Guest zline Posted February 26, 2003 Share Posted February 26, 2003 Basically its time for me to do my suspension i was just going to do the arizona z car coilover conversion, camber plates, 375lb springs all around, 4 piston front brakes 2 piston rear, and use Koni inserts. What are the advantages of sectioning your struts besides using different inserts? post your opinions/experience please...have you done it? yes - why? no - why not? Thanks@!! Dan. Quote Link to comment Share on other sites More sharing options...
fl327 Posted February 26, 2003 Share Posted February 26, 2003 sectioning your struts is the true way to lower your car, it makes the suspension travel even out, handles better, say you lower your car and didnt section the struts, your suspension travel is going to be funny-i havent sectioned my struts but i do understand the principle. just be careful, my buddy runs the same suspension you just mentioned, but he cut his struts down too much, so every bump he hits really hurts, and he has to run his adjustable shocks at MAX or else his wheels rub everywhere. sectioning is good thing if you are going to lower more than 1", i would also watch those spring rates, 375 is hemeroids waiting to happen on the street, ask auxilary. Quote Link to comment Share on other sites More sharing options...
Guest zline Posted February 26, 2003 Share Posted February 26, 2003 sectioning your struts is the true way to lower your car, it makes the suspension travel even out, handles better, say you lower your car and didnt section the struts, your suspension travel is going to be funny-i havent sectioned my struts but i do understand the principle. just be careful, my buddy runs the same suspension you just mentioned, but he cut his struts down too much, so every bump he hits really hurts, and he has to run his adjustable shocks at MAX or else his wheels rub everywhere. sectioning is good thing if you are going to lower more than 1", i would also watch those spring rates, 375 is hemeroids waiting to happen on the street, ask auxilary. hehe i dont know how to convert lb/inch to kg/mm so if someone could give me the relationship i could work out the proper lb/in i need but 375 seems not to bad =) where i live the streets are nice. Okay so thats 1 yay for sectioning. Has anyone written a how-to? or is it just clamp cut weld? Quote Link to comment Share on other sites More sharing options...
blueovalz Posted February 26, 2003 Share Posted February 26, 2003 Try multiplying the spring rate (lbs in the lbs/in") by .0179. This is a simplification of converting lbs to Kg (2.2lbs/Kg) and converting 1 inch to 25.4mm, then dividing the two (.4545/25.4). It will seem like a very odd number, but it should work. 375lb/in should convert to 6.71 kg/mm. Quote Link to comment Share on other sites More sharing options...
Guest zline Posted February 26, 2003 Share Posted February 26, 2003 Try multiplying the spring rate (lbs in the lbs/in") by .0179. This is a simplification of converting lbs to Kg (2.2lbs/Kg) and converting 1 inch to 25.4mm, then dividing the two (.4545/25.4). It will seem like a very odd number, but it should work. 375lb/in should convert to 6.71 kg/mm. sweet thanks. thats pretty good not to stiff actually =) would anyone happen to know of a writeup on strut sectioning? Quote Link to comment Share on other sites More sharing options...
johnc Posted February 26, 2003 Share Posted February 26, 2003 > 375lb springs all around You better have a welded in 8 point roll cage in the car to run those spring rates. The biggest springs I've heard run in ITS are 350s. Quote Link to comment Share on other sites More sharing options...
Guest zline Posted February 26, 2003 Share Posted February 26, 2003 > 375lb springs all around You better have a welded in 8 point roll cage in the car to run those spring rates. The biggest springs I've heard run in ITS are 350s. this car is for the more "illegal" versions of club rally etc., =) John, you got a writeup or know of where i can find one on strut sectioning. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted February 26, 2003 Share Posted February 26, 2003 Hey, Zline. I've been running Dave's coilover setup for 9 months now and I just did the the five lug conversion brake kit. I love them both. You might consider using the 250lb springs, the 375's are a little rough for the street, especially if you are running a low profile tire.(mine are 235-40-17) I did not section my struts for the koni inserts, I just used a spacer below the insert(1-1/2" x 1/8" wall aluminum tubing) of the apropriate length to keep it from moving up and down. I've had no problems with this setup. Cheers, Mike. Quote Link to comment Share on other sites More sharing options...
