Guest jens Posted October 15, 2002 Share Posted October 15, 2002 Is it possible to do more than coilovers. Im thinking cutting them in the bottom under the shock and move the upper part + shocktower 1.5" or is the shock to long to do this?. Quote Link to comment Share on other sites More sharing options...
johnc Posted October 15, 2002 Share Posted October 15, 2002 I'm not clear on what you're cutting and moving. Are you talking about the front or rear struts (or both)? If you're talking about the front, the whole strut and spindle are essentially one unit and its important to retain the geometric relationship between strut top mount, lower control arm mount, and the ball joint/steering arm. You might be able to put a small curve in the strut tube but then getting the shock inside would be tough. FYI... the shock fills up most of the length of the strut tube. If you're talking about the rear, again you need to retain the geometric relationship but you don't have steering to worry about. In either case you're talking about a significant redesign of a critical part of the suspension. How wide a tire do you want to fit? BTW... I'm moving this topic to the Suspension section. Quote Link to comment Share on other sites More sharing options...
gene_w Posted October 15, 2002 Share Posted October 15, 2002 I'm also not quite sure what you're trying to describe. Maybe you could provide a bit better explanation. I would be careful as far as changing the suspension geometry too much unless you have a real good idea what you're doing. Lots of planning and research went into the original setup. One thing you might consider to gain a little bit more room is the addition of a coilover setup. These have a smaller diameter spring that allows you to tuck your tires a little bit farther in. Another option would be to add flares to your fenders to let the tires stick out a bit more. As an extreme measure, you could make your own fenders and quarters out of fiberglass and run any size tire you want. Terry Oxandale made his own and shows that you can fit 17x11 wheels with 315/35ZR17 tires. Gene Quote Link to comment Share on other sites More sharing options...
Guest jens Posted October 15, 2002 Share Posted October 15, 2002 Its in the rear. I dont want to change the geometry i just want the biggest tire without narrowing the rear. Just moving the shocktower and modify the struts would be easier. something like 275x50x15 would be nice. The car is unwelded and the paint is good and i dont like flares i want a clean look. Flares is legal in europe but positive offset wheels are not unless nissan says its ok for the bearings. They also want tax for changing the look. The car has enkei 15x7 wheels with 225x50 tires and as far as i can see there is 2.5" left on the inside if the struts are moved a bit. But its probably true that the shock goes all the way to the bottom of the strut i just wanted to know so i dont waste my time to see that it cant be done. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted October 15, 2002 Share Posted October 15, 2002 Have you checked into simply moving the spring perch up so the top edge of the tire you want to run is below it? I believe this is what Scottie GNZ did with his 240Z; I'm not sure how much room it gave, but it would be at least as much if not more than the coil-over setup. You might have to build some custom springs to keep your ride height. Quote Link to comment Share on other sites More sharing options...
Guest jens Posted October 15, 2002 Share Posted October 15, 2002 I know that an will do it because im not sure i would be satisfied with a stiff racing suspension. Scottie has mentioned something about using zx springs. I dont know if its because they are shorter or just stiffer. Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted October 15, 2002 Share Posted October 15, 2002 275/50-15 is a very tall tire (26"). Moving the spring perch up as JTR recommends will give clearance to move the tire in and place the bottom of the perch just above the outside edge of the tire. The trick is finding a wheel with the maximum offset to move it in as much as possible. A 5" BS should do it but I stil wonder about fender lip clearance with 275s, especially at 26". If you do the spring perch mod, you have to use the recommended 280ZX 2+2 springs. Cutting and using any "normal" Z or ZX spring will cause binding. Despite the stigma of cutting springs, I used it in Z IRS with very good success and that is what 240Z Turbo is currently using. It can be a relatively inexpensive mod if you can grind off the weld for the perch and reweld it yourself or have it done inexpensively. You should be able to find the springs in a JY for a reasonable price. However, if the price difference is within $50 of a coilover, then I recommend the coilovers for that added ride height/spring rate adjustment. Quote Link to comment Share on other sites More sharing options...
gene_w Posted October 15, 2002 Share Posted October 15, 2002 Originally posted by jens:I can weld so thats not a problem but anything bigger than 245 would touch the strut as discussed several times. Sounds like it might be time for you to give in and do a Corvette IRS like Scottie-GNZ did(check out his site). You could probably mount the shock/spring differently than he did so you can move the tires in quite a bit. I would imagine you could fit a pretty fat tire in if done right. Gene Quote Link to comment Share on other sites More sharing options...
Mike C Posted October 15, 2002 Share Posted October 15, 2002 Your limiting factor is your wheels. If you really want the maximum diameter tire, you will have to mod your strut as noted above, and buy wheels that will work with the tire you want. IME, more backspacing on the Z, front and rear, make for a better driving car. Going to larger diameter rims reduces the sidewall height which in turn reduces sidewall flex giving you more control (ability to run tighter clearances) as well. This also gives you more clearance at the strut since the tube is at an angle and the wheel lip is higher up the angled tube, you can run more backspacing. Scotties mod and 17" wheels. You've been looking for an excuse anyhow, right? Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted October 15, 2002 Share Posted October 15, 2002 Go to Pete Paraska's home page. He has 17x9" wheels under his stock wheel well Zcar. He has 8" coilovers on the rear. They are mounted high on the strut to allow clearance. I think he has 255/40/17's or something like that. 300# rate springs though Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted October 16, 2002 Share Posted October 16, 2002 I can weld so thats not a problem but anything bigger than 245 would touch the strut as discussed several times. Once again, it depends on the BS of the wheel. I ran 275/50-15 BFG DRs on 15x8 Weld wheels with a 4.5" BS on my Z IRS with the spring perch mod. Granted, I had flares and did not care about the fender lip, but as I stated, that mod will put the bottom of the spring perch ABOVE the inside edge of the tire. With the 4.5" BS, there was still room to move the wheel/tire inward and still not hit the strut. That is why I said a 5" BS would do it. Here is a pic of the modded strut. Note the "ring" below the bottom of the perch. That is the original position of the perch. Also remember that the strut angles in as it goes up, so the higher the perch, the farther it is away from the wheel/tire. Quote Link to comment Share on other sites More sharing options...
