818c-r?

[DanielsDM]

Hello everyone. I just joined this forum and have been kicking around the idea of building an 818 for NASA STx/TTx. I don't like the idea of running an open cockpit car on the track at the same time as full bodied production cars so I was thinking of a 818R but adding a windshield and changing the original roll cage to a full cage with opening doors. Then I saw pictures of the hardtop for the 818S. Now I'm thinking of starting with an 818S kit and building a full cage that will fit inside the hardtop. Sounds simple enough, like most things until you actually start doing it. What challenges do you think I'll run into? What other differences are there in the two kits besides the obvious windshield and roll cage?
Thank you for your input.
Dan

[FFRSpec72]

Not sure what bothers you about and open car ? and on the track with full bodied production cars ? FFR builds a very very good cage, I drive a challenge car also and I have been t-boned in drivers door before by an E30 and only fiberglass damage (and rear axle) and the E30 was a total front clip replacement. If you run NASA/SCCA most likely you will be on the track with open wheel cars at the same time also. Personally this is not an issue for me, I feel very safe in a FFR designed roll cage, I would not feel the same way with an 818S that someone has modified and added a full cage.

[DanielsDM]

Tony,
Thanks for your input. Personal safety is well... a personal issue.
Do you what the other differences there are between the kits?

Dan

[Santiago]

Hi Dan,

One of the early R-builders posted some chassis differences on his build page...damn, can't remember who it was. Ah, wait, I think it was Bob's build here, though post #59 gives the best shots.
Anyway, the main differences seem to be:
- Reinforced front cabin supports under windscreen (extra minor hoop and minor triangulation from side to front)
- Taller main hoop
- Main hoop-to-front bars along the sides
- Door bars - this includes a lot of extra reinforcement, so you might want to study pics of it

I side with Tony in feeling that the FFR design is very safe and robust. The only complaint I have about it really is that they didn't make the door bars bow out to give more room in the cabin. If you're going to take an S-car and make it go (wah-wah-wahhh), be sure to have a good cage designer have a look. Also, you might want to sit in an S-car with a helmet on to see if you feel safe with that much (read: little) headroom to spare.

Another option to consider is getting an R-car and building a halo and forward downbars to meet the chassis. Lots of the Challenge cars have been modified in this way (though I think it looks awkward - the focus is on safety not looks). That would be easier than converting an S-car.

Best,
-j

[Pearldrummer7]

Hi Dan,

One of the early R-builders posted some chassis differences on his build page...damn, can't remember who it was. Ah, wait, I think it was Bob's build here, though post #59 gives the best shots.
Anyway, the main differences seem to be:
- Reinforced front cabin supports under windscreen (extra minor hoop and minor triangulation from side to front)
- Taller main hoop
- Main hoop-to-front bars along the sides
- Door bars - this includes a lot of extra reinforcement, so you might want to study pics of it

I side with Tony in feeling that the FFR design is very safe and robust. The only complaint I have about it really is that they didn't make the door bars bow out to give more room in the cabin. If you're going to take an S-car and make it go (wah-wah-wahhh), be sure to have a good cage designer have a look. Also, you might want to sit in an S-car with a helmet on to see if you feel safe with that much (read: little) headroom to spare.

Another option to consider is getting an R-car and building a halo and forward downbars to meet the chassis. Lots of the Challenge cars have been modified in this way (though I think it looks awkward - the focus is on safety not looks). That would be easier than converting an S-car.

Best,
-j

+1 for R frame, with halo if necessary.


People with 2-Elevens do the same for wheel-to-wheel racing, from what I've read.

http://www.topgear.com/uk/imageresiz...600&Height=339

[C.Plavan]

Well- Being that I just got my 818R annual Tech'd last weekend, NASA scrutineers were not too happy with parts of the cage. They were going to call Jim to have him address some issues and ask some questions. The Scrutineers did bring up some valid concerns. In fact, a contingent of them came over to look at it again where I was pitted.
1. They did not like the open square tube the rear rollbar is welded to (makes sense)
2. The angled bars on the main hoop should be in the corner of the roll bar hoop radius, not below.
3. They picked out a few other concerns about the side bars.

[DanielsDM]

J,
Thanks for the info and the link to the pics. Sounds like the only differences in the kits are cage windshield and door frames? I think I will show the pictures of the R and S chassis' to my cage builder and get his opinion on which would be better to start from. I showed him pics of the 818R on the FFR website a few weeks ago and the first thing he pointed out was the connection point of the angled bars to the main hoop (that Chad said the NASA techs didn't like).

Dan

[FFRSpec72]

I have had my cage inspected by ICSCC and SCCA and no issues, the items pointed out are not rule infringements of the NASA CCR (see section 15.6), BUT this is still a pain to deal with until the orgs get to know the car and how the cage was built, so I do expect some amount of push back as most cage inspectors are not used to seeing low front hoop cages. I agree that #2 could have been done differently but but not a violation. #1 is how the Challenge car cage is built also. #3 side bars are legal, they may not have liked them but they are per rules. Again these are a pain to deal with as they cause issues and delays at the track as we are at the mercy of the tech inspectors.

[Santiago]

J,
Sounds like the only differences in the kits are cage windshield and door frames?

No, not correct. From a distance (or from pics) these seem to be the only differences, but that's not true. The main hoop itself is different. The S-car's hoop is both narrower and shorter. So to make an S-car into a comparable R-car, you'd need to cut out the main hoop and start from scratch - which depending on what your cage builder has in mind is either a good thing or just more work. I suspect it's just more work, since they're almost certainly going to want at least the same height as the R-car's hoop. So that's why my vote was for starting with an R-car and go from there as is your pleasure.

Best,
-j

[Grintch]

Well- Being that I just got my 818R annual Tech'd last weekend, NASA scrutineers were not too happy with parts of the cage. They were going to call Jim to have him address some issues and ask some questions. The Scrutineers did bring up some valid concerns. In fact, a contingent of them came over to look at it again where I was pitted.
1. They did not like the open square tube the rear rollbar is welded to (makes sense)
2. The angled bars on the main hoop should be in the corner of the roll bar hoop radius, not below.
3. They picked out a few other concerns about the side bars.

#2 - do you mean the diagonal brace, or the rear braces?

It apears to me that when they increased the height of the main hoop, they left all the braces in their old positions. Thus making them borderline too low. But I haven't seen an R in person yet.

[C.Plavan]

#2 - do you mean the diagonal brace, or the rear braces?

It apears to me that when they increased the height of the main hoop, they left all the braces in their old positions. Thus making them borderline too low. But I haven't seen an R in person yet.

Yes, the hoop diagonals. They are all kind of connected, if you move one, you should adjust the other.