Mikelly Posted January 2, 2001 Share Posted January 2, 2001 Just ordered my new coil overs for the buildup... They (Ground Control) advised 250# springs (Actually higher initially) for the speeds the car is hitting... Should be interesting to see how the car handles with that spring setup. They will be here early next week and should be installed by next weekend! Mike ------------------ http://hometown.aol.com/dat74z/myhomepage/auto.html "I will not be a spectator in the sport of life!" mjk Quote Link to comment Share on other sites More sharing options...
Danno74Z Posted January 2, 2001 Share Posted January 2, 2001 Mike, Happy 2001 to you. Questions - Are you using camber plates and if you are will you be using GC's? Are you using 250lbs on all for corners and what length springs? Do you know at this time where and how much your cutting the strut tubes? Thanks, Dan Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted January 3, 2001 Share Posted January 3, 2001 i run 250 in rear and 225 in front.car is good on smooth freeway but has to have tokico set on 3 minimum to control rebound.only use gc camber plates cause they have the least amount of rattle.i am taking the carrera camber plates out of rear of my car cause the noise is driving me nuts.gc send a big washer to use the oem uper cushon if you want and i am going to try this in rear with adjustable lower control arms.if you use oem upper cushion use a 70-73 z part cause it is shorter than 75-78 part. Quote Link to comment Share on other sites More sharing options...
Mikelly Posted January 3, 2001 Author Share Posted January 3, 2001 I'm planning to use the stock strut housing UNCUT, and I also may employee a camber plate, not sure yet. Spring length is 10 inches. One thing I will caution those using V8 motors on is oilpan clearance. I went with the 250# springs at all four corners due to the almost perfect 50/50 weight balance and the approximate 2700# of weight the car will have with the addition of the 22 gallon fuel cell (Full) and the additional bracing and tubing weight of the infrastucture. Mike ------------------ http://hometown.aol.com/dat74z/myhomepage/auto.html "I will not be a spectator in the sport of life!" mjk [This message has been edited by Mikelly (edited January 03, 2001).] Quote Link to comment Share on other sites More sharing options...
pparaska Posted January 3, 2001 Share Posted January 3, 2001 Mike, I don't know if you realize this or not, but for you and those that might not know, I'll put it here: There is a reason that the rear springs are stiffer on many cars - to avoid pitching harmonics when you hit bumps. If the front and rear rates are the same, somewhat regardless of the weight distribution front to rear, you get into a problem with pitching of the car (for/aft). Puhn covers this, but I haven't read that book in a while. But this is what I remember reading in this and other suspension books. It has to do with the speed at which you hit bumps and the difference in the spring rates. I would think that shock rates front to rear would also be an issue, but shock manufacturers probably factor this in and make the rear shocks (nee cartridges) a bit stiffer than the rears. Just some food for thought. ------------------ Pete Paraska - 73 540Z - Marathon Z Project pparaska@home.com Pete's V8 Datsun 240Z Pages Quote Link to comment Share on other sites More sharing options...
Mikelly Posted January 3, 2001 Author Share Posted January 3, 2001 Pete, I'm aware of that and posed the same question. I was on the phone with the guys at Ground Control for about 30 minutes while we discused the car setup and they actually have data on file for other cars that have run the open road races in Nevada and Texas. They keep customer feedback and were able to provide me with the setup based on what they had on file for vehicles of similar weight and intended use. They actually wanted me to run a stiffer spring (300#-400#) until this last data dump was discovered for the spring 2000 run. Seems that most of the high flyers ran faster with softer settings than previous years. To harsh and the vehicle is actually harder to drive at speed. I wanted 250# and 275# springs. They advised against it since the car was more neutral with the JTR setback and the additional weight of the T56. I will be adding about 1/2 to 1 inch of rake to the front to rear height though. Seems the car will do better set up with a little of the stink bug pose! Mike Mike ------------------ http://hometown.aol.com/dat74z/myhomepage/auto.html "I will not be a spectator in the sport of life!" mjk Quote Link to comment Share on other sites More sharing options...
pparaska Posted January 3, 2001 Share Posted January 3, 2001 Cool. As I've read before, and you've again reiterated it - the guys at Ground Control are on the ball... ------------------ Pete Paraska - 73 540Z - Marathon Z Project pparaska@home.com Pete's V8 Datsun 240Z Pages Quote Link to comment Share on other sites More sharing options...
Modern Motorsports Ltd Posted January 3, 2001 Share Posted January 3, 2001 quote: Originally posted by pparaska: Cool. As I've read before, and you've again reiterated it - the guys at Ground Control are on the ball... I'll reiterate their susp. experience. They don't have near the same experience with 280ZX's but nailed my setup down first try for my mixed roadracing/autox setup. I'm a rookie as roadrace drivers go but a few others v. experienced commented on how neutral/balanced the ride/setup was so I based my thoughts on that. on the 5 way Illumina's I found they need to be at least '3' for roadracing and 2 or 1 for autox to get my responsiveness at lower speed. Just my exp. and YMMV. Mike Kelly, do you know for sure with your planned wheels/tires you have room for a spring perch beside your tread b/t tread and strut? I didn't so had to go to 7" springs. Once I swap to my camber plates I'll be able to step back to an 8 or possible (doubt it) a 9" spring. Just curious....they sent me 8's and they interfered a LOT which ticked me off as I told them my EXACT setup which susp. wise was quite basic....I'd of likely stepped straight to camber plates initially to keep a longer (8" min.) spring. ------------------ Of all the things I've lost, I miss my mind the most. Quote Link to comment Share on other sites More sharing options...
