240jz Posted February 6, 2004 Share Posted February 6, 2004 I'm trying to decide what spring rate to use on my '71. I was wondering what rate comes stock? What rates do you use? I plan on using my car for autox and street duty. I can live with a somewhat diminised ride quality, just not something assinine. I plan on using Tokinko Iluminas and coilovers. What do you guys think? Oh yeah as far as brand, eibach or hypercoil? I can get them from my work for cheap. Thanks, Matt Quote Link to comment Share on other sites More sharing options...
auxilary Posted February 6, 2004 Share Posted February 6, 2004 110 stock. for compromise of street/autox, 175 front/225 rear would be doable, but about the limit you want if you're running a stockish motor. Quote Link to comment Share on other sites More sharing options...
zguy95135 Posted February 6, 2004 Share Posted February 6, 2004 since you have tokicos you wont want to run anything over 200 Quote Link to comment Share on other sites More sharing options...
auxilary Posted February 6, 2004 Share Posted February 6, 2004 since you have tokicos you wont want to run anything over 200 300 Quote Link to comment Share on other sites More sharing options...
zguy95135 Posted February 6, 2004 Share Posted February 6, 2004 hmmm, people have been telling me 200 Quote Link to comment Share on other sites More sharing options...
auxilary Posted February 6, 2004 Share Posted February 6, 2004 illuminas lose their effectiveness on rebound dampening if spring rates are over 300, per john coffey Quote Link to comment Share on other sites More sharing options...
gramercyjam Posted February 6, 2004 Share Posted February 6, 2004 I've been running 300# with the illuminas since last year. Seems to work OK for cheapo shocks. Quote Link to comment Share on other sites More sharing options...
johnc Posted February 6, 2004 Share Posted February 6, 2004 illuminas lose their effectiveness on rebound dampening if spring rates are over 300, per john coffey Ive changed my tune since talking with the Tokico techs. From about 225 lb. in. you're at 4 on the adjuster to get enough rebound control for those springs. At 250 you're at 5 and at 275 and above you need more rebound control then the shock provides. But, the bigger problem is that the Tokico adjuster also increases compresion damping, which you don't want if you're trying to control the spring. On settings 4 and above there is too much compression damping for a 2,400 lb car. The car tends to skip over bumps and hunt under braking. Now, if you're on a flat, smooth surface, then too much compression damping isn't as much of a problem. Quote Link to comment Share on other sites More sharing options...
240jz Posted February 6, 2004 Author Share Posted February 6, 2004 Well if Tokico's aren't the ticket what would you suggest? Is there a shock that has both a compression and rebound adjustment and fits our vehicles? Quote Link to comment Share on other sites More sharing options...
johnc Posted February 6, 2004 Share Posted February 6, 2004 Tokicos probably aren't the ticket if your spring rates are over 225 lb. in. but they are reasonably priced, I have sucessfully autocrossed on them at higher spring rates on a fairly flat surface, and they are great for a street car with spring rates at 200 or below. If you're running rates from 200 to 325 (which I personally feel are too stiff for the street) I recommend the Koni 8610s which have a single rebound adjustment and a set compression rate of 187 lbs @ 13 inches per second. At a spring rate of 250 lb. in. you're right in the middle of the rebound adjustment range. Quote Link to comment Share on other sites More sharing options...
260DET Posted February 7, 2004 Share Posted February 7, 2004 Are you going to stiffen up the body eg with a roll cage? The heavier the springs the more your stock body will flex, and Z bodies are flexy. I'm in the process of striffening mine, with springs around 250 - 300 body flex was making it impossible to set the suspension up properly. I think, we'll see. Quote Link to comment Share on other sites More sharing options...
240jz Posted February 7, 2004 Author Share Posted February 7, 2004 Yeah I was thinking about doing a roll cage. I think 175F/225R will work for me untill I get really serious about AutoX. But as far as roll cages go will the Jegs or other out of a box type actually do anything for torsional rigidity or will it have to be custom? As far as the Tokico's, does anyone have the product number? It would help me tons in ordering it. Thanks Quote Link to comment Share on other sites More sharing options...
silicone boy Posted February 8, 2004 Share Posted February 8, 2004 I used to obsess about spring rates, sway bar diameters, etc. Unfortunately, I noticed that many of the stock drivers were faster than me. They tuned suspensions with alignment settings and tire pressures. The point is, you can worry too much about the perfect setup, when what will really make your car perform better is investing in improving your driving skill. We all like to think that we are great drivers, but we could all become better.Practice a lot and go to racing school . You'll be far better off. Quote Link to comment Share on other sites More sharing options...
