johnc Posted January 11, 2002 Share Posted January 11, 2002 Shocks are the major contributor to how a car "feels." All the low priced performance shocks for the Z (Tokico, KYB, Koni, Bilstien) have too much compression damping at high piston speeds and you feel this as an impact on expansion joints. A good race shock will have medium compression damping at high piston speeds allowing the suspension to follow the surface. The car will feel more supple and will actually be more comfortable to drive. In my 240Z, with 300+ springs all around and Penske triple adjsutable shocks, the car rides much nicer than when I had 250 lb springs and Tokicos Illuminas. Sharp bumps are felt more as a "push" on the car than as an impact. BTW... Mike - 500 lb in springs!? Whatever shock you had (short of custom Penskes or Konis) could not control that spring in rebound. My guess is that your car (on a bumpy road) felt like four pogo sticks traveling in loose formation (to paraphrase Carroll Smith.) Quote Link to comment Share on other sites More sharing options...
RB30-ZED Posted January 12, 2002 Share Posted January 12, 2002 This is an Austrilian spring site , look under the Pro Sport section, it has a fantastic range, and the Aust dollar if half the US. The single rate 250mm springs are around $65 each Aust. www.kingsprings.com.au Steven Quote Link to comment Share on other sites More sharing options...
RB30-ZED Posted January 12, 2002 Share Posted January 12, 2002 Sorry link didnt work try http://www.kingsprings.com/prosportframe.html Steven Quote Link to comment Share on other sites More sharing options...
Tim240z Posted January 12, 2002 Share Posted January 12, 2002 Originally posted by John Coffey: quoteShocks are the major contributor to how a car "feels." All the low priced performance shocks for the Z (Tokico, KYB, Koni, Bilstien) have too much compression damping at high piston speeds and you feel this as an impact on expansion joints. John, are the Penske's out of reach of us mere mortals? Do they have the remote reservoir? Are they really 'that' much of an upgrade for street use with soft (250lb/in range) springs? I thought that the adjustable Tokikos allowed compression and damp adjust? If not, I'm just going to order a set of Billies (Bilsteins that is) from a contact overseas. I was planning on running the Tokikos, but if the improvement is vast, I'll drop the $$ for the Billies. Tim Quote Link to comment Share on other sites More sharing options...
johnc Posted January 12, 2002 Share Posted January 12, 2002 Depending on which Penske you price, they can be anywhere from $500 each for the single adjustable 7300/7500 to $2600 for the quad adjustable 8760. What makes them even more expensive is that they are not inserts. Erik at EMI Racing had to do some engineering to use the Penske threaded shock body as the strut tube itself. At that price they are really for racing and then only for those folks that have more money than sense... Quote Link to comment Share on other sites More sharing options...
CruxGNZ Posted January 12, 2002 Author Share Posted January 12, 2002 Well, I figured it out. I'm going to run 175lb. in front and 200lb. out back. Oh, yes I do have ST sway bars, poly bushings, and (soon to come) coilovers . Now I have to read about strut sectioning, and find out what Tokico shocks I have to buy, by that I mean for which car the shocks are intended for. Thanks everyone for all the replies. !M! Quote Link to comment Share on other sites More sharing options...
AlbatrossCafe Posted August 17, 2018 Share Posted August 17, 2018 (edited) On 1/10/2002 at 6:42 AM, jeromio said: 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. For real. I'm at 225/280 on my coilovers. It is miserable on the street over bumps. 280z with L28ET. It would handle great on smooth track, but over potholes/bumps, I feel like I actually lose out on handling because it bounces me to the other side of the road. Edited August 17, 2018 by AlbatrossCafe Quote Link to comment Share on other sites More sharing options...
Leon Posted August 17, 2018 Share Posted August 17, 2018 Sounds like you guys have damping/travel issues. Quote Link to comment Share on other sites More sharing options...
Miles Posted August 17, 2018 Share Posted August 17, 2018 1972 240 SBC 350 Front 180lb/in. Rear 200lb/in. All poly suspension bushings and Tokico shocks. Comfortable ride: Ride is stiff, but not harsh. Not like a skate board. Quote Link to comment Share on other sites More sharing options...
socorob Posted August 19, 2018 Share Posted August 19, 2018 78 280z. Bought the TTT setup and had 250 front , 300 rear on konis. Felt too soft, swapped to 300 up front. It is slightly stiff but feels much better than the 250s. 250s are way too light for the rear. The shocks are probably around 2/3 compressed at ride height. Just bought 350s, haven't installed them to know if they are going to be too stiff, but at 1620 rear weight with me, spare, full tank, etc. it should be around 1/3 compressed at ride height. Quote Link to comment Share on other sites More sharing options...
