CruxGNZ Posted January 10, 2002 Share Posted January 10, 2002 What spring rates is everyone using on their L powered 240Z and what do you use your car for (street, track, 1320)? I say L powered, because my car will weigh about the same as a non-hybrid Z. I need to find out before this Friday the 11th, so Mike Gibson can send out my coilovers. I will have Tokico 5-ways to go with the coilovers. I was thinking now, maybe 225lb. in front and 250lb. or 275lb. in the rear. Is this about right? My car will be seeing about 80% street and 20% track/1320. Any help is appreciated. !M! Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 10, 2002 Share Posted January 10, 2002 I run 225 all around, you are on the right track. My car is also a street car with quite a bit of road course time. 250# or 275 in the rear would also work well in my opinion. My car is a V-8, weighs about 2650. Hope that helps. Mark Quote Link to comment Share on other sites More sharing options...
RB30-ZED Posted January 10, 2002 Share Posted January 10, 2002 Hi Mat, im running 300lbs front and 350lbs rear, sounds a bit stiff but works fine. I use the car for street and hill climbs and run a RB30DE so its around the standard weight. Steven Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 10, 2002 Share Posted January 10, 2002 I am still trying to figure out what a stock Z spring rate is . Can any one enlighten me?? My idea is to increase (150 to 175#)over the stock spring rate and use 2 plus 2 sway bars with 12-14 inch coilovers on one or two inch shortened struts and save the strut cartridges from prematurely wearng out. Ross Corrigan and I were discussing this via email when the holidays intervened. Any one have suggestions.?????? I don't want to race just look like I was the winner at the track. With my reflex's I could not get the engine started before the race ended! Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 10, 2002 Share Posted January 10, 2002 I have 200 frt, 250 rear. I think 225 frt would be better. You're getting camber plates too right? My springs with 2 degrees camber frt, and 1--1.5 rear works great. I was amazed at how fast I could dive into the corners. With the coil overs you'll be able to adjust any oversteer or under that you like. You'll also want to think about a 1" frt sway bar if you dont already have one. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 10, 2002 Share Posted January 10, 2002 BTW, that was before the V8.... Quote Link to comment Share on other sites More sharing options...
Mikelly Posted January 10, 2002 Share Posted January 10, 2002 I'm running 250# springs at all corners. BLKMGK bought (I think) 200# for the rear and 225# for the front and he felt that the rear was to soft. So you may want to consider that... Mike Kelly Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted January 10, 2002 Share Posted January 10, 2002 250 front, 225 rear I believe. MikeSCCA says I've got them bassackwards so when I get motivated to swap my stub axles out and install CVs I'll also be swapping the springs front for rear. Quote Link to comment Share on other sites More sharing options...
jeromio Posted January 10, 2002 Share Posted January 10, 2002 I'm the odd man out with "soft" springs - 150/175. I marvel at those running stiffer springs. This is with an L28, but I believe my LS1 will weigh slightly less. My car is crazy, punishing stiff. No track for me yet. Handles great IMO, but I do wish it wasn't so rough over expansion joints, etc. Quote Link to comment Share on other sites More sharing options...
Dan Baldwin Posted January 10, 2002 Share Posted January 10, 2002 I run 160 lb/in front, 200 rear on my street/track 3.1 liter 240Z. VERY good compromise in my opinion. A bit stiff for the street and somewhat soft for the track (I guess). I still outhandle a lot of track-only vehicles at the track. Dan Baldwin '71 240Z 3.1 COMSCC #7 SPB Quote Link to comment Share on other sites More sharing options...
