Roman Posted May 2, 2011 Share Posted May 2, 2011 As above, my car (AA60 carina) has a parallel 4 link setup (currently with factory rubber bushes) and a rose jointed panhard rod. Springs and shocks are quite stiff, yet I'm getting really bad axle tramp in the wet. Any ideas what could cause this? I searched, but most are to do with leave spring setups. I've got a set of nolathane bushes here for the 4 link, but I've heard that soft engine mounts or gearbox mount could also cause this, is that true? Cheers! Quote Link to comment Share on other sites More sharing options...
KKtrips Posted May 2, 2011 Share Posted May 2, 2011 First thought I have is you may have incorrect pinion angle.. It should be tilted slightly down - Not 100% sure on best angle but someone here will know it.. Quote Link to comment Share on other sites More sharing options...
Roman Posted May 2, 2011 Author Share Posted May 2, 2011 Yeah definitely possible... Car is actually sitting higher in the rear than it's going to, so the issue will presumably worsen if that is the cause, as the ride height drops. Quote Link to comment Share on other sites More sharing options...
Testament Posted May 2, 2011 Share Posted May 2, 2011 As kk said angle of the diff is the first thing to look at, especially as I'm guessing you have your coil overs on "how is that so slammed" setting and maybe thats got the diff head on an extreme angle. also how many uni's are there in the driveshaft? 1 or 2? if you have 2 the axis of the pinion should be pointing directly at (or just a little below) the uj at the gearbox end. if you have 1 UJ the axis of the pinion should be paralell with the axis of the gearbox output (or just slightly below) if you are off those it will put a vibration in the driveline and certain speeds which may be setting off the tramp. The other question would be on the goodness of your shocks esp if you have very stiff springs. Quote Link to comment Share on other sites More sharing options...
KKtrips Posted May 2, 2011 Share Posted May 2, 2011 Are the 4 bars adjustable? or are they factory fitment? Being super slammed and you will be getting cert anyway - spend a few bucks and get the top arms made adjustable with a suitable sized Left/Right threaded turnbuckle. Also a too hard shock/spring combo could make a small amount of axle tramp feel like EPIC amounts of it... Whay Tomstamint said about the UJ's is real important too.. Quote Link to comment Share on other sites More sharing options...
smokin' joe Posted May 2, 2011 Share Posted May 2, 2011 pinion angle needs to be adjustable if the ride height is to be able to be changed, unless the car has parralell- equal lenght links. from memory, centreline of pinion wants to be 2-5 degrees higher at nose?? (spring rate dependant) easiest way tomake adjustable top links to suit Toyotas is to use rear toe control rods from #V30 (or similar) Camry. they have a nice rose joint in each end. alternatively, i have also used the same adjuster from a Mazda 323 and welded them in. Quote Link to comment Share on other sites More sharing options...
Celica RA45 Posted May 2, 2011 Share Posted May 2, 2011 dave have you put the nolathane in the rear lateral bars yet ,if you have this will bind your rear end up /1 sounds like your rear springs or shockers could be to hard you wont the back end to squat when you accelerate ,but cold tyres will make it wind up as well reading this again wet roads with stiff springs and shocks will cause wind up my race car has only 200 lb rears and 300 fronts with a hard rebound and soft bump also what you can do is undo all of the trailing arm bolts on a drive on hoist and then when level retighten them all up ,see how that goes also a 2 peice tail shaft helps the pinion angle Quote Link to comment Share on other sites More sharing options...
Roman Posted May 2, 2011 Author Share Posted May 2, 2011 Nah I havent put nolathane in rear yet... Have got a spare set of trailing arms so was gonna put in those to see how it goes. But definitely not a good idea? Hmmm so that's about 3.5kgmm rear and 5kgmm front springs.... Definitely a lot softer than I'd have thought! This wasnt really a problem when I had the softer springs in the rear, but I guess I might have gone from too soft straight to too hard. The bushes in my spare set of trailing arms dont really look as though they have much compliance anyway. Glenn do you have adjustable top and bottom rear arms or anything like that? Do you have a picture of how low your car sits? Running a factory 2 piece driveshaft. The tires are pretty good (Toyo proxes T1R) But they're a few years old and I'vedone a few trackdays with them in the MR2 and a stack of street driving before this, so its quite likely a contributing factor that my tires are shagged. But in saying this I've driven other cars with crappy tires in the wet and dont get the same issue. Also Glenn what do you use in terms of engine and gearbox mounts? Mine are factory mounts from Altezza gearbox and a 1S, so could they be too soft and the motor/gearbox jumping around cause this perhaps. Quote Link to comment Share on other sites More sharing options...
Celica RA45 Posted May 2, 2011 Share Posted May 2, 2011 im using 2 s engine mounts and std ra60 gearbox mount also you can still buy the trailing arm bushes from toyota from ra60 series celicas. my car sits 600mm from ground to center of the front arch on guard using stub axle as a center point and rear is 615 at center rear axle and center of rear arch in quarter panel front struts are ra40 and rear is a 7.5 live axle set up std trailing arms with std rubber but i also use a adjustable rear panhard rod .which can move up or down 25mm in new holes i have made up at the moment my panhard rod is lower by 25mm than the std set up .this will change rear roll center and also helps the rear to squat as well ps im using bilstein shockers front and rear Quote Link to comment Share on other sites More sharing options...
fulloc Posted May 2, 2011 Share Posted May 2, 2011 The point about tightening the bolts at ride height is important. Quote Link to comment Share on other sites More sharing options...
