Re: Vorshlag BMW E46 - Daily Driven Track Car Project
continued from above
I had a "evaluation ride" by one of the Instructors that runs with TDE a lot on Sunday to see if I "have what it takes" to run in the red group and possibly be an instructor with this HPDE organization. He had read the build thread for this car so he was excited to ride along - even if we didn't have harnesses in the car yet (they were installed shortly after).
I hadn't run the 3.1 mile configuration at MSR-Cresson since 2013 so I was a bit rusty, but managed to run some quick-ish times (2:33.593) in two of my three sessions. The weather was beautiful and we had fun - but the lack of competitive element always leaves me... wanting. Amy had a blast and finally drove the 330 for an entire day. She got more comfortable in this car than ever before, and really liked the brakes, handling and grip. By my last session Sunday the tires were really falling off and I was slowing down. It was time for a new set of Hoosiers...
4-POINT ROLL BAR FABRICATION
After the TDE event the next track on the schedule was TWS with NASA, and I was determined to not run at this track again without a roll bar and real harnesses. This track has a tendency to "eat cars" - each year it seems there are more cars damaged at TWS than at all other road courses in the state of Texas combined.
Making the decision to build this welded in roll bar involved some internal debate over which of these 3 "rollover protection" options we should use for this car:
1. Buy a pre-made 4-point roll bar and fit it, weld it together, and bolt it in
2. Build a custom 4-point roll bar and weld it into the car
3. Build a full 6-point roll cage that is welded into the car.
Option 1 wasn't really exciting to me as these bolt-in roll bar kits tend to be made to fit around interior bits (headliner, full interior panels, back seat) which we no longer have in this car. Plus I had done this in the blue 330 before. The compromises of building around the interior keeps the tubing 2-3+ inches below the roofline in a semi-gutted car like ours. The rear downbar mounts (below right) are also "less than ideal" and not fitted well. I get why they do that, but its just a compromise.
Bolt-in 4-point roll bar kit fitted, welded together, and bolted into our blue E46 330
Option 2 - a custom, welded 4-point roll bar - would fit better than Option 1, but the time it would take was a bit of an unknown. Why? We don't do this type of "half cage" deal often.
Option 3 - a full roll cage - didn't fit this car's "daily driven track car" goals, as its almost impossible to make a "safe" roll cage that isn't dangerous on the street. Hitting your head on an upper cage/door bar without a helmet on is risky. We can sometimes pull this off with shorter drivers or larger cars, but for me, in this car... wasn't going to ever be safe. We also know a full cage would eat up 60 hours of "lost billable hours" + $800 in materials, so that's pretty expensive even for a shop owner (we always have a waiting list of customer fab work we can do). So we went with option 2.
I was still worried about the amount of time a custom 4-point it would eat up, so I kept a close eye on that. And in the end it took about 1/3rd the time (a hair over 20 hours) to completely fabricate and weld in this custom roll bar. Pleasantly surprised, and with the hours and materials added up compared to the cost of a typical 4-point bolt-in bar + install, it comes to about the same price. Due to that realization we are going to do this type of custom 4-point more often rather than the 4-point bolt ins, with fewer compromises.
The rear carpet section was removed and the floor was cleaned where the steel mounting plates would be welded in. Leaving the factory shoulder belt anchors in the B-pillar was a point of contention, but I wanted to keep the OEM 3-point belts functional for a while longer - in case this car was still street driven (turns out that was a good idea). This kept the main hoop from touching the metal B-pillar structure, so the rear interior panels were also left in place - for now. Using a template from previous E46 cages, Ryan bent up a slightly narrower main hoop out with 1.75" dia x .095" wall DOM tubing. The tubing still fits very tight to the roof - inches closer than the bolt-in rollbar kits made for this chassis.
Like I pointed out above, one of the main drawbacks from the pre-made roll bar kits is where they mount the rear downbars to the chassis - at the rear sheet metal inner wheel wells, which aren't the strongest location on the E46. I asked Ryan to mount these diagonals to plates welded on top of the formed rear frame rails instead. This might cause some controversy, but its something that makes the most sense to us. Some folks fixate on mounting these rear downbars to the shock towers, or tying into or rear subframe mounts, but we don't feel that either location is ideal for a majority of the roll cage equipped BMWs out there, nor this car. We don't ever plan to use a "coilover rear shock", nor do we see rear subframes ripping out of BMWs when large chassis reinforcement plates are welded in properly.