johnc Posted January 10, 2002 Share Posted January 10, 2002 From 250 to 300 front and from 275 to 325 rear depending on the track and how big my balls are that day. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted January 10, 2002 Share Posted January 10, 2002 This issue when dealing with street cars is definitely a preference issue. I rode in a guys car one time and he thought it handeled like it was on rails... I took him for a ride in mine (At the time my 240Z had some free #500 springs at all four corners) and he was in shock at how the car was flickable at 45-50 MPH on smooth pavement... But I cringed at overpasses and train track crossings... I also think that running the right strut and the right length of spring in the coil over kit will also be critical. The shorter the spring, the harsher the ride. But again, it truly depends on your definition of comfort! Another thing to factor in... You mention you will be focusing on the 1320club... I'd run a softer spring in the rear. You want all the weight transfer you can get to the rear of the car... Maybe a 200# front and a 175# rear... Mike Kelly Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 10, 2002 Share Posted January 10, 2002 For Rick Johnson: Did you shorten/section your strut tubes????? And how much ?? Would you recomend 2 inches be removed???? How long are your springs???? Did you replace the VW cartridges in the front struts??? or all the way around?? Some people prefer the Toyota MR2cartridge over the VW Rabbit in the front. Your information on the rubber cushion sounds logical since a rubber ball will bounce after impact. If longer springs as another post suggests would provide more cushion--could you get a 14 inch spring to work adequetely on a 2 inch sectioned strut tube ?? I have no wheel offset problem to interfere with the spring action. I have to use big 8 and 10 inch wheels and 3.5 offset to get the Tommahawk Z to look right because of the huge wheel well openings. Quote Link to comment Share on other sites More sharing options...
CruxGNZ Posted January 11, 2002 Author Share Posted January 11, 2002 Oh boy, now I don't know what to run! I'm getting high rates and low rates. My car will see street mostly, so I guess I should set it up for the street. The reason for the high rate in the rear is, because I wanted to run a 9" wheel and I needed a 8" spring length and the softest a 8" spring came in was 250lb. or 275lb (not sure yet). I'm now thinking to just forget it and go with 17X8" wheels in the rear so I can set up my car right from the begining and use longer springs with softer rates. My sole purpose of building this car is to show up all the exotics around here. I mean there is Vipers, Porsche Turbo's, Lotus's, Lambo's, Cobra's (2 real ones, a few fakes), Ferrari's, Mallet and Lingenfelter Vettes, you name it, it's here. Most of these people are stuck up, so all the more reason to show them what a car built for under $10K (including car) can do. I want to see the look on peoples faces when I go to a track and turn some good lap times with my Z. I want to take it to the drag strip and have fun... sorry for the rambling, just don't know what to do and I want to get it right the first time. !M! Quote Link to comment Share on other sites More sharing options...
Guest Rick Johnson Posted January 11, 2002 Share Posted January 11, 2002 Mat, I understand the need for shorter springs in the rear, so you can put the tires under the spring perch. I designed custom 4" diameter springs and modified my stock spring perch to be adjustable using some threaded pipe and pipe nuts from the hardware store. There was a huge amount of machining and fabricating required. The end result is a 190# spring, about 10" long, that sits above my rear tire. What a hassle but I would not want much stiffer. Since our cars are about the same weight in the front and rear, we want softer springs in front to avoid freeway hop (or that constant pitching front to rear) as you drive over expansion joints. To figure it out exactly you figure the natural frequency front and rear and then determine what speed you want to tune for. Just figure about 15% softer in front and you will be close enough. Quote Link to comment Share on other sites More sharing options...
Guest Rick Johnson Posted January 11, 2002 Share Posted January 11, 2002 L Johnson, I sectioned my front struts about 1 5/8. By adjusting my bumper heights and installing a sleeve on my strut shaft I achieved 3 1/4 " of compression and 2 3/4" of rebound travel. Of course this is based on the ride height I felt was nice to my eye. I ran 12" springs to avoid coil bind (the 10" springs I tried coil bound with a bang before my rubber bumpers came into play.) - As far as ride goes, it is the spring rate you are concerned about, not the actual length. It just happens that longer springs can have lighter rates and provide enough total compression travel to avoid coil bind. If you check out the spring section in ground control's web site you can look at overall travel as it relates to spring rate and length. The first thing to do is establish the ride height you like and then start cutting things. As far as strut selection goes, I had to beg the guy at Tokico to give me enough information on damping to determine which struts that would fit and would have the least compression damping. The VW struts made sense to me. Unfortunately damping is a lot like spring rates, everyone has their own opinion and expectations. A higher percentage of compression damping will minimize the pitching and rolling at the expense of ride comfort. Quote Link to comment Share on other sites More sharing options...
