clarkspeed

I still enjoy bench racing on this forum also. So many things have been covered but technology changes with time and there is a real hardcore group here. I have a bunch of FB pages I comment on but it is just not the same as this forum.

Very true, but when I said very very fast I meant it. AutoX and Runoffs National Champions. I don't think Greg Ira will mind I dropped his name here. That is hard to argue against. And at roughly $400 each, they are a bargain. On the other hand, I know Greg's program well, and I don't think shocks are a big contributer to his many podiums. I don't know anyone racing the 8610 single adjustable. There were some posts on here a few years ago on the valving, but even that is probably outdated.

For what it worth, I happen to know some very very fast Z cars run the plain old 8611 Koni double adjustable. And they dont have any problems with premature failure. I think the lower settings fall right into the window you are looking for. The adjustment steps are kind of coarse, but at some point you are splitting hairs.

After Cary brought this up, I was thinking about the same thing. Really the only problem is having enough room and solid mounting for the shock. I don't see any reason you could not hook it to the sway bar mount preferrably in line with the end link. Yes you would need a solid end link, but 1/2 would probably work, hopefully not a 5/8, but I would need to think about the forces involved. I don't think shock travel has any influence. When selecting shocks, you can see there are a lot of travel lengths available. The shorter shock usually has shorter travel so it kind of works out. So if you have a non-binding place to mount it, you can probably find a shock to for the application. The tricky part is the shock will have a different motion ratio than the struts had. So if it is at a greater angle than the struts, the travel will be less than the struts and the damping greater. Essentially, the valving will be higher than what you had with the struts. The Z has a motion ratio of like .9 or something. If you mounted shocks at 60 or 70 degrees, you would need a much higher shock damping due to the motion ratio. If you use adjustable dampers, then you just adjust. Probably end up more in the middle range of the shock adjustments. So maybe your 100/100 ends up at 300/300. It all depends on the angle you mount and how far the lower mounting point is away from the struts centerline. Springs and roll bars should not be affected by this at all. Springs control the weight, and shocks control the velocity. The downside is weight. I am obsessed with it on the car I am building. Can't avoid some extra sprung and unsprung weight. But if you could do it right, that could be minimized.

This is also what I was told in a suspension setup class from a few years ago. The correct thing to do in the rain is change spring rates and roll bar rates to increase grip. But depending on the situation, that is usually not practical. So most go for a shock adjustment because it is better than nothing.

I have thought about doing this also. Do you have any pictures of this type of setup?

I ended with the same full circle you did about 4 years ago. I was, and I guess still convinced a race shock that is rebuild able by the user would be the best low cost option. I'm sure with a few trials I could get real close to the optimum damping. But paying $450 a rebuild adds up quickly when you just want to experiment. That low speed damping is just so critical for driver feel and different drivers like different feels. For me it is most detectable under braking, I go to full brakes fast and hard. It is like a timer, as you provide input through steering wheel or brakes, the harder the shock is, the longer it takes for the car to absorb the input and reach a steady state. Too hard a shock and you never reach steady state before the next input is given. Too soft, and it overshoots the input bounces back. Luckily there is a lot of margin in between and close is probably good enough My current car has a very old set of non-adjustable Tokikos on front and Konis on back. No complaints. But I want something much more sophisticated on the tube car I am building. I will need to extract all the grip I can to meet my goals. I plan to go at least 2 way adjustable and have suspension position sensors ready to go for data collection.