Ryan wanted to zip some welds along the cross bar at the base of the main hoop (which are never on bolt-in cages), as they fit tight to the tub here. But no, that wouldn't be TTD legal. If we go to TT1/2/3/4 with this car, however, it might get some additional tie-ins to the chassis at this location and the B-pillar. If we want to turn this roll bar into a roll cage it would require cutting out the body mounts or removing the roof - and the latter is preferred (swapping to a carbon roof in an E46 isn't as hard as I once thought).
A single diagonal was added into the plane of the main hoop and another diagonal was added from the same junction between the two rear downbars. Two horizontal bars were also added - one at the base of the main hoop and one between the two rear downbars - which are above and beyond a normal bolt-in 4-point roll bar. Everything was TIG welded together other than the plates to the chassis, which were MIG welded to the tub. Much more substantial, and better fitting, than most bolt-in 4-point roll bar kits can offer.
Once Ryan had finished the fab work, Brad used ScotchBrite on the entire cage and then cleaned it up for paint. Using paper around everything left on the interior he applied two coats of VHT "Roll Bar & Chassis Paint" in semi-flat black.
With the paint drying overnight we could remove the tape and paper and had a pretty damn good looking, custom fitted roll bar. We had test fit seats into the car before the harness bar was added, and even with the seat slid back for me there was no need to "kick" the harness bar back behind the plane of the main hoop.
With the roll bar completed Aaron installed the Schroth Profi-II 6-point harnesses into the lap belt (reinforced at floor) and anti-sub (anchored at seat bracket). Then the seats went in and everything was adjusted to fit.
Hours before we were going to load up the car to go to TWS, the sticker set of Hoosier R7s arrived and were mounted up on our lone set of 17x10" wheels. I'm worried about only having one set of race wheels - which is just asking for trouble - but with a multi-month backlog for existing orders, we will look at other options. There is a plan in place for "the next two sets" of race wheels, which I will talk about in a future post. These 17x10's will become the practice/street set then.
Right: Corner weight shown with driver and fuel level as shown.
I blew the dust from fabrication out of the interior, Aaron vacuumed the remaining bits of carpet (in front of the front seats), and Brad washed the exterior before the 330 was loaded into the trailer Friday before the TWS event in April. The rear carpet section would need extensive trimming to fit around the main hoop and lower cross bar so it was left out. The curtain airbags were also removed, as they would be routed over the main hoop at the roof line, possibly making them dangerous if they were deployed in an accident. We weighed the car and the roll bar added about 50 pounds, so two 25 pound plates of ballast were removed (we also had a full tank of fuel in the car).
The car is looking better, except for the ratty bumper cover, hammer clearanced rear fenders, and tires touching at all four corners. Gotta work on flares next - but the ones we ordered showed up for the wrong car, so we didn't get them on before TWS. I will show that work soon...
NASA at TWS, APRIL 22-23, 2017
With the fresh set of sticker tires, newly added roll bar + harnesses, and a bit more power than when we ran at TWS last October we towed down to College Station on the Friday before the NASA race weekend to unload the trailer. We parked "on the beach" once again and grabbed some dinner at one of the wide variety of local restaurants, then we went to crash at our friend's. the Costas', where I helped wrench on his GT1 Camaro a little. We started with the #JankyStick to point out the less than perfect things on this car.
Which didn't matter - it still set the fastest lap time for the event that weekend, running in TTU. Paul Costas is an old racer buddy who has co-driven together with me in autocrosses and track cars for nearly three decades. He set the fastest lap time in our TTD E46 last October, finding two tenths where I wasn't looking for time at all. Thousands of laps and hundreds of wins at TWS can do that for ya. He's also an excellent "Setup Coach" and if I had the time and money I suspect he'd help us find more time in this car using his data logging skills, real time tire temp array, and driving tips.
continued below
continued from above
I had a "evaluation ride" by one of the Instructors that runs with TDE a lot on Sunday to see if I "have what it takes" to run in the red group and possibly be an instructor with this HPDE organization. He had read the build thread for this car so he was excited to ride along - even if we didn't have harnesses in the car yet (they were installed shortly after).