PETEW Posted February 8, 2004 Share Posted February 8, 2004 Best thing you can do is talk to Ross at Modern Motorsports. He can lead you in the right direction if you tell him what you want to do with the car. I was really worried about setting up my car right and he really helped. Check out his website and send him an email. http://www.modern-motorsports.com/ Quote Link to comment Share on other sites More sharing options...
260DET Posted February 9, 2004 Share Posted February 9, 2004 I used to obsess about spring rates, sway bar diameters, etc. Unfortunately, I noticed that many of the stock drivers were faster than me. They tuned suspensions with alignment settings and tire pressures. The point is, you can worry too much about the perfect setup, when what will really make your car perform better is investing in improving your driving skill. We all like to think that we are great drivers, but we could all become better.Practice a lot and go to racing school . You'll be far better off. Mate, I know I'm not the best of drivers. You are absolutely right about investing in driving skills, probably the best race investment one can make. I rode with an instructor on a race track the other day, by my standards he braked late and deep into corners, trail braked and lent on to the front wheels to get turn in grip, lined it up, bang on the accelerator and out of there. Seemed like he would have been picking up at least a second per corner over me. Quote Link to comment Share on other sites More sharing options...
silicone boy Posted February 9, 2004 Share Posted February 9, 2004 You are absolutely right about investing in driving skills, probably the best race investment one can make. I'll be really upset this year if my I get beaten in my 3rd Gen RX7 by a better driver in a Yugo. You know what? It's probably going to happen. Quote Link to comment Share on other sites More sharing options...
katman Posted February 9, 2004 Share Posted February 9, 2004 Yeah I was thinking about doing a roll cage. I think 175F/225R will work for me untill I get really serious about AutoX. But as far as roll cages go will the Jegs or other out of a box type actually do anything for torsional rigidity or will it have to be custom? As far as the Tokico's' date=' does anyone have the product number? It would help me tons in ordering it.Thanks[/quote'] IMHO, coming from somebody that's built and prepped dominating cars for SCCA Solo II and ITS, you don't need a cage unless the rules require it (the driver and tires in AutoX is so much a factor I've seen good drivers with $500 clapped out Z cars kick butt). The payback in what you gain for chassis stiffness isn't worth the weight penalty, ESPECIALLY for any sane street spring rates. A "double especially" for any kind of "out of the box" cage, and a "triple expecially" for the overweight Chassisworks and S&W cages (their wall thickness is driven by NHRA reqm'ts I believe). Now, when you get into a EProd level of prep and 350-400 lb/in spring rates that's different. To comment on something Mr. Coffey mentioned earlier- I'd second the recommendation on the Koni 8610 series shocks for dual purpose cars with the caveat that their upper bushings seem to wear out quickly, but there really isn't another alternative for the spring rates he mentions without spending big bucks on custom shocks. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted February 9, 2004 Share Posted February 9, 2004 I'd echo what Katman said about the cage issue... You could get away with a couple strut braces and some frame rails and be very happy with less weight if it is gonna be an autocross/ street car. If you plan to do real track day events at high speeds, then a cage is worth the money for safety alone... But for a street car... That said, my Zcars have had cages in the from a safety standpoint alone... There is a weight hit, for sure. Mike 8) Quote Link to comment Share on other sites More sharing options...
johnc Posted February 9, 2004 Share Posted February 9, 2004 For autocross you don't need a roll cage, as Keith says. Vic Sias's car ran with only strut tower braces and he won BSP against the C4 Corvettes. If you're planning on doing autocross and open track (time trial) events then I suggest a welded in roll bar with the rear braces attached to the top of the strut towers. This will give you some rollover protection. And spend a lot of money on an FIA approved race seat, harness, and proper mounting of both. Quote Link to comment Share on other sites More sharing options...
260DET Posted February 10, 2004 Share Posted February 10, 2004 Interesting about roll cages. With 250 - 300 springs the rear of my '77 creaks when reversing diagonally over spoon drains. My mate's Z has a 'behind the driver' half cage ie hoop, stays back to the strut towers and a strut bar. It does not creak and seems to turn in, particularly, better than mine. So I've designed a structural type half cage that will give protection and am building it now. Pics some time in the future, if it works that is. But it is the driver that really matters, still it is fun to 'improve' the car. Quote Link to comment Share on other sites More sharing options...
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