From ‘72T to 2.5 S-R: GeLo Racing #44

[matteo68]

But then I do have a problem!

[matteo68]

…crash bars add weight and my target is 960 kgs…

[stretch]

Matt...why are you dumping all the lightweight parts that were Homologated for the ST.? Do you have the exact parts that your car was wearing in period.?

[matteo68]

Because Dave, and I know this is all completely bonkers, they weren’t allowed in ‘72!!

[matteo68]

It’s my crazy journey to build the most accurate 2.5 ST possible and it’s all your fault!!!

[stretch]

Because Dave, and I know this is all completely bonkers, they weren’t allowed in ‘72!!

Matt. I don't believe the source of that document. If it's Homologated in the early 3025 document it can be used. Look at all the 2.5 ST cars in period race photo's.... they are nearly all running with front bonnet dog bones and GRP front bumpers. Not the place to discuss this.... let's chat over a pint at the DDK meet.

[matteo68]

Sure thing Dave but this is the document which I downloaded from the FIA website:



https://www.dropbox.com/scl/fi/zfjvea16 ... n3oqj&dl=0

(See page 137 and also Art. 266 on page 139 for Special GT (Group 4)

This is also relevant:



(“f.i.” = for instance)

So I could have fitted my front fibreglass arches to my car as these would have been legal following this U-turn by the CSI / FIA but I don’t know whether this was done by Chrzanowski / Loos (I doubt it but I still might), however it is quite clear that fibreglass bonnets were not permitted for the ‘72 season. I have also had this confirmed by Matt Blast (0495), Thomas Andersen (0550) and Flo Feustel at Raceline in Switzerland (1155 and 1417).

Always happy to talk all things ST / S-R over a pint though!

[stretch]

So you can use full GRP front wings or just GRP flares but no hood.? What about the front GRP bumper. I still can't imagine nearly all 72 ST cars running dog bones to hold down a steel bonnet. Any chance that this was challenged in period.? What about the aluminium door skins .? I am convinced from period photo's not from owners that probably were in nappies when there cars hit the track.

[matteo68]

Yes. Well that’s my strict interpretation of the regs anyway. You could use the fibreglass S bumper because this was a series production part (not optional) on the ‘72 MY S, at least up to VIN 0385.

The dog bones were partly to save a bit of weight having no locks and associated cabling and tubing even though the bonnet had to remain a steel part. However more importantly, they were also shown as mandatory requirement in the ACO scrutineering ‘Carnet de Pesage’ for Le Mans. My copy of this for GeLo #44 also confirms under Poste III - Bodywork Examination: “Material: steel”…

The Competition Spares List for the 2.5 911 S lists very few competition body parts and none in fibreglass and only the engine lid in aluminium.

It also states at point 8 of the Preface “Spare parts which are not in this list are to be taken from the normal catalogue 911 S, model 72.”:

[matteo68]

I’ve looked at hundred of period photos of the 21 and spoken to several owners as well. I have the “Aktennotiz” from 16.09.71 in which the spec of the cars was agreed and some of the actual competition execution sheets listing the parts and works required. Oh and I was just out of nappies in ‘72 Dave…

I believe these cars were very different to the 2.3 ST with their various kits and I’m sticking with this fundamental premise for my build.

[stretch]

I bow to your superior research Matt. I hope your not using them modern Canford classic chinese front brakes. Why have you chosen not to run the ally doors.? It still wouldn't surprise me if that bonnet rule was overturned in 72 as i can't see nearly every 72 ST car running dog bones to save weight. Guess the answers out there somewhere. Anyway...never mind all that...when this car hitting the road.

[matteo68]

PMB refurbished Ate S alu front brakes all the way Dave!

[matteo68]

Interestingly the 1973 Appendix J regs contained the same ‘Important’ clarification regarding lightweight body parts as 1972 Appendix J and went further regarding plastic bumpers:




I think it’s pretty clear from this that no reversal of this ruling was made during the 1972 season

[_Baudett]

i came across this magnificent post to praise your great work and dedication in finding every detail for the vehicle, model, and year. I will be paying more attention to this forum and this post. For now, after a 'brief' reading, I consider it extremely comprehensive regarding how to and how not to do an S/T depending on the dates within the same year... Again, my congratulations to your entire team!!

[matteo68]

Just spoken to Lee Maxted-Page and he said alu door skins were a complete myth and a load of nonsense in his opinion: R6 didn’t have them and that ran in Group 5!!