bjhines

Before you go and find your calculator... The type of tubing and the way it is formed will greatly affect it's performance... You need a lot of information about specific tubing types... The other issue is that you have only a general idea of how much force will be applied... this will vary from car to car depending on chassis modifications, spring rates, tires, overall weight and balance, brakes, engine power, driveline mounting, suspension geometry, track surface, etc., etc., etc....

The best bet is to look at what is being used for similar weight and power cars... 1" OD seems pretty common... That is what I used... Swedged aluminum tie-rod tubes with lightweight aluminum rod ends would be great... but they will wear out(threads in tubes gall, aluminum rod ends may pound out in sizes less than 1/2")... sourcing aluminum jam nuts and gun-drilled, ball-milled, titanium attachment bolts would be ideal...

Well... For a budget.... Running hardline will double the number of fittings you must purchase... Running a long hose is usually less expensive if you stick with the cheap hose... Cheap hose may end up costing you more in the long run... It will wear out... especially if it is exposed to heat and the elements... but it can get you on the road for a few seasons before it will need to be replaced... That said.. I recently saw a car plumbed with hardlines and the most expensive hose and fittings known to man... (3/8" hose to the tune of $36 per foot)... If you plan on going with autoparts store rubber hose and barbed fittings... You should get high quality fuel injection grade clamps... Hose clamps tend to extrude the hose over repeated cycles of heating and cooling... they will gradually loosen no matter how tight you screw them down initially... in fact, you should only tighten them enough to seal the first time... overtightening the hose clamps can make the hose extrude faster and in a more leak prone manner.... I would use only crimped-on hose fittings in places where I could not easily reach for repairs... Crimped fitting are superior to all of the other fittings available... Crimping sleeves provide optimum clamping force under all conditions and allow expansion and contraction of the hose materials without extrusion... BMW uses a cheap verison of this type of crimped clamp for use on normal rubber hose and fittings... Hardline has MANY advantages... but it adds cost and complexity... hose shielding/insulation/sheathing can extend the useful life of any hose... especially if it is exposed to heat, elements, bending, or abrasion... but it can add a great deal of cost... I would advise against running fuel hoses through the interior... many people do this... but in an accident there is great risk of fuel lines getting severed where they enter/exit the chassis... possibly spraying the driver and interior with fuel...

Read the rules for the class you plan to enter... Generally speaking... anything NOT attached to the cage is open game...

I just picked up the March issue of Sport Compact Car and was reading the article on the COVER CARs... Autobacs ASM S-2000 and the Dent Sport 240RS MAXI These are some highly modified purpose built TRACK CARS... There is lots of cage work and lots of expensive hardware.... all in all they appear to be FULL RACE cars with no streetability left in them... as I was reading along I found that they were tested at Virginia International Raceway... I just compelted an event there THIS PAST WEEKEND... The Autobacs S-2000 ran a 2:28.187 lap The Dent Sport 240RS ran a 2:26.136 lap Quote: Sport Compact Car ""Believe what you want. But the fact is the car rockets around Virginia International Raceway with a vengance, netting ASM lap times in the two-minute, 28 second range"" I was instantly chuckling... How could such a highly prepared... Cover-Story pair of cars be so damn slow??? I ran a 2:26 lap with my BSP 240Z.. easily... I can shave a few more seconds on a warmer day with a track surface temp above freezing... and not to mention I run Toyo RA1s... I can easily shave some more time off with full race slicks... My car has it's original L24, 4 speed, open diff, sport springs, tokico blues, ST sway bars, stock upper mounts, too little camber, not enough caster, 15x7" wheels with relatively small 225/50/15 tires... What I am getting at is... I could buy and prepare a 240Z to kick the Cover Cars' tails up and down the track... for less $$$ than the wheel and tire package they put on those cars... WHAT A JOKE!!!! Here is some vid from my SUPERCAR TRACK TIMES.... ....

