Who is running a Z3 in ITA? -- Please reply if you are

[Joe Gilmore]

I'm trying to find out how much strength in numbers there is for the Z3. If you are running one, or building one, or planning to, post a reply. Thanks!

Regards to all,

Joe Gilmore
Colorado Region

[Z3_GoCar]

A Z3, yes but not in ITA

Mine is a 2.8l Z3, not classed in any form of IT except for ITE, the catch all class of IT. Actually I asked a similar question about a year ago, but to find out about information about preping of the M-44 for competition. Not many cars are being raced with the M-44 let alone Z3's, but that should change with loosing of 50lbs, it's more up to the task. The real advantage to the Z3 is in the slower twistier tracks. Good luck,

James

[nlevine]

There are two of us here in New England - Doc Bro and myself. Both of our cars were TC Kline-built ex-SSB cars. Mine was first raced in SSB out in your region (Bob and Patty Tunnell of Bimmerhaus fame were the first racers of my car). Based on the logbooks, I'm the 4th race owner, and I did the conversion from SSB to ITA specs.

Rob (Doc Bro) has been doing a lot of dyno testing and exhaust experiments.

-noam

[Joe Gilmore]

Well, I guess we are a small and exclusive group. I bought Jim Leithauser's Z3 and ran it in SSB, then put it into a wall. Rebuilding it to E Prod, hope to get in a couple of races this year but I will be running underprepped with a mostly stock engine. Obviously there isn't a whole lot we have in common tech/rules wise, I just wanted to see who else was out there.

Good luck to you guys as well.

Joe

[Z3_GoCar]

I considered converting mine over to e-prod. I assume that I can just plant an M-44 in along with the proper trans and ignore the vin number. But to be competitive you need a fully built motor(custom forged crank, ground cams, ect) probably with a custom dual webber carbs manifold. One question, are you able to meet the minimum weight listed? Did you cut off the windshield frame as is custom in prod?
Thanks,

James

[Joe Gilmore]

James,

I can't see anything wrong with stuffing an M44 into your car, but I'm not an SCCA rulemaker, so I would want a ruling before I did it.

Yes, the windshield and frame are gone. Tony Rivera built a slick asymmetrical cage in it, penetrated the firewall and connected the low front hoop to the front strut towers.

I have used the passenger area for fuel cell (inside a custom aluminum box to meet the bulkhead requirement), battery, and fire bottle.

As to the motor, if I get the car trackable for this summer, I will be running stock with Electromotive Tech 3r, no power steering pump, and an underdrive pulley on the alternator.

I guess it depends on how competitive you want to be and how quickly you want to get there. I'm content to develop the motor in stages. When we build it, I'm going to see what happens using the stock FI rather than the Webers. I've been told that the stock crank is very strong, so first step will just be rods and 12:1 pistons.

Don't know where the weight is, will weigh it in a few weeks.

Joe

[Doc Bro]

Hey Joe,

I'm the "other guy" with a Z3. It will be curious to see where you go with the m44. It does not lend itself well to IT prep but may respond favorably to prod. prep. As I see it, based on the research garnered so far, it needs big pistons and cams and abandoning the ECU for MOTEC. It should respond better to prod. mods. (I suspect you'll be calling Europe more than you thought, however, as the US answer to power is Downing-Atlantic!!) It breathes really well in stock form so modification of exhaust yields virtually nothing without those other mods. that are IT illegal. It is a very strong motor and in my opinion is a great motor for a rookie. We're going on 6 seasons without a refresh (38K on motor) and I have made some over-rev mistakes (misshifts & premature downshifts) without ill effect.

Will you leave or disable the DISA valve on the intake?
Where did you get the underdrive pulley?
What LSD ratio will you run (3:45 or 4:44)?
What upgrades are you planning for the rear suspension (very weak in my opinion)?

I can give you more of the history of modifications to my car and dyno results if you're interested. I do think prod may be a "happier home" for the Z3 than ITA as the weight, rear susp, and allowable motor mods all seem to be holding it back in IT. Prod is not without its fair share of grizzly bears too though.

Good Luck,
R

OH yea...I almost forgot your original post. This is the "strength in numbers". We're hoping the meek will inherit the earth!!

R

[Joe Gilmore]

Hi Rob,

Here's what I can answer:

Current thinking is disable the DISA because I will spend very little time below the switchover RPM. Not carved in stone.

Underdrive pulley came from Sunbelt for an E36. I had to machine a spacer to align it fore-and-aft with the other pulleys. With the ps pump removed, it worked okay. If you would like, I can get you a number for the correct length belt.

Diff is Metric Mechanic 3.90 4-disc LSD with ramp angles machined to 30 degrees. See their website for details. Prod rules state original diff housing, so has to be the small 168mm diff. James would have to change that from the medium size diff that I believe came on the 6-cyl Z3. I will probably wind up with a 4.10 as well. Metric Mechanic also offers a 4.27.

Not much that I see can be done on a restricted suspension rear end. I have replaced the subframe bushings and rear diff cover mount with delrin. Don't know exactly what springs and swaybar will be run. The semi-trailing arm rear is going to suffer toe change regardless. Any ideas? I'm running TCK/Koni DAs all the way around. I tend to like softer springs and stiffer swaybars.

I would like to continue this dialogue with you when I get back to working on the car. Right now I am trying to finish up my second year of law school , so it has taken a back seat.

Regards,

Joe

[Joe Gilmore]

Doc Bro,

Got the E Prod Z3 on the track last weekend. Some info for you:

Running the engine underprepped. Mods are: underdrive pulley on alternator, removed power steering pump, boosted fuel pressure to 60 psi, Electromotive Tech 3r with MAP sensor instead of MAF sensor, premium unleaded pump gas, K&N cone. Car made 160.9 hp/144 ft.lbs. at the wheels. Torque curve very flat, minimum was 123. The DISA valve is only adding about 1 hp at its optimum, which was found and set to switch at 5000 rpm. Apparently the advantage is in part throttle operation, but I was surprised at the low 1 hp yield nonetheless.

Exhaust is stock with cat, just not using the post-cat O2 sensor, with a pretty quiet performance muffler from the car's SSB days. Running that setup just because I didn't have time to change it.

I would be interested in the exhaust data that you have accumulated. I need to get the cat and muffler off, even if it doesn't make that much more hp until I develop the motor, just to get a little more weight off the car.

Email me at [email protected]. I'll be happy to send photos and any other info that might be useful to you in IT, or maybe I can talk you into going Prod. The car is a blast and easy to drive.

Regards,

Joe Gilmore