johnc Posted February 26, 2003 Share Posted February 26, 2003 Maybe I should have rephrased my reply. Running spring rates over about 225 lb. in. on a stock chassis 240Z will turn the chassis itself into a spring. The chassis begins to flex when forces at that level are fed into the strut towers. Adding strut tower braces will let you run about 250 lb. in in the front and 275 lb. in in the rear. Your 375 lb. in. springs are close to the 400 lb. in. springs the old C Production racers ran when they had 12 and 14 point roll cages welded into their race cars. Again, the stiffest springs run in ITS are about 350 lb. in. and those cars have welded in 8 point roll cages. Regarding strut sectioning: Strut sectioning means cutting out a section of the strut tube and welding it back together. This is done on a lowered car to gain back some bump travel in the suspension. Wayne Burstein wrote up a good description of this for IZCC and its reprinted below with his permission: Let's start by defining the task at hand. We want to lower the car in order to lower the center of gravity. I'll skip all the analysis on why we want to do this because there are lots of good books on the subject, and confine my comments to what you might run into in performing this on a Z. First I need to define a couple of terms: Bump -- suspension travel in the compression direction (i.e. the result of hitting a high spot in the road). Rebound -- suspension travel in the opposite direction (i.e. the result of going over a hill and the wheels leaving the ground). The first problem we run into is that when we shorten the springs, we are reducing the available bump travel in the strut cartridges by the same amount we lowered the car. With all the travel available in a stock Z, this is not too much of an issue when we lower the car only an inch or so. For those of us who are racing our cars, we often lower them much more; for instance, in the SCCA's IT class, we are allowed to lower the car until the rockers are no lower than 5" above the ground. This causes a problem because the suspension is almost fully compressed when the car is sitting at rest. When you hit a bump, the suspension quickly bottoms out (hopefully on a bump stop of resilient material). This is a real problem because in effect, the spring rate increases very dramatically and negates all of our efforts to drive the car smoothly. When driving at or near the limit, this often is the beginning of a very impressive crash. Well, we now have the car at the desired ride height, but need to increase the travel in bump. The way to do that is to shorten the struts. Now things get pretty messy. Don was correct in stating that this is dependent on the length of the struts; however, this is only partly true. The struts need to be long enough to insert the cartridges of choice. For racing, the ones that I would recommend are Carerra, Koni, or Tokico, in that order ( this should cause a bit of discussion on its own). If we automatically shorten the strut to exactly fit the cartridge, we might actually shorten it too much. This leaves us without adequate rebound travel. Just in case this does not scare you, it should. I learned my lesson the hard way when I had the rear wheels pick off the ground while cresting a hill that had a slight turn to it. That made for a looooong full lock slide at 100 MPH! Ok, now we need to decide just how much we want to shorten the strut housing. The desired end result is to have about equal bump and rebound travel. In other words, when the car is sitting at rest, we want the struts half way compressed. On a street car, this is fairly easy to do, because we generally set the car up once and never play with it. Race cars are another situation entirely. First of all, different tires require different ride heights -- for instance, switching from 60 series to 50 series tires lowered my car by .75", causing me to have to raise the car by the same amount. We also play with spring rates, and assuming that we are using coil overs, need to keep the spring collar low enough on the strut housing to avoid it interfering with suspension travel. The bottom line is that before cutting anything off your struts, you should carefully think about what you anticipate doing to the car over the next few years as far as tire/wheel, strut, spring or ride height changes, and then come up with a compromise that works for you. FWIW, most people shorten struts 1-2". If you figure out that you want to go more than this, recheck everything before cutting. Yes, you can add a section, but speaking from experience, it is much easier to remove than to add. I almost forgot to mention this, but if your strut housing is longer than the cartridge, you need to put a spacer below the cartridge inside the housing -- typically, these are just pieces of tubing that is slightly smaller in diameter than the inside dimension of the housing. Just a couple of tips to consider: 1) The best way I have figured out to cut the struts is to use a large pipe cutter. This gives a fairly straight cut with minimal cleanup -- you need to grind the burr off the inside of the housing and bevel the outside edge before welding them together. Be careful not to make the cut so high on the strut that you hit the threads for the gland nut! 2) To remove the original spring perch, the quickest way I have found is to cut through it just above the housing with a grinder or cut-off tool, and then grind the remaining metal off. I found it much easier to do this before cutting the strut because even though I was not cutting the section with the perch off, it did interfere with the cutter. 3) After lowering the car, you need to align the suspension because you have added negative camber at both the front and rear wheels. Of course, you should probably do this any time you remove suspension components anyway. Wayne Burstein WDCR SCCA ITS #10 IZCC #214, NVZCC wburstein@mountainmotorsports.net http://www.mountainmotorsports.net Quote Link to comment Share on other sites More sharing options...
Guest zline Posted February 26, 2003 Share Posted February 26, 2003 Hey' date=' Zline. I've been running Dave's coilover setup for 9 months now and I just did the the five lug conversion brake kit. I love them both. You might consider using the 250lb springs, the 375's are a little rough for the street, especially if you are running a low profile tire.(mine are 235-40-17) I did not section my struts for the koni inserts, I just used a spacer below the insert(1-1/2" x 1/8" wall aluminum tubing) of the apropriate length to keep it from moving up and down. I've had no problems with this setup. Cheers, Mike.[/quote'] Mike you got a link to this? Dave = AZC? John thanks for the writeup man... .. okay so change the springs to 250lbs, and apparently I need to section because i want about a 2" drop +/- some so i figure i'll section 1.75-2" out to compensate for everything. This board is a huge help to me in the suspension department!! Quote Link to comment Share on other sites More sharing options...