Guest jens Posted October 16, 2002 Share Posted October 16, 2002 I can weld so thats not a problem but anything bigger than 245 would touch the strut as discussed several times. Quote Link to comment Share on other sites More sharing options...
ZROSSA Posted October 16, 2002 Share Posted October 16, 2002 Jens, How much welding do you want to do? You know as well as I, that anything is possable. Move the top mounts of the struts inward, Fab adjustable lower arms. Mabye put extenstions where the strut meets the hub so you can run more back spacing? Its really not that hard when you think about it. I would sugest that you make a jig so that it doesnt move when you weld. The front strut on my race car is front a front wheel drive sentra, mated to a rx7 hub with custom a arm. All mounted in a ke35 corolla chassis. I can send you a photo or two if you would like. Let me know? Douglas Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 17, 2002 Share Posted October 17, 2002 I used the stock upper strut isolator. That forced me to 8" springs to keep the perch enough above the tire sidewall to just miss it. (This was all engineered by Jim Biondo, who I bought the wheels from and used his coilover ideas.) As soon as I find some round tuit's I'll try the 225 lb/in springs in the rear. The fear is that they'll coil bind on sharp bumps and dips. I have urethane bumpstops, so that should help. The 300 lb/in springs back there are too stiff for my tastes. I'd think you could use a camber plate or other top strut mount that was shorter than the stock strut isolator and use a 10" spring that would keep the bottom spring perch on the coilover high enough for the 255/45-17s I have on there. The difference between 255s and 275s isn't a ton. Use a sticky tire like a Potenza S03 in the 255 and you'd be far ahead of a 275 hi performance tire, as far as traction. Quote Link to comment Share on other sites More sharing options...
Guest jens Posted October 17, 2002 Share Posted October 17, 2002 The reason i want 275x50x15 tires is because i want to run it in a 1/8 mile class in dk called street there the breakout is 8 seconds. That would be easy if the rules allowed softcompound tires like dragradials and nittos. Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted October 17, 2002 Share Posted October 17, 2002 jens, I am sure you know this but I will reemphasize it. A bigger and wider tire does not necessarily translate into better traction, especially in drag racing. After Montgomery, a few folks here will testify to that. I believe MikeKZ is running 295s and he blew them away easily. Closest tire you can get to a DR but still be considered legal is the Toyo Proxes RA1, which comes already shaved down to a 6/32nd tread depth. Most amazing thing I ever saw was a 911TT that was driven from NJ to So FL (1300 miles) and went high 9s with 255/50-16s Toyos pulling the front wheels in 1st, 2nd AND 3rd. Granted it was a rear-engined car but that is insane traction. Bottom line is, focus on the tire that will provide the best traction and that is not necessarily the widest tire. Quote Link to comment Share on other sites More sharing options...
240Z Turbo Posted October 17, 2002 Share Posted October 17, 2002 You can cut the perch and move it up above the tire to run more back spacing. Use a cutdown 2+2 rear spring. My 15x8 rim has a 275/50-15 Nitto Drag radial and the rim has a 4.5" backspacing. You CAN run this same tire with a 5.5" backspacing on the same setup, but I am not sure if it will clear the fender lip. I would think it would. I can remeasure the exact clearance my tire has with the strut tube and with 4.5" backspacing. BTW, watching the videos of my car racing, the passenger rear is bottomed out all the way down the track so I think I need more spring rate for racing. It really torques the car over. Quote Link to comment Share on other sites More sharing options...
Guest jens Posted October 17, 2002 Share Posted October 17, 2002 Is it a real steelradial. toyo describe it as a competition radial. The next problem there the f*** can i find a 16" enkei wheel to match the front wheels. I have found out how to modify the strut i have to mill the bottom end off and weld a new offset tube on it not easy but easier than a vette rearend that wont go through inspection in europe. Is it really true that it only takes 5 minutes to go through inspection in us because they only care for the smog test. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted October 17, 2002 Share Posted October 17, 2002 Originally posted by jens:Is it really true that it only takes 5 minutes to go through inspection in us because they only care for the smog test. True, my friend. I don't live in the most restrictive part of the country, but in Colorado they just check the emissions (safety inspections ended here in about 1975). As a matter of fact the only piece of emissions equipment they check for here is the catalytic converter (the federal model Zs never came with them), and my lack of EGR was never detected. Quote Link to comment Share on other sites More sharing options...
Guest jens Posted October 17, 2002 Share Posted October 17, 2002 Damn in denmark everything is illegal unless its documented. Getting a streetrod through inspection takes months and 4000$ for the papers and tests that only 2 places in dk is certified to do. Streetrods is the only cars that have been allowed to run wider rear tires. They test the topspeed, cornering and makes a vibration test to test if the frame is strong enough. Coilovers and fourlink + competition brakes is only allowed on rally cars only used for legal racing on public roads and maximum 25 km driving from home without using a trailer. I envy you all. The car im going to buy has a transmission adapter (the trans is actually a toyota but it looks factory installed) because they want tax if too much parts is changed. Todays offer in dk is called buy 1 car pay for 3. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.