clarkspeed

Brakes are a challenge, but those cantilever slicks are the bomb. Roughly 9.5 tread width on a a 7" wide rim. There is nothing else like that. I may end up with them if I can't beat it. But surprising enough, a 245 Hoosier R7 generates very similar lateral g's but with more weight to carry. Greg runs a fairly simple brake setup. He uses the vented disks up front and a Maxima setup in the rear if I am not mistaken. I don't think he does anything special to the rotors, just cheap off the shelf. He does use a VERY high quality pad which is also off the shelf. I think you are only limited by rotor diameter in EP. I may go back and take a look at the rules to see if there are some better options like Cary mentioned. Greg also runs very high quality wheels. Volk or Jongbloed Not sure how much that factors into his success.

Let's get a update in. I had a damn sinus infection which slowed me down for a couple weeks, but I'm still chugging along. After the rear alignment I dropped it off the rotisserie onto jackstands. Spent a couple hours planning out the final welding push up front. I've got to mount a radiator, oil cooler, along with G-nose braces and air dam braces. Along with shroud for radiator and pulling cool air for the engine and brakes. Quite a bit of packaging. The good news is I got the front sway bar all worked out. It was a leap of faith that everything would clear.

Now you tell me!. Just kidding. I have been running this design for years and never noticed it before, but yes adjusters are super sensitive. A full turn is probably over 1" of toe change or more. If I ever make some more rear arms, I will definitely address this. This exercise has been very beneficial so far. I found I had the wrong springs installed, interference with the helper springs, and L/R cambers uneven due to stack height of the hats/bearings. All corrected yesterday. In the end, I have exactly 1mm wider track on passenger side than driver's side, but stub axles are not fully torqued down and that is location of the error. Rear set to 0 camber, 0 toe nominally to start and "centered" to chassis. I am satisfied with the rear. I have another idea that has been baking in my head for a couple years. I want to fab a hub mounted alignment system that also incorporates scales for corner weighting. I don't know why no one had done this before. Heavy duty inline load cells are $50-100 and a digital read out/load cell amplifier/programmer is less than $10. It would need to have a leveling mechanism (laser reference) and ablity to slide a little so camber can be adjusted. Lasers are also super cheap.

I am quite proud of this little tool. I did a dry run tonight and it looks like it works. The 3d printed brackets have pins that slide into the front control arm holes. The 24x1" scale is really just there to keep everything square. The 60x2" scale slides through the brackets and is aligned to center of chassis by the marker pins in the bracket. 23.5 between holes. I installed cast iron rotors on the rear and measure to the rear control arm bolt to adjust control arm length even on both sides with zero camber. Then will use a line laser to the the front scale to set rear toe to zero and verify the left and right CA lengths are the same. That should ensure rear is aligned with chassis and later, much later, I can thrust align front to rear. I'm not sure all this is necessary, but with double adjustable control arms Front and rear, it sure seems easy to get the track and toe uneven left to right and have the chassis tracking sideways. I ran these rear control arms on another car and first thing I found were the lengths were different even though the rod end stick out looked the same.

I am dying to know what you are going to do on exterior. But I will patiently wait.

Congrats. Spraying the interior of a race car with full cage is extreemly difficult. Nothing like an exterior body panel. Thats why many powder coat whole chassis now. I remember changing my safety glasses multiple times from the blow back. And no matter how careful you are, you will always pass the gun over a surface that is 12" too close and generate a run. The cool thing is, if you have full coverage, none of your mistakes will be noticable. Complex surfaces mean mistakes will blend into the background. And it will look spectacular once loaded with equipment. The only thing that makes me crazy on my previous cars was finding a small section of cage or whatever that i missed. Thats an interesting 2 tone split. Dont think i have seen that before. Keep in mind all of those bars near the driver will need padding so it might throw off your feng shui a little.

No comments on my color choices? Step by step. I have designed a measuring tool that fits to the front crossmember control arm holes. It will allow me to thrust align the rear wheels to the chassis. Then at a later date I will align front with rear and set toe. I spent many a nights thinking about this and studying alignment methods and machines. If both front and rear control arms have adjustable toe and adjustable length, and you want symetric, then there is no fixed reference other than suspension pick up points. I will post pics when available.

