bjhines

Umm yes... curvies abound... I just want it stronger stiffer and twice as powerful...and not much heavier... <2500 lbs is what I'm shooting for... other than the straights...I really don't need anymore power to be fast... I just wan't to take my driving to the next level... learning to drive a lightweight car with <8# per HP is definitely going require a new level of skillz... My current car... mostly stock drivetrain 240Z VIR north course..Home base Click here to see Video Roebling Road... lots of fast sweepers..

I like what you did there for the rocker tips The cage design is THOUROUGH!!!

Does anyone have pics of the BRE rocker tip to tower reinforcement...???

here is the chassis dimension drawing to scribble on... http://i46.photobucket.com/albums/f127/bjhines/V8%20240Z%20project/roll%20cage/240Z_Chassis_Dimmensions.jpg

Here is the original chassis veiw to draw on... http://i46.photobucket.com/albums/f127/bjhines/V8%20240Z%20project/roll%20cage/240Z_Chassis_Dimmensions.jpg

Here are some examples of what I have found around... This is a pretty car... nice execution... but the door bars dont look like they meet all criteria... This one look like it would pass tech.. but does it really stiffen the chassis...???? I think this is Darius at work... he builds some mean machines.... This looks like an example of the cross brace in back... I pulled strings.. this is what you get... I was told that SCCA want's 2 door bars in competition.... an X welded in the middle is considered one bar... 2 "V" shaped bars gusseted together are still considered 2 bars.... I guess that is what i'll be doing.... it's just that most folks dont do this.. even in race chassis...

well... that is still an option.. though I was hoping to make a more simple design that allowed easier access.... My thought was that the design I have at the top of the page would still give me stiffness at the expense of being actual door protection bars... I would not want to make it anymore dangerous... but I was trying to be minimalist here and really focus on stiffness more than protection... I strung up the beefy x bar path on another car... man that is going to be a pain to get in and out of... ...

ahhh that makes sense.... Jon... how is your cage set up? in relation to this... what do you think about the low mounted door bars.???

A single diagonal and a harness bar are part of the design.... It sounds like I could remove the single diagonal and trade for the x to the strut towers.... ????... the knee bar is something I will have to look into... I'll pull a string today and see what I can do with it...

I overpurchased tubing for this project... I still have 2 uncut 22' sticks of 1.5" .095 DOM on the rack... I have plenty of 1.5" square tubing... I also have some 1" sq. tubing... I have a box of 50 preformed "taco" gussets... The problem is that it all weighs 200lbs... Keep in mind that I am using this car for Time Trials and track days... I only need a rear hoop with one diagonal and 2 supports... the rest of the cage is to maximize the stiffness of the car... and make my wife feel better.... I just got my instructor certification this year and I plan to make maximum use of it... I get a lot of seat time... but I am not at great risk of side impact collisions... rear impact seems most common... front end into Armco would be a worst case situation...

I like the ideas for the roof bracing work... that really makes the roof work for me to stiffen the strut towers... Can I do that with smaller tubing? I am using 1.5 .095 DOM for the main tubes... what would you use for the gussets and bracing...???? The ARB mounts are a part of my plan... obviously most folks go from the tower >>forward and down to reinforce the sway bar mounts... though Tube80s plan seems interesting.... Tube80s plan would need to be removable in order to allow engine installation... Tube80??? have you run a string along that path with a 1st gen SB350 in place????? the other thing is that the center crosspoint is in empty space... Is that a problem???? I like the idea for the rear (black lined X brace)... but is that redundant considering the sheer number of panels and frame rails involved in that area already...??? The K-member is a great idea... especially combined with tying in the rocker tips.... but does it allow the exhaust sytem to exit the engine bay??? I'm just concerned with access.... have you tried it before??? was it removable? John C. thanks for the chime in... I will be ordering a FG rear hatch from you for this project... Are you speaking of adding a second bar crossing below the dash and steering column...??? there is a dash bar in my plan.. but it is weird... I am trying to make maximum use of the original torque box in this area.... Most of you won't like it... but I am pretty fond of my bent dash bar...

try Photobucket... easy to use... man.. I tried the welding wire thing... but it does not take into account the Torque Boxes in the unibody design... how the hell do you model that easily...

very good points.... PnW.... thank you... I did a test on a section of the 14G square stock... I used a bunch of that stuff for a ladder rack at one point... I have several 20' sticks on the shelf... I drilled a 3 foot section similarly to what you see in the horizontal sections... I set it up on 2 "I" beams and tried to bend it... With my full weight jumping up and down on it I could not make it fail... however... a moderate blow with a 5pound mallet creased it and it failed easily after that... It seems that the tubing is incredibly ridgid until it is creased in a small spot.. then it will fail easily.... A full section without holes was MUCH harder to crease... more like contiuous pounding and jumping was required to make it bend.. even then the bent section had considerable stregnth... notice that I only drilled the top and bottom of the longitudinal sections... the horizontal sections are shorter and I beleive they are less stressed in an accident.. the tubing is only to support the fuel cell... and to replace the floor sheet and tire well... none of this was very strong to begin with... and I do not want to make the ends of the car any stiffer in an accident... think crush zones.... the subframe connectors have holes in the top section that will be stiched to the rust free floor panel...(original sheet metal will add redundancy on top) I also drilled access/drain holes in 2 locations on the bottom sides... these holes will aloow me access with the welder to better stich the ends to existing structure... I am trying to consider all of these points... water entrapment is a large part of considerations.... in far more areas than just the subframe connectors... The plan for hole punching follows original bends and beads... the rear cargo area is 2 layers thinck in areas... the top lip is untouched.. and many folks have cut out the entire panel... I also have a full cage in the car... soo I am relying on the cage to add more stiffness than would be possible with sheet metal in the first place... PnW.. I would like some criticizm on my door bar placement and the validity of my rocker tip/ to TC and frame rail supports..

