Building a 900 for hillclimbs

[Luke]

Impressive! Thats really looking great! looks like it will be a really solid cage in no time.

[DrewP]

Nice work!.. those welds look pretty good in my book.

That's better than I can MIG weld, that looks great! - I think I have some kind of mental block about it or something, cause the instant I get a wirefeed gun in my hand I lose the ability to weld. I can make two pieces of metal stick to each other, but that ain't weldin'!

There was something in 253 that stated how big the gussets had to be to 'count', it was something like 2 x tube-diameters or 2.5xdia from the CL of the tubes minimum, although I am on my second one of these:






....... so I won't be digging into it right now, just thought I'd throw it out there for the ones that may be required if you're planning it to be 253 compliant for inspections or what have you.

[Jordan]

....... so I won't be digging into it right now, just thought I'd throw it out there for the ones that may be required if you're planning it to be 253 compliant for inspections or what have you.

Those are so good! and like 9% abv

[KPAero]

....... so I won't be digging into it right now, just thought I'd throw it out there for the ones that may be required if you're planning it to be 253 compliant for inspections or what have you.

Those are so good! and like 9% abv

Mmmm, looks like something I need to try.

Here is the gusset rule:

8.2.14 Gusset :
Reinforcement for a bend or junction made from bent sheet metal
with a U shape (drawing 253-34) the thickness of which must not
be less than 1.0 mm.
The ends of this reinforcement must be situated at a distance from
the top of the angle of between 2 to 4 times the diameter of the
biggest of the tubes joined.

I thought that since those were not required they wouldn't need to meet the size requirements, or am I wrong? Nasa does require some sort of gusset in the intersections of the brow bar, but the roof bar intersections would cover me there, and the tacos would be extra. I also kind of thought that since these are 1/8 inch plate making them bigger would have been a bit excessive. Of course, all the other gussets will be made to the correct size.

[DrewP]

I have a feeling you're right that since they aren't required for your car's vintage it won't actually matter - but I also have a feeling that has to do with how subjective the particular scrutineers you get are as well.

[KPAero]

Worked on this over the weekend, and had Monday off, so I made a push to try and get the cage done. Didn't quite happen, but things are getting close. I ran out of gas Monday evening and it kind of killed my motivation to work late. At this point there are a few bars that I have made that need to be welded in, and gussets need to be made.

I also got the transmission back and a new base gasket, so hopefully that will start going back in soon.

First I made the bars for the corners of the doors before welding the feet in place.

[KPAero]

After welding the feet in I made some plates to go on the sill that the sill bar rests on and is welded to, so it will be welded at the ends, and two spots in the middle of the bar.



Then door bars were made.

Then I started on the rear section.





Finally, I decided to add the A-pillar supports. I made them as short as possible while still being within the rules to help minimize the effect on entry and egress.

[Jordan]

I don't think you really *need* a-pillar supports ,either from a rules or safety stand point, unless you run into an over-zealous tech inspector, or the rules changed . The a-pillar length is on a 99/900 is sort of a gray area I thought. But I guess it is a little late for that now

Everything looks really good though. Props to you.

[Geoff]

It looks pretty good! You should be ready soon now :)

The FIA needs to clarify the A-pillar supports (aka "Windscreen pillar reinforcement"). The terminology in the article shows a dimension that isn't well defined. It appears as if "A" is the dimension at the height of the "transversal member" (windshield bar) of the distance between two center lines. These center lines being the center line of the windshield bar and the center line of the bottom leg of the "lateral half-rollbars". But in our cars the windshield bar is typically not straight across (typically it has two bends in it to bring it forward) and could even be an arc. So is "A" at the center line of a potential straight section in the windshield bar? If the windshield bar is an arc shape where is "A" measured from in relation to the windshield bar? Is the left side of "A" in Figure 253-15 taken at the intersection of the windshield bar and the lateral half-rollbars? And of course the bottom leg of the lateral half-rollbars are not always vertical so is the measurement taken along the center line of the bottom leg or is it taken vertically from the center point of the intersection of the lateral half-rollbar and the mounting foot? Nobody knows....

[DrewP]

I interpreted that the most conservative way possible, that you measure from the point where the windscreen cross-beam meets the verticals, regardless of the span of the cross-beam does.

Of course the underlined:

Cars homologated as from 1/1/2006 only means that it's not necessary for a C900 anyway....

[Luke]

I interpreted that the most conservative way possible, that you measure from the point where the windscreen cross-beam meets the verticals, regardless of the span of the cross-beam does.

Of course the underlined:

Cars homologated as from 1/1/2006 only means that it's not necessary for a C900 anyway....

Well, sorta, the actual SAAB 900 fia homolagation (for group A) expired a long time back - like 1988 or something, so thats not even relevant anyway because we can't enter an fia international event in any modern class. But the way RallyCar and NASA interpret that date (I know this is retarded but its what they do) is as the date of issue for the vehicles logbook -

[KPAero]

I interpreted that the most conservative way possible, that you measure from the point where the windscreen cross-beam meets the verticals, regardless of the span of the cross-beam does.

Thats how I would read it too, and like you said, not required for a 900/99 because of the homologation dates, but after seeing them in Mike White's car I decided to mock some up and see what it would look like. With them joining the a-pillar down low like that they don't look like they will get in the way trying to get in and out. It actually might make it easier to pull yourself out of the seat. So I figured it couldn't hurt to throw them in.

[KPAero]

Also, any thoughts on adding a bar down low between the main hoop feet? Id think the X would already make it pretty strong, so would that be overkill?

[DrewP]

..... But the way RallyCar and NASA interpret that date (I know this is retarded but its what they do) is as the date of issue for the vehicles logbook -

Ahhhhh..... that I did not know.

I was just thinking over the weekend I need to get on the horn with one of the SoCal scrutineers and see if it's even possible to get mine logged for something sanctioned since I did my cage with a halo hoop - I was originally planning on only doing road racing so it wouldn't matter, but I've been getting bi-curious (bi-road-surface-curious I guess you could say) and trying to stick as close to the rules as possible. Need to study up on what the recent changes were, since the car probably won't slot into any historic classes here now either....

[KPAero]

Well, sorta, the actual SAAB 900 fia homolagation (for group A) expired a long time back - like 1988 or something, so thats not even relevant anyway because we can't enter an fia international event in any modern class. But the way RallyCar and NASA interpret that date (I know this is retarded but its what they do) is as the date of issue for the vehicles logbook -

Aahh, didn't realize that. Seems like RA likes to interpret a lot of FIA rules in new and interesting ways, fuel cells....