BMW Compact Rally Car Build

[DaveKern]

More bloody tires... All told, you've got to have close to 30 laying around?

Mark Mark Mark, you always underestimate me...this time by more than a factor of two!

BMW:
10 Michelin Rally (practice & shakedown)
2 Hankook W202 (b/c you need 4 matched for AWD)
4 Winterforce

Evo:
4 Dunlop Dirrezza Star Specs (track days)
3 All seasons (don't lend wheels/tires to someone for PPIHC )
4 Blizzaks WS-60 (BWDS tracks)
4 Hankook I-Pikes (winter commuting to BWDS tracks, Rally-x)
8 Yokohama A-036 (PPIHC)
8 Kumho W700 (PPIHC)
4 BFG Drag Radials (PPIHC)
4 Hankook W204 (abrasive hillclimbs)
10 BFG Rally (Dirt hillclimbs, rally)

Audi
4 Yokohama W-Drive (currently mounted)
4 Goodyear (summer tires)

GMC Sierra
4 Blizzak W965

GTX
4 Blizzaks (I don't even own the car anymore)

My name is Dave, and I think I have an addiction.

[DaveKern]

The liquid nitrogen did a great job of removing the undercoating, but the paint is left in place. Before seam welding can take place, we need to grind the paint off, so the welds will be clean. Here's Mark & Grant working with the grinders. We found using a wire wheel on one, and a flap wheel on the other made the job go quickest. Me...I got the scraper.





Dave

[Dogsbody]

Mark Mark Mark, you always underestimate me...this time by more than a factor of two!

BMW:
10 Michelin Rally (practice & shakedown)
2 Hankook W202 (b/c you need 4 matched for AWD)
4 Winterforce

Evo:
4 Dunlop Dirrezza Star Specs (track days)
3 All seasons (don't lend wheels/tires to someone for PPIHC )
4 Blizzaks WS-60 (BWDS tracks)
4 Hankook I-Pikes (winter commuting to BWDS tracks, Rally-x)
8 Yokohama A-036 (PPIHC)
8 Kumho W700 (PPIHC)
4 BFG Drag Radials (PPIHC)
4 Hankook W204 (abrasive hillclimbs)
10 BFG Rally (Dirt hillclimbs, rally)

Audi
4 Yokohama W-Drive (currently mounted)
4 Goodyear (summer tires)

GMC Sierra
4 Blizzak W965

GTX
4 Blizzaks (I don't even own the car anymore)

My name is Dave, and I think I have an addiction.

Did you forget the kart and the spare around your middle? Not that I've any room to talk...

[DaveKern]

Did you forget the kart and the spare around your middle? Not that I've any room to talk...

Crap, I did forget the kart (3 sets of slicks, and 1 set of rains)...but I keep those tires in the house so they don't get exposed to different temps.

Tire in the middle...working on it...just not sure in what direction.

Dave

[mjOlson]

Back to the cage. Good to see you can add x-bar gussetts. How about further strengthening of the sills for side impact (like with a tree)? Have followed a bit of the WRC testing on side impacts and most builders add a bar in the sill itself. There is also a new seat out, by Recaro I believe, that has had a lot of testing in WRC last season. How about tieing in the down tubes and main hoop to the A and B pillars?

[DaveKern]

Back to the cage. Good to see you can add x-bar gussetts. How about further strengthening of the sills for side impact (like with a tree)?

I've made the decision to go with a 'one off' cage for this project rather than going the prefab Custom Cages T45 route. I just couldn't look past a 10 year old cage design when its only benefit is that its under 100 lbs. Since I won't be using a kit with an FIA stamp, I'll need to follow the Rally America build rules, so our cage weight will be closer to 150 lbs. 1.75x0.095 for the main hoop, and 1.5x0.095 for many of the other bars.

Have followed a bit of the WRC testing on side impacts and most builders add a bar in the sill itself. How about tieing in the down tubes and main hoop to the A and B pillars?

Yep, the sill bar is one place rally cars can use some extra reinforcement. Nothing like going off the road into a field of tree stumps. The lack of a sill bar is probably the thing that bothers me most about the cage I've got in my Evo (seen below), but the rest of the design is much more modern than the BMW Compact offering. My Evo cage is also setup with the "HANS Bar" option, so rather than having the belts attach 3' back, there's another bar in the same plane as the vertical X in the main hoop. It also has gusset plates that run the length of the a-pillar, and short gusset plates that tie in to the b-pillar just above where the top of the door X connects to the main hoop.



I think the basic design of the cage in the BMW will be similar, but I'll be trying to read up on places that might be beneficial to tie in, like with the rear diff and rear suspension pickup points. We also may incorporate nascar type door bars instead, that way if I ever wanted to track the car, its an option.

I hope to have some additional details to share about the cage in the coming days, but in the interim, if anyone has any suggestions, I'm all ears.

There is also a new seat out, by Recaro I believe, that has had a lot of testing in WRC last season.

That seat looks really nice. Lots of extra padding built into the shoulder to head region on the outside facing side of the seat. In rally cars, the side impacts are the scary ones.

