Upgrades/options and mods to P2125

Chet Schwer

Lifetime Supporter
Looks like the plate you have on the rear would also work on the front without using the sway bar holes? Where to buy?
Chet
 

Steve C

Steve
GT40s Supporter
If you look close the rear plate spans the upper hoop bolts and upper shock bolt. The sway bar connection is made between the two mountings. It was custom fabbed. Did it before Jim C reported his failure and still think was sufficient to prevent failure like his but, I wanted to be doubly safe so decided to add the front plates from Pathfinder.

The Pathfinder plates (as a pair) although not providing the same method of sway bar attach as mine should be more than sufficient to prevent any likelyhood of shock bracket tear.

OK?

Steve
 

Seymour Snerd

Lifetime Supporter
Looks like the plate you have on the rear would also work on the front without using the sway bar holes? Where to buy?
Chet
Notice that Steve's rear plate being flat requires a spacer, which weakens the whole structure compared to the Pathfinder solution. The purpose of his rear plate was to relocate the anti-roll bar because of FE exhaust system and/or transaxle interference, not to strengthen the rear frame. (right, Steve?). In fact, it isn't clear that his setup is stiffer since the anti-roll bar now has even more leverage over the shock mount. It does use a vey thick piece of steel, though.

If you use a flat plate in a non-FE SPF you'd have to use a much longer bolt throught the shock eye, another spacer in front, and as a side effect would be relocated the anti-roll bar about an inch to rear. All of this to a certain extent going in a big circle since the cantilevered loads on the shock bolt are what create the problem in the first place.

And of course most SPFs still have the too-short vertical link to the anti-roll bar which is a large contributor if not the root cause of the problem that so far almost everyone is ignoring but is in fact easier to fix.
 
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Steve C

Steve
GT40s Supporter
Alan,

I am a Nuclear and Electrical Engineer (former EO on Nuclear Submarine) not a degreed ME. I have not performed a structural stress analysis but, I believe your criticism is unfounded.

You are correct that the original reason for constructing the sway bar mount for P2125 was related to exhaust/transaxle spacing but Olthoff also told me that the 1/4" plate would also offer a significant robustness to the sway bar forces on the upper shock mount.

The plate on P2125 that bridges the upper transaxle hoop to the rear shock ear is 1/4" steel (see pic in post above) vs the standard SPF gauge mounting ear and the sway bar mount is connected to that plate mid length between the hoop and shock mount therby spreading/dividing the force. It is already a big improvement to the original design. IMO using the thinner gauge Pathfinder rear plate with the sway bar mount connected directly to the rear shock ear allows greater transmission of the rotational force on the rear ear due to the thinner gauge Pathfinder plate not providing as much resistance to the forces as with the force generated mid span on the 1/4" plate in P2125 and shared between the hoop and shock ear).

I decided to install the Pathfinder front plates to further support what I think was the weaker zone in my application and with that plate see no likelyhood of any possible fracture of either the front or rear original shock ears.

No way to conclusively prove either way without a strain gauge test but, I think my solution is robust enough to handle any possible condition.

I have seen pics of a number of cars with the sway bar mount as SPF builds (without any stiffeners). A few that come to mind are J8 (see The Ford That Beat Ferrari page 169 and the Holman Moody MK11 (see Ford GT40 by Trevor Legate page 149) as examples showing the mount same as SPF standard builds. What has been done to P2125 is likely overbuild.

Steve P2125

PS: FWIW: I do not like the appearance of the sway bar mounted to the top of the shock mount as it usually necessitates running the sway bay over the exhaust.
 
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Seymour Snerd

Lifetime Supporter
I believe your criticism is unfounded...

I have seen pics of a number of cars with the sway bar mount as SPF builds (without any stiffeners). A few that come to mind are J8 (see The Ford That Beat Ferrari page 169 and the Holman Moody MK11 (see Ford GT40 by Trevor Legate page 149) as examples showing the mount same as SPF standard builds..
Steve --

I didn't criticise your installation in any way. I simply said "It isn't clear that his setup is stiffer." You seem to agree by saying it would take a strain gauge test to establish that either way. So we have no disagreement about your installation.