I hadn't run the 3.1 mile configuration at MSR-Cresson since 2013 so I was a bit rusty, but managed to run some quick-ish times (2:33.593) in two of my three sessions. The weather was beautiful and we had fun - but the lack of competitive element always leaves me... wanting. Amy had a blast and finally drove the 330 for an entire day. She got more comfortable in this car than ever before, and really liked the brakes, handling and grip. By my last session Sunday the tires were really falling off and I was slowing down. It was time for a new set of Hoosiers...
4-POINT ROLL BAR FABRICATION
After the TDE event the next track on the schedule was TWS with NASA, and I was determined to not run at this track again without a roll bar and real harnesses. This track has a tendency to "eat cars" - each year it seems there are more cars damaged at TWS than at all other road courses in the state of Texas combined.
Making the decision to build this welded in roll bar involved some internal debate over which of these 3 "rollover protection" options we should use for this car:
1. Buy a pre-made 4-point roll bar and fit it, weld it together, and bolt it in
2. Build a custom 4-point roll bar and weld it into the car
3. Build a full 6-point roll cage that is welded into the car.
Option 1 wasn't really exciting to me as these bolt-in roll bar kits tend to be made to fit around interior bits (headliner, full interior panels, back seat) which we no longer have in this car. Plus I had done this in the blue 330 before. The compromises of building around the interior keeps the tubing 2-3+ inches below the roofline in a semi-gutted car like ours. The rear downbar mounts (below right) are also "less than ideal" and not fitted well. I get why they do that, but its just a compromise.
Bolt-in 4-point roll bar kit fitted, welded together, and bolted into our blue E46 330
Option 2 - a custom, welded 4-point roll bar - would fit better than Option 1, but the time it would take was a bit of an unknown. Why? We don't do this type of "half cage" deal often.
Option 3 - a full roll cage - didn't fit this car's "daily driven track car" goals, as its almost impossible to make a "safe" roll cage that isn't dangerous on the street. Hitting your head on an upper cage/door bar without a helmet on is risky. We can sometimes pull this off with shorter drivers or larger cars, but for me, in this car... wasn't going to ever be safe. We also know a full cage would eat up 60 hours of "lost billable hours" + $800 in materials, so that's pretty expensive even for a shop owner (we always have a waiting list of customer fab work we can do). So we went with option 2.
I was still worried about the amount of time a custom 4-point it would eat up, so I kept a close eye on that. And in the end it took about 1/3rd the time (a hair over 20 hours) to completely fabricate and weld in this custom roll bar. Pleasantly surprised, and with the hours and materials added up compared to the cost of a typical 4-point bolt-in bar + install, it comes to about the same price. Due to that realization we are going to do this type of custom 4-point more often rather than the 4-point bolt ins, with fewer compromises.
The rear carpet section was removed and the floor was cleaned where the steel mounting plates would be welded in. Leaving the factory shoulder belt anchors in the B-pillar was a point of contention, but I wanted to keep the OEM 3-point belts functional for a while longer - in case this car was still street driven (turns out that was a good idea). This kept the main hoop from touching the metal B-pillar structure, so the rear interior panels were also left in place - for now. Using a template from previous E46 cages, Ryan bent up a slightly narrower main hoop out with 1.75" dia x .095" wall DOM tubing. The tubing still fits very tight to the roof - inches closer than the bolt-in rollbar kits made for this chassis.
Like I pointed out above, one of the main drawbacks from the pre-made roll bar kits is where they mount the rear downbars to the chassis - at the rear sheet metal inner wheel wells, which aren't the strongest location on the E46. I asked Ryan to mount these diagonals to plates welded on top of the formed rear frame rails instead. This might cause some controversy, but its something that makes the most sense to us. Some folks fixate on mounting these rear downbars to the shock towers, or tying into or rear subframe mounts, but we don't feel that either location is ideal for a majority of the roll cage equipped BMWs out there, nor this car. We don't ever plan to use a "coilover rear shock", nor do we see rear subframes ripping out of BMWs when large chassis reinforcement plates are welded in properly.
