Carpokes Porsche Forum

gruhsy wrote: Mon Jan 15, 2024 6:07 am https://www.autoweek.com/racing/more-ra ... gic-death/


Little background about Al Holbert

Amazing read. There is a lot about him in the reflections of so many who were a part of it all. I knew very little of Al Holbert so thanks for posting the link - it's definitely an article to save.

There are a few photos of the car if you google it.
Either using Al Holbert or Alan Johnson 944 turbo…..brings up the race class type of car.

gruhsy wrote: Mon Jan 15, 2024 6:07 am https://www.autoweek.com/racing/more-ra ... gic-death/


Little background about Al Holbert

Wow...great read! Clearly a big loss to the motor racing community.

The engine is still on the dyno while a custom wire harness for the M1 MoTeC is being made. The ancient turbo was sent to a respected turbo shop in Florida to determine what the Garrett turbo is, whether it still might be suitable, and if so to freshen it for initial dyno baseline runs. Then, if there's a modern turbo that will provide better performance, we'll get that one for a back-to-back dyno comparison.

Other progress is ongoing. The 4 corners have been disassembled, A-arms crack tested, and new bearings and rod ends installed. The (also ancient) double adjustable Penske shocks have been sent to Penske for a rebuild. The axles have been examined and the CV's freshened. The chassis was stripped, power washed and repainted. Tires on the car at the moment are 18" Michelin radial slicks. Here again, we're going back to original for a baseline. Bias ply slicks and 16"x12" wheels will be used since the chassis and suspension were designed for them. I ran bias successfully on my own tube frame GTR, so that's where we'll start.

We're also putting the 944GTR on a diet. Fabcar reported an initial weight of 1980 lbs. It's many hundreds of pounds over that now, so we're stripping out lots of unneeded stuff. Final weight is TBD.

Michael, in your experience what was the comparison between bias ply tyres vs modern slicks? I always pictured the bias ply tyres moving around a lot more laterally on the sidewall and just more squirmy in general. I imagine that you would have to wait a lot longer for the bias ply to 'take a set' and then applying right pedal compared to modern tyres.

In my experience, bias tires are more forgiving since they'll let you go past the limit of adhesion and still save it. Radials, on the other hand, tend to lose grip suddenly if you're dancing on the edge. Bias slicks will also come up to temperature more quickly. For example, I'd let the car move around a lot on the first lap to build tire heat. I could then take the final corner on the first lap at 10 tenths. That said, bias tires will overheat when continuously pushing them super hard. It's surely disappointing to be chasing someone down and have to back off because you've overheated your tires and they've gotten greasy. Bias ply tires, with their flexible side walls, don't want near as much camber as radial's. I ran 1.75 deg (front) camber on my GTR, whereas Cup cars on radials will run the fronts at or near 4.5 degrees these days.

I'm a bias fan because that's what I'm familiar with. Radials, however, will win in the end if the driver is skilled enough to keep the car on the edge and not end up in the weeds.

That's what I thought. We ran my car on the front with max -neg as we could get and this is on a road legal R spec tyre. I think you'd quite like the tyre we use which is the Yokohama AO50 but I don't think they're available in the US? My guess is that they'd sit somewhere between the Radial and Bias ply offerings. You can get them in a few different compounds.

MM, thank you for the pictures and alerting us about the project and most of all sharing your experiences and photos.
I look forward to following this as well!

A little cleanup prior to and during reassembly.

That last picture piques my interest Michael. Do you know what the gearbox is? When viewing the incar video it really sounds like they have straight cut dog engagement gearing as he is able to shift very quickly. Maybe flat shift? I'm trying to source something for my car that will offer equally quick shifts while minimising boost loss. The video:


I was advised that the driver is a Colin D. Apparently they were having some issues and he wasn't driving super quickly.