Photo Request: 308 Race Cars!

@sherpa23 What size tires are on that thing? The rear's look massive!

 

Countach tires. 225/50 15 and 335/35 15
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335....and to think I was all proud of my skinny little 295s on the back

Do you happen to know the alignment specs? toe, camber, caster?

 

I keep forgetting to copy those mirror braces! I buzzed the GT4 today and one of the mirrors bounced down

 

I do. They’re in the file. I don’t remember where I ended up as I aligned it a few times until I had the ride height and the cornering feel where I wanted it. But I saved it all and threw it in binder for the car.

 

Would you be willing to share that info? I'm kind of curious where others have ended up. My engine is dead again so it will be fall or next spring before I'm out driving again to test anything but still pondering starting points.

 

I tried to send them to you via PM but looks like your account won’t take a PM from me.

 

Yeah, I stopped paying so it stopped working...funny how goes.

[email protected]

 

surprised nobody posted this from last week!

 

While looking at the dimensions of the axle shafts, this scares me.

 

You should see the propellor shaft on a Testarossa or Boxer, its the diameter of my index finger and carries all of the engine power to the gearbox.

 

I think you can't compare the loads which occur on that propellor-shaft with that mix of loads on the wheels. You have torque, shear, bending and tensile stress on the wheel axle. Possibly all at once while you just have the torque on the propellor shaft.
I remember discussions 20 years ago about broken stub axles. Of all people it was Brian (rifledriver), who first mentioned too big, sticky tyres as a possible cause.
Here's one of them:
https://www.ferrarichat.com/forum/threads/lost-a-wheel.119568/

Best Regards
Martin

 

What’s scary about it? It’s an FIA group 4 car. It’s made for tarmac rallies, like the Monte Carlo Rally. You’re scared about sticky tires?

Do you know what the Group 4 cars are? Do you think it’s just some regular 308 that someone glues on wide fenders and ours wide wheels on? I don”t know what you think it is but it’s not some tarted up regular 308 that someone stuck wide race tires on. Perhaps you think this is a regular 308 with still stub axles.

If you don’t know what it is then maybe start here:

Kari Makela made a few a to FIA spec and you can look through what goes into one here : https://www.mat.fi/projects/55

 

See my post #88 from this minute.

 

Someone with a Michelotto Gr.4 car told me, they x-ray the axle shafts on a regular basis. If you do this as well, all should be fine.

Best
Martin

 

I've never heard of a broken axle...its the stub axles. Its a well known issues, I was warned about it when I bought my car in 2002 and started talking about adding hp and was told all the race cars get an upgrade or lose a wheel then get an upgrade. 30 years ago it was a big sticky tire and lots or laps type issue but modern "street" tires on stock size rims are now delivering over 1g corner loads and the issue has moved to street (legal) cars. Its on my winter upgrade list for my car.

 

My understanding is those cars have a 45mmID outer bearing and a big radius where the flange meets the axle vs the OEM 40mm ID bearing and a near 0mm radius in the corner. Same design change that became standard on the 348.

 

I get what you're saying but it's the stub axles which are a different design and constuction. Look through that gallery and there are a couple of pics where you see they're different and they have a bigger bearing and the reinforcements.

All of the cars used in competition get the x ray of various parts from time to time (there are other tests too). Even for the historic events like Modena Cento Ore and Tour Auto.

 

Another extensive discussion from almost 20 years ago:
https://www.ferrarichat.com/forum/threads/problem-with-axle-shaft-rear-wheel-bearings-308.186447/

[The stock radius is around 2mm]

 

I would love to see such an improved and reinforced stub axle without going through thousands of gallery pics.
Best
Martin

 

YES! I'm planning to do something this winter ....it there is interest maybe a batch could be made? My thought was basically a 348 design tweeked to work in a 308 wheel carrier. I'm pretty sure the carrier can just be bored to hold the larger bearing with no issue so then it just a matter of getting stub axles made.

....and we are WAY off topic I guess.

 

Keep in mind Martin, not all of the Gr 4 cars (including the clones) are being raced....or even driven that hard. You could mount Corvette ZR1 tires (wider than the Countach's) and it wouldn't matter as long as you're not stressing the driveline.

I'd be interested Mark. I'm not planning to mount any steamrollers, but will be heading down a path intended to get my car more track-worthy. No rush here as I have plenty to do in that regard, but be sure and post if/when it pops-up to the top of your list.
- Dave