You can't make analogies that don't represent the real conditions... Your chassis does not "grab the middle of the bar and bow it"... In fact... by looking at this in that way... You are comming up with exactly the opposite of reality for a straight tube... I see your thoughts on this.. I understand that you figure a rigid structure is always stronger than a hinged structure... But that is simply not the case... Look at large stadiums... The buttresses under the stands are commonly mounted with a large hinged joint... to aviod any tendancy to bend the supports.. which could cause them to collapse... If you must make a bend in the bar/tube... then you are getting into an entirely different situation... If the tube is bent.. then it will gain some strength from a welded/solid mounting...

An easy way to get some redneck camber is to purposely reset the angle of the castings on the strut tubes... you have to grind the welds on the bottom of the strut casting(that hold the tube in).... Then heat the assembly hot enough to loosen the brazing(they did this at the factory to hold it in position until it was welded)... Set the new angle and weld it up... Violla... free camber with original parts... Though...This takes 2 people and some teamwork with the torch and leverage... It takes a lot of grunt to get any results... and you can warp the tube to the point the cartridge wont fit...

You won't likely need any more rear camber... and rear toe would require the G-machine offset bushings.. If you buy into the G-machine bushings then you might as well do all 4 corners... then you can get ~some camber in the front end as well... caster in front is tough to get enough of without modifying the front suspension... but you can sometimes balance it out with a few well placed washers... A lot of the problems you run into are realated to past accidents... Camber: Camber is usually way off left to right on the front end... Camber problems can be due to the strut bottom castings getting knocked crooked on the strut tubes... That can sometimes be fixed(check for cracked welds on the bottom of the castings too)... You can check each strut by measuring the distance between the rim and the strut tube... they should be the same left to right... an old cheater set up was to purposely bend them to gain more camber(especially on front)... Camber problems can also be the result of the frame rails getting knocked out of square with the strut towers... they can be moved one way a half an inch and it can wreak havoc with camber settings... One way to fix this is by slotting the crossmember mounting holes enough to move it slightly left or right... you can usually get camber even left to right with this simple fix(one side is slotted from the factory)... In general the front ends have the most pronounced problems... Ohhh... a note worthy of looking into: Many people have replaced the Tension-compression Rod (TC-rod) BUSHINGS with harder ones... This can lead to bending and eventual failure of the factory TC rod(right where it is necked down)... many TC rods are bent already(check it by rolling it on the edge of a table)... You may need to asses the condition of your TC rods before you go slamming it around the racetrack... Motorsport Auto sells a ball and cup TC rod kit that allows freedom of movement with a stiff support... You should always use a factory-soft-rubber bushing for the inside(rear) bushing on ANY TC bushing SET UP...(this is where the leverage to break the TC rods comes from)...

You can't really do much with the stock 240Z parts.... but we need to see the alignment numbers for all 4 wheels to move on from there... You want to get a little toe out in front... just a hair.. or neutral... Beyond that.. you need aftermarket parts to do anything else... Once you get the numbers for your alignment.. then post em here and we can give you some ideas for getting it sorted out... a lot of improvements can be made without a lot of expensive parts... but we need to see the state of things to start off with... In addition... shifting some weight to the rear ~can~ improve things greatly... Removing weight from the front end can make noticable improvements as well... Optima makes a GROUP-24 sized battery that can knock 20lbs off the high front(moving the battery to the rear is stage II)... removing the air pump and anything emission related in the engine compartment, aluminum radiator, lightweight headers, basically remove anything that isn't needed to run the car will help a great deal with handling...

Align It!!!!!

I like the ZZ4 because it is realatively inexpensive for a NEW MOTOR... and over 300HP... in stock form it has over 400ft-lbs of torque at relatively low RPMs... it will be VERY satisfying to drive around town or on the track... and it has plenty of potential for future upgrades... first off being the valvetrain... I have been told that the bottom end is reliable to 6200 RPM in constant use... it is the top end that will suffer from high RPM abuse.. and that is relatively easy to improve under the shade tree... The ZZ4 is DEFINITELY my engine of choice... especially since it even comes with a dealership warranty... If it fails I just drop it off on their doorstep... no $$$ shipping for me...!!!

