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chassis reinforcement


Guest tejas74260

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The first sets of 240 full length frame rails were shipped out this week and sometime next week we hope for the reviews of our new product to be posted. The rails go from approx. 9 inches in front of the firewall and tie into the body cross member in the rear wheel well. They are made from 12 guage steel, come in two sections, and add 23 lbs to the car.

 

We strongly believe these to be but one of three things needed to strengthen your Z. The first being a cage. The second being a triangular front strut tower bar, and the last is our frame rail caps.

 

After I replace the camera my teenage son dropped three days ago, I will post pics of the rails. Most likely this weekend.

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gnosez are you the baddogparts dude? if so, thanks again! ill get some finished pics to you when i can so you can post em on your site. bjhines here is another quick drawing (in between classes) of a generalized cage that would need some anglework in my stress analysis programs.

overall design is good IMO just a little more thought needs to go in to some of the parts. red is an optional side gaurd strengthening bar, if its a street car you wouldnt want this because it would be a PITA to get in and out.

cage2.jpg

again, some of the angles are off, like the front frame rails (rails are inside wheel bulges not outside) but you get the general idea of it. hope it helps with a design of your own.

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Yes, the bar going between the rear strut towers is welded to them.

 

These are the only pictures I could find of the front inside of the car.

 

PICT0050.JPG

 

Here is a picture of the interior after it was reassembled.

 

PICT0038.JPG

 

The tubes of the door bars penetrate the floor, and are welded to the cluster in front of the firewall, and attached to the front of the rocker panel with a gusset.

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Some of the issues that I had to overcome in the construction of my chassis are the same as ones that you will encounter with add-on reinforcement.

 

First, the z car is very narrow, and space within the passenger compartment is at a premium. In order to not crowd the driver more than absolutely necessary, it is mandatory that the main hoop is constructed to fit as tightly as possible to the B-pillar and roof. This foundation allows all attachments to the main hoop to be place as far away from the driver as possible. For a street car, the door bars cannot penetrate in to the door (much), and if they are being relied upon to provide fore and aft stiffness, they should be straight and triangulated.

 

Second, the cowl area limits the height at which tubes can penetrate the firewall. In my design, I wanted to not modify the cowl and I also wanted to have the load path of the tubing go from the front strut tower, through the door bars and to the attach point of the main hoop. In order to achieve this, my door bar starts at the bottom of the main hoop and proceeds at a shallow angle to the highest point of the firewall allowed by the cowl. There, it penetrates the firewall and joins a cluster of tubes that proceed to the frame and strut tower. The shallow angle of the lower door bar forces the intersection point of the two door bars forward and down. Keeping the intersection point of the door bars low and forward has the benefit of making it fairly easy to get in and out of the car. In the following image you can see where the door bars penetrate the firewall and join the tringulated tubing thatsupports the front strut tower and frame. Here you can also see that the tubing has to be place as far ouboard as possible to clear the clutch master cylinder.

 

FrontEnd.jpg

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gnosez are you the baddogparts dude? if so' date=' thanks again! ill get some finished pics to you when i can so you can post em on your site. bjhines here is another quick drawing (in between classes) of a generalized cage that would need some anglework in my stress analysis programs.

overall design is good IMO just a little more thought needs to go in to some of the parts. red is an optional side gaurd strengthening bar, if its a street car you wouldnt want this because it would be a PITA to get in and out.

[img']http://i11.photobucket.com/albums/a172/djpaul8/cage2.jpg[/img]

again, some of the angles are off, like the front frame rails (rails are inside wheel bulges not outside) but you get the general idea of it. hope it helps with a design of your own.

Looks like this design shows the hoop attaching to the rear strut towers. Can't really do that because the rear strut towers are well behind the roof crossmember. Also I'd forget about bracing to the very back of the car unless you're particularly worried about impacts to the rear. More important to brace the strut towers as much as possible since they're flexible and control your camber angles in turns. Since the main hoop can't really do that as your drawing shows (unless maybe 2+2???) your cross brace can attach to the strut towers - that's how johnc did it. But attaching some substantial part of the cage to the strut towers is very important.

 

I love 74's car but I'm not that talented. My solution is to stitch weld the chassis, install a roll bar that attaches to the roof, the rear of the rocker panels and the strut towers, weld in rear strut bar, triangulated front strut bar, and Bad Dog's new subframe connectors. I'll probably have a couple more braces here and there, but that's the main part of the structure anyway.