Yes, you are correct. There is friction present. It takes maybe 3-4 oz pull to make them move in my estimation. I could measure but it will not help me. I think over time it will be less. But main thing is there is no change with velocity. It took a lot of pumping to get all the oil out. I made a design for a bearing loaded strut tube with a HD strut shaft (low friction). I would cost maybe $100/corner. I decided I would postpone because this is cheaper and I need to proove the concept.

Slow progress. Close to finishing up the rear suspension. I keep finding things I need to clean and paint. But it is getting there. I suppose its time for the big reveal. Based on Cary's sugggestion, I am going with an external shock. Not sure I can get away with it, but its easily reversable. It was surprisingly easy to do. I used adjustable shock brackets from AA Manufacturing with a some angle iron for strength. Even easier in the front to connect to tubing. I used 1/2 threaded rod with rod ends to mock it up. I 3d printed a shock body to make sure there was clearance. I took a set of cheap Toyota MR2 struts and drilled a little hole in the bottom to drain out the oil. They are loaded in the strut tubes just for keeping geometry, no friction. The only tricky part is the motion ratio is different than the strut. Right now I am thinking Penske 7500's for the shock. They are reasonably priced, come custom valved to my parameters, have multiple lengths, and are double adjustable.

With those giant rotors, you will not generate very much heat into the pad (relative of course). The Wilwood pads are surprisingly excellent for that application in street or track duty.

That's a creative idea for the windshield. I always cut oversize to a template I have and then work it back down with a sander. If I ever mess that up, I will copy you for sure. If there is 1 thing I learned building the tube car, it's adapting what you have to what you need. Try your best to mount it flush with surrounding metal. Which it looks like you side panels do that. If you can, try to get the window to have a smooth transition onto the roof. Depending on what you end up with, maybe some caulk or rtv to smooth it.

I try to keep up with damper technology as it has been developing rapidly over the last 10 years or so. Basically what was F1 technology 10 years ago is now available to the public. Most high end dampers still rely on some way of controlling a fluid with valves, orifices, tubes or sleeves with special features to control extreme forces. The highest end are infinitely adjustable, consistent, and repeatable over long distances. Active and semi-active systems are often banned in motorsports and are just now becoming more popular. Most modern sports cars have semi-active dampers that can be programmed for various effects and conditions. Corvettes have a very highly developed version of this. A suspension "master" spends countless hours developing the few programs that end up in the production version, up to and including sending test teams with 100's of tires to the Nuremberg Ring each year. Now that technology is available to the aftermarket. There are a few providers out there but I was really intrigued with these guys in Netherlands. https://tractivesuspension.com/ They sell a fully programmable stand alone strut with g force sensors that can be adapted to many platforms. What really shocked me was the price. $6-7000 for a full package. I know that seems expensive, but compared to high end struts (check out Motion Control strut prices) this is a total bargain. They can be programmed to fully control stiffness, roll, dive, and squat so no roll bars needed. Imagine 30+ year old car that is fully comfortable on the street, yet capable of setting lap records with a program change. Pretty much like a new Porsche or Corvette.

It's funny when you talk about painting a car, most everyone thinks about the physical act of spraying it. When it comes to bodywork, spraying is equivalent to the last 5 minutes in the history of the universe.

I am no coating expert for sure. I do deal with coatings in my job just not paint so much., more like hardness and TBC. But as you already know, any coating is a system that has to work together. Every material laid down must bond with the previous layer. Surface finish, mixing, cure, thickness, and cleanliness must all be controlled along with chemical compatability. If you follow the rules, I think most stuff will come out ok from a durability standpoint. No one uses laquer anymore. I have never been really happy with anything our a spray can at an auto or big box store. Just fast and convienient. If you really want durable, look into single shot industrial coatings and fleet coatings (sherwin, ppg, etc). As a do-it-yourself amateur, I personally like working with single shot acrylic urethanes with a hardner mixed in. No can spray can match the pop of a real paint.