jeromio Posted February 26, 2003 Share Posted February 26, 2003 Brief write-up on my site (link below). I have 150 front 175 rear on my car. A friend who drove it described it well - like a skateboard. Stiff. Very. I cannot even fathom 250lb/in springs. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted February 26, 2003 Share Posted February 26, 2003 Hey, Zline. You may want to carefully read the Quote by Wayne Burstein posted for us by John C., especially the part about adequate rebound travel. (Thanks John, And I know.... the car was supposed to get a cage about 6 months ago but our machine shop has more work than we know what to do with right now,so no cage yet.) The reason I did not section my struts is because I don't want to lower my car very much; here's why... If you look at a stock z's lower control arms you will notice that they angle downwards from the center of the car towards the wheel area, and will not reach horizontal for about 3" or so of travel. This is not just to provide adequate wheel travel, but also to provide a slightly negative or zero camber angle. When you lower the car too much (more than 1.5-2") without moving your inside suspension pickup pionts you will lose the downward suspension angle for the lower control arms. The problem with this is that when your lower control arm is horizontal at ride height, and then sees compression, by design the strut assembly can only move in the direction of positive camber. Positive camber is bad. No? This condition is relatively easy to fix in the front of the car with the so called bump steer spacers, or by moving the inner suspension pickup points.The rear however is another matter. I know the cars look cool lowered, but the last thing I want is negative camber when I'm in that corner at 90MPH and I hit a little bump in the road. Sorry, I don't know how to post links yet.(still learning) Cheers, Mike. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted February 26, 2003 Share Posted February 26, 2003 DOOHHH ,I meant to write. I know the cars look cool lowered, but the last thing I want is POSITIVE camber when I'm in that corner at 90MPH and I hit a little bump in the road. Duh.. Cheers, Mike. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted February 26, 2003 Share Posted February 26, 2003 Man I love this site!!! Quote Link to comment Share on other sites More sharing options...
Guest zline Posted February 26, 2003 Share Posted February 26, 2003 Man I love this site!!! me too. 4bbl - I'm going to first section out 1 inch IF I need it at all as it is easier to take out than to add. Also, with the camber plates I should be able to fix any + camber I encounter. The reason I asked about sectioning is I want to keep everything a Z part to simplify things for myself. Thanks for everyones input!! Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted February 26, 2003 Share Posted February 26, 2003 4bbl - I'm going to first section out 1 inch IF I need it at all as it is easier to take out than to add. Also' date=' with the camber plates I should be able to fix any + camber I encounter. The reason I asked about sectioning is I want to keep everything a Z part to simplify things for myself. Thanks for everyones input!![/quote'] What I think 4BBL73Z was trying to convey (and please correct me if I'm wrong) was an extremely lowered Z car with stock pickup points will have trouble with camber GAIN (not the absolute value, but the rate of change). So even if you are able to correct for the positive camber with plates, on suspension compression you will lose negative camber (go more positive) instead of gain more to improve stability. Quote Link to comment Share on other sites More sharing options...
deMideon Posted February 26, 2003 Share Posted February 26, 2003 I have a question on this too... On a 510 I had I removed the insulating rubber at the top of the strut where it mounts to the body and fabricated a new seat for the bearing. On the 510 it gave me about a 1 1/2" drop and removed a significant amount of flex. Has this been done on the Zs? How much of a drop do you get? How significant is the flex? Thanks! Quote Link to comment Share on other sites More sharing options...
auxilary Posted February 26, 2003 Share Posted February 26, 2003 i would also watch those spring rates, 375 is hemeroids waiting to happen on the street, ask auxilary. If I dial the tokicos to 1 out of 5, it can almost be daily driven. I'm only running 200lb/in springs, actually Quote Link to comment Share on other sites More sharing options...
Guest zline Posted February 26, 2003 Share Posted February 26, 2003 i would also watch those spring rates' date=' 375 is hemeroids waiting to happen on the street, ask auxilary. [/quote']If I dial the tokicos to 1 out of 5, it can almost be daily driven. I'm only running 200lb/in springs, actually well damn thats pretty stiff. How much should I section, and how should I remount the pickup points? *edit* HAH I dont need to section. I just talked to Dave and for 1050 the full coilover kit (camber plates, inserts, coilover conversion, springs) the plates give you an inch and a half more of suspension travel eliminating the need for strut sectioning!!~!@ All his molds for 32000...anyone wanna pitch in? I do some nasty c/f work =) Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted February 27, 2003 Share Posted February 27, 2003 Hey, all. Sleeper, yes you are correct. I didn't know the correct name for it(camber gain), thanks. Zline, I guess thats why I didn't see the need to section the struts when I put the kit on the car! I forget that most of you guys are still running those big rubber thingies (technical term) on the tops of your stock struts. I never really looked at the stock setup. The first thing we did when I got the car was put it up on jack stands, removed all the stock suspension parts, and threw away all the useless bits. Then we hacked up the top of my strut towers, and welded in the camber plates, then replaced those rubber thingies with the pillowball mounts. I think I may have some digital photos of the install somewhere. I'll see if I can find them. Cheers, Mike. Quote Link to comment Share on other sites More sharing options...
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