Yes, I got the jacking thing backwards. Too much rebound causes it and that is not your problem. I went back and looked at some of my shock tuning info and your setup with 100/100 was not a bad idea at all. That should feel very responsive in transitions which would be beneficial for AutoX. I think the devil is in the details for shocks though. The shock dyno shows what is happening, but without adjustments, how do you know more or less will help or hurt? I did think the Bilsteins could be tuned anyway you want. I just assumed they use the same valves as all their other race shocks which are interchangeable. Linear valving is usually too harsh at higher shock speeds. Obviously if you lower the force to be compliant on the high speed stuff, you will have very low forces in the 0-1in/sec low speed range and that might be your problem? Normally you are trying to get the shock to respond in the 0-1 in/sec range with pitch and roll characteristics that "feel" good to the driver and compliant at higher speeds as not to skip over bumps. That usually equals a digressive shock but not always. If you have the $$, take a look at Motion Control. I talked to one of their reps last year and he thought he could hook me up. And I notice they have a cartridge listed now for the 1st gen Rabbit, which is what the P30's were. If I can gather the funds, they will go on my next car.

OK then. Yes a school that puts the coach in the passenger seat or even better, let a national champ drive your car with you riding. I friend of mine who was a very respected driver let John Thomas drive his car one time and was blown away at the techniques he used. The one area where sim racing = real racing is thinking out of the box. That is what separates the good drivers from the mediocre. Being able to try something new and learn from it immediately. Guys like me are doing that to gain seconds, the pros do it to gain tenths. And no substitute for more seat time. Anyway, from my race experience, anyone less than professional level drivers can usually gain the most time by driver improvement. And for both racing and Autox, easy to drive, comfortable, confidence in the car makes you faster. Sounds like you are way ahead of me on sim racing. I run the Thrustmaster stuff on iRacing and don't know any difference. Personally i think AutoX and lapping are just too different to make a direct comparison. An unfamiliar 60s blast averaging 40mph through cones with slaloms is not like lapping a big track. Personally I suck at Autox for that reason. I am still not exactly sure my sim racing will directly affect my actual track racing. Time will tell. A SCCA Runoffs driver I worked with ran sims for a couple of months, then hired a local driver coach for feedback during practice, then hired me to analyze his data for a new track he went to. That covered all the bases and his driving was near perfect and he got a podium. There are also many differences between the sim cars and an actual race car. The sim cars seem kind of sterile compared to the real thing. There are so many variables they hold constant. Long story short, IMHO, online coaching in a sim racing format would not equal faster AutoX times. Learning a new track? Probably. Being a better sim driver, definitely. Like most things, the question is not if you can get from point A to point B in skill, of course you can with practice. But can you get there faster with coaching? Personally data analysis is my thing, I am very good at it, but I have yet to look at a single lap from my sim runs. I am usually about 2-3 sec behind the fastest person and I am confident I could find another second if I had more seat time (time to experiment). If I ever I feel like I have hit a wall and can't find anymore speed, I will dive in. Finding speed myself and learning race craft still seems like the fastest way up in sim for me, which is not the case at all when I am racing a real car. So tires are a "no brainer". They usually are. Shocks sound like a good investment also. I had the Bilsteins on my last car. I called them and gave them my sprung and unsprung weights and motion ratios. They send me back valving equivalent to 300/100. Which looked like the 100 compression was linear and the 300 rebound was digressive on the dyno chart. I raced those for a number of years and they felt pretty good. If you are 100/100 you are probably jacking down during a run. Anyway, a revalve can make the car feel much different if the low speed valving changes. Low speed shock valving is probably the secret sauce to a good Autox run due to all the quick transitions. Clark

Just switch to flat top pistons to up your CR.

You are mostly autox'n correct? That is a special category. If HPDE or time trials let me know, it will be a different answer. First of all, for a beginner, DA is easiest applied to driver analysis. Next concern is analyzing a 60s run you can only look for major issues or make a comparison between run 1 and run 2. If you tried a slalom 2 different ways, you could definitely determine the best choice, but analyzing a single run is doubtful you would see something you dont already know. I am interested in your online coaching statement. I assume you are racing online. I also run iRacing quite a bit. I personally wouldnt invest more in sim driver analysis unless I wanted to improve my sim racing. I couldn't imagine sim coaching would make me better in a real car. I am not going to list the reasons now. Based on your post, I would say there are 3 definite ways to get faster (WIN). A real school, either autox or track. Lowest cost way to improve the driver. Shocks if you really need them, but that is another $$ catagory.. Tires, always make you faster for the next race, and fiberglass??? I say do that in addition to whatever else you decide. I just started down my fiberglass learning curve and it is fun, and not that expensive. You can definitely master it quickly.

