914-6 GT tribute prep for racing Options

[jhynesrockmtn]

I bought this car out of Livermore CA in 2018. It's a 6cyl GT Tribute built on a 73 4 cyl chassis with donor parts from a factory six. I know, wouldn't do that today most likely. It wasn't running at the time due to mostly sitting for years. After a refresh of the fuel system and carb rebuild (thanks Jack Morris) it fired right up. New brakes all around courtesy of PMB and new fuel system components from Tangerine Racing. Thanks vendors! A few drives and compression numbers seem excellent. 180-190 on all cylinders. I'm going to pull the motor now to do valve adjustment, belt change, etc.

While the motor is out I'm wondering about how best to prep to install the shoulder harnesses in a better way. You can see from the photos that there is one point through the rear firewall with no extra metal that holds the shoulder harnesses at this point.

I'd prefer not to install a bar behind the seat on the cage due to wanting the seat to be able to go back as far as possible. I'll be mounting a Kirkey or OMP seat I already have. I'm 6-1 and pretty long legged.

I'm thinking about welding plates to the rear firewall about the point you see the 3 plastic plugs currently and then put two eye bolts per side to mount the shoulder harnesses.

The car will be used for some vintage race events and DE's. It was originally built for PCA solo events.

Thoughts, advice, pics of your installs?

Pic of engine compartment with existing eye bolt for harnesses



Current drivers seat



Passenger side with seat removed, same as driver's currently



Gratuitous pics of car

[wndsrfr]

Here's how I did it on my /4. Pay attention to the angle of the shoulder strap through the seat cutouts so best to mount the seat first. You'll also need to add a window net and a fire bottle within your reach. I'll post photos of the install on my /6 in a bit.

[jhynesrockmtn]

Here's how I did it on my /4. Pay attention to the angle of the shoulder strap through the seat cutouts so best to mount the seat first. You'll also need to add a window net and a fire bottle within your reach. I'll post photos of the install on my /6 in a bit.

Thanks for the pic! That's roughly where I was thinking. Is there any benefit to welding the plate in that area vs. how it is show in your photo?

I've got some work to do in figuring out which seat to use. I have a Kirkey with mounts that came out of a /4 I was going to race but passed that on to a buddy when I found this /6. I also have a couple of older OMP seats from a vintage 911 that was in an accident many years back and I bought some stuff off of it. I'm likely going to use the Kirkey and hopefully maintain the capability to mount stock seats if I want to use the car off of the track.

I have a net to install and will figure out the fire system. I also need to wire in the cut off switch and do a bunch of other stuff before it is ready to be on track.

[wndsrfr]

Here's the welded in plates on the /6 track car. You will want to mount the seat slam down on the floor in order to get the best angle for the shoulder belts to route--supposed to be no more than 15 degrees below horizontal IIRC. That will mean placing the eye bolts as near to the top as possible--I'm only 5'8" and mine just barely meets.

[wndsrfr]

Window net...

[wndsrfr]

Inside view...

[wndsrfr]

Fire bottle between seats...

[jhynesrockmtn]

John,

Thanks. That is very helpful! Would love to see your car some day!

Cheers,
Jerry

[brant]

Nice seats.
I sold my set just like them years ago

most of the Wheel to Wheel vintage race organizations will require you to have a seat with a submarine strap hole in the seat, and side strap holes in the seat

you may have to modify or replace your seats with safer ones, made for 5 point belts... to be accepted by tech for vintage racing

[brant]

I should have added....

most sanctioning bodies have their own established rules
those rules usually cover the seat belt mounting angle
the angle changes slightly with a HANS unit
most organizations are now requiring the HANS... not all but most


you may want to seek the rules out for any local groups that you may potentially run with in the future.

our opinions are just opinions.. . the sanctioning body rules will be the standard for your car

I'm the porsche eligibility chair for our local vintage club
I highly recommend you contact the eligibility body for any club you may join... and get advice from them so that you don't have to make updates or changes later.

[jhynesrockmtn]

I should have added....

most sanctioning bodies have their own established rules
those rules usually cover the seat belt mounting angle
the angle changes slightly with a HANS unit
most organizations are now requiring the HANS... not all but most


you may want to seek the rules out for any local groups that you may potentially run with in the future.

our opinions are just opinions.. . the sanctioning body rules will be the standard for your car

I'm the porsche eligibility chair for our local vintage club
I highly recommend you contact the eligibility body for any club you may join... and get advice from them so that you don't have to make updates or changes later.

Thanks Brant! I do have seat options on the shelf which will work with 5 or 6 point systems. I have a Kirkey that was fit to /4 car I was prepping for racing. That car was then sold to a friend but I kept the seat and mounts a local fabricator had built for me. I also have a couple of older OMP racing seats I my consider. I'll keep these Koenig's in case I take the GT back to a street car. It would be a bit of a pain to do so but not horrible. It still has its glass, lights, etc. The wipers, fans, that kind of stuff were removed. That's one of the issues I am wrestling with. How race car do I go?
If I try and stay with the spirit of vintage I won't make too many more mods. We have a tech guy in town here for our race club SOVREN. That's a good suggestion to reach out to him ahead of time.

