Hi all,
Some of you might know of Grassroots Motorsports $200x Challenge - basically build a car where the budget is the year. The event this coming April will have a budget of $2005.

So my idea is to build a stripped-down 320i powered by a supercharged m10 for 2006. My goal at this point is to bring the car down to 2000 lbs, and get ~175 hp to the wheels using an Eaton m45 or m62 supercharger with about 6-8 lbs of boost.

I'm thinking S/C for simplicity's sake. That way I don't have to fab a turbo exhaust manifold and figure out bypass valves, or worry about turbo lag during the autocross portion. It seems like the hardest part about superchargers is fabricating a blower mount and getting the belt tensioned properly.

The main problem I see with running boost is fuel management. I'd like to set up megasquirt, but I don't think it will work with k-jetronic since it's not strictly an electronic system and doesn't have modern fuel injectors. What's a good way to run boost on one of these engines? I've heard of using m42 injectors. Is that possible? Would adapting k-jetronic be feasible?

Ideally I'd like to use a car from 1980 or before, since I can register that car as an antique and not have to pass any emissions test (straight pipe!). Are the engines in the <1980 cars suitable for boost?

Is it possible to get these cars down to 2000 lbs without resorting to expensive materials like aluminum and carbon fiber? I'd be gutting the interior, removing the a/c and heater cores as well as things like the windshield washer system - anything that doesn't make the car go, stop or turn would be removed and sold to recoup the budget.

Any thoughts or advice? Is there a showstopper I haven't thought of?

Sounds like a cool Idea. My E21 is turbocharged and I'm pretty sure I spent less then the year 2000. The main prob. I would see about SCing is the bracket, and the getting a pully to fit the bigger belt. Other then that I think all you will need is bigger injectors and MSD's Boost timing master and your pretty much done, Thats if you dont want to get an intercooler, BOV etc etc. I dont thing you will be able to reach your goal of 175rwhp with that setup. You will need to run around 12psi to get it and do ALOT of mods. I'm running 12-13psi and the M10 is highly modded and I'm just right there at the motor (I'm going to dyno soon) and my trq is about 185 at the wheels. As far as getting the car down to 2000lbs, well I think the lightest E21 on her is 2200lbs. Good luck.

My e21 is running a MS now and it's not that difficult to do but it's not an inexpensive thing. The ECU will cost about $200 if you can assemble it yourself but the rest of the parts is what adds up fast. I have about $700 into my EFI conversion and I did a lot of scrounging.... Well worth the effort/expense-it makes WAY more power than a kjet can.

An early 2.0L m10 is a great candidate for moderate boost if it's in good condition.

Use an '84 318i intake/fuel rail/regulator and the electronic injectors of your choice to match your HP level. My engine is a mild N/A 2.0L and I run 26lb Delphi injectors bought new on ebay for $50 for the set of 4.

A key to good hp will be your exhaust header/exhaust system. The difference between an off the shelf header like the Stahl or Pacesetter and a custom header for your engine configuration would be significant.

It would be very tough to build a competitive car for $2006 unless you get very lucky finding most of your parts.

The good news is the chassis does not require a bunch of $$ to handle well-used springs, some decent struts/shocks, 320is front and rear sway bars, and decent wheels/tires should do it. For wheels you could use e30 14x6 with some 205 series tires. They fit with some simple spacers that you can machine from aluminum stock. Don't believe those that say they must be hubcentirc, I have been running a set on my '82 320is for well over a year and thousands of miles with no problems what so ever and just moved them to my '78 320i this summer.

Check out my website at www.e21motorsports.com/kendanielson to see my cars and learn about headers.

ken

hey ken i was reading up on some of your site. Just curious how much you charge for a set of your headers for a 320i 1.8L?

there is a guy on MyE28.com who will be your competition... he is building a 533, however im not exactly sure what he'll be doing... Think you can get an S/C on the M10 for under 2k? Not to mention you are probably going to want to do a bit of suspension work as well, right? Sounds like a great idea, and i was thinking of entering the challenge as well, however, my recent purchase already broke the bank. Good luck though!

Cheers,
Jonas

Thanks guys. A couple clarifications:

I dont thing you will be able to reach your goal of 175rwhp with that setup. You will need to run around 12psi to get it and do ALOT of mods.
I've seen in a few places that the rule of thumb for the M10 is 3 lbs of boost = 50 additional horsepower. So if we start with an engine that makes 100hp or so, and boost it 7 lbs, wouldn't that be about 175 rwhp after drivetrain losses?

What is the most boost I can run on a stock engine in good condition? Are there any really inexpensive fixes that can be done to allow it to run more boost? New head gasket or o-rings perhaps?

As far as getting the car down to 2000lbs, well I think the lightest E21 on her is 2200lbs.
Is that the lightest street car that you know of? I plan on even removing the bumpers, window glass and regulators. It won't be comfortable to drive for very long, but it will be light.

The ECU will cost about $200 if you can assemble it yourself but the rest of the parts is what adds up fast. I have about $700 into my EFI conversion and I did a lot of scrounging....
What other parts are necessary besides that stuff you mentioned from the e30 318i?

A key to good hp will be your exhaust header/exhaust system. The difference between an off the shelf header like the Stahl or Pacesetter and a custom header for your engine configuration would be significant.
Unless I can find someone to fab a custom header for cheap, I think I'll be stuck scrounging a used off-the-shelf piece. Either way it's going to eat up a good portion of the budget.

It would be very tough to build a competitive car for $2006 unless you get very lucky finding most of your parts.
Fortunately I'd only be competing against other $2006 cars. :)

The 3lbs=50hp is sadly not true. Like I said I'm running 12-13psi and I think we are at about 165rwhp and that with alot of mods. I'm putting in a new turbo and hopefully will be at 175rwhp and 200rwtrq and thats still with the CIS system. On a SC your boost limit is really the pully and teh setup, so I think that at about 7psi you may only have 150-160hp at the motor WITH other mods. The 2200lbs car is a race car not a street car. Good luck.

I SORTA disagree with that 2200lbs car not being a street car....but then again I have a much more screwed idea of what a street car is....

....do you REALLY need carpet and a back seat to be a street car? AC? Heater (although I still have mine for now)?

oldskool3,
The street header I have currently on my car was designed for a stock engine. I have about $250 in parts alone but it works VERY well. I have a jig in the works to make header construction easier and less wear and tear on my daily driver. I plan to develop an improved Stahl type 4-1 header using modern header design concepts to update the 40year old design. Hopefully I can get the price down to a reasonable level. This will take time-I have many other things going on.

wludavid,
You need an ECU, intake, fuel rail, injectors, fuel pressure regulator, fuel filter, fuel pump, hoses/plumbing, relays, wiring, sensors, throttle body, O2 sensor (wide band if you want to run boost, or risk melt down), throttle cable/bracket, connectors for sensors/injectors, laptop for tuning. If you have a late cylinder head with the injector ports you will need to plug them or install an early head. I also run a Mallory hyfire VI ignition CD box which gives a clean signal to the ECU but won't operate the factory tach without a filter from Mallory ($30 or so). I use a MegaSquirt Relay box too but it's not required, just easier.

As far as the weight of the car, if you can find a non-sunroof car and strip it I think you will make 2000lb without a lot of effort. Back seats? I don't need no stinking back seat!!! Think lexan for all glass other than the windshield...

ken