Thanks Cary, My front ARB is mounted with needle bearings enclosed in a fixed tube. Aka stock car style. The rear is located in Delrin bearings because I ran out of time and space getting that one to comply. Maybe a future upgrade? I use SusProg3d also. Let me say it is sooo much easier on a rotisserie. But even with that I probably have 8 hours in this round of measurements and still have a few I want to verify. If you ever want to compare anything let me know. I think (hope) I finally have the damn struts dimensioned. Not easy even on a bench. That book looks very interesting. I probably have room on my shelf for 1 more :-). If it can expand on what I presented in the attachment of my previous post, let me know! A resource I recently found on data acq is "Your Data Driven" from Samir Abid. Website, book, and podcasts. I have not had time to explore deeply yet but looks promising. I picked it up from Bentley's "Speed Secrets" podcast. I have been slowly going through that entire collection. A lot of great driving instruction, but some interesting engineering insights also. I have been doing a lot of podcasts recently. My "free" time outside of work, family, real estate adventures, and building this car have been consummed with my recently acquired 77' Alfa Spider daily driver. That cost me 4 new books recently. Anyone on this forum care to know how I perfected tuning SPICA fuel injection? The AlfaBB forum doesn't like things that deviate from the norm. Don't ever mention engine swap on there. I guess that's why this forum has Hybrid in the name.

Sometimes stopping to collect your thoughts makes a world of difference. I had pages and pages of notes and book excerpts that have been directing my general path along with past experience on things that I know work. So I stopped and put them all on 1 sheet which was definitely beneficial in making things clear for me. I call it my chassis KPI's. Some are starting points and some are must have. Most of my modifications to this tube car were adding adjustment where there was none or little before. All production based cars have limits on what you can do for adjustment and alignment, along with plenty of fixed dimensions and weights you cannot overcome. My goal all along has been to transform this shell into more of a purpose built race car like a spec racer or formula car, but keeping the basic strut suspension. The fastest setup may end up being something very close to a limited prep Improved Touring car, but it does give me almost infinite adjustability and possibilities for for radical changes in the future. One of the basic goals was the lowest ride height (and CG) I can stand without botttoming while still maintaining suspension performance. That is not in the KPI's but implied. That is not easy so easy to achieve with a MacPherson Strut car. I use SusProg3d for my chassis simulation software. By measuring everything on the rotisserie with giant t-squares, with 24" and 6" machinist scales, I was able to measure things out much closer than I have in the past. The usual process is the car level on jack stands and plumb bobs pointing at masking tape on the floor. When I start weighing everything and get the car sitting on wheels. the final calculations can begin. So why did I do this? Well knowing what I know now, I think I could actually get in the ball park with most of these suspension KPI's without resorting to such detail. I have been working lately with some Excel based equations that approximate the software output. But each equation takes you down a path, making it difficult to see how changes affect other things. For example, if I extend the front control arm 1", how would that affect camber gain, weight transfer, toe change, Ackerman, and so on, and so on. With the software I can change virtually anything and instantly know what other things change with it. In addition, it provides a baseline for the car I can track over time up to and including damage assessment. Most importantly for me, it provides a basis to understand and visualize what is happening when I make changes at the track or the garage, it gives me "hints" on what changes I may want to make, it documents the "formula" for what works, and it can answer most of my future stupid questions. So here are my KPI's. I invite Cary and others to chime in if these are in line with what they have experienced. Based on my experience these numbers will get you close enough to where you want to be to begin track testing and the car will be docile at high speeds. The 3 catagories are things that I will just verify, measurements I will make in final configuration, and predicted results from the software. Some of my initial results are listed although may not be exactly what I wanted. I may change springs and bars again before I even get to the track. But not ready for that decision yet. This is really the first time I got all the numbers in. All of the settings are nomimal at the moment until I can get the car on the ground. Clark Suspension Design Parameters.pdf

Got a little painting done this afternoon. I started putting together my suspension "targets". I will post it as soon as I clean it up. It can answer some questions others may have on what I am trying to do. Just general guidelines that put you in the ballpark.

That post wasn't directed at you Aiden. My advice for you is "ask Greg". If you still need some holes filled, I'm sure myself and others can chip in. And there are relatively simple equations that can ball park most stuff. Being an engineer and more importantly, a part time race engineer, I want to know my car intamately. And hopefully I can save a lot of time when actually dialing it in at the track.