[brant]

I should have added....

most sanctioning bodies have their own established rules
those rules usually cover the seat belt mounting angle
the angle changes slightly with a HANS unit
most organizations are now requiring the HANS... not all but most


you may want to seek the rules out for any local groups that you may potentially run with in the future.

our opinions are just opinions.. . the sanctioning body rules will be the standard for your car

I'm the porsche eligibility chair for our local vintage club
I highly recommend you contact the eligibility body for any club you may join... and get advice from them so that you don't have to make updates or changes later.

Thanks Brant! I do have seat options on the shelf which will work with 5 or 6 point systems. I have a Kirkey that was fit to /4 car I was prepping for racing. That car was then sold to a friend but I kept the seat and mounts a local fabricator had built for me. I also have a couple of older OMP racing seats I my consider. I'll keep these Koenig's in case I take the GT back to a street car. It would be a bit of a pain to do so but not horrible. It still has its glass, lights, etc. The wipers, fans, that kind of stuff were removed. That's one of the issues I am wrestling with. How race car do I go?
If I try and stay with the spirit of vintage I won't make too many more mods. We have a tech guy in town here for our race club SOVREN. That's a good suggestion to reach out to him ahead of time.

Good deal...
sounds like you are covered!

I just know that I see applications for our club (rmvr) and people get so mad at me when I point out things like the seat belt angle, or seats.... they get so mad at me
but they should have called or contacted me prior to finishing the car and I could have directed them to the rule before they spent the money or time.

[stownsen914]

Brant's advice is good to check with whatever group you plan to run with. Read the rules and talk to one of their inspectors.

One random thing I noticed in your pics - both shoulder straps are mounted to a single eye bolt on the firewall. I think most rules will want to see one per strap. The backing plates shouldn't need to be welded in place, but of course that wouldn't hurt.

[jhynesrockmtn]

Brant's advice is good to check with whatever group you plan to run with. Read the rules and talk to one of their inspectors.

One random thing I noticed in your pics - both shoulder straps are mounted to a single eye bolt on the firewall. I think most rules will want to see one per strap. The backing plates shouldn't need to be welded in place, but of course that wouldn't hurt.

Yes, that was something I was planning to correct. I reviewed the FIA docs for a HANS device yesterday and will check with a tech guy for our org. It notes the angle on the shoulder is recommended at 0-20 degrees. The other item I wouldn't have thought of is the degree of spread between the shoulder straps at the device is to be between 20 and 25 degrees which affects how far the eye bolts are from each other.

I've been wearing a HANS since 2008 in my previous race car.

[mlindner]

I'm fabricating a set of GT style harness mounts, but these will have a full front plate. Back side with have the standard backer plate, spacer and nut that can be welded. Mark

[jhynesrockmtn]

I'm fabricating a set of GT style harness mounts, but these will have a full front plate. Back side with have the standard backer plate, spacer and nut that can be welded. Mark

I'd be interested to learn more and see more pics. I was thinking of welding on a plate to the upper rear firewall area with welded on nuts. My GT style engine cover is still mounted with the hinge setup near the rear window and I'm worried about interfering with that. I could change that though and remove the hinge and just pin it like the other side closer to the rear.

[stownsen914]

Mlindner's approach could be an interesting one. A couple things to keep in mind:
Check the recommended spacing between shoulder straps. For HANS compatibility, I believe it may be recommended to have the mounts closer together than full shoulder width.
Also, it might be a good idea to make sure the U bolts are at least 7/16" diameter threads. That's standard seat belt bolt diameter. And they should be graded bolts, like grade 5 at least. Common hardware store stuff is often grade 2.

[jhynesrockmtn]

Mlindner's approach could be an interesting one. A couple things to keep in mind:
Check the recommended spacing between shoulder straps. For HANS compatibility, I believe it may be recommended to have the mounts closer together than full shoulder width.
Also, it might be a good idea to make sure the U bolts are at least 7/16" diameter threads. That's standard seat belt bolt diameter. And they should be graded bolts, like grade 5 at least. Common hardware store stuff is often grade 2.

I'm going to test fit my seat in the next few days and once I'm comfortable I have that set I'll look closer as to how to mount the harnesses. I've got a lot of hardware from various mounts with DE cars and my old FV over the years. I need to go through those boxes.

I'll post up some pics before I start drilling or welding :-)

[mlindner]

These will have the plates to weld on the back and go around the factory hinges. I'll post more pictures when it comes to mounting. Best, Mark

[jhynesrockmtn]

A bit of an update and check in. Comments and suggestions welcomed.

I have an older FIA certified OMP seat that I picked up with some other 911/912 race parts years ago. Our club won't check the seat certification and it's in good shape. I will need to get a sub belt hole installed which I can do or have a local upholsterer take care of.

I'm 6' 1" so getting leg room was a premium and also getting it as low as possible was a consideration. I may in the end need to have a pro add a small hoop to the cage above my head. I'm well below the bar with no helmet on but may be within an inch or so with a helmet.

After much fitting and cutting off the stock seat mount hinges I think I got a decent fit.

Then to figure out how to get a solid mount. I read through several threads on it and settled on this design which will bolt to the boxed section of the floor with a steel bracket and set of shaped slats I cut and welded. I'll bolt the back of the seat through the floor.