There is a good deal going on the GM crate ZZ4 engines... they are light and powerful... and they are $3800 new with warranty... best of all.. you can have them delivered to your local GM dealership so shipping is not an issue... I have heard good things about the ZZ4 from some professional race team managers... They have a 10:1 C.R. aluminum L-98 heads forged steel crank PM rods forged pistons Hyd roller cam The only downpoints seem to be in the valvetrain... stamped steel rockers and stock rocker studs... You could modify the valvetrain and change cams to come up with a few more horses easily... It looks like the bottom end could handle more than 5800RPMs max suggested

You might just try getting it aligned.... generally neutral toe or a little TOE OUT IN FRONT is the ticket for performance driving... make sure camber and caster are in spec... actually get as much camber as you can in front... alignment is usually responsible for 90% of the handling problems I have seen on club member's Z-cars...

L28 with flat tops and a nice head with an agressive cam... compression ratio to match cam... That will get you a nice NA motor with an easy 200HP... you won't need to wind it to 7kRPM with that combo.. so the SUs will work OK... Z-Therapy has nicely rebuilt SUs that will give you even better performance and better reliability than brand new... They can breathe to about 5600RPM... You will need triples or F.I. for High RPM... post some pics when you get it home.. we can offer suggestions once you get the car in hand...

you could simply change the dimensions to accomodate stock angles... It will get close to the handbrake hardware if you try to raise it more than 1/2"

I have been quite busy this month... I have a hatch sitting on my workbench with the glass removed awaiting completion of the Pantera mod... several of the sideskirts and airdams have been procured and fitted... We have quite a long wait before test day and things are moving along slowly...

Increasing front spring rate will reduce pitch... This is not immediately intuitive... There is more "windup" or length of compression in a weaker spring... In effect.. the wheel will still have some spring tension on it even at relatively long extension... Where the stiff spring will move only a small amount before it begins to rattle loosly on it's perches... When you jack up a race sprung car this becomes instantly obvious... you only get a few pumps of the handle before the weight is completely off the wheels... Under acceleration the front end lift gets very little "help" lifting because there is so little windup in the stiff springs..If it moves a little more than an inch then the spring is no longer helping at all... where the stock springs have several inches of windup.. the front end gets a "lift" from the springs all the way until the struts fully extend... even further because you actually have to compress the springs to remove them at FULL EXTENSION...

We have 2 current builders(J.M. and I) who have ample evidence that this IS NOT STIFF ENOUGH... There are 2 gussets inside the upper torque box(cowl box) that tie all sides together... they are fairly far apart... I have seen numerous designs that span these 2 points on the engine bay side of the firewall... This is one step to attaining a strong mounting point.. BUT!!!! there is a caviat... The driver's side internal gusset does not continue to the inner cowl panel of the torque box.. It is cut off half way to allow room for the wiper arm inside the cowl... That also allows a great deal of movement on the driver's side even when you span the 2 intenal gussets... The driver's side gusset needs to be extended all the way through in order to provide stiffness... ANY ATTEMPT to put pressure on the center of the firewall without addressing these issues... 1. will cause the upper lip of the cowl box to flex.. It bends upwards in the middle... 2. improper reinforcement will simply cause the windshield mounting lip to flex(also part of the cowl box top) 3. failure to modify the driver's side internal gusset will cause the entire cowl box to flex on one side... especially at the lower windshield lip.... If any of you wish to dispute this fact then I can produce a video showing the amount of deflection, approximate pressure to delfect and the total amount of deflection on a dial guage... That is a fair amount of work.. But like I said.. You provide some personal experience and/or proof one way and I will provide proof my way...

and I would add that closing the top of the rectangle will not stop the structure from warping into a parallelogram... The triangle to the center firewall is an indirect approach.. but as John C. said... it is the most important approach in real life...

They only work in tension and compression.. the typical cheapo heim joints are rated to ~5000lbs... they don't give under tensile loads... The round plate is redundant weight... attach to the 2 bolts.. that is it... keep in mind that a lot of us dont have bolts anymore.. we have fabricated brackets that are welded to the tower top plate... the idea is to use several bars to triangulate the structure... all bars take tensile loads only.. no shear no twist... you won't get shear and twist strength from a long tube no matter how you attach it...

