Guest tejas74260 Posted November 27, 2004 Share Posted November 27, 2004 alright i know its been covered a lot...but i couldnt seem to find the right solution for me. does anyone have an opinion about how much work will i need to do to the rear suspension to be able to take a max 400lb/ft of torque (street driving)? once again i looked it up in the archives and i couldnt seem to find a clear solution. thanks. Mark Quote Link to comment Share on other sites More sharing options...
Dudeboy Posted November 27, 2004 Share Posted November 27, 2004 Got to Pete Paraska's site "Alteredz" it has some of the best information for structural integrity. Mr. Paraska is a Admin and moderator of this site as well so he and a few others can point you in the right direction. Quote Link to comment Share on other sites More sharing options...
Guest tejas74260 Posted November 27, 2004 Share Posted November 27, 2004 yeah i know i've gone over his site a lot...im not sure if im up for that much modification though...maybe possibly strengthening the rear rails and adding a 6 point rollbar would go a long way...but i dont think im up for the surgery that his car went under...either way let me know what you think Mark Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted November 27, 2004 Share Posted November 27, 2004 What year Z you are driving will make a big difference in how many structural problems you could see. The earlier years flex more than the later ones. Pete's subframe connectors are a bit more elaborate then most guys may want because he was completely replacing the floor boards anyway. IMO if you will add a lot of rigidity of you just remove and/or replace the existing subframe connectors with heavier steel, and running them completely from the front to the back. Still requires welding (which requires a good bit of undercoating work), but not the the level Pete did it. I have also seen a post where a guy sold this flat U channel that could be run along the floor boards on the inside of the car. there was some question how much rigidity that would add, but seemed easy enough to do. I was in a drywall shop earlier this year and they sold formed metal structural bracing for different purposes. They sold a T shaped piece that looked like it could be used in various capacities to stiffen a Z. Most people gravitate toward 1/8 inch steel channel. While easy to work with and undoubtably strong, you can get more rigidity with less weight by using formed sheet metal. Some time back there was a guy in LA offering a convertible kit. The kit had bolt in subframe connectors that included cross braces in the back. Do a search and see if you can find the specifics of that kit. Of course front and rear strut tower braces are a must. Running diagonal braces from the front towers to the firewall seems like a good idea to me. Quote Link to comment Share on other sites More sharing options...
Dudeboy Posted November 27, 2004 Share Posted November 27, 2004 Up to 400hp/torque and how you drive will direct how you maintain the Z structural integrity. Me and my Dad were considering dropping a GM ZZ430 clone in my Z (1977 280). I came to the conclusion for that amount of horsepower and the way I plan to drive(street/track) it would be too much for the unibody with just doing the minimal support mods like strut braces and a roll bar for safety (4 point). I am sourcing parts now and looking at between 300-380hp just so I do not pop windows A Chevy Vega twisted is a wild sight I can only imagine what it could do to 240-260-280. Your plan is more in depth than mine so outside of the minimim mods keep in mind how you are going to drive and the added weight and rigidity. I will know soon. Quote Link to comment Share on other sites More sharing options...
Guest tejas74260 Posted November 28, 2004 Share Posted November 28, 2004 so to avoid having to go to the extent pete did on his car...if i just have the front and rear rails tied together by connectors would that benefit me very much? plus add the rest of what i was talking about (4pt rollbar, heavy-duty cv axles)...could all that work well to sustain the absolute max of 400lb/ft of torque load i would plan to have? it will be mostly street driven with a few trips to the track (pissing contests) tied into that..but anyway....thanks for the help ya'll Mark Quote Link to comment Share on other sites More sharing options...
qwik240z Posted November 28, 2004 Share Posted November 28, 2004 Here is the a link to the eBay auction for the convertible kit with the subframe connectors. You can contact him and see if they sell them seperately. I would think they would. http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=4506342025&category=10076&sspagename=WDVW Quote Link to comment Share on other sites More sharing options...