Dave

[finebykris]

Subscribed. I hope to someday get into rallying. the dirt/snow is just fun

[mjOlson]

Don't forget foot protection which would be another bar from the fwd mounting plate to the dead pedal area; likely lots of pics on this forum of foot protection. As for NASCAR bars, I think there is a good reason you do not see them in WRC where the side impacts can be much more brutal than wheel to wheel. How about X-bar with impact foam? Look through Jaffster's build thread for some info or get in touch with him on his experience with incorporating this into his cage design.

Looking at your EVO cage pic again. The EVO is a right hand drive? :-)

[DaveKern]

Don't forget foot protection which would be another bar from the fwd mounting plate to the dead pedal area; likely lots of pics on this forum of foot protection. As for NASCAR bars, I think there is a good reason you do not see them in WRC where the side impacts can be much more brutal than wheel to wheel. How about X-bar with impact foam? Look through Jaffster's build thread for some info or get in touch with him on his experience with incorporating this into his cage design.

Looking at your EVO cage pic again. The EVO is a right hand drive? :-)

Modern rally cages aren't really LHD or RHD specific since they've got to protect people on both sides of the car. The image I linked is a RHD car as you can see the brackets that get welded into place for the steering column. Basically, everything with those kits comes separate and your fab guy has to put everything together.

On the impact foam, the only way I'd be able to use that would be if I gutted the doors, and taking out the crash beam is a no-no as far as rally rules go. You are allowed to remove the beam, but it needs to be replaced with the high dollar WRC hex-cell aluminum/carbon/kevlar stuff...and at that point, you lose the ability to have roll-up windows. FWIW, that's why this season's WRC cars all have those sliding window sections now. I haven't decided if I'm dumping enough $$ into the project to invest in lexan windows.

Thanks for the tip on the foot protection, I'll look into that.

Dave

[mjOlson]

Modern rally cages aren't really LHD or RHD specific since they've got to protect people on both sides of the car. The image I linked is a RHD car as you can see the brackets that get welded into place for the steering column. Basically, everything with those kits comes separate and your fab guy has to put everything together.

Gotcha. I thought perhaps the cage designer put the steering wheel on Alison's side of the car to make it go faster.

[DaveKern]

Gotcha. I thought perhaps the cage designer put the steering wheel on Alison's side of the car to make it go faster.

I didn't know this site was a breeding ground for comedians?

In all seriousness, if things go according to plan, Allison may drive the BMW at a few hillclimbs, and I'll drive it at rallies...just need to figure out the logistics of getting two cars to a race.

Dave

[DaveKern]

Grant H. has been helping me out with the seam welding on the BMW, here's a few shots of him at work. He's going to be re-preping his Merkur XR4-TI later this winter, and I'm looking forward to some battles next summer.



Seam welding is a stinky business! No matter how clean you have things on one side, there's something to burn and smoke on the other.



The bottom of the car is now done being seam welded.













Dave

[DaveKern]

Good day today even though I didn't actually do any work on the car.

Grant B., a long time friend of mine that I met when first getting into auto-x-ing, and I reconnected last summer when I put up a post looking for some help. Always looking to get close to the action and help in any way possible, he headed up my service crew for the Lancer Evolution at the Pikes Peak International Hill Climb.

A couple months later I started thinking about building a "new" car for PPIHC when its all paved, and Grant, now an avid road-racer, was the first guy I called with all sorts of questions and ideas. He competes in events with his wife in their Mini and also in his Stohr sports-racer. My sports-racer idea didn't pan out, and after my wife an I spent a weekend at Rally Colorado, we decided rally was really what we wanted to get into.

After researching and settling on a BMW, I knew it was time to give Grant a call, because many of the cars he's built recently have been BMWs. His shop, Built-by-Bones (fabrication) works closely with SCR Performance (performance, race engineering and track/rally support). As part of the track prep, most cars end up getting some attention from both shops to ensure a complete package hits the track ready to run. After spending some time up at the shops and chatting with the owners, I liked their down-to-earth approach to building cars, and the fact that they can make solid recommendations for each budget level of build that I inquired about.

What's the point of my post? We're going to be joining the BBB/SCR team this year, representing the shop with the rally side of things. Big thanks to Grant (BBB) and Mark (SCR)!!

I hope to finish my end of the chassis prep over the next couple of weeks, and tentative plans call for the BMW to be delivered to Built-by-Bones in mid-February when the roll cage fabrication will begin.


Thanks for reading,

Dave

[DaveKern]

Not too much happening on the car in the past week, but I did pick up some bits for the car.

Here's the fire system we will be using in the car. Rally regulations call for two fire bottles in the car, but I much prefer having a system so it'll easily cover the engine & passengers with foam in the event of a fire. This system has a push button rather than a pull handle. Hopefully we'll never need to use it!



I will also have hand-held bottle, so if we come across another car on fire, we're able to lend a hand.

Dave

[boriksh]

so, the extinguisher is actually foam? I thought it has to be filled with Halon.

