818R frame mod

[driveslikejehu]

I’m kinda regretting starting with an R version. I don’t intend to race, but I do plan on track days. With most organizers around here, the car needs to be street legal, so my R will be. I’ve done over 50 track days in a variety of cars; with the 818, I’m looking forward to the learning and challenge of setting up and tuning suspension, brakes, everything.

My issue is the R frame, specifically the diagonal tube from the roll bar to the front. Not only egress and visibility somewhat limited but my big issue is rollover. As I noted in another post, taking the “broomstick test” seriously, here’s what might happen. I don’t think there is any way out.
818r prof sml.jpg

Some of the folks that race have installed a “halo” type roll bar modification, which is what I may end up doing.
Back to the car mission, a bit of summer fun and a few track days each year. I see folks are doing track days with the S version, which I probably would.

The S frame…
818s frame.jpg
…versus the R frame
818r frame 2.jpg

So I might remove those diagonals…
818r frame 2 mod.jpg
The thinking is, still quite a bit more steel, more stiffness than an S. I’m not sure what those diagonal bars are for, a vehicle landing on you? So a little less protection than an R and more than an S. And I might be able to get out if it goes over.

I might be too scary about a rollover but saw one in front of me last year at VIR. I’ve seen a few fairly bad results over the years though I've never had a serious off. And it’s more likely with cars without anti-skid, traction control, ABS, etc.
Thoughts?

[Dave 53]

My 818S broom stick rollbar was designed and fabricated by John Pagel who travels the country as the lead safety rule writer and inspector for the LeMons races. He is a roll bar guru. LeMons roll bar rules set the bar. I'm trying to say, he knows his ****.

On my S, he ran the fore and aft diagonals to the top of the roll bar, not just 70% of the way up. Also, when he cut the OEM S roll bar off, he discovered there were no frame welds under the roll bar where they mounted to the chassis (he had a few words for Factory Five upon discovering this before fixing it). Also, he was very explicit that the ends of the square tubing that the roll bar mounts to needs to be boxed off instead of being left open. The roll bar material is also very very important. I'm not sure what material FFR uses, and I can't remember what material John used on mine, but it is of the highest quality. Most likely stronger and more appropriately suited for a roll bar than what FFR used.

We looked at pictures and talked about the R setup. Bottom line... according to John, my setup is every bit as good as the R setup and it doesn't have the bar that traps you in when upside down.roll bar 2.jpgthill 3-20-22.jpg

Interesting that you have to have a street legal car. At the California HPDE, it just can't be open wheel or, ironically, a LeMons car.

[driveslikejehu]

Thanks for the info
I think some guys must be relying on what Colin Chapman called "the compressibility of bums" to pass the broom stick test with a factory rollbar.
I'm a little surprised sanctioning bodies allow the diagonal; thinking of extraction
It seems FFR got a lot of design ideas from the Lotus 2 Eleven. You even see the low roll bar and cockpit diagonals.
2 eleven.jpg
As some of the 818 racers have done, the "halo" type setup seems best for full racing.
2 eleven halo.jpg

Starting during Covid, most track day organizers I'm familiar with don't do an actual inspection at "tech," just hand in a self tech form. Requiring cars to be street legal works for their insurance/liability?

[Sgt.Gator]

The best argument for the side diagonals is when you slide under another car, under-thru a guardrail, or a large object hits you straight on.

I think I have the only full halo 818R, and yes it is modeled after the Lotus 2-11 FIA GT4 design. If I were doing mine again I would add a bit more rearward rake to the front hoop. Otherwise I'm happy with it. Smaller drivers go in under the halo, I just jump up on it, swing my legs inside, and drop in.

New Graphics 1.jpg