Sorry, I should have mentioned powder coating. It really is the best solution for finish quality, color selection, and durability. Some of the most stupid stuff I post on this tread are when I take strange things off the shelf and use them for solutions on this car.

I have measured all the hard points for input into software. I use a program called Susprog3d. There are others out there. I think I have every hard point measured to within 2 or 3 mm. It is difficult and time consuming but the chassis diagram from the FSM does help a little if you have stock chassis points. So why invest all this time any money? If you study suspension design, there are certain targets you want to hit. Some critical are suspension frequency, roll angle, F/R stiffness %, and roll center. I have a good idea of where I want these based on study and past experience. Taking all the measurements and putting into software will let me know where I am. Even if I did not know what I wanted, going through the process at least let's me know where I am and any changes can be documented and reversed along with a possible direction to pursue.. Bottom line, if I get this right, it will save countless hours of testing time on the track. For example, I took a wild guess on my sway bar rates when I bought the bars. And the arm length is just what I needed to make it fit. I needed this all just to mock up the suspension. After I got all the data input, I think I am much closer to a desired roll rate and F/R stiffness than I thought. I believe I can at least start testing with current rates. And if I purchase a few extra springs or bars I know which way to go. Springs at $60-70ea and roll bars at 100-150ea are relatively cheap, if you have a plan for what you want. I have been ask before "can you give me your measurements". There are a few problems with that. I spent a lot of time doing it and perfecting my methods, every car is different, and most importantly, doing it yourself is about the only way to understand what you are doing. If someone just gave me the numbers, I would be lost forever. However with that said, if anyone is trying something similar with Susprog3d software or an alternative, I am more than happy to provide guidance. I have been working with my own developed Excel based system to make it more simple, but I just don't have enough time to finish it.

It's the stuff used to coat internal windings of electric motors. Developed many years ago and hot rodders picked up on it to coat internal engine blocks. Sheds oil well and encapsulates casting flash forever. That's what I bought it for and it works well, but it is expensive. I'm not building many engines now and was amazed it still looked great after all these years. Again, why not? Otherwise it will sit another few years. Durable finish is an understatement. A good idea I found for suspension is stainless steel spray paint. Steel it is the brand. Kind of a dull silver finish but again, durable as hell and easy to apply. It also is expensive, but doesnt take a lot of product to fully cover so it goes way longer than say a color spray paint. I bought a couple cans to use, but since everything else is silver or black I wanted a different color for the unsprung stuff.

I was going to resurrect this thread soon also. Once I pull the chassis off the roterssere I plan to measure every component I install. I have a set of digital corner weight scales that seem pretty accurate.

First I have seen this thread. Very ambitious. Good luck and glad to see you finally got back to your dream car.

No picture updates. 2 tasks before I take it off roterssire. I am measuring all the suspension points to put into my simulation software program. If I play this right, all future adjustments will be predictable and repeatable. Trying to get all the points within a couple mm. It is much easier now than on the ground. And the last thing will be painting suspension parts. I debated over this for weeks on end. I just could not decide. I ended up choosing a 10 Yr old+ can of red Glyptal I had sitting on the shelf I had used for some block coatings way back when. It stirred out like new, flows out beautiful to reduce brush strokes, durable as hell, looked great on my sample part, and essentially free. Problem solved.

I don't know what I am doing? Is that a good answer? I usually shoot cars just like you are doing. Having painted 3 or 4 like that, I decided to try something different. My last car was painted a battleship grey which came out great. For interiors, I usually shoot a straight cheap industrial urethane (no UV protection), with hardner, no primer. But I don't usually shoot over so much bare metal as you have. I did some research on the Google and found a log of drag racers using the hammer tone paint to good effect. Plus I had some mental pictures of a titanium color interior. The hammer tone is easy to brush, easy to match spray, durable, and super easy to touch up. So I thought why not a 2 tone? Not really much more difficult. What did I learn? Shooting the interior with a gun is still best way to go. But the 2 coat rattle can spray hammertone on my interior panels came out decent and seems durable. And easy to touch up if needed. But not as "nice" a finish as I would like. IF you want to do the cage in a different color, I HIGHLY recommend the brush on hammertone. For some reason it lays down perfect on the curved surfaces. And you don't have to mask off anything. On the downside, I think the brush on only comes in silver, grey, and black.