914World.com > Roll Cage

Randal

Feb 25 2009, 11:10 AM

QUOTE(Brett W @ Feb 25 2009, 07:31 AM)

The RX8 is two individual bars that do not bisect each other, but do touch each other at the apex. Then are reinforced over a 20in span on both sides. In addition to two 1.75in tubes capping the end of the gussets.

The problem with the simple X bar is the lack of weld surface area. Basically you have the small weld area at the point of contact on either side of the tube. That is the point of failure. By adding the gussets you increase the surface area of the weld ten fold.

BTY Brett, nice quality work (and design) on the RX8.

grantsfo

Feb 25 2009, 11:27 AM

QUOTE(Randal @ Feb 19 2009, 01:35 PM)

There she is naked.

Click to view attachment

...keeping those plastic sill plates to make sure passengers dont scratch paint when they get in the car?

Looking forward to seeing the new cage! Are you planning on Hoopa this year? I definitely going with the Boxster.

Brett W

Feb 25 2009, 12:37 PM

Thanks.

ChrisFoley

Feb 25 2009, 01:43 PM

QUOTE(Phoenix 914-6GT @ Feb 25 2009, 01:16 AM)

From what I gather is Chris is saying the X is bad as it really bring two bars to a single bar strength at the intersection. The RX8 looks to actually be two bars that do not cross though. Chris? popcorn[1].gif

Yes!

QUOTE

The problem with the simple X bar is the lack of weld surface area. Basically you have the small weld area at the point of contact on either side of the tube. That is the point of failure. By adding the gussets you increase the surface area of the weld ten fold.

Not exactly. The point of failure is the single bar thickness at the center. The weld heat affected zone (HAZ) on either side just creates stress risers where a crack can start more easily. From there the single tube just tears in two. Taco gussets on top and bottom will put a lot of metal at the center that would also have to tear for the joint to fail.

Chevota79

Feb 25 2009, 04:09 PM

What are all you guys using for your main cage material 1.5"x.120? or .095....DOM?

Randal

Feb 25 2009, 08:35 PM

QUOTE(grantsfo @ Feb 25 2009, 09:27 AM)

QUOTE(Randal @ Feb 19 2009, 01:35 PM)

There she is naked.

Click to view attachment

...keeping those plastic sill plates to make sure passengers dont scratch paint when they get in the car?

Looking forward to seeing the new cage! Are you planning on Hoopa this year? I definitely going with the Boxster.

Hoopa is on the list.

Brett W

Feb 26 2009, 08:31 AM

1.5x.095 -1.75x.095 DOM 1018-1020. Rules don't allow an advantage for the hassles when dealing with chromoly.

GaroldShaffer

Mar 1 2009, 10:06 PM

A little late to the game, but here is my

This is the way I bought it.

Brett W

Mar 2 2009, 10:07 AM

If I were the typical SCCA weenie protestor I would protest the two production cars here for illegal body modifications. You can't cut out or modify the front of the rear trunk. Both cars would be illegal by the rules.

ChrisFoley

Mar 2 2009, 12:48 PM

QUOTE(Brett W @ Mar 2 2009, 11:07 AM)

If I were the typical SCCA weenie protestor I would protest the two production cars here for illegal body modifications. You can't cut out or modify the front of the rear trunk. Both cars would be illegal by the rules.

Actually, Brett, when they re-wrote the rules a couple of years ago that rule was altered. There is no longer any restriction from creating openings between the trunk and engine compartment. Also, the chassis can be lightened as long as structural integrity is maintained.

Brett W

Mar 2 2009, 02:15 PM

Now if they would just allow real brakes on the car, Production might be an interesting class again. In the meantime I'll stick with ST.

Randal

Mar 4 2009, 11:46 PM

Hey Mike, I hear that Aaron has some cool ideas on what he is going to do with your cage.

koozy

Mar 5 2009, 12:41 AM

Oh yea... I'm very excited. I'm getting closer to finalizing the paperwork on the car it's going in. I hope to have it home in 3 weeks. How close are you with your cage?

koozy

Mar 5 2009, 12:44 AM

What does he have in mind?

Randal

Mar 5 2009, 12:25 PM

QUOTE(koozy @ Mar 4 2009, 10:44 PM)

What does he have in mind?

My guess is something to do with the door bars, i.e., like I'm going to do mine... but knowing Aaron it will be trick.

He just move his shop down to Morgan Hill, so has been busy doing that. He says he'll be back on 222 shortly.

koozy

Mar 6 2009, 11:20 AM

Sounds cool. I just got word on my car. I'll be picking it up on Monday. I'll have plenty of work to do before I'm ready for any fab, but this car should be ready and tested before the shootout. It may not be completely sorted by then, but close.

Randal

Mar 6 2009, 02:38 PM

QUOTE(koozy @ Mar 6 2009, 09:20 AM)

Sounds cool. I just got word on my car. I'll be picking it up on Monday. I'll have plenty of work to do before I'm ready for any fab, but this car should be ready and tested before the shootout. It may not be completely sorted by then, but close.

It takes a ton of time to sort out cars Mike.

You ought to put a plan together on how you want to start testing your car, but first all those things you want to change before day one, i.e., all front and rear suspension components and settings, cage, tires and (very important) lowering and alignment.

Probably the biggest part of the sort out is the iterative process the driver has to go through to understand what needs to be changed.

koozy

Mar 7 2009, 12:21 AM

I hear ya. I'll need to learn how to drive before I can do any of that.... ha ha ha

I think I'll just get the stuff I have in and start learning the car this year. Then, next year I'll try to figure out what it needs. I'm pretty set on the parts I'll use, where it will sit and so on. No LSD this year though.