BimmerWorld - E46 M3 Street/Track Car Build

Originally Posted by vaio76109

So, uh, 2:05?

Perceptive. That was the number I was thinking of. We will see. Not racecar light, but light. Very good power and very good grip. No full cage, so that hurts chassis stiffness...

You should definitely paint the splitter gold, it'll help with downforce and make 2:05's easy.

Originally Posted by vaio76109

You should definitely paint the splitter gold, it'll help with downforce and make 2:05's easy.

Then why aren't you fast?

Originally Posted by JamesC

Then why aren't you fast?

I see what you did there. And the answer is tires... yes, tires.

Originally Posted by JamesC

Then why aren't you fast?

Because his splitter is black like yours, not gold

Originally Posted by FTWeisse

Because his splitter is black like yours, not gold

Negative. His picture has a black splitter.

Originally Posted by JamesC

Negative. His picture has a black splitter.

Originally Posted by JamesC

Negative. His picture has a black splitter.

http://img709.imageshack.us/img709/3383/img0725m.jpg
Is that... is that gold? God that Greg guy is just ballin' outta control.

Sorry James, I don't mean to steal your thunder.

Ooooh....like the OEM E9X wheels!

James - looking at the Bimmerworld pictures of the Moton race struts, am I seeing things, or is the part that mounts to the kingpin bent?

2:05.988, good job James.

Loving the wheels, and the whole project for the matter.

Originally Posted by murph1379

James - looking at the Bimmerworld pictures of the Moton race struts, am I seeing things, or is the part that mounts to the kingpin bent?

Not what we are using here, but yes - that is a Touring Car damper with added camber.

Originally Posted by vaio76109

2:05.988, good job James.

Thanks - will do an update when I get back. 100 degree heat didn't help anything, but I'll take it!

the finished product is amazing! great job guys looking forward to the last update with parts and prices

"Finally, an update" you say. Yup. I warned you guys that this was a scramble to build. Stack on the UTCC day at VIR, a PM photoshoot with the car, a tripp 4 hours north to Summit Point, and a weekend instructing the BimmerWorld Club Racing School and I was nicely behind. Now, I am starting to dig out.

Now, in the style of the great George Lucas, this is Episode I of the Final Mid-Project BimmerWorld Update Trilogy. And if I can get it in gear, USA Network-style, you will get one per night to fill your weekend with reading fun. If.

First a quick disclaimer - "Mid-Project"? Uh-huh - the UTCC was the very fast initial build of this car and had a stopwatch nicely attached to the event so the results were evident. But we still have a few items in prototype stage and some in final design. So the project will go on a little further - probably until someone buys the car, moving all our tinkering efforts back to my street car.

Episode I - Build Catch-Up
Right - we aren't going to jump right into the UTCC results. You wouldn't pick up a book and read the last chapter would you? So here is a short retrospective of the final stages of the work that got the car out the door.

Checklists. If you are organized you use them along with good pre-planning to eliminate surprises. Ours is getting shorter here.


What is missing here?

Pretty black Performance Friction calipers you say? Remember they aren't part of our budget. Rust? No - we have that, taunting our wallet to spend more money... Caliper retaining clips! Those little pieces of spring steel that keep a BMW rubber-mounted, single-piston floating caliper from twisting quite as much as they might want to. One of our little tricks typically for street/track cars, not full street or a lot of inclement weather use - Solid Brake Guides. These brass bushings replace the [typically worn out] rubber caliper guides with something precise. Like a solid suspension point - less movement means more accuracy. These won't get us to BBK territory, but with the PFC Direct Drive rotors and some good pads, we made a nice jump that direction for a bit less money.

Aero... The wing was easy - we already designed that piece, so it was a 30 minute bolt-on. But getting rear downforce is always easy. What people neglect is the matching and very hard to create front downforce. The best we can do on a car built to this scope (no relocated engine, semi-tube chassis, etc) is a good front splitter and undertray. Thanks to friend and customer Josh's build, we started our fast design project with an ebay lip.


After mounting the lip (we like to call it a riser - part aerodynamically connecting the bumper to the undertray), we design the undertray with cardboard - going back as far as possible - typically the centerline of the front wheels.


Now recreate with alumalite (we will do carbon for a production part, but this is the fast and cheap route)


And mount on the car. We made standoffs to mount the undertray so if the splitter rips off on(off) track, the bumper doesn't feel the need to follow.


Racetech seats and Schroth Profi-II harnesses for track use - standard seatbelts also installed for street duty, because 1)I feel like an idiot driving with harnesses on the street and 2)a 3-point is specifically designed so than in a wreck on the street, where help may not be quite so trained or quick as the track, 1 cut gets you out - that's just good safety.


The Hotchkis logo. On our Hotchkis swaybars. They're the biggest in production, which works the best in my opinion. And they are tubular so they are light and very adjustable.


And the results are in. On 93 pump gas, no trickery, and in full street trim - 338 rear wheel Hp. BAM!


Stay tuned for Eposide II - the UTCC (and Summit Point) report...

Wow, thats an impressive rear wheel horspower figure, isn't that somewhere close to almost 400hp at the flywheel?

Originally Posted by haplo_84

Wow, thats an impressive rear wheel horspower figure, isn't that somewhere close to almost 400hp at the flywheel?

Why yes - its more like 412Hp if we use 18% as the driveline loss of this chassis, which I feel is fairly typical for the driveline parts used.

Awe, i was using 15% which put me right at 397ish, sorry I'm a number cruncher. Been working on statistical analysis and differential equations here lately so its like my wind down math i guess you can say. It makes me stop playing with numbers as much.

Originally Posted by haplo_84

Awe, i was using 15% which put me right at 397ish, sorry I'm a number cruncher. Been working on statistical analysis and differential equations here lately so its like my wind down math i guess you can say. It makes me stop playing with numbers as much.

15% is pretty optimistic. We can get there on a racecar, but remember - no trickery on this car...

of course i was getting my drivetrain loses percentage from when i used to run around with my fwd imports and what not. I got that from sport compact car, which i kinda miss cause it was more technical than the rest of the fluff these days.