240Z2NV Posted November 28, 2004 Share Posted November 28, 2004 The shell that I bought for my hybrid had some THIN subframe 'connectors' like some seen on eBay. They were crap, and you don't want to cut corners when it comes to chassis reinforcement. I welded 1"x3" channel/box steel from front to rear (subframe), and it will do ALOT for chassis strengthening. The triangulated strut tower bracing in the engine compartment will pretty much do the rest. I know guys that have just done that, run NO sway bars, have good coilovers and adjustable struts, push 400 ft./lbs. of torque, and the car handles well. Not race track well; but very well for spirited street driving. There are alot of engineering geniuses on this site, that have done some inspiring mods to their chassis and suspension. You just have to decide what YOUR limitations are: $$, time, skill....... A guy who has raced alot of Zs bought one of my shells recently, and he told me that as long as you connect the subframes WELL, and do the front triangulated bracing, you will DRAMATICALLY enhance the stiffness of the car. He went on to teach me ways to 'tie the drivetrain together' with long 'rods' connecting the diff to the transmission. The focus should be on tying the drivetrain together and stiffening the 'frame', and the body will not be a consequence. My .02 Quote Link to comment Share on other sites More sharing options...
Mikelly Posted November 28, 2004 Share Posted November 28, 2004 At a minimum, You need Pete's frame rail design. We are having his framerails put in Jim McNemar's GORGIOUS wide body Zcar. Jim was going to coil overs and 325 springs in the rear with 300 springs up front. His floor pans and frame rails were very thin, so we contacted a local fabricator, I printed out Pete's frame rail blueprint, and the guys at the shop copied them to a "T" and then commented on how well done the design and instructions were. Next on the list for Jim's Z is the cage. His car is going to see some track days. So we're having his 355 Chevy motor fortified with goodies, and plan to make closer to 500 Crank HP... We'll be adding an 8-10 point cromoly cage to his car to make it safe for Jim. We'll also be putting in a fuel cell... Now Keep in mind, this is STILL a street car. I'd consider a 6 point cage, as I've seen the seems in the roofline pull appart, as well as the TC boxes seperate under torque loads in heavy cornering. Mike 8) Quote Link to comment Share on other sites More sharing options...
SHO-Z Posted November 28, 2004 Share Posted November 28, 2004 Here is how I reinforced my convertible with 2"x1" tube stock. For a V8 I would add "X" bracing between the rails. I did extend the rails further back and rolled up the ends. On a convert there is some torsional flexing. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted November 29, 2004 Share Posted November 29, 2004 Someone correct me if I am wrong, but it looks like Pete's connectors extend both above and below the stopck floor pan. So to put in Pete's stuff does that mean you need to cut a strip of metal out of the floor pans to properly center the connectors top to bottom? Great idea if you are replacing the pans anyway. But if you have a car with solid floors, why not attach something to the underside of the car only? I think it was Denny411 posted some pics a long time ago where he basically supersized the stock connectors and made them run the full distance front to back. Use heavier gage steel than the stock units, but I still maintain 1/8 steel channel is adding non-productive weight. Of course adding a pickup truck like subframe makes for convenient jacking points. I also think the best way to do this requires welding. IMO attaching the connectors to the floors along their full length is the best way to distribute the load evenly under the whole car. Also on that convertible subframe kit, does anyone know where the rear cross pieces mount? Are they only needed if cutting the top? Doesn't seem necessary for a V8 only upgrade. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted November 29, 2004 Share Posted November 29, 2004 Pop, I've had 5 Zs now with replaced frame rails/ Floor pans... Pete's way does something the OTHERS I had did NOT do. By cutting the strip out of the floor to accomidate the frame rail, you then can use some sheet steel (18 gage or thicker) on a 90 degree bend to tie the rails to the floor pans. This insures the rails are tied to the pan and that the pans won't allow moisture to get trapped between the pan and rail, and start a whole new cycle of rust prevention... Seam sealers can work, but after 17 years and 18 Zcars , I'm no longer a fan of 30 year old datsun tin overlapping any new construction. It also makes the rails look factory. Mike Quote Link to comment Share on other sites More sharing options...