AlbatrossCafe Posted August 30, 2018 Share Posted August 30, 2018 On 1/11/2002 at 12:28 AM, Guest Rick Johnson said: 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. 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. I was running 4k (224#) springs front and 5k (280#) rear. I just bought 3k (168#) to put on the front and move my 4k to the rear. I thought the stiffness was springs. I had no idea a concept like you mentioned with the tension rods even existed. If the softer spring rates don't fix my harsh ride over expansion joints, I'll definitely give your idea a shot next. Thanks. btw yes I know I am replying to a 16 year-old post lol Quote Link to comment Share on other sites More sharing options...
HuD 91gt Posted August 30, 2018 Share Posted August 30, 2018 A little off topic, but in regards to the post above. What is everyone opinion of this setup thezstore sells. Tension control cup system. It was one of the first items I did to my suspension and I’ve always found my car to be very stiff. http://www.thezstore.com/page/TZS/PROD/classic20j/23-4190 Quote Link to comment Share on other sites More sharing options...
Leon Posted August 30, 2018 Share Posted August 30, 2018 3 hours ago, AlbatrossCafe said: I was running 4k (224#) springs front and 5k (280#) rear. I just bought 3k (168#) to put on the front and move my 4k to the rear. I thought the stiffness was springs. I had no idea a concept like you mentioned with the tension rods even existed. If the softer spring rates don't fix my harsh ride over expansion joints, I'll definitely give your idea a shot next. Thanks. btw yes I know I am replying to a 16 year-old post lol Ride comfort is a systemic attribute, it's not just springs or bushings or... Spring rates set ride frequency which sets the amount of force, thus acceleration (F=ma), your body will see from road inputs. These accelerations are tuned via dampers and isolators. This is mostly reflected in how "stiff" the car feels when hitting bumps and dips in the road. Then there's the matter of impact harshness from road imperfections. This is more of a noise and resonance issue. This is dealt with via something called compliance. The bushings responsible for controlling the amount of longitudinal compliance were already mentioned in the post you found. This is all assuming you're not running out of travel on your suspension. Fixing harshness is going to involve making sure you have soft compliance bushings and top mounts. If you're running coilovers with a solid top mount (ball joint), that's not helping. Quote Link to comment Share on other sites More sharing options...
AlbatrossCafe Posted August 30, 2018 Share Posted August 30, 2018 16 minutes ago, Leon said: Fixing harshness is going to involve making sure you have soft compliance bushings and top mounts. If you're running coilovers with a solid top mount (ball joint), that's not helping. Yep... coilovers with hard top plate (no more pillow mount), poly bushings, and nylon at the tension rod lol. I have everything going against me. Makes more sense now, at least. Quote Link to comment Share on other sites More sharing options...
Gollum Posted August 30, 2018 Share Posted August 30, 2018 Also for what it's worth, you'd be amazed how "smooth" a well performing suspension can be. Stiff might feel sporty, but remember that the goal is to maintain contact over the road surface, not skip over it. Also don't forget that spring rates are acting as a force between two points. Required spring rate to reach max travel target is subject to weight of wheel package as well as chassis weight. Then there's also suspension geometey which is a huge reason some chassis run wildly different rates. A 400# spring on a 240sx might feel soft but absolutely brutal on a s30. 1 Quote Link to comment Share on other sites More sharing options...
Miles Posted August 31, 2018 Share Posted August 31, 2018 4 hours ago, HuD 91gt said: A little off topic, but in regards to the post above. What is everyone opinion of this setup thezstore sells. Tension control cup system. It was one of the first items I did to my suspension and I’ve always found my car to be very stiff. http://www.thezstore.com/page/TZS/PROD/classic20j/23-4190 Leave the T/C rod bushings stock rubber. The T/C rod can snap under load with hard bushings such as aluminum or polyurethane. There are pictures on Hybridz. All of my suspension bushings are polyurethane except for the rubber T/C bushings. Ride is razer sharp, but not harsh Quote Link to comment Share on other sites More sharing options...
Leon Posted August 31, 2018 Share Posted August 31, 2018 The ball-and-socket kit won't bind or snap TC rods but it will be harsher than rubber. Quote Link to comment Share on other sites More sharing options...
jessejames Posted September 2, 2018 Share Posted September 2, 2018 I'm running 375lbs front. 325lbs rear. I have the St away bars as well. Quote Link to comment Share on other sites More sharing options...
rabrooks Posted February 23, 2019 Share Posted February 23, 2019 All the talk of ride harshness makes me wonder how many of these cars mentioned in these posts are lowered, changing the optimum suspension geometry to something less forgiving. That too will add to the harshness of the ride. That being said, there is a great deal to consider and design in when making suspension changes. Quote Link to comment Share on other sites More sharing options...
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