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Discussion Starter #1 (Edited)
I have been looking all over the internet and cannot find detailed pics/instructions on what cage requirements I need to run 7.50's. Any help is appreciated.

Is this something that would be in the NHRA rulebook?

I believe this is the certification spec I need will be stock suspension truck with unmodified floors or firewall and full factory frame.
 

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Discussion Starter #3
Are there alot of changes from 8.50 to 7.50 certifications?

I guess I will just need to spend the money, just trying to figure out if this is something I want to tackle myself or not.
 

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I think you will need to add a funny car cage if you don't already have one, and a metal floor on the drivers side. You may need to a little more, but I know 850 cage can be up graded to 750.
 

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Discussion Starter #7
Thanks for the help I got to look at local chassis shops SFI spec book for a 25.5 certification today and there is actually very little to do being as I have a full frame truck.
 

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Discussion Starter #9
Big bags-O-money! :D



LOL, yeah the website I found that number on had some misinformation. But according to SFI 25.5 spec because my truck has a full OEM frame and unmodified floor and firewall I only need to add another bar to make an X where I currently have a single door bar (easy enough), and a funny car cage around the driver, and a headrest style pad behind my head. Something kinda strange to me is that trucks with OE frames and unmodified floor/firewalls do not require the rear support bars coming from the main hoop back to the rear framerails (I already have these though).

Time to get the SFI book for myself and get to welding.:D
 

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The 25.5 spec is more aimed at door cars that still retain some given amount of the original factory floor/firewall/chassis structure in the finished build (like a back-half, mini-tub, or stock suspension build). It allows the use of both mild steel & 'moly as the building material. With the SFI mild steel tubing specs you will be using both .118" wall & .108" wall minimums for tubing wall thickness (most of the time) depending on what tube OD size is used. The 'moly specs call for the use of .083", .065", & .058" wall tubing for the bulk of the build.

The 25.5 spec calls for "X" door bars, and a funnycar cage much like the other SFI door car specs do (like 25.1E, 25.2, & 25.4). One big difference between the other mentioned SFI specs and the 25.5 spec is 25.5 also has additional requirements for the "rear" frame/cage structure (running from the main hoop back to the rear bumper), the 25.1E, 25.2, 25.4 specs don't at this time.

Also 25.5 might require additional floor "X" brace & and outer floor diagonals depending on how much of the factory body's sheetmetal floor/rocker sill/door frame structure is still retained.

Anyone shooting for any of the SFI certs should do themselves a favor and spend the $35 bucks and get an SFI book. It's cheap knowledge/insurance.
 

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Discussion Starter #11
Dave I do fully intend on getting the SFI Spec book to finish upgrading to a 25.5 spec cage. It surprised me a little how much of the stuff is not required for a truck such as mine (stock firewall/floorpan/suspension). There are a few bars that I have that are not required and a couple areas that I went above the minumum spec of SFI (such as the outriggers from the frame to the rollcage)

As Dave said spend the money on the specs their are alot of variables within the specs that need to be addressed. I wanted to get a sneek peek at what it was gonna take.
 

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Are there alot of changes from 8.50 to 7.50 certifications?

I guess I will just need to spend the money, just trying to figure out if this is something I want to tackle myself or not.

I will give you what I do know, considering I just did this and passed.

The X door bars
Rocker bars
Short bar from rocker to subframe
Roof cross bar
Complete brain bar
No X under car unless fire wall has been altered

Hope this helps
Dan
Looking around $1500 plus the cert
 

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Discussion Starter #13
Actually I have the SFI book now and it is not gonna be difficult at all I do have to cut out the current shoulder bar that I have and install an 1 5/8 bar in its place and add the funny car cage. I am confused about the #15 bar and whether I need it or not as the book lists it for ladderbar and fourlinks but I am running leaf springs. The local chassis shop says to put it in just below the shoulder bar that even though it will not be utilized as a suspension attachment point it is still required. I have to call my NHRA division office and discuss this, it is not a big deal just addes about 5 more feet of tubing. I will be buying a funny car conversion kit for mine and with the additional tubing believe the materials cost will be ~$400 then $200 for the inspection.
 

