran the wiring for the gauge illumination, I researched a bit, found a wire for dimmable power but after hooking it up the gauges didn't dim. That was frustrating. I'll put a dab of black rtv on each corner of the panel and that combined with the tight pressure fit in the dash surround should hold it securely.
It had a bit of idle surge as I didn't have the cold side piping tightened down as I'm taking off the throttle body soon to get a throttle cable made up. It smoked from burning off the oil on the manifold but I was happy with how it ran otherwise. The radiator pressurized and nothing leaked, so that was good to see. Still lots of work ahead but happy to have hit this milestone.
Finished up the throttle cable today. I ended up finding a universal throttle cable on Amazon for $20, I ditched the cable ends but the rest of the cable and firewall clip made things easy to install. I fabbed up a bracket that mounts to the fuel rail that allowed the cable to maintain a straight path to the throttle body with no binding. The only tricky part was making the cable ends, I got a kit of ends from Orielly for $3. I narrowed one to fit the throttle body and enlarged the hole for the cable, adding a set screw to hold the cable finished that side of the cable. The gas pedal side was a bit trickier and I ended up reusing the oem bmw connector by splicing it to the new cable.
I also received the driveshaft I ordered from Coleman Racing. All that's left to get it moving under its own power is to put the trans yoke and diff flange on the driveshaft, then install it. I think I'll have to clearance the rear shifter mount on the chassis for the 2-1/2" driveshaft, which sucks as I had hoped to avoid any permanent changes to the body.
I haven't updated this in a while because installing the driveshaft kicked my ass. I had quite a few issues to overcome but I did manage to get the car mobile. I drove it a couple hundred yards in its maiden voyage, it did move but it also revealed a few problems that need to be solved.
The first issue I had was the fact that I used a one piece driveshaft instead of the two piece that BMW uses. The subframe actually encircles the front of the diff and the shaft goes through a hole in the front. This isn't an issue when you can telescope the driveshaft but things become more complicated with a solid tube. With the driveshaft yoke fully inserted in the transmission I went to swing the rear flange to the diff and noticed I was a dummy.
The easy solution was to drop the diff from the subframe while leaving the axles attached. That way the diff could move back far enough to get the driveshaft into the subframe then move the driveshaft forward once the yoke was in the transmission. Only I couldn't insert the yoke because the rear support mount for the shifter was hitting the driveshaft. I tried to avoid any permanent changes to the chassis and had succeeded up to this point but this was unavoidable. Once the driveshaft and diff were bolted back in place I noticed I was having a very slight clearance issue with the shaft on the gas tank. It was only rubbing but I wanted to get at least a 1/4" of space to allow for deflection in the rear subframe and motor mounts. The gas tank couldn't be beaten out of the way with a hammer or removed like the shifter mount so I ended up making 1cm shims out of steel tubing to get the required clearance.
Once those were installed, everything spun freely so I dropped the car down and fired it up. The clutch isn't fully disengaging so I ended up starting the car in gear to test drive it, so I'll have to dig into a way to remedy that. It does move now though so all the issues that need addressing are outweighed by my excitement to being closer to driving the car on the road.
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