72 Club Racer Resto and Modernization

bdigel

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A few years ago I acquired Harold Audaer's 72 Bavaria that he club raced with BMW CCA CR , This car was log book # 20 and took 2ed over all in BMW CCA CRs 1st two club races . Harold had parked the car decades ago where it sat untill his retirement , and when he sold his shop reached out to me to see if I would be interested in taking it from him . Knowing the cars history and Harold being an important mentor of mine I jumped on the opportunity . Chances are if you were involved in driving events with BMW in the south east you are familiar with the car . I plan on restoring it and updating a few things to make it legal to run with currant clubs Pictured here sometime in the 90s
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pictured below the state that I got the car inDSCN4098.JPGDSCN4099.JPGDSCN4101.JPGDSCN4102.JPGDSCN4103.JPG
 

Patton

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I can’t wait for the next post where Brendon shows you everything he’s done to Harold’s Bravaria.

Brendon does some magnificent work. Details to follow?

Forum members, you’re going to love the pictorial.

RP
 

bdigel

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After the car had sat in Harolds Shop for Decades the 1st thing I wanted to do was to see what condition the paint was in , at the time the shop I worked at had a young fella doing detail work , He did a paint correction and some other labor intensive work which surprisingly had great results esp for a race car
 

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bdigel

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To meet the demands of racing with modern cars one thing I learned from years of racing an e12 was the rear suspension needed to be updated , mostly so have access to a wider choice of diff ratios and better LSD set ups along with bolt on options for rear brakes , . I sourced an entire rear suspension from an E28 , subframe , Trailing Arms ,etc, I got an e 30 4.10 LSD and rear brakes of a e34 540 , the shocks are custom MCS . I had custom solid bushings made for the subframe mounts and spherical bushing made for the trailing arms built by David Green at syncro Designs
 

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bdigel

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With the modified E28 rear subframe , we made it so the Trailing arms could be adjusted for toe and camber , This mod leaves no clearance between the top of the trailing arms and the bottom of the floor , , We fabbed up some pockets for the trailing arms fit and rotate
 

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bdigel

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As mentioned earlier the main reason I do this swap is the increased selection of bolt on brakes and Limited Slip diffs . I choose to use the same brakes I used successfully on my other cars , namely so That I have the same pads and rotors , easy to swap if necessary , I use E31 4 Piston Brembos from a 840 and e32/ e34 540/ 740 rears . Its been a great combo esp with out the aid of ABS . The Diff is a very modified e30 410 the LSD chunk done by David Green at Syncro
 

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Redrumm3

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A few years ago I acquired Harold Audaer's 72 Bavaria that he club raced with BMW CCA CR , This car was log book # 20 and took 2ed over all in BMW CCA CRs 1st two club races . Harold had parked the car decades ago where it sat untill his retirement , and when he sold his shop reached out to me to see if I would be interested in taking it from him . Knowing the cars history and Harold being an important mentor of mine I jumped on the opportunity . Chances are if you were involved in driving events with BMW in the south east you are familiar with the car . I plan on restoring it and updating a few things to make it legal to run with currant clubs Pictured here sometime in the 90s
.
Congrats to you on restoring this car. I remember it well with Harold driving at the likes of Road Atlanta, Sebring and Roebling Road. He blew past me at Sebring in my E30 like I was standing still. Looking forward to see what you do with the car.

Scott
 

bdigel

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Congrats to you on restoring this car. I remember it well with Harold driving at the likes of Road Atlanta, Sebring and Roebling Road. He blew past me at Sebring in my E30 like I was standing still. Looking forward to see what you do with the car.

Scott
Thats awesome ! I have heard that from many folks who were around those days , Im soo excited to have this opportunity.
 

bdigel

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Some pics of the Brakes installed along with the custom Motion Control Suspension shocks or dampeners as they refer to them as, Once again Lucky to have a connection with those folks and even luckier that the US portion of MCS is in north Atlanta
 

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bdigel

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Out with the siezed Engine, Harold had a what I think was an old Turbo 3.5 block with custom Pistons , a very ported head lager valves , tripple webbers , and a gaint Cam that Im not sure what duration it was / is
 

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bdigel

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Harold had a e28 based HydroBoost system for the brakes , it was missing a few parts so I sourced this trick piece from Massive Brakes , It goes in place of the booster and has dual Tilton brake masters one for the front and rear .
 

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bdigel

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Jumping to the fun stuff the new Engine assembly . Just over 3.6 L 11 to1 CR , B35 head with a giant Cam
 

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CSBM5

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So cool! Love to see it sometime in action. What cam are you using, and do you plan on triple Webers still? In my ancient memory, I would think of a Schrick 328 or something similar as a full on cam.

Any thoughts on aero? I tracked my Bavaria from 1980-1990, and in the early 80s was in grad school specializing in heat transfer and fluid dynamics and doing aero research for NASA for my thesis. So for a while in the early 80s I did a lot of thinking, analysis and experimentation with the aerodynamics of the E3 including in-motion tuft analysis to try to understand how to improve its barn door drag (Cd well north of 0.40, seem to recall ~0.48 quoted someplace). Since the power required to overcome aerodynamic drag varies with the cube of velocity, I could just feel this thing turn into a slug on the back straight at Road Atlanta as speeds climbed over 100mph (had a Korman built M30, triple Webers, etc, in the car so a good bit more power than stock). A full front airdam worked wonders up front as the underside of an E3 is extremely dirty from an aero point of view, so redirecting flow around the car is helpful. However, there is a humongous wake off the rear, with of course boundary layer separation at the rear edge of the roof, and a huge recirculating vortex behind the rear window and above the trunk (airflow at the surface is going forward in the middle of the trunk along the centerline).