Even my heavily modified front end structure MUST HAVE some removable components... the strut bars cannot be welded to the chassis.. This is simply not an option... So we can assume ALL FRONT strut bars will be BOLT ON... I did weld my rear strut bars in place... to save money and weight if nothing else... So what is the difference between a strut bar using Hiem joints and one using BOLTS???? They dont take bending and twisting loads anyway... How on earth does leaning on your bar at home represent anything that they will go through in use???? There are so many more points that ARE IMPORTANT in designing your strut bars... Heim joints affer a lot of other advantages... The structures the strut bars attach to could benefit from some modifications... For instance... 1. the tops of the towers have a thin layer of metal skinning a thick steel plate.. it is important to weld through the thin stuff in order to get a good connection to the heavy steel top tower plate.. 2. The firewall connection is totally unacceptable without modifications... The easiest way to avoid the weak/flexible center firewall is to go right through it and attach to the roll-cage dash-bar... but that eliminates factory windshield wipers... 3. eliminating twist in the towers is more easily accomplished using gussets and/or additional welded bars that run to the sides of the firewall and down to the frame rails... 4. The connection between the strut tower base and the frame rail is practically NONEXISTANT... there is only ONE layer of 24guage metal... hence the gussets I added to the frame rail tower interface... 5. the rear strut bars can and probably should be welded in place... but AGAIN the sheet metal skinning the top tower plate must be welded through to attach to the heavy tower top plate... there are actually several light guage strips of metal near the tops of the rear strut towers... these must be cut back to expose the heavy guage top plate for welding... 6. vertical bracing is not easily accomplished with removable strut tower bars... although I have seen some neat ideas for this... I would have to test them myself before I believed they work... I have seen dozens of S-30 z-cars using a triangle front brace attached to the center firewall... I have on several occasions asked about the ridgidity of this attachment point... everyone I have ever asked has said "It's fine... the firewall is stiff enough" I can say from direct observation that THE FIREWALL IS NOT STIFF ENOUGH TO BRACE AGAINST IT WITHOUT SERIOUS MODIFICATION...

I see your point... Bent bar vs. high offset mounting... That would require a detailed analysis to determine which designs are actually better... this would depend on the type of tubing and size.. as well as the structure used for an offset mount... there is a happy medium in there somewhere between the 2 approaches... But Hiem joints are a handy dandy way to build a better bar...

Dudes... Have you ever noticed how thick the upper mounting plate in the tower is???? Besides that.. the upper insulator is a mighty thick piece as well...The strut bar mount does not need to wrap around the top or anything crazy like that... There are already several layers of thick metal... The bar is pretty easy to bend... So what if you have hiem joints or not.. the damn bar will twist with very little resistance... hiems or not.. the bar only ties the 2 sides together... It works in tension and compression.. not in sheer or twist... I cannot believe no one here has really addressed the issue I have with many of the designs out there...!!!??? High offets from the mounting plate to the actual bar itself... Now that is friggin stupid... I realize they needed engine clearance... but I would rather have a slight bend in the bar instead of the highly offset/raised bar in relation to the mount... I think a lot of you are imagining that these bars do more than is reasonable to assume... Explain to me how a Heim joint is any worse than a nut and bolt..???? especially considering that the damn strut bars ONLY WORK IN TENSION AND COMPRESSION??? splain me that one...

Whoa on the heim joint bashing... As long as the braces are as straight as possible.. and their mountings are not offset or poorly designed... Heim joints are perfectly acceptable... and mighty damn handy when you want a little preload one way or the other... This is my heim jointed upper front brace.. and the firewall is reinforced as well... I like this strut bar.. but it can be a pain to reinstall... and it is not a triangle brace...

Those carbys would work fine in a warm climate... But they are stupid trouble in cold weather for most folks... In any case.. Your biggest hurdle is going from a low maintenance modern car to all the regular headaches of an old carburated car.. with POINTS ignition no less... Even a fully restored 1972 240Z with completely new, concourse winning mechanicals is a pile of headaches compared to a modern car... If you want things to work a little easier... you should convert it to a later fuel injection system... That does require some mechanical abilities though... I went the opposite direction with mine.. I race it with triple webers... and man does it fly... but it is 10 times as complicated to tune...