there are a lot of finer points I do not fully understand about this.... various patterns and hole sizes are used on aircraft parts... this depends entirely on the shape and size of the panel and adjoining parts... If someone finds a good website for this please link to it....

I have gathered together a lot of pictures of what people have done to add cages and stiffen the 240Z chassis.... Tube frame conversions are too much for my tastes... too much to be streetable... IMHO... Race cages usually don't allow the doors to stay intact and they use "petty bars" that make the passenger seat useless... Bolt in cages and roll bars don't do much to stiffen the chassis... My car is rust free.. so front end/ frame rail replacement is overkill.... This is a rough picture of what I am doing.... ... The blue lines are "bolt in" tower braces... the rear has a diagonal to the floor... The green lines are roughly my cage outline... not exactly isometric but close... the red lines are door bars and strut tower extensions... (this is the area I need to decide on) the 2 yellow lines are rocker to TC bucket bars.... ( I would like some opinions on these....)

well.... there is a flat area on the outer circumference of the die.... it is there to flatten out the sheet stock with every hole... I have used lots of different things to do this for aluminum aircraft parts... the sheets always come out warped.... the Mittler Bros dies flatten the sheet back out with every hole... for $40 each I suggest you get the 1" greenlee punch and a 1" flaring die... it is a very useful size... there are different bead profiles as well.... I use a round flare....

In the HP vs weight argument.... My take on it is that... It is hard to use a lot of horsepower to it's fullest degree.... I drive a 240Z that only puts 160 HP to the rear wheels in track alignment... I can embarass factory supercars with my current lightweight/ low HP 240Z... especially at tracks in the South East.... I have wonderful video of my car chasing down 911s, 350Zs, Cx Corvetts, Mustangs, Camaros, BMWs... many of them highly prepped and on race slicks.... They leave me like I'm standing still on the straights... they get 100s of yards away.... and them im back in their tailpipe by turn 3 or 4.... on 17 turn tracks... they get passing flags at every station until they submit... I have a lot of fun with them now.... and I just don't see a lot of horsepower making a huge difference in my times... certainly not what most of you would expect.... That is why I am being so careful to make sure this is a COMPLETE transformatoin.... stiffer, stronger, lighter, balanced, and adjustable....

Mitler bros machine tools carry a whole line of punches.... I'll try to dig up the catalog.... someone here turned me onto them.... MikeKelly???

1972 240Z 2499 with me in it and 8 gal of gas.... LF:675 RF:611 LR:618 RR:595 1:30.2 lap at Roebling Road Raceway... ...

tough crowd... hey I just type this stuff out without a lot of political correctness editing... I am looking for suggestions... and feedback... I just get a little frustrated with some of the Why's... There is another thread about this same project active... I have posted dozens of pictures... It is just nuts for someone to pop in and say..."what a waste of time"... why would you do that?... provide ideas.. not naive critical blurts. This kind of thing has been done since men put things in motion... there is a great deal of hard science to back this up... punching, flanging, beading... it all matters to someone who want's to do everything possible to make their car fast on an actual race track... This is to be a no holds barred supercar... in all respects... 18 posts could be cut out of this thread because they go back and forth over the validity of lightening the chassis... rediculous... Please don't get too sensitive about my PC... I have a lot of friends in a lot of clubs... We can all deal with each other face to face without a great deal of PC editing in our communications..

If I weld anything to the backside of the visible body work... it will crease there and look ugly....

Hey nice work!!!!! .... I still can't agree with the pedal actually dropping all the way to the floor.... I think you will find that pedal to the floor is quite a bit different than the action you were describing....

I am pretty much ignoring anything aft of the strut towers.... all bracing will be tied into the cage BETWEEN the strut towers... I realize that this is technically not aft of the towers... but i have several tubes tying the towers inot the cage already.... I did box the tops of the towers this was because I am using this area to tie into the main hoop and cage... the B-pillar area that holds the door striker will be gusseted to the main hoop...

yea.. the cage can add over a hundred pounds.... but I swear I dont know what is keeping my current track car so heavy.... It seemed odd to me as well.... I have removed the bumpers and lightened the battery... most of the interior is still in place... no spare tire... of course... I weigh 170 pounds... so we are not far off... espcially considering mine has a cage...

I might be doing what you are saying.. draw me a picture and I will try to get one together for you.. There will be a firewall triangle brace.. removable of course... there is also a tube running from the back of the front tower through the firewall to the A-pillar bar and through the droor X-bar and through the hoop to the front of the rear tower...