I only use those things to answer the question "what's going on under there"? I run a full data acquisition system and add forward and rear facing cameras when in a race. I got real heavy in the data side of things a few years ago and now do analysis for others too. If you want to dip your toes in data, the phone apps are getting pretty good. Also the Aim Solo. And I think some of the new action cameras collect data.

For quick down and dirty videos I have a couple of rechargeable cameras that record to microSD like these: https://www.ebay.com/itm/Nanny-Cam-Video-Camera-Tiny-Small-Pinhole-DVR-Digital-Spy-Hidden-Secret-Wireless-/381414328453?_trksid=p2349624.m46890.l49292 I bought them used a few years ago, but I see you can order from China for 12.95. They record a good 45 minutes or more and are easy to ty-wrap in unusual locations (no jokes please). You have to manual turn on, but they are pretty durable in a metal case even though I don't care if they got destroyed. I've mounted them in fender wells, under the hood, pointed at gauges, and pointed at my feet. Race Render software is really good If you want to sync with other videos and edit. Easy to use. If you want track videos, I recommend an old GoPro or clone that is hidef. They are just so cheap now and easier to mount than a phone.

A GoPro or similar mounted underneath can give a wealth of info of what is going on. I bought a couple of tiny 720p cameras for 20/ea and ty-wrap those things everywhere. I lay video snap shots in PowerPoint and estimate max distance traveled for each component. Poor man's data acquisition!

Makes perfect sense to me. I will incorporate in future builds!

Kind of off topic, but here is a picture of the adjustment I added to a stock arm. Pretty simple and it was just bolted on to the roll bar and a clevis was bolted to the control arm. It worked perfectly.

Comparing the control arm angles and tie rod is the starting point. Actually measuring bump steer is the logical next step. I'm not sure what ends you have on the Woodward rack, but perhaps you could also add an adjustment there? You can do the larger spacers (2"?) at the steering knuckle, but you might end up having interference with the tire/wheel. Keep an eye on that. If you are using a 5/8 bolt or tapered bolt at the knuckle, it should be plenty strong enough.

Most road racers run the R180 with some type of limited slip. I run a R200 only because I have a couple of Quaife LSD's made for them. You could probably even get away with a R160 for sprint races. CV's are debatable. Consensus is they have less drag. But for durability I have seen as many S30 CV's fail (road racing) as u-joints. For best reliability of either, best to have the angles as level as possible. I have seen Z drag racers with drag slicks and 600+ HP run fine with some spicer u-joints. They just made sure the squat on green light made the axles horizontal. But a CV will definitely work better and last longer at more extreme angles.

John, I anticipated you had already considered everything on my list. Your car has more planning and engineering in it than I could imagine. I just thought I would list some of the lessons I have learned. I did make a mistake above, I didn't run a rear bar with the stock front bar. Writing about jogged my memory. That is how I ended up with a stock front bar. I was running your standard front and rear aftermarket bars that I had made adjustable. It was a perfectly balanced setup, but I wanted to drop the rear bar to get the power down better and save weight. After doing the math, I found I didn't need very much spring rate in the front to keep the same F/R roll resistance. For everyone else reading, the roll bar is basically another spring when cornering. So if the spring provides 500 lbs/in resistance and the roll bar has 200 lbs/in then you have 700 lbs/in effective spring rate. It's a little more complicated than that due to motion ratios and roll bar configuration, but you get the idea. So it you have 700lbs in front and say a 450 spring and a 150 lb bar in back (600), and you remove the 150 lb bar, you can imagine the 700 in front combined with the new 450 in the back will roll considerably more in the back and will understeer until you get the total F/R stiffness ratio back to where you started. So....to make a long story short, if you remove the rear bar, without any other changes, you probably need a smaller front bar. I will try to find some pictures of my adjustable mods.