[DaveKern]

so, the extinguisher is actually foam? I thought it has to be filled with Halon.

I have an AFFF setup in my Evo for the fire system, but I can't remember what type the hand-held is. I bought both from a local shop that supplies safety equipment for rally cars, Checkpoint Racing. If you're in the Denver area and need safety stuff, check 'em out & support companies that support racing.

Here's the rules from the Rally America rule book on fire systems:

5.6. FIRE EXTINGUISHERS

A. Any fire requiring the discharge or partial discharge of any portable or
on-board fire system shall be reason to file an Incident Report.

B. On-Board Systems:
1. It is recommended that vehicles be equipped with on-board fire
systems meeting SFI or FIA standards. Manual or automatic release
is allowed. On board systems shall be installed and serviced per
instructions from the manufacturer. These instructions shall be
available during a technical inspection. In addition, a hand-held
extinguisher of at least 10 B:C shall be installed, mounted in
accordance with Article 5.6.C.3 below.
2. The fire system cylinder shall be securely mounted, in such a
manner that it can be checked during a technical inspection and may
be removed for weighing periodically to check compliance to the full
weight shown on the cylinder. (Weight is without valve assembly).
3. All on-board fire systems shall be identified with 2 circle "E" decals,
one at the release location and the second on the outside bodywork
in line with or as near to the release location as possible.

C. Portable Devices:
1. As an alternative, vehicles may be equipped with a minimum of 2
hand-held fire extinguishers, of at least 10 B:C UL rating or
equivalent each for a total minimum of 20 B:C. Additional containers
and/or capacity are allowed. Hand-held extinguishers may contain
any approved agent. For systems not rated in B:C units, the
capacity in pounds multiplied by 2 is the equivalent, i.e., a 5 pound
extinguisher is equal to 10 B:C. For systems measured in liters, 2.25
is the minimum allowed.
2. Dry chemical extinguishers shall bear certification that they have
been serviced annually. Each dry chemical extinguisher shall be
removed at scrutineering and shaken to ensure that the chemical is
not compacted in the extinguisher. All extinguishers shall be
equipped with a visible indication of the state of charge. All
extinguishers shall be approved for vehicular use by the DOT, U.S.
Coast Guard, SFI or FIA.
3. The fire extinguisher(s) shall be securely mounted in the cockpit. All
mounting brackets shall be metal with a quick-type release.
Brackets shall be those designated by the manufacturer for
'vehicular' use.

[boriksh]

I might be confused with the handheld units in the class other than rally. Looking good. keep us updated.

[DaveKern]

I might be confused with the handheld units in the class other than rally. Looking good. keep us updated.

I may be wrong here, but I believe that the AFFF kits are now the preferred method, I want to say that the halon stuff is bad for you.

Dug this up on the rally forum specialstage.com:

Disregarding the cost of Halon since it is no longer made (there are other gaseous extinguishing agents available), the problem with it is that once it dissapates, the fire can reignite. As an example, consider an oil line at a turbo popping off. The very turbo can ignite the oil. If Halon or another gaseous agent is used, the fire will be put out but the oil is still present and the turbo may still be hot. Re-ignition can happen.

This can also happen with a powder if the oil or other liquid is flowing in any way. The powder gets washed away and re-ignition can happen.

Supposedly AFFF helps with this by lingering. The carbon encapsulating agents (Cold Fire) are said to complete eliminate the problem but I am not sure. Go to the SCCA emergency services forum and you can find a long debate on this.

[boriksh]

Wow, Dave that is good to know, i gotta read more about that. I have halon in my car, but i guess it is time to reconsider that option.

[mulholland]

http://www.bmwblog.com/2010/02/06/di...comment-189664


thought this might interest you if you'd never seen it OP.

[DaveKern]

http://www.bmwblog.com/2010/02/06/di...comment-189664


thought this might interest you if you'd never seen it OP.

I had heard about a one-off M-Compact, but didn't realize that they used the the 3.2. I had always figured they used the 3.0 that was offered in 1995.

Dave

[boriksh]

Dave, any progress on your project?

[DaveKern]

Dave, any progress on your project?

Didn't have a chance to work on it this weekend as I was up working at BWDS. I plan to put in some hours next weekend though.

Dave

[nineball12]

ever figure out what diff you're going to run? i have recently come into a 4.44lsd that i can't use for anything

[DaveKern]

ever figure out what diff you're going to run? i have recently come into a 4.44lsd that i can't use for anything

Is it a 188 medium case that'll work on a TI? LSD or open?

I haven't made a decision one way or the other yet, but I've been keeping my eyes out for a high ratio diff like that. There were some changes made at work that's going to put a crimp in how much I'm able to spend on the project (no more OT pay), so one of the things I was thinking about was just finding an open diff and doing the weld it up trick to get through our first few events. I know its far from ideal, but I think a welded diff on a rally car is less of a problem than a welded diff on an auto-x or "grip" type car. Dropping $2k on a diff just isn't in the picture anymore.

Thanks,

Dave