QWKDTSN Posted November 22, 2000 Share Posted November 22, 2000 Okay, guys.. I've read a bunch of stuff about sectioning struts, on the web and in the JTR book. I'm still not totally sure what it is.. but it sounds like a messy procedure. It seems like everyone's done it, though.. Are there any ways to reliably upgrade my suspension without sectioning the struts, or is it a must-do procedure for good handling? TIA.. [This message has been edited by Nion (edited November 21, 2000).] Quote Link to comment Share on other sites More sharing options...
Mikelly Posted November 22, 2000 Share Posted November 22, 2000 I don't really agree with sectioning struts... I never have done them and I'm not sure it is really needed. 1st question is what are you trying to get the suspension to do? If you are gonna plus up on your wheels and are switching to coilovers, I'd not think you "Need" to do this mod... Some have done it on this board and if you do a search on Coilovers you will find a more technical description on the topic! However, I still say you can live without it. Mike ------------------ "I will not be a spectator in the sport of life!" mjk [This message has been edited by Mikelly (edited November 22, 2000).] Quote Link to comment Share on other sites More sharing options...
Guest scca Posted November 22, 2000 Share Posted November 22, 2000 the answer is maybe.. depends on howlow you want the ride height and what springs you are using and the rims/tire combination . etc.... with 14" tires lowered 3" YES shorten the struts with 17" rims and lowered 3" with coilovers its not a necessity. if your using camber plates then you get more travel back as well.. all of this affects whether or not you need to section the strut tubes. the only reason to section the struts is to get suspension travel back from lowering the car. ------------------ Mike mike@fonebooth.com http://www.fonebooth.com/brakes.html raceparts and brake upgrades. Quote Link to comment Share on other sites More sharing options...
QWKDTSN Posted November 22, 2000 Author Share Posted November 22, 2000 Thanks, Mike and Mike I suppose I shoule go over what I'm planning to do . I just got my '71 240Z a couple of months ago and I haven't begun to upgrade it yet (fixing all the little parts that don't work first). I'm hoping to do the major upgrades to my suspension first, then brakes, then wheels, then do my 350 engine swap next summer when I have time to really work. I'm hoping to run a 16x8 wheel with coilovers F/R if possible, with disc brakes rear and the Toyota caliper/vented rotors up front. I'm going to be autocrossing once or twice a month, and hopefully travelling up north to race on some real tracks. I'm young so I don't care if the suspension is pretty stiff, but I don't want it to be a total killer on me because it's going to be a streetable car. any logical inconsistencies here? What do you guys reccommend? [This message has been edited by Nion (edited November 22, 2000).] Quote Link to comment Share on other sites More sharing options...
Guest scca Posted November 23, 2000 Share Posted November 23, 2000 sounds about right..do the coilovers first and get rims and drive it -- what your going to do seems correct except that if you plan to run sears or Thill the toyota fronts will likely not be enough braking. i dont know how hard Bwillow is on brakes. not like portland with the chicane. North for you is Sears and almost everything else so depends on where you want to try tracks out. sears and thill arent really hard on brakes but they are super high speed long straights and you need massive heat dissipation to keep driving more than 10 minutes. ------------------ Mike mike@fonebooth.com http://www.fonebooth.com/brakes.html raceparts and brake upgrades. Quote Link to comment Share on other sites More sharing options...
TimZ Posted November 28, 2000 Share Posted November 28, 2000 quote: Originally posted by scca: (snip) with 14" tires lowered 3" YES shorten the struts with 17" rims and lowered 3" with coilovers its not a necessity. Okay, I agree with the rest of the post, but can you explain the logic behind this? It seems to me that you'd me more likely to need to shorten the struts with a 17" rim and 3" drop. Most tires that you'd use with this rim would not be shorter than stock, which would necessitate the suspension to be lowered even farther to acheive the 3" drop. ------------------ Quote Link to comment Share on other sites More sharing options...