Much more importantly I've personally inspected the HM Mk II frame very closely in this area and others and the claim that the SPF design is the same as the Holman Moody Mk II is completely and utterly false. The HM shock mounts are substantially thicker and formed from two layers of sheet metal. If you ever get the chance to visit HM you should. You'll be surprised how different the frames are, all in the direction of increased stiffness and strength.

Also the HM Mark II rear anti-roll bar vertical links, like all the original GT40s, are the correct length so there are none of the unnecessary but substantial longitudinal forces on the anti-roll bar mount as there are with the SPF design. If you really want to bullet-proof your car, lengthen the vertical links until the anti-roll bar arms are level at static ride height.

The SPF design is significantly different from any original GT40, and it is substantially inferior, hence the need for the reinforcement band-aids.

As for J8, I haven't seen it up close.
 
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Pathfinder Motorsports

Sponsoring Vendor
Hi guys:

There seems to be some interest regarding the Superformance GT40 chassis and its level of originality. As most of you know, Pathfinder Motorsports is all about building the most accurate, competitive, and race-eligible GT40s available for a fraction of the price of a Gelscoe car.

It was because of their highly-accurate chassis that we selected Superformance to provide us with their licensed continuation rollers, and also why we have an exclusive partnership with Holman & Moody - one of Ford's original GT40 racing teams - to help us engineer and build very authentic GT40s for the track and street.

Alan Watkins is correct about how Holman & Moody MK II frames are different from the Superformance frame - in the same way that the original Abbey Panels and Tennant Panels frames are different from the Holman & Moody frame. For more on this, I asked Lee Holman for some clarification and he kindly sent me the following to pass along:

Hi Alan:

Holman & Moody has been working with its partner Pathfinder Motorsports LLC for almost two years, serving as an advisor and builder of GT40R cars for both the track and street. During that time we have had the opportunity to carefully inspect the Hi-Tech/Superformance GT40 frame, and I can confirm that it is an extremely accurate copy of the 1966 frames built by Abbey Panels, and later Tennant Panels. I should know since I have almost a dozen of the original Tennant Panel frames in my shop.

What is also true is that many, if not most, GT40 frames were reinforced and modified by the various teams as a result of racing experience. Here at Holman & Moody, for example, we reinforced several areas of the original frames for our Ford GT40 Mk II program. It is for this reason that there are frequently differences between original frames as delivered from Abbey or Tennant, and those campaigned by Holman & Moody and other teams. The GT40 racing program was very dynamic with unique frame and other changes made to the different cars throughout the years. You might be interested to know that, back in the day, Ford required that after each race the race cars from Holman & Moody be sent to Shelby, and the race cars from Shelby be sent to Holman & Moody, so that each team could see the work and modifications the other team had made.

Regarding the Pathfinder Motorsports GT40Rs, we are very impressed with the quality and authenticity of the frames as they are delivered from Superformance. I believe the Superformance chassis is a very correct copy of the street GT40 that Ford built and sold in 1966. While a very good chassis, they were not intended to have, nor do they need, all of the changes or modifications required to race for 24 hours.

But just as with those original cars, Holman & Moody is making subtle but important improvements throughout the cars we are building in partnership with Pathfinder so as to offer the owner a competitive and reliable race car that is very close to the original race cars. And as you know, we are building several FIA HTP-compliant Holman & Moody/Pathfinder cars that are destined for racing in Europe.

I hope this clarifies some of the questions that have been raised regarding the Superformance GT40 frame. Looking forward to seeing you next week in Charlotte!

Warm regards,

Lee Holman

I have got to admit, one of the really cool aspects of my job is being able to work every week with a legend like Lee Holman - one of the few honest-to-goodness experts on the GT40.

The whole frame issue boils down to this: The frames we use on our GT40Rs are almost exact duplicates of the original frames as they were delivered from Abbey and Tennant Panels, but those original frames were rarely raced without some enhancement and structural modifications by the various racing teams. Just like today's race cars, improvements are made race-to-race, and so too was it back in the 1960's.

A good example is the Pathfinder GT40 shock reinforcement plate that was designed and built for us by Holman & Moody: It wasn't on the original Abbey Panels or Superformance chassis but evolved from street and track experience. This is just one of the upgrades that is now included in the Pathfinder/Holman Moody GT40R.

Interesting conversation guys! I hope this adds to it.

Alan
 

Pathfinder Motorsports

Sponsoring Vendor
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