Phantom Posted June 24, 2003 Share Posted June 24, 2003 I've read a lot of comments about chassis reinforcing for the V-8 installs. My '77 280Z currently has absolutely no chassis reinforcing anywhere. I've got strut tower braces that I haven't installed yet but right now there is nothing. I've been driving it with the LS1 & T56 for about a month now and haven't noticed anything bad happening. Someone want to chime in here and convince me I need to do something? Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted June 24, 2003 Share Posted June 24, 2003 I think most people add roll cages for safety, not stiffness. The ITS spec cage Katman posted an article for says the rules specifically limit the number of chassis attachment points and prohibit passing the cage through the firewall. good for safety in a roll over or collision, but I wonder if the limits are to force cars to race with closer to stock stiffness. Add some sticky tires and 40 or 50 more HP and you may not notice bad things until after they have happened. Also if I remember right you are running with fairly soft springs (Nissan Euro springs?) Like someone posted here once, if you stiffen the suspension, then the rest of the car starts to act like a spring. Maybe just the combination of relatively soft springs, street tires and lack of truely competative driving means you will not notice the body flex. The paint cracks on my stock 1970 240 tell me I need to do something, V8 or not. Quote Link to comment Share on other sites More sharing options...
auxilary Posted June 24, 2003 Share Posted June 24, 2003 280 chassis is somewhat more rigid than a 240. usually it's the early 240zs that don't hold up to twisting torque and abuse. Quote Link to comment Share on other sites More sharing options...
Phantom Posted June 24, 2003 Author Share Posted June 24, 2003 Thanks for feedback guys. Guess I'll look for the cracks in the paint. In the meantime I'll install the strut tower braces and just keep enjoying as a daily driver with the "occaisional" full throttle bursts. Quote Link to comment Share on other sites More sharing options...
Dan Juday Posted June 24, 2003 Share Posted June 24, 2003 I have to disagree with Alex (Gee, never done that before ). I think the late 280's are signifcantly stronger than the early 240's. Rory Bateman cut's the tops off them for his Tomahawks and adds NO reinforcements. I don't recommend that but I think it is a testamony to how much Nissan learned during the the 1st gen run. Quote Link to comment Share on other sites More sharing options...
Tim240z Posted June 24, 2003 Share Posted June 24, 2003 Keep an eye on the lead filled area in the 'pillar' between the rear 1/4 window and the edge of the hatch. That's usually the first place that you will see evidence of chassis twisting. The paint will begin to show hairline cracks. You will need to look really carefully. Tim Quote Link to comment Share on other sites More sharing options...
Phantom Posted June 24, 2003 Author Share Posted June 24, 2003 Know that area well. Had a minor problem there on my first 280. I'll keep an eye on it. Thanks. Quote Link to comment Share on other sites More sharing options...
mas28O Posted June 24, 2003 Share Posted June 24, 2003 I had low 11 sec 1977 280z for about 5 years without any chassis reinforcing. I never had a problem with anything, but this time I am going to run a cage and subframe conn on my 240z. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted July 6, 2003 Share Posted July 6, 2003 "Keep an eye on the lead filled area in the 'pillar' between the rear 1/4 window and the edge of the hatch." Tim 240Z I have two cracks going from my hatch running down and connecting to the rear quarter window driprail (don't know why I haven't cut it off though). On both sides in the same location. Its like in the C-pillar area but on the outside of course. Is that what you are referring to? [/img] Quote Link to comment Share on other sites More sharing options...
DavyZ Posted July 6, 2003 Share Posted July 6, 2003 "Keep an eye on the lead filled area in the 'pillar' between the rear 1/4 window and the edge of the hatch." Tim 240Z I have two cracks going from my hatch running down and connecting to the rear quarter window driprail (don't know why I haven't cut it off though). On both sides in the same location. Its like in the C-pillar area but on the outside of course. Is that what you are referring to? [/img] YES. I have seen these cracks on some Z cars at MSA Natl's and the like. I think drag launches on sticky tires twist a chassis more then anything else' date=' and the 240Z loses to the 280Z in this arena. Plus, the 280Z has frame rails that extend through the rear of the car and the 240Z does not. The tranny tunnel of a 280Z is supposed to be bigger (bigger is better, no?) in diameter which [i']should[/i] lend to more stiffness then a narrower tunnel (seems like it would anyway). Davy Quote Link to comment Share on other sites More sharing options...
fl327 Posted July 6, 2003 Share Posted July 6, 2003 a 240z with no reinforcement will warp quick if subjected to hard launches, v8 torque, a manual trans, and the FL327 way of doing things. the pillar will be your first sign, man the early cars have almost no frame to speak of. a 280z, 77-8 models are dang near a full frame 75-76 is pretty close, but dont have as big of a door bar as the 77-8 cars do, those things have some heavy doors man. a v8 in a 280z saves you some time in a v8 conversion i think, and you can run the suspension a little more sloppy for drag racing, something you cant do in a 240z. many have r200 stock, and all had efi, whats not to love. ace the bumpers, put on an msa kit or adapt 240z bumpers, right there you have a great car to work with. and no exhaust smell, and i have original weatherstripping yes i love my daily driving turbo bov'd Z, YES I DO! Quote Link to comment Share on other sites More sharing options...
80LS1T Posted July 6, 2003 Share Posted July 6, 2003 So how much better is the 280ZX frame than the 280Z? I am putting in a triagulated strut bar in front and I have a 4 point rollbar in the back. Is that enough? I was thinking subframe connectors but now you guys have me thinking that this is enough(for the 400HP@flywheel that I have)??? Guy Quote Link to comment Share on other sites More sharing options...