johnc Posted January 3, 2001 Share Posted January 3, 2001 > I will be adding about 1/2 to 1 inch of > rake to the front to rear height though. > Seems the car will do better set up with > a little of the stink bug pose. Go to a good racing suspension/tuning shop in your area and get the car corner weighted and aligned BEFORE you put the rake in. Expect to pay about $300 to have this done. Normally, rake is added to increase traction on the front by moving weight forward (there goes your "50/50" weight distribution). FYI... a 1" rake is a lot. ------------------ John Coffey johnc@betamotorsports.com [This message has been edited by johnc (edited January 03, 2001).] Quote Link to comment Share on other sites More sharing options...
Mikelly Posted January 4, 2001 Author Share Posted January 4, 2001 Ross, What was the backspacing on your wheels? I'm running flares and plan to run no more than 5 inches of backspacing, so I should clear the perches with the 2.5 inch coil over setup. You cannot do this with a stock fendered Z, which is probably what you are thinking. Mike ------------------ http://hometown.aol.com/dat74z/myhomepage/auto.html "I will not be a spectator in the sport of life!" mjk Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted January 4, 2001 Share Posted January 4, 2001 for running on open road you need to have some give to suspension so tires wont bounce on bumps.a guy with a v8 z i talked to said his z came up heavier in rear when done.setting up alignment for a open road car would not be to hard.not to much negative camber.some caster and some toe in.drive line balence and alignment would be very critical because most of these cars dont run od to keep drive shaft speeds down.good luck with car.mr kelly -are you running in neveda?send email and i will take my z out to watch. Quote Link to comment Share on other sites More sharing options...
Modern Motorsports Ltd Posted January 4, 2001 Share Posted January 4, 2001 quote: Originally posted by Mikelly: Ross, What was the backspacing on your wheels? I'm running flares and plan to run no more than 5 inches of backspacing, so I should clear the perches with the 2.5 inch coil over setup. You cannot do this with a stock fendered Z, which is probably what you are thinking. Mike I wasn't thinking of fenders at all (never have really, just make sure I'm not slicing tires on 'em after;^) but simply strut/offset wheel/tire clearance. My struts are 280ZX so different from yours (no idea how much different, but worth going thru this excercise for our confirmation and others interest) What do the numbers from your present combo to proposed generate for clearance at the strut? This will tell you right off if it's close or not. I usually work in offsets as I'm dealing in various hubs/rotors/overall scenario but see if I follow this thru right: 16x8 +50mm wheels WITH 1.25" spacers, so ~9" wide and 4-3/4" net backspacing correct? (9" wide, 4.5" with 0 offset, and net +.25" so 4.75" backspacing) I have 1/8" MAX clearance 245/45/16 treads to my lower threaded collar/welded washer support (ground washer flush/parallel with tire to only a 1/8" width near tireas threaded collar is so thin this is plenty of seat for it). This is at the top of my tire which does not flex much if any being at the top, on markes on treads after roadracing Thill and SIR etc. I only have 1/4" more I can space out on my ARP 3" (they're not 3" of thread at all BTW, misnomer). Quote Link to comment Share on other sites More sharing options...
Mikelly Posted January 5, 2001 Author Share Posted January 5, 2001 My most recent setup was with 265-50-15s which were 10.5 inches wide on 15X8 wheels with zero offset. I had about 1/3 inch clearance from the stock spring perch. I'm planning to move to a 17X9.5 with 5inches of backspacing. The tire will be about 12 inches wide. Now the factory spring is about 4inches in diameter ( I think) so I'm assuming I should be alright with the tire and wheel combo. Thoughts?? Mike ------------------ http://hometown.aol.com/dat74z/myhomepage/auto.html "I will not be a spectator in the sport of life!" mjk Quote Link to comment Share on other sites More sharing options...
Modern Motorsports Ltd Posted January 5, 2001 Share Posted January 5, 2001 Mike, 1/3" from spring perch to .......? tire or rim? (JTR manual not handy to see those pics...) But it looks good: -old setup was ~9" overall rims, 4.5" backspacing with 1/3" clearance (to tire or rim) -new setup is 10.5" rims so ~11.5" overall and 5" bspacing so net .5" moved outward (gained .5" clearance from rim edge to strut/whatever) -new tires 1.5" wider overall so .75" per side minus .5" clearance gained from rim change says you moved your inner tire edge inward .25", assuming your prior clearance of 1/3" was was tire to strut you now have 1/3"-1/4"=1/12" clearance TO OE STRUT -you say ~4" diam OEM (51mm radius), struts are ~42mm? so 21mm diam, then ~1/2" (maybe more?) for threaded tube/lower perch of GC is 13mm +21mm=>23mm so 51mm-23mm= 1.1" gained clearance + your 1/12 should leave you with ~1-3/16" clearance using your 'approximate' numbers...sounds v. kewl:-) I walked thru the numbers as I get enough personal q's on this and lately I've sent a lot searching the hybridz site here and they're v. happy with the great data everyone is leaving:-) Keep it up folks ------------------ Of all the things I've lost, I miss my mind the most. Quote Link to comment Share on other sites More sharing options...
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