Roman Posted May 2, 2011 Author Share Posted May 2, 2011 Yeah, cool. Thanks for the info Glenn as my car runs pretty much exactly the same setup as yours. So at least I know that it's unlikely to be the bushes causing the problem. I'm thinking that the rear shocks could be struggling to control the spring rate that's in there at the moment. I'll work out the spring rates of what's in there at the moment and then go from there. IF spring rates seem really high then I'll fit something softer, if the spring rate seems reasonable then I'll look at getting some shocks which can control the springs better. edit: Okay sweet I'll definitely check that out about tightening bushes at ride height. Quote Link to comment Share on other sites More sharing options...
kpr Posted May 2, 2011 Share Posted May 2, 2011 a had a bit of tramp on the kp. going to harder springs seemed to fix it. found this on my font tug starlet also, too much damper would make it tramp Quote Link to comment Share on other sites More sharing options...
Celica RA45 Posted May 2, 2011 Share Posted May 2, 2011 when you set that up then try a 27mm front adjustable front bar with 4 holes and on the back just run the std ae86 rear sway bar thats all i run on front struts i have a spacer of 35mm for lower arms and strut to sit on and also running some cusco adjustable strut tops for 5and 1/2 caster and 5 degress neg camber by running mx 62 lower arms also tyres are re55s 205 x50x15 inch all round with AP 4spots front and rear 310mm x28mm rotors and 265x22mm on the back Quote Link to comment Share on other sites More sharing options...
Roman Posted May 2, 2011 Author Share Posted May 2, 2011 Okay cool yep it sounds like my suspension setup is pretty similar. Up front is all standard carina bits but cusco strut tops, adjustable spring perch, bigger brakes, different shocks (Cant remember what) No swaybar at the moment because none of the standard ones fit around the front of the sump. Rear is F series live axle same as yours, bigger brakes, cusco LSD, standard 4 link and whiteline adjustable panard rod. Just needs some tweaking to get it all good hopefully. What sort of LSD is in yours Glenn? My cusco 2 way is really tight even with the friction modifier oil, feels like its making the car sledge at the front more than it would otherwise. Thinking a torsen diff would probably be better suited for what I want. Quote Link to comment Share on other sites More sharing options...
UTERUS Posted May 2, 2011 Share Posted May 2, 2011 Is it sleding on decel or under power or both? Having the alignment sorted should help, when i went from an open diff, to a locker, to the trd lsd I just changed my driving to suit and all is well Sucks about the tramp, feels like the car is being ripped apart \ Quote Link to comment Share on other sites More sharing options...
Unclejake Posted May 2, 2011 Share Posted May 2, 2011 a had a bit of tramp on the kp. going to harder springs seemed to fix it. Harder springs solved my tramp problems too. I used to get tramp in 3rd gear in the damp Quote Link to comment Share on other sites More sharing options...
Celica RA45 Posted May 2, 2011 Share Posted May 2, 2011 trd lsd is 1.5 way 2 way is ok with no grunt try a ra40/ae86 sway bar to see if it fits around sump and rear bar no bigger than std about 13mm thick dia 18mm could be a problem also your whiteline rear bar could be making axle wind up, disconnect and then try also 2 way works under and off power 1.5 just works under power and is off like std lsd could also be a problem you might have change your driving to suit diff car might sledge with no front sway bar Quote Link to comment Share on other sites More sharing options...
drftnmaz Posted May 2, 2011 Share Posted May 2, 2011 yea no front bar would make for a horrible driving car! you know snell springs can custom make you a sway bar to whatever specs you want, seemed reasonably priced last time i talked to him, better to go in there and show him rather than call tho... have you fitted rear traction brackets? they go on your diff where the lower arm should connect and then remount the lower arm ~50mm downwards, repairing some of the angle from lowering also some extra track in the front to add some camber will reduce sledging abit... Quote Link to comment Share on other sites More sharing options...
Roman Posted May 3, 2011 Author Share Posted May 3, 2011 No traction brackets, but has been on my mind. Bottom arm angles are sweet at the moment though, as the car really aint much lower than factory in the rear currently. I'm not keen on the idea to add camber to balance out the LSD causing sledging... Seems like making each end of the car fight each other, taking away grip from both ends rather than addressing the issue that's causing it. Might pull the diff back out and take it back to the diff shop. I've seen pics of people rearranging the clutch plates inside to change the strength of the LSD, and will also see if I can get it set to 1.5 way. I just pulled out one of the rear springs. Works out to being about a 5kgmm spring rate, vs Glenn using about 3.5kgmm in his car. So could go to a softer spring and see how it goes. Quote Link to comment Share on other sites More sharing options...
KKtrips Posted May 3, 2011 Share Posted May 3, 2011 I did a little research re pinion angle - According to Jerry Bickel (a top competition chassis builder), a ladder-bar suspension normally requires ½ degree of pinion angle, a four-link requires 1-2½ degrees, and a leaf-spring suspension requires up to 6 to 7 degrees. In all examples, were talking about negative pinion angle, i.e., the pinion is nose-down in relation to the driveshaft Hope that helps... note - a good read ---> http://www.carcraft.com/howto/91758/index.html Quote Link to comment Share on other sites More sharing options...
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