My test track was the old layout Road Atlanta where I went to numerous track events (no such thing as an "HPDE" yet back then) and evaluated peak speeds reached at the end of the back straight right at the braking point going uphill toward the bridge (I purposely exited turn 7 at 30mph indicated and hit the throttle at the same track out point in a crude attempt to create a repeatable starting condition). That front airdam gained about 3mph by itself. I later modified it with longer sides and a splitter out in front of it but never got back to RA to test it having moved to near Summit Point by then. Anyway, I never got to working on the rear aero of the car as my new job, kids, etc, absorbed extra time plus I was never sure if I wanted to drill/modify the body and trunk lid. I wanted to try the E9 CSL rear window deflector (or a modified/adapted version of it) as it attempts to keep flow attached longer over that transition from the roof to the rear window and should reduce the size of that centerline recirculating vortex. The E3 rear window angle is very abrupt however, so I was pondering this situation a lot. Something like the E30 M3 rear window treatment would be better to lower the angle most likely. Anything that can reduce the size and intensity of that centerline trailing vortex...

So my final rear aero plan was to use a CSL type rear window deflector (tall enough to capture most all the boundary layer at the rear of the roof before it separates) and a fairly large traditional spoiler at the rear of trunk...shooting for a length ~8" and an angle in the 30-40 degree range. I still have that image in my head...wish I had made it happen! :) I still have pictures of the tuft analysis I took with a friend driving the Bavaria down the interstate while my wife drove the chase car while I hung out the window taking pictures.

Regards,
Chuck
 
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bdigel

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So cool! Love to see it sometime in action. What cam are you using, and do you plan on triple Webers still? In my ancient memory, I would think of a Schrick 328 or something similar as a full on cam.

Any thoughts on aero? I tracked my Bavaria from 1980-1990, and in the early 80s was in grad school specializing in heat transfer and fluid dynamics and doing aero research for NASA for my thesis. So for a while in the early 80s I did a lot of thinking, analysis and experimentation with the aerodynamics of the E3 including in-motion tuft analysis to try to understand how to improve its barn door drag (Cd well north of 0.40, seem to recall ~0.48 quoted someplace). Since the power required to overcome aerodynamic drag varies with the cube of velocity, I could just feel this thing turn into a slug on the back straight at Road Atlanta as speeds climbed over 100mph (had a Korman built M30, triple Webers, etc, in the car so a good bit more power than stock). A full front airdam worked wonders up front as the underside of an E3 is extremely dirty from an aero point of view, so redirecting flow around the car is helpful. However, there is a humongous wake off the rear, with of course boundary layer separation at the rear edge of the roof, and a huge recirculating vortex behind the rear window and above the trunk (airflow at the surface is going forward in the middle of the trunk along the centerline).

My test track was the old layout Road Atlanta where I went to numerous track events (no such thing as an "HPDE" yet back then) and evaluated peak speeds reached at the end of the back straight right at the braking point going uphill toward the bridge (I purposely exited turn 7 at 30mph indicated and hit the throttle at the same track out point in a crude attempt to create a repeatable starting condition). That front airdam gained about 3mph by itself. I later modified it with longer sides and a splitter out in front of it but never got back to RA to test it having moved to near Summit Point by then. Anyway, I never got to working on the rear aero of the car as my new job, kids, etc, absorbed extra time plus I was never sure if I wanted to drill/modify the body and trunk lid. I wanted to try the E9 CSL rear window deflector (or a modified/adapted version of it) as it attempts to keep flow attached longer over that transition from the roof to the rear window and should reduce the size of that centerline recirculating vortex. The E3 rear window angle is very abrupt however, so I was pondering this situation a lot. Something like the E30 M3 rear window treatment would be better to lower the angle most likely. Anything that can reduce the size and intensity of that centerline trailing vortex...

So my final rear aero plan was to use a CSL type rear window deflector (tall enough to capture most all the boundary layer at the rear of the roof before it separates) and a fairly large traditional spoiler at the rear of trunk...shooting for a length ~8" and an angle in the 30-40 degree range. I still have that image in my head...wish I had made it happen! :) I still have pictures of the tuft analysis I took with a friend driving the Bavaria down the interstate while my wife drove the chase car while I hung out the window taking pictures.

Regards,
Chuck
Thanks for the info Chuck , some great stuff to think about, I am planning on putting a "CSL" style front spoiler and making a splitter that goes to the axle , had not thought anything about the rear , would love to talk with you more about what you found after I get it up and running . I reused Harolds Cam , never could find any info on it other than it was a shcrick and it is huge . The webbers will not be reused I have a strict no carb policy hahhaha stay tuned for webbers replacement
 

bdigel

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Pics of the bottom assembly process
 

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bdigel

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Continuing with the engine assembly



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bdigel

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