nemesis500548 Posted January 30, 2006 Share Posted January 30, 2006 My target is 500 HP/ 500 LB torque, with mostly street use and occasional track. When I presented this to my local shop they suggested fabbing up an entire separate frame and mounting the car to the frame. While sounding good in theory, I'm concerned what this will do to ride height and clearance, as one of the benefits of a 240Z is it's very low to the ground. Also, this will be very expensive, like 8 to 10 grand. So will full length frame rails and tower braces be enough to keep all four tires on the ground? I'm not really concerned with time or money, but why waste it if you don't have to right. Quote Link to comment Share on other sites More sharing options...
turbo_fb Posted January 30, 2006 Share Posted January 30, 2006 Great picture from SHO-Z What would happen if u put a 500hp engine in a Z without any body reinforcements ? Also some great video's on this page on resturation: http://forums.hybridz.org/showthread.php?t=106731 Quote Link to comment Share on other sites More sharing options...
Clifton Posted January 30, 2006 Share Posted January 30, 2006 What would happen if u put a 500hp engine in a Z without any body reinforcements ? Nothing. With over a year at 533 rwhp and 570 rwtq I have only broke 1 U-joint. Quote Link to comment Share on other sites More sharing options...
boodlefoof Posted January 30, 2006 Share Posted January 30, 2006 nemesis, Building a full frame is one option that would work well, but only if done right. And, doing it right will involve cutting up your car a bit and lots of fabrication work. Ride height can easily be set in the design, but may (or may not) involve raising the floor. That said, I'm going to build a full spaceframe for my 240-Z. Quote Link to comment Share on other sites More sharing options...
dj paul Posted January 30, 2006 Share Posted January 30, 2006 you dont really need rear suspension modifications for a z to handle the power. the only real thing you would want are the subframe connectors everyone is talking about. since you are putting a v8 in the car i would definately put these in. theres a difference between a 500 hp v8 and a 500 hp straight 6 in terms of torque output and structural twisting. i suggest if you dont want to do too much work, go to [LINK]www.baddogparts.com[/LINK] and check out his rails that go over your existing ones and help tie in the front, even though i replaced my rails with thicker gauge alltogether, i put these on my car to help tie everthing together and to spread out the stresses. check out my website and keep in mind this is my first time doing all this work so you definately can do it yourself. i might in the near future design some bolt in subframe connectors for people who dont want to weld. bolt in would not do as much as weld on but it would still help. ill let everyone know if i do because im about to get to that design part on my car. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted January 30, 2006 Share Posted January 30, 2006 We've had members here with LESS HP who twisted their unibody chassis to the point that the doors would OPEN UP under hard acceleration. Remember, these cars weren't built with the intention of the torque loads being currently applied by higher HP #s seen in some of these Zcars. BY tying the front and rear subframes together, you seriously reduce the twisting effect applied to the unibody. Short of doing a serious cage in the car, framework Like Pete's (the alteredZ.com blueprints) will net you the absolute best tie in between the two ends of the plane that twist under hard torque loads. Add sticky tires to the 300+torque loads most of these turbo and V8 cars are now putting down and you'll accelerate the damage done to the unibody. You'll see the seams in the roofline at the a and b pillar (Rear hatch) start to spread as the body starts to twist. Anyone who does all this work to their cars to get the increase in HP, then stiffer suspensions and bigger brakes, but without the proper attention to the chassis, will certainly regret that oversite. Mike Quote Link to comment Share on other sites More sharing options...
nazar Posted January 30, 2006 Share Posted January 30, 2006 how much would an 8 point roll cage help? Thats what im getting and Im hoping, along with safety, it will tie the car together nicely for my estimated 400ft/lb of torque out of my lt1... Now, i wonder whats gonna happen when I hit the spray??? lol Quote Link to comment Share on other sites More sharing options...
Mikelly Posted January 30, 2006 Share Posted January 30, 2006 It really depends on the cage design, how it is tied in, and all the material used for the footers, backing plates and such. If you go here: http://photos.yahoo.com/dat74z and click on the new Zcar project folder, you'll see the way the footers were tied into the rocker boxes on my Z. Also, I'd shoot for removing that rear storage box and moving the rear footers up there onto that shelf area... You can see how mine was done in the pics. I still say, even with a cage, subframes are a worthwhile investment in time and materials. Mike Quote Link to comment Share on other sites More sharing options...
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