Ryan wanted to zip some welds along the cross bar at the base of the main hoop (which are never on bolt-in cages), as they fit tight to the tub here. But no, that wouldn't be TTD legal. If we go to TT1/2/3/4 with this car, however, it might get some additional tie-ins to the chassis at this location and the B-pillar. If we want to turn this roll bar into a roll cage it would require cutting out the body mounts or removing the roof - and the latter is preferred (swapping to a carbon roof in an E46 isn't as hard as I once thought).
A single diagonal was added into the plane of the main hoop and another diagonal was added from the same junction between the two rear downbars. Two horizontal bars were also added - one at the base of the main hoop and one between the two rear downbars - which are above and beyond a normal bolt-in 4-point roll bar. Everything was TIG welded together other than the plates to the chassis, which were MIG welded to the tub. Much more substantial, and better fitting, than most bolt-in 4-point roll bar kits can offer.
Once Ryan had finished the fab work, Brad used ScotchBrite on the entire cage and then cleaned it up for paint. Using paper around everything left on the interior he applied two coats of VHT "Roll Bar & Chassis Paint" in semi-flat black.
With the paint drying overnight we could remove the tape and paper and had a pretty damn good looking, custom fitted roll bar. We had test fit seats into the car before the harness bar was added, and even with the seat slid back for me there was no need to "kick" the harness bar back behind the plane of the main hoop.
With the roll bar completed Aaron installed the Schroth Profi-II 6-point harnesses into the lap belt (reinforced at floor) and anti-sub (anchored at seat bracket). Then the seats went in and everything was adjusted to fit.
Hours before we were going to load up the car to go to TWS, the sticker set of Hoosier R7s arrived and were mounted up on our lone set of 17x10" wheels. I'm worried about only having one set of race wheels - which is just asking for trouble - but with a multi-month backlog for existing orders, we will look at other options. There is a plan in place for "the next two sets" of race wheels, which I will talk about in a future post. These 17x10's will become the practice/street set then.
Right: Corner weight shown with driver and fuel level as shown.
I blew the dust from fabrication out of the interior, Aaron vacuumed the remaining bits of carpet (in front of the front seats), and Brad washed the exterior before the 330 was loaded into the trailer Friday before the TWS event in April. The rear carpet section would need extensive trimming to fit around the main hoop and lower cross bar so it was left out. The curtain airbags were also removed, as they would be routed over the main hoop at the roof line, possibly making them dangerous if they were deployed in an accident. We weighed the car and the roll bar added about 50 pounds, so two 25 pound plates of ballast were removed (we also had a full tank of fuel in the car).
The car is looking better, except for the ratty bumper cover, hammer clearanced rear fenders, and tires touching at all four corners. Gotta work on flares next - but the ones we ordered showed up for the wrong car, so we didn't get them on before TWS. I will show that work soon...
NASA at TWS, APRIL 22-23, 2017
With the fresh set of sticker tires, newly added roll bar + harnesses, and a bit more power than when we ran at TWS last October we towed down to College Station on the Friday before the NASA race weekend to unload the trailer. We parked "on the beach" once again and grabbed some dinner at one of the wide variety of local restaurants, then we went to crash at our friend's. the Costas', where I helped wrench on his GT1 Camaro a little. We started with the #JankyStick to point out the less than perfect things on this car.
Which didn't matter - it still set the fastest lap time for the event that weekend, running in TTU. Paul Costas is an old racer buddy who has co-driven together with me in autocrosses and track cars for nearly three decades. He set the fastest lap time in our TTD E46 last October, finding two tenths where I wasn't looking for time at all. Thousands of laps and hundreds of wins at TWS can do that for ya. He's also an excellent "Setup Coach" and if I had the time and money I suspect he'd help us find more time in this car using his data logging skills, real time tire temp array, and driving tips.
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