That is a lot to digest, but I think I follow your journey. Some things I have run across in my current and previous designs: 1. Weight is a concern. If you end up with a setup considerably heavier than a couple Suspension Technique bars and bolt style end links, you are going in wrong direction. 2. I usually target around 1 degree of body roll at max lateral G. So if I run relatively stiffer springs, then sway bar rate can be reduced. I once set a car up with 400 lb springs, a stock front sway bar, and a ST bar in the rear. Both made adjustable (so the front was actually stiffer than stock). 3. Running small to medium size bars have other advantages in weight reduction. For argument, I will say medium is less than a 1" solid bar with 14" legs. You can weld on adjustment brackets with simple angle iron. And you can use smaller rod ends. I think I ran 1/4" with the stock bar, maybe 5/16, I can't remember. But less than 3/8. And if you are running a hollow circle track style bar, you can go with aluminum arms. They say they flex and move around, but that is only a problem at higher bar spring rates. I also try to keep the arms as short as possible to keep the arm weight down and reduce flex. 4. It looks like you solved the binding problem. When running very short end links you end up giving the control arm adjustment holes also to match up. I have also done this with a simple piece of angle drilled and bolted to the arms. 5. I like the rod end mounting. Kind of makes sense at least for reducing friction. I would put a camera under there to see what the are doing under load. I've seen mounted in roller bearings also. 6. It doesnt take much adjustment to make a big difference. You can do the math, but for me 1/2" is usually difference between understeer and oversteer. So if you have selected the correct bar rates, you really only need one bar to be adjustable.

Some of the main differences from EP to other racing classes is 15x7 wheels with slicks, full fiberglass fenders, hood, and hatch to meet min weights, along with engine mods. If really going for it, I would recommend a turn key engine build from a race shop that specializes in this formula. A 240 also fits into ITS class with much less modification. Vintage cars are typically built to 1972 SCCA production rules. Some organizations are tight on rules, others not so much. Either way, they will still group the car to race. Check out SVRA website for some 240Z rules. I you want to give racing a shot, I suggest doing a SCCA school with a rented car or one of the other national schools that provide the car. I specialize in restoring and building old race cars for the vintage circuits. If you give up on your project, I might be interested.😀

22 rod ends are not going to be light either. I can't help but to guess that F/R conversion will add more weight than any performance gains.

Not sure why you want to reinforce the pedal box? The firewall can flex some, but the box is pretty solid. Installing dual MCs is a different topic all together. I don't think dual MCs are really necessary for the street, but if you really want them, the easy/cheap way is to modify the existing pedal box. You need to remove the box and cut access holes for the balance bar. Weld a bushing in the brake pedal arm, and weld a laser cut plate to the firewall with the 2 mounting holes or make the plate yourself. Easier I think than trying to fab up mounting a pedal set in an area that is difficult to access. But it has been done many times.

If your first race car, does that mean new to racing also? Been to school yet? Then having a reliable car and getting as much seat time as possible is very important. EP is a very fast class and most have serious built cars in my region. Not necessarily the best class to start with but not impossible. I am mostly into vintage racing but have done some engineering for the EP guys.

Now that is some brake cooling! I think most switch to rear disk for convience. No adjustments, easy to change, pads cheaper than shoes. Both will stop equally. When racing stock brakes and running 20 minute spint races, I never had much issue as long as I changed pads frequently and didn't try to stretch out the life. It doesn't take much wear on the front pads before they lose all temp control. MaybeI Improved cooling like in the pic would help. I never ran cooling to the drums, but always did use finned aluminum. Oh, and most racers I know just use plain old cheap $40 solid rotors up front. Cheap to change out when they get a little wear.