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I have been told that the rear X brace is not of any real benefit..aside from rear impact protection... I think I'll save the weight...

 

It looks like the subframe connectors are IN...

 

I likw the idea of tying the "door bar" into the rockers AND frame rails/tcbuckets.

 

It looks like i will use the design of my existing hoop and add the front half in the new 240Z...

 

My current track 240Z has a half cage...with the hoop tied into the lower frame on the lowest "shelf" behind the seats... the rear supports are tied into the front tops of the rear strut towers with a gusset plate... there is also a diagonal brace frmo the top left down to the bottom right joined to the hoop and floor frame.. and a seat bar that is curved on the ends to provide extra clearance...there is also a cross brace welded between the rear supports close to where they tie into the strut towers...

 

 

I have not tied this into the roof of the car or the sides... only the rear frame and the strut towers.... I notice that there is quite a bit of movement in the roof frmo side to side... It is enough to drive you crazy with squeaking noises on the dome trim panel...

 

I would love to know where to buy the sheet metal punches that press the lipped lightening holes for the roof/A pillar gusset plates...

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BJ, I was told by Mitch at Piper motorsports that they just buy them pre-fabb'ed in large sheets. You could probably find them at one of the many race car fabrication shops online. I love mine. Makes the whole application look trick as heck! :2thumbs:

 

Mike

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i wasnt thinking the rear xbrace did much either, i was just using what ive seen in a few track cars. so cross that out, lol. when i actually have time, if anyone is interested, i will actually take measurements and draw a design out. i created those pics in under 5 minutes to give a general idea and i know some of the placement/angles are wrong. hopefully it still helped some people though.

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How many X's can you spot in this picture? http://rally.subaru.com/rally/servlet/CarBuildingDetail?part=1&imageId=23

 

Another cage with a big X from the hoop to the rear suspension pickups. http://e30m3performance.com/tech_articles/cage_symposium/e46-1/index.htm

 

IIRC the old SCCA rules said you could run a diagonal brace from the driver's side head area to the passenger floor, or you could run an X back to the strut towers. John Coffey chose the X to the strut towers which says a lot, but that was back when you could run 1.5 x .090 IIRC.

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Thanks for the linky Tube80Z....!!!! Jon.. those BMW E46 pics are great... The Subarooo is wayyy over the top for my track car... That thing could roll 50 times down a sheer cliff and drive away with bent rims..

 

I am somewhat boggled by the list... I own a complete electricians set of Greenlee punches 3/4" up to 2" conduit... with multiple bearings and bolts... $450 set plus a few individual extras... I think I will only need the top listed set..assuming I can fit the Greenlees inside with no problems..??? ..

 

 

I need to figure this out before I purchase the wrong things...or half the equation if I need thier punches too...

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I am somewhat boggled by the list... I own a complete electricians set of Greenlee punches 3/4" up to 2" conduit... with multiple bearings and bolts... $450 set plus a few individual extras... I think I will only need the top listed set..assuming I can fit the Greenlees inside with no problems..

 

I use a holesaw or step drill to make the base hole. Then I use these to flange the edge. I'm not sure that helps. The flangers inside ID is the hole size. So if your punches make that size hole then it sounds like you only need what's on top.

 

Cary

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I figured it out.... I only need to use one side/half of my hole punch set... the other side is entirely replaced by the flaring cup...I can use them with the greenlee punches... hole sizes are faily accurate for both designs.. soo they should work easily together....

 

This is a wonderful find... fairly affordable for a cool custom fab tool...

Thanks again Tube80Z!!!!

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  • 4 months later...
Guest jjs6996

i am new to the club, but i have been whating to do the V8 swap for quite some time now. i want to put a 350 stroker (383) with a 700R4 trans in a z:D, origonaly into a 280 bcause of the extra body reinforcements, saftey stuff, suspension (R200 rear end, sway bars, etc.) which all add weight. i am going to reinforce the body anyway and put a rollcage an some kind of sub frame. but most people seem to have a 240. basicly i just want to know what some of u guys recamend between a 240z or 280z?

it will be a street/ strip and occasionally some canyon carving

 

i was going to say more but its getting late so...

 

thanks for any and all replays, thoughts or comments. sorry for the long story, thanks for ur time, and the chassie reinforcement ideas and plans they all help a bunch

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