Gavin Posted February 4, 2007 Share Posted February 4, 2007 My 78 280z has a tendency to understeer. On the dry pavement on a warm day I have to try to make it happen (know the limits pretty well by this point) but on a cold day with some grit on the ground its horrendous and just dangerous. Heres my setup. My alignment figures would probably help, but I dont have them unfortunitely.. 78 280z 205/55R15 BFG G-Force KDWs, 34 Psi all arround Tokico Blues with matching springs by Tokico (~1 inch drop) Front roll center adjusters (ebay special) Most of a Energy Suspension bushing kit installed (not sure whats relevant, just ask) Thats all I can think of that would be relevant... Also I have reduced the weight in the front a lot with a CF hood, fiberglass bumper, and heavily stripped down engine bay. Still have the bumper in the rear, allong with a full sized spare... I also have a pair of those MSA camber plates waiting to be installed, so if adjusting my rear camber would help I can do that. But should I need to? What could I try adjusting or what could be going wrong to cause my car to push the way it does? Any input would help. Thanks Quote Link to comment Share on other sites More sharing options...
MrFancypants Posted February 4, 2007 Share Posted February 4, 2007 What bushings did you install? I'd look at the swaybars first. If the rear bar is too soft or the front bar is too stiff, you'll push. - Greg - Quote Link to comment Share on other sites More sharing options...
Gavin Posted February 4, 2007 Author Share Posted February 4, 2007 If either is too soft, eh? Actually one pair, think its the rear, is still on the old bushings where it attaches to the links (I either misplaced them or they didnt come in the box, kinda pissed about it). Both are well tightened down though. Anyone know where to get these seperately? OK well thats a good start! Other ideas? Edit - Oh I had misread your post. That must be it. Sweet! Quote Link to comment Share on other sites More sharing options...
katman Posted February 4, 2007 Share Posted February 4, 2007 Cold day with grit on the ground? What do you expect? Don't drive fast on grit. Now are you saying you want to be able to handle neutral on grit? Then we need the Baha setup.... You aren't going to handle neutral under all conditions. Pick one you want and then we'll help. Quote Link to comment Share on other sites More sharing options...
Gavin Posted February 4, 2007 Author Share Posted February 4, 2007 I dont care about handling well in the cold and grit, but I figured its a good reflection of how the car handles in general (a lot easier to reach/test the limits in a sandy parking lot). Am I wrong? If not, thats good news, but it still understeers more than I'd like under ideal conditions. Quote Link to comment Share on other sites More sharing options...
datsunlover Posted February 4, 2007 Share Posted February 4, 2007 Yah it sounds to me like the front end is a little too stiff (suspension combined with those BFGs), and being lightened isn't helping. I had a ZX that used to behave like that in the winter. (yes, I know... WHY? It was the only car I had... ) The suspension was stock, with no rear sway bar, which wasn't too bad... but when I threw cinder blocks in the rear for traction weight, (4 actually... ) and put on crapy front tires, but good winter tires on the rear, it got bad. It was basicaly a recipie for dangerous understear, but it would go up most hills and THROUGH almost anything! Quote Link to comment Share on other sites More sharing options...
MrFancypants Posted February 4, 2007 Share Posted February 4, 2007 Actually one pair, think its the rear, is still on the old bushings where it attaches to the links (I either misplaced them or they didnt come in the box, kinda pissed about it). Both are well tightened down though. Anyone know where to get these seperately? Sounds like a possible culprit. The rear sway bar wont transfer weight because it is flexing in the bushings, leading to understeer. You should get Energy Suspension kits 7.5110 and 9.8120. Lots of online retailers -- try www.ultrarev.com. - Greg - Quote Link to comment Share on other sites More sharing options...
mom'sZ Posted February 5, 2007 Share Posted February 5, 2007 I'm not sure if this is what you are talking about, but the sway bar bushing for the front bar (this is the bushing where the bar actually bolts to the frame, not the end links, your description wasn't 100% clear) doesn't come with the kit because there are three different size bars that came on our cars, so you have to measure your bar and order them sepparately Quote Link to comment Share on other sites More sharing options...
kyle Posted February 5, 2007 Share Posted February 5, 2007 I got a huge improvement in my 240z by putting the rear swaybar back on. Roughly 1" front, 3/4" rear, addcos with PU bushings. Quote Link to comment Share on other sites More sharing options...
Gavin Posted February 5, 2007 Author Share Posted February 5, 2007 I am using the original bushings in the front where it attaches to the frame, but not at the links (they are in real good shape though, somehow). Other way around in the rear - I have new bushings where it ataches to the frame and oldies at the links. What has bean installed from my Energy Suspension master kit was done over a long period, between me and my father, so yeah... things are a little disorganized. I'm gonna check out the local parts places today and see if I can find a suitable replacement for the rear sway link bushings. Quote Link to comment Share on other sites More sharing options...
nat0_240_chevZ Posted February 6, 2007 Share Posted February 6, 2007 sounds like your trying to get the car sideways (drifting/powersliding) and understeering instead. first thing is the zeds tend to have really good grip in the rear due to the extra camber, irs and moderate spring rates. 2nd is you probably have an open diff, which really pushes the front when wheels turned, especially on loose surface, when i poped my lsd in mine made a *****humungous****** difference. 3rdly is tyre compounds and grip levels are a huge thing also, (although doesnt matter what tyre, if your on grit etc) grippy tyre brand on front hard durable on the rear=oversteer, but vice versa = your condition. If you have same tyres front & rear, then proply a bit of understeer bcause of the rear irs & camber. starting to follow me here, on a stock car only stock wheel alignment are capable, more castor will help the front bite in a bit, but by sounds of it u dont have extensive susp mods etc. one last thing, knowing when to put the power down cant be taught easily, timing is everything!!! nato Quote Link to comment Share on other sites More sharing options...