Dan Juday Posted July 6, 2003 Share Posted July 6, 2003 Just offering up some observations on the ZX. Pluses: Nissan was farther up the learning curve on chassis design and manufacturing techniques. Started with a clean slate (new body style) to work with. Nissan knew this car was going to get more power from the turbo motor. Minuses: '79 was first year of the new body, untested in real world. Weight is higher, more mass to throw around stressing the body. Longer wheel base and wider track means greater twisting leverage on the body. I think ultimately you need to talk with the guys that have and drive their ZX's, i.e. Dave Greimann. Dave has no frame reinforcements that I know of other than some well executed strut bracing, and this, I believe, is a recent addition. He has driven this car for several years with the V8 and, to my knowledge, has had no problems with twiting or cracking of the body. Dave, am I right? Someone else who might shed some light is John Washington. He sells Daytona Spyder kits for the ZX. I wonder what, if any, frame reinforcement he recommends when you cut the top off one. Paging Dr. Greimann, Dr. Washington. Quote Link to comment Share on other sites More sharing options...
Phantom Posted October 27, 2003 Author Share Posted October 27, 2003 Let's bring this one back to life. I made my second trip to the track last Friday in the 280Z28. It has a total of 7 runs down the track plus the "unofficial power demonstrations". I have been watching the 'B' pillar like a hawk and noticed a hairline crack on the passenger side this weekend. I have triangulated front and rear strut tower braces now and I'm definitely going to add a 4-pt roll bar. I've noticed suggestions about tieing it into the top/sides of the car. Any further observations? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted October 27, 2003 Share Posted October 27, 2003 When I installed my home made strut tower bars front and rear I went for a test drive. There was a turn in the road that I was very familiar with, a 15 mph bend over the crest of a hill, slightly off camber. The car had previously always pushed a little around that corner. When I drove it at the same speed as I always did with my strut tower bars on, I actually ran off the road on the INSIDE of the corner. What a HUGE difference they make!!! No push at all. I had to relearn the car! I never bothered with them because I had a negative attitude resulting from seeing too many Hondas with stock everything and a cold air intake and huge strut tower bar. Needless to say my prejudice against the bars was a little shortsighted. I still think you need to be pushing the car pretty hard to feel them, but when you get to that level, they are a necessity. I made mine from 5/8" ID aluminum tap tube from Coleman Racing. They were cheap to build and lightweight. Made brackets from 1/8" plate, and welded them to the strut towers. I also triangulated to the firewall in the front. Strut tower bars are now HIGHLY RECOMMENDED, IMO. Of course I have a 240, but just by the design of the strut towers I still think they will have a beneficial effect on your 280. I don't really have any comment as to how they will affect the cracking in the B pillar. Jon Quote Link to comment Share on other sites More sharing options...
JMortensen Posted October 27, 2003 Share Posted October 27, 2003 OK, I commented on the strut tower bars, and you wanted comments on the roll bar . So I've got more for you: A friend of mine had a bar made which tied into the strut tops and had a plate welded from the map light area to the hoop. He said his plastic panels in the back no longer squeaked when he went into driveways. That's a pretty darn good indication that he had eliminated a lot of flex. Never seen another welded to the roof like his, but that's what I'm going to do when I do my cage for sure. Jon Quote Link to comment Share on other sites More sharing options...
Phantom Posted October 27, 2003 Author Share Posted October 27, 2003 Oops - was writing this while you were writing yours. Jon - I have the Top End Racing strut tower braces front and rear now. Just added them in the past two weeks. The front runs across AND triangulates back to the firewall. The rear runs accross the top of the strut towers and then triangulates down on the driver side. I, too, have noticed the difference in handling when under power on a corner. I'm concerned that it's not enough, however, so I'm planning to add the four point roll bar and also reinforce the frame rails beneath the car. It will cost me some time due to the additional weight but it will still be faster than a two-piece car. My big question was in reference to attachment tabs to the underside of the roof and at the side to integrate the chassis more solidly into the roll bar. Your thoughts? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted October 27, 2003 Share Posted October 27, 2003 I think my second reply addressed that. This guy's chassis was TIRED, he would pull into parking lots and the thing squeaked big time. He is the guy I know who ripped off the A pillar at an autox! When that happened he welded the A pillar back on and added the bar. Made a big difference, and I think most of that came from tying into the roof and strut towers. Jon Quote Link to comment Share on other sites More sharing options...
zero Posted October 28, 2003 Share Posted October 28, 2003 my car has had its frame rails replaced, and i do not particularly like the quality of the work that was done. I will replace them again at some point, but because I do not have the ability to do the job right on a rotisserie, I will be welding in a full cage. I plan to tie the rear strut towers together, to the hoop, then having a general cage with low side bars, and going through the firewall at two points per side(near hood height and low near the rails) to tie to the front towers. I will make a front strut tower brace, and also triangulate them to the firewall. I hope to have it stiff enough that it could support the weight of the car without relying on the frame rail. at some point i may add enough tube frame that i will remove the load bearing members of the old chassis, but i am getting ahead of myself. Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted October 28, 2003 Share Posted October 28, 2003 My 77 has those stress cracks on both B-pillars... Fortunately it is a temporary "home" for the turbo drivetrain until it's new home (71 240z) is ready Quote Link to comment Share on other sites More sharing options...
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