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The #15 bar is the lower horizontal cage support and it is required. The #18 bar lower vertical cage support is not required on all cages. The #15 Bar is what your funny car cage will be hooked to. My SFI spec. are dated 6/10/02. I've looked at all the changes and I think you still need #15 bar.
 

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The #15 bar is always required on all of the above mentioned SFI "door car" specs. The minimum tube OD & wall required for the #15 bar depends on a number of things like material used, driver placement in relation to the main hoop, and if it's a 4-link vs ladder bar setup.

The #18 bars are always required on a ladder bar car. On a 4-link car the #18 bars may be left out if the 4-link brackets (A) attach/weld around both bar #1 & bar #15 by at least 180*, (B) are made of the required thickness (C) are boxed at the front with the correct material & (D) each pair of installed & boxed brackets have the required total outside combined width. In this situation the boxed 4-link brackets take the place of the #18 bars.
 

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Discussion Starter #16
Ok then I guess my confusion is do I use the #15 bar as the shoulder bar or do I need that above the number 15 bar as well? The chassis shop told me the #15 bar should be just above the floor about 6 inchs and to also put in a shoulder bar but the book does not show just a shoulder bar?
 

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If you are doing a cage for 8.49 and quicker Door Car you don't need a shoulder bar. You need a funny car cage witch replaces the shoulder bar. If you make your cage like the picture shows and you will not have any problem.
 

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Like jarhead said the "nhra/ihra" shoulder/seat cross bar isn't needed on a SFI door car cert because the FC cage & #15 bar is required.

The height of the #15 bar above the floor (and/or the #1 bar) is determined by many factors when building the car. At the very least the #15 bar needs to be high enough up in the car to pass over the top of the driveshaft with enough additional clearance to allow for full vertical driveshaft/suspension travel so the driveshaft never hits the bar at any point in the travel.

So as an example a low slung full chassis car with the #1 bar only 4" off the ground, that also has super tall 34.5" slicks, is going to need the #15 bar installed fairly high in the car above the #1 bar/floor to clear the driveshaft (around 12+" is common in this example). But on the other hand a back-half car with the #1 bar around 7" off the ground, and say with 31" tall slicks, isn't going to need the #15 bar installed as high above the #1 bar as the full chassis example does. In this example the back-half car might need the #15 bar only around 6, 7, 8 (etc) inches above the #1 bar/floor (depending on the combo).

In the past I have seen a few guys install the #15 bar so high in the car that it in effect took the place of the shoulder/seat cross bar, even though it didn't need to be installed anywhere near that high to clear the driveshaft. There isn't really any problem doing it this way other than you do end up using more tubing than what is really needed to get the job done.
 

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Discussion Starter #19
Ok now that you mention the #1 bar I have a new question, I am doing this with a truck and used .120" wall 2x2" square tubing as outriggers which I mounted up tight to the floors to keep them concealed. Can I use 1 5/8 .134" wall DOM to run on the outside of the frame from the bottom of the framerails up to the outriggers then run same thing on the inside of the frame rails to make the #1 bar, the SFI book says a maximum 3" bend is allowed which would seem perfect to do that? I would end up with a \I__I/ shape if you were looking at it from the rear, although not quite that much angle (lol).
 

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I'm kinda confused, can't picture exactly how the 2x2 "outriggers" you mentioned are installed under the truck. Might be an idea to post a pic of them.

Are they each way out next/parallel to the body's rocker panels, and act as the #7a-7b "rocker bars"? Or are the outriggers inboard some and act as the "inner frame rails" (the #2a-2b bars)? If the 2x2 outriggers are in fact the "rocker bars" (7a-7b) the 2x2 material is too small to be the driver side rocker bar (7a), but is OK as the passenger side rocker bar (7b).

As for the #1 bar my 25.5 copy doesn't mention any bend limit to that bar (3" or otherwise) that I can see. Maybe you're thinking of the center section-forward crossmember bar #6c, (aka trans crossmember bar). It (6c) does have a 3" bend offset limit.
 
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