Gavin Posted February 6, 2007 Author Share Posted February 6, 2007 Yes I am following you, actually. I'm just beginning to understand suspension dynamics and am really eager to learn. Reading what you guys have to say is invaluable and I appreciate your answering my easy questions. Quote Link to comment Share on other sites More sharing options...
EMWHYR0HEN Posted February 7, 2007 Share Posted February 7, 2007 I dont care about handling well in the cold and grit, but I figured its a good reflection of how the car handles in general (a lot easier to reach/test the limits in a sandy parking lot). Am I wrong? If not, thats good news, but it still understeers more than I'd like under ideal conditions. I think your testing in the wrong spot. Heck, anything with street tires will understeer on a sandy road, even an F1 car. Go to an open parking lot that has a CLEAN surface, or if you feel your not putting yourself or others in danger, go out to a canyon road or something. Aside from that, check: Camber dampening sway bars overall alignment Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted February 7, 2007 Share Posted February 7, 2007 I found that removing the heavy front bumper really helped the 280Z feel more like a 240Z in the steering/handling department. Loosen the front sway bar end links so they have a tiny bit of play in the bushing stack, play with tire pressure, tighten up the rear swaybar bushings, try trail-braking, try -1.5 to -2 degrees of front camber if possible, lengthen the T/C rods to increase caster (I used a couple of thick washers), set front toe to near zero, and last but no least, don't turn in has hard when entering the corner. Oh and search hybridZ. Lots of info about understeer. Quote Link to comment Share on other sites More sharing options...
bjhines Posted February 7, 2007 Share Posted February 7, 2007 You might just try getting it aligned.... generally neutral toe or a little TOE OUT IN FRONT is the ticket for performance driving... make sure camber and caster are in spec... actually get as much camber as you can in front... alignment is usually responsible for 90% of the handling problems I have seen on club member's Z-cars... Quote Link to comment Share on other sites More sharing options...
Savage42 Posted February 7, 2007 Share Posted February 7, 2007 I am using the original bushings in the front where it attaches to the frame, but not at the links (they are in real good shape though, somehow). Other way around in the rear - I have new bushings where it ataches to the frame and oldies at the links. What has bean installed from my Energy Suspension master kit was done over a long period, between me and my father, so yeah... things are a little disorganized. I'm gonna check out the local parts places today and see if I can find a suitable replacement for the rear sway link bushings. I've got all the poly sway bar bushings for a 280 that I am not using, along with the T/C bushings. Let me know if you want them for a few bucks. I recommend rubber endlink bushings on the front bar, which will soften it up and give you better turn-in, if you have too much understeer. Aside from that, poly is great! Quote Link to comment Share on other sites More sharing options...
TONY C Posted February 7, 2007 Share Posted February 7, 2007 driving style is key. a car with understeer can become a car with oversteer with a simple driver change. a harder set of rear tires might put you where you want to be. try letting off the throttle a split sec sooner and throttle it a bit harder for a sec after. depending what kind of driving [like drifting] you got the clutch pedal "pump" that works great too. just don't try that 1 on public streets. if you got some front camber platesthat woould be great too but with stock springs things get tight in the strut tower. a huge turbo or v8 helps understeer. lol Quote Link to comment Share on other sites More sharing options...
Gavin Posted February 8, 2007 Author Share Posted February 8, 2007 I've got all the poly sway bar bushings for a 280 that I am not using, along with the T/C bushings. Let me know if you want them for a few bucks. That would be great! I'll PM you when I finish typing this. Maybe I'll expiriment with moving the old bushings to the front. I know how to trail brake. I fooled arround in this lot a few times, the last was with a friend who has a lot of racing experience of all kinds and a NASA instructor liscence, and he pointed out the understeer without my saying anything. Im talking about a lot of understeer at times when there really shouldnt be any. But ya, thats under pretty much the worst possible conditions. I will check out my alignment ASAP. Camber is visably quite negative in the front just from being lowered.. wish I had the numbers. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted February 8, 2007 Share Posted February 8, 2007 Just lowering a Z 1" will get you less than 1 degree negative. You need to put in your camber plates, eccentric LCA bushings, relocate the LCA mount, or get adjustable LCA's. From the sound of it though, you need to go over the whole car front to back and get back to basics first. Quote Link to comment Share on other sites More sharing options...
Pennyman Posted February 8, 2007 Share Posted February 8, 2007 I just installed my coilovers and realized my car understeered a bunch too. I figure it's not only the fact that I'm on street tires, but also because the front is stiffer than the rear. I'm going to lower the settings on my front illuminas, and that should help. Braking enough before the turn could help as well. Quote Link to comment Share on other sites More sharing options...
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