Guest scca Posted November 28, 2000 Share Posted November 28, 2000 with the smaller rims and using likely 215/60 the car is probably closer to the ground than with 225/50/17 tires. thats all i was thinking..whats the overall size compared. i wasnt thinking of a stock 185-70-14. i've seem some with 195-50-14 really low profile so it all comes down to the ride height in the end. Mike Quote Link to comment Share on other sites More sharing options...
pparaska Posted November 28, 2000 Share Posted November 28, 2000 Doesn't it just come down to how much you are lowering the car and by what method? If you lower the car by ONLY using shorter springs, or by using coilovers and lowering the bottom spring perch enough to lower the car by 1.5"+, you are effectively taking that much bump travel out of the suspension, if you do nothing else. You can handle this problem with much stiffer springs to keep from hitting the bumpstops, but you have to decide if that's what you really want, especially on the street. If, however, you lower the car by using a shorter tire by that amount (half the tire diameter decrease from stock), then yes, you wouldn't need to section the struts, since you'd have the same bump travel - that is you didn't lower the car by changing anything with the springs or the suspension. But is that recommended? - the tires are already on th small diameter side anyway - especially if you are going to a 17" rim. There's another way to lower the Z - use a shorter top spring perch attachment to the car. The stock 280Z perch/isolator is taller than the 240Z perch/isolator, which is also a good bit taller than the aftermarket coilover spring perches and camber plates (these do vary though). So swapping these parts in and out has an effect on ride height (CG height) without messing with the spring length, the bump travel, etc. For the street, I chose to keep the 240Z isolators - call me a wimp, I don't care. All the vertical impact loads of the tires going over bumps goes through the strut cartridge and into the top strut mount, be it a stock isolator or a camber plate. Talk about a huge effect on NVH! So the option of shorter top spring perch/camber-plates or shorter isolators for lowering the car was out for me. I may take a half inch out of the rear 240Z isolator, but that is more to allow a longer spring with less stiffness than to lower the car, another topic. I actually increased my tire diameter with my wheel and tire combination (this helps traction by the way - larger contact patch) so I needed to lower the car by shortening the strut height. I did this by using coilovers to make that dimension adjustable. The problem with this method is that if you want to retain the same bump travel you need to shorten the strut tube (and cartridge) by an amount close to what you will be taking out of the strut height by using shorter springs of adjustable perches on the coilover. I chose to be conservative and took 1.5" out. I used a 1.25" larger diameter tire in the rear, so I raised the hub height by half that, 0.6". So I allowed myself about 1" of lowering with the coilovers to have the same bump travel as stock. In the front, the tires are 1/2" taller than stock, so I raised the hub height 1/4", giving me a 1-1/4" lowering capability with the same bump travel. Note I can raise and lower about these points, but I gain and lose (respectively) bump travel and lose and gain (respectively) droop travel. Both are important for good handling. Losing too much bump travel is bad because you hit the bump stops and traction goes away . Losing too much droop travel is bad because you can lose tire contact over sharp rises in the road/track. Wayne Burstein, an ITS racer out in East USA, went too far with strut sectioning and found this out the hard way at the track. He said adding tube material back to the strut tube was no fun. Anyway, that's the way I see it. If I've screwed something up here, let me know as I want to get this right. ------------------ Pete Paraska - 73 540Z - Marathon Z Project - pparaska@home.com">pparaska@home.com - Quote Link to comment Share on other sites More sharing options...
TimZ Posted November 28, 2000 Share Posted November 28, 2000 Pete... IMHO, you are right on the money. What I was trying to point out was that scca's post mentioned shortening the strut with the 14" rims (i.e., shorter rolling radius), and not shortening them with the 17" rims (larger radius), which I believe is backwards. BTW, I do not think you are a wimp for keeping the 240 isolators. I used the camber plates on all four corners for a while, and finally tore them out of the rear(and subsequently resized the struts again) and replaced them with the stock isolators. The camber plates were annoyingly loud/harsh, and didn't offer that much benefit, since by design, you can only use them to decrease camber. I modified the stock upper perch to locate the 2.5"id springs, and am much happier now. For a race only car, they would be fine, but IMHO the camber plates are unacceptable NVH-wise for a primarily street driven car (in the rear, anyway). ------------------ Quote Link to comment Share on other sites More sharing options...
Guest scca Posted November 29, 2000 Share Posted November 29, 2000 i have camber plates in my street car and it needs them ... not all cars get the ideal .5 to 1.0 degree . i hate off center bushings so i needed plates to get the car to where i wanted it. ------------------ Mike mike@fonebooth.com http://www.fonebooth.com/brakes.html raceparts and brake upgrades. Quote Link to comment Share on other sites More sharing options...
Guest scca Posted November 29, 2000 Share Posted November 29, 2000 WOW! thats a long post! Pete first i said IF you lower the car 3" in the first post.... now i'll read what you said. oh and i meant by suspension mods only . everything else being equal-the rest of what you said seems correct. and its not hard to add length. i just take another pair of struts and re-do them ------------------ Mike mike@fonebooth.com http://www.fonebooth.com/brakes.html raceparts and brake upgrades. Quote Link to comment Share on other sites More sharing options...
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