Guest Rick Johnson Posted January 11, 2002 Share Posted January 11, 2002 quote: Originally posted by jeromio: I'm the odd man out with "soft" springs - 150/175. I marvel at those running stiffer springs. This is with an L28, but I believe my LS1 will weigh slightly less. My car is crazy, punishing stiff. No track for me yet. Handles great IMO, but I do wish it wasn't so rough over expansion joints, etc. Quote Link to comment Share on other sites More sharing options...
Guest Rick Johnson Posted January 11, 2002 Share Posted January 11, 2002 Regarding the comment about the suspension being stiff on square edges orr expansion joints. I use 165 # front and 190# rear spring rates. I have a 1" front bar and a 3/4" rear bar. The secret to a plush ride on square edges is to have compliance (or a spring of some sort) in series with the shock absorber or strut in our case. They call this tailored damping. It allows the shocks to be stiff enough to control roll etc. but provides some cushion from the initial shock of contacting the square edge on the road. In practice this compliance comes from rubber control arm bushings and strut mounts. The rubber acts as the spring in series with the shock. The most critical axis for isolation from smaller square edge road disturbances is horizontal in the rearward direction. This allows the wheels to move rearward immediately while the strut gets around to allowing the wheel to travel upwards. On our 240z's, the two most critical locations for horizontal rearward isolation are the tension rod mounts to the frame and the forward rear control arm mounts. Typically people put hard urethane or even worse, nylon, in these locations. Converting back to the rubber in these two locations will make a big difference in ride comfort. ( I actually shimmed the rubber tension rod bushings to preload them which minimized tension rod movement.) It was still a huge improvement over the nylon pieces I had there. Additionally, the strut selection is critical. I chose the Tokico illumina struts intended for a Volkwagon Rabbit because they had a lower percentage of compression damping for the same amount of rebound damping. They definately helped the ride when compared to the struts intended for the 240Z. Be carefull if running spring rates over 225 because the VW struts will not have enough rebound damping for real high spring rates. I can imagine that the hard core racers are laughing at these lower spring rates and talk of road imput isolation, but if you value your ride comfort like I do, these turned out to be reasonable compromises. Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted January 11, 2002 Share Posted January 11, 2002 Rick, excellent point on compliance and dealing with square edges and expansion joints. As I am dialing in the Vette IRS, I believe using poly bushings in the suspension links was a mistake and I will probably switch to new OEM rubber bushings. Another $35. Damn, this project is getting expensive I am running 160#, 12" rear springs, but as Rick pointed out, a longer spring allows for a softer spring. Besides, I need them for the 1320 and my old bones like a plusher ride. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 11, 2002 Share Posted January 11, 2002 My projection for a firm street ride after Hybrid advice: section struts 2 inches with Toyota MR2 cartridges in front and 280 Z fronts in rear;12 inch coilovers at 160#(+/-) in front and 180#(+/-)at rear;rubber bushings not urethane;strut spacers at steering knuckles;280Z 2+2 sway bars; 7/8 inch bumpsteer modification to front crossmember and lower control arm;early Toyota 4x4 front brake calipers;brake adjustable proportioning valve;2+2 vaccum brake booster;camber adjustment by slotting strut adjustment holes 1/4 inch either way;stress bars between strut towers // Are urethane steering coupler and steering rack bushings a solution or problem????????????????I don't want carpal tunnel syndrome to develope on a short ride from wheel feed back to my hands.Any suggestions to the suspension modifications not my frail physical condition!!!!!!!!! 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.