Can I weld the main hoop to the rocker to rocker bar in the picture below or does the main hoop definately have to go to its own 6x6 plates on the floor? I like this way but I do not feel that it is as structurally sound as having the hoop independent of the rocker bar, no evidence as to why just speculation. I have seen people recommend several different fillers for Cromoly but what do you cage builders recommend? Also I know its not necessary but I would like to add gussetts to my cage, I have never seen any in Cromoly so is it really worth it since I would be welding mild steel gussetts to a moly cage?




Also the rear bars, as far as strength goes, I see some put 6x6 plates toward the rear and some weld those bars to the rear shock towers, any of you have personal preferences as to where you like the rear bars and why?

 

Yes, you can. That is how we build all of our drag cages. We put a slight bend in the tube that runs between driver and passenger rockers so it clear the exhaust tunnel or driveshaft tunnel on rwd cars.

ER-70S2 is the best choice for filler on the 4130.

Good Luck!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by XtremeRaceCars &raquo;</TD></TR><TR><TD CLASS="quote">Yes, you can. That is how we build all of our drag cages. We put a slight bend in the tube that runs between driver and passenger rockers so it clear the exhaust tunnel or driveshaft tunnel on rwd cars.

ER-70S2 is the best choice for filler on the 4130.

Good Luck!</TD></TR></TABLE>

Thanks for the responce Someone told me that you should not heat Cromoly to bend it, is there any truth in that? I am guessing no but who knows, I have no experience with this.

 

That is correct, you do not want to heat the material to bend it.

 

i definitely would not do that. in the event of rollover its going to put a huge bending moment on that middle tube since it is on an unsupported length, unless you have further tubing connecting those nodes to the floor with plates.

also used er802-d2 filler for 4130 when not heat treating. not 70-s2

 

even though that would make doing the cage a whole lot easier, its sketchy IMO. i wouldnt think that would be legal however i have no idea if it is or not

 

You most lilely won't pass any tech/cert like that. If anything, run the main hoop to 6x6 plates on the floor like normal, and then incorporate kick-outs to the rockers from the main hoop.

Honestly though your picture looks like a very bad idea...Unless you were to tie that rocker to rocker bar into the floor at several points besides the rockers.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Turbo-charged &raquo;</TD></TR><TR><TD CLASS="quote">even though that would make doing the cage a whole lot easier, its sketchy IMO. i wouldnt think that would be legal however i have no idea if it is or not

</TD></TR></TABLE>

Sketchy, yes that is why I asked, all the load will be placed on the 2 rocker plates/welds, I have revised it to include 2 short verticals underneath the hoop to their own plates, I think this design takes the worry out of the downward load. The rocker bar will also be welded down its legnth to a plate on the exhaust tunnel.

Just to clarify, the main reason why I am doing this is my hoop is apparently almost 3/4 out in height from one side to the other and I dont want a big gap from the bar to the ceiling, so by mounting the hoop on the rocker bar I can trim off excess and even both sides out, I think by adding those short 8" bars that would defintely do the trick in the event of a rollover.




<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dfoxengr &raquo;</TD></TR><TR><TD CLASS="quote">

also used er802-d2 filler for 4130 when not heat treating. not 70-s2</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by XtremeRaceCars &raquo;</TD></TR><TR><TD CLASS="quote">ER-70S2 is the best choice for filler on the 4130.

Good Luck!</TD></TR></TABLE>

Lol, so which one is it fella's? I am def not sticking my car in a oven so its not going to be heat treated


Modified by 96 GSR-T at 2:35 PM 3/23/2008

 

search for yourself and you can see what rod to use. both of us have our opinions.

 

I have and I came up with

ER80S-D2
an alternative but not as good ER-70S-2
and lastly ER70S-6

and now er802-d2, I guess I was looking for a majority vote on the type of rod, any others on rod preference?

 

i actually tried calling NHRA to see if it was legal to do it like in your 2nd pic, but they didnt get back to me in time so i just did it the old trusty way

 

just remember, main hoop must be 1 piece and connect via 6x6 plates. i dont think intersecting it like that is allowed. best bet is to connect the hoop directly to the floor, and run a separate sill bar for the d-bars, or even, just run the d-bars to their own 6x6 plates on the floor. (and yes it is LEGAL) i have an e-mail from my local NHRA tech stating so, i sent him pics as well, an they cert'd my chassis

 

when i had my cage certified, he said the first pic was the best way to do it. he was actually building one for his son just like that when i was there.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by turbotypeR@SPEC &raquo;</TD></TR><TR><TD CLASS="quote">when i had my cage certified, he said the first pic was the best way to do it. he was actually building one for his son just like that when i was there. </TD></TR></TABLE>

wow very interesting, I got a list of local inspectors, I am going to call one today and get an email and get his opinion, I want to do it this way but I think I am going to add those 2 short verticals, which IMO would make a bug difference structurally to the cage.

 

I just got off the phone with one of the inspectors in Reading, PA he said he does not recommend it the way I have drawn it but to have the Rocker Bar independent of the main hoop and run the D-Bars to it, he also said they were enforcing that around here for any cars running in the sfwd class, and would fail a car for having the D-Bars to plates on the floor (what a joke the whole inspection proces is, it must depend on what state you live in/who the inspector is) but with NOPI now on the scene he said he does not know what they are going to enforce now. There is an inspector closer to me that I have to call tonight to get his opinion, he will be the one doing my inspection some day down the road.