tube80z

This sounds very similar to the setup on Dave's LS2 car. We use the FA rears but had issues with the fronts earlier this year. We had been using pictures and a pyrometer to set camber and running similar temps to yours. After watching closely what it appeared was we were killing the tires by dragging the inside in the corners. We had a couple of pictures where we could see a line around the tire that showed what was touching the ground, which also seemed to be where they wore out. On the inside 1.5 inches or so (familiar?) I just noticed you have outer edge wear. Do you have any pics of the car loaded up in a corner? Are you running camber plates or stock isolators? It still sounds like you have too much roll or perhaps a compliance steer problem that's leading to excessive toe-in (you might check the steering joints). The rest of the advice is probably not worth a lot but I'll leave it in case you find it interesting. To fix this we reduced the camber to about 1.5 degrees negative in the front. Added more caster 8 to 10 degrees (may do more but ran out of adjustment and into tire clearance issues). This helped the brakes work better and tire temps were down a bit (5 to 10 hot on the inside). Also keep in mind I'd run at least double your spring rate. I think that's a problem. You also need to be very aggressive at controlling roll. We did this using droop limiters. This will help you run a lot less camber too. You may want to check the toe too. Here's a trick. Try running the car over a piece of sheet aluminum on top of some salt or glass beads (something low friction) with about half lock on on the inside tire. Does the car push the sheet away or pull it under? You can use this to help figure out if you need more toe out (although I wouldn't go beyond 3/8 of an inch). We run 1/4 to 5/16. My suggestions 1. Double spring rates 2. Less camber 3. More caster 4. Limit droop for better roll control Hope this helps, Cary

Good question. And it would be good to have the rest of the temps and alignment. We had similar problems earlier this year and have ideas on how to fix it assuming you have the FA tires. Cary

I don't think you read anything wrong. I'm still going through a lot of this myself and was interested in seeing what was proposed as a better solution. There's more info that's being released in this area as the FIA has made it a hot topic. With regards to the Subarus I'm pretty sure FIA regulations require the door bars not to protrude into the doors (all mechanisms must work etc.) and the doors may have the stock safety beams in place too. So the cage may be a secondary safety device designed to work with the shell. To be quite honest I only found the link and it appeared it had some decent data and passed it along before looking very deep. I'm currently pretty messed up on pain pills so if what I'm writing isn't making sense you've been warned. Cary

Some more reading for the safety minded, https://dspace.lib.cranfield.ac.uk/bitstream/1826/2282/1/Corrected_Roll_Cage_Thesis.pdf Rally car side impact protection. Cary

If you cut the rotor you now have a spot that is thinner. So under severe use that will get hotter and will expand more, which leads to runout when used hard. If you don't cut the rotor and shim the hat then you don't have this issue. At least that's what I'm getting out of this. Cary

I used similar hardware. I also installed vertical bracing in the center that touched the windshield and helped it keep its shape. I the painted black around the edge and a big strip at the top. If I recall correctly this saved abut 15 pounds over the windshield and rubber gasket that were replaced. If you need a water tight seal you can use silicone to build it up but you'll probably need to use a different spacer arrangement. You need to use special cleaners and be very careful with this stuff or it will scratch as everyone as said. I bought a kit of cleaner scratch remover from aircraft spruce that worked very well. I've also found that you can use wax to help shed water and protect the surface. And what ever you do make sure you don't use an ammonia based cleaner or it will cause the lexan to whiten. Cary

bummer

Go the SCCA website and look at the current fasttrack. This is listed under items for the BOD to vote on. It's not a done deal but generally when they get this far it's a pretty good bet.

If you read some of the latest news coming from the SCCA they are allowing 200 pounds off the min weight by sticking with 275 or smaller tires. One of the issues I'd see trying to do SM2 in the Z is 18s are going to raise the car. And to take advantage of the narrow track I'd think you'd want to do all you can to lower the CG. SM2 cars are really fast from the results I saw from nationals. But I'd look at CSP for some inspiration of what can be done with a lot less power. The problem with a lot of the packages I've seen is they are difficult to drive to the limit. Have you driven a 400 to 500 HP S30 in an autox. It's a lot of fun but to get the last little bit is a real trick. And forget all the fancy shock stuff unless you have a datalogging system and know how to use it. I've seen plenty of Penskes on cars that would have been better off with non-adjustable Bilsteins. In the end there are probably four key things to keep in mind. You need to build the car and you need to remember what makes a car fast, not what everyone else is doing or how much horsepower someone has. You need to be able to drive the car, which means you need to be comfortable and the car needs to be easy to drive. You need to be able to tune the car and ideally this needs to be done to the track and to the conditions. I've been to a number of national tours and I rarely see this being done. And lastly the car needs to be easy to work on. It's probably going to eat a lot of parts to be competitive. I'd vote for XP personally. More room to work on the problem areas. Either way it sounds like a fun project. Cary

You could take a few clues from newer cars. Almost all have a stout bar running across the dash expanse tied into the door frames. And they have a bar across the car below the seats. I'd also think in a S30 a rear strut bar could serve some function in side impact, assuming it's a little bigger than normal. And the bars from the front of the rockers to the TC boxes would help some to spread load from a side hit. If you have a really old S30 consider some newer doors with door beams. Cary

These lasted about three events before pounding out the liners. We switched to Aurora bearings, AM series if I remember correctly, and they are doing better. But even these are taking a lot of abuse. They were very stiff when put on the car and now are very easy to move. I recommend the 3/4 rod ends to Jon because they have a lot more bearing surface area and the price difference isn't that much. I would have thought the front would take more of the load too. It was a 3/4 QA-1 part and it had no slop and was still pretty tight. The same batch of 5/8 QA-1s were used in the lower front control arms and for TC rods. These are holding up fine. So I do think there's a lot of stress back here. Of course this is a V8 car driven by a couple of immature adults that giggle everytime they see 14 inch black marks get laid down. Cary

Not that it matters on track days but if you autox some people get fairly pissy about wheel base changes. Given that I'd opt to do the change up front for more caster. Are you just wanting to center the wheels in the wheel well or is there some other reason driving this?

The arms I made ended up about 3/8 wider than stock to get the CV axles to work. We ended up modifying the arms to where they are maybe stock or an 1/8 wider. The axles still have some room to move. The rear arms are very close to flat (as in the pics I sent) and you have to watch droop or you'll start to loose free play in the axles. We moved the upper pickup point for the plate out to get camber in check. The hoosier radials don't seem to like a lot of negative camber (-1 in this case). The key as you mention is to find an axle and then build everything around that. And you have to decide if you want a narrow or wide car. Cary

Not sure, but I would at least make sure to keep the same front to rear distance. What I was looking at doing was moving both points back a little to make it possible to raise them up a bit. Cary

Another option is to shift the mounting points back a bit to gain clearance. You're still going to have to do some work in the sheet metal probably but you could change the inner mounts to rod ends and use custom arms as in a couple of the other threads. The benefit of doing all this is you have the ability to start playing with squat. You do need to be careful when you raise the inner point you don't foul the half shafts. The car above may look cool but that rear suspension isn't going to work very well. If you're flat statically you may find the having the arms drop a little as above helps to put the power down. At least that's one things we've seen from the cars setup this way. Another option is to change the outer as Terry did in yet another thread. Lots and lots of options -- pick wisely Cary

My vote is more rear percentage. What I've seen is the more power you have the more static weight on the rear helps. I had to run 200 lbs. of ballast to be legal in FP and when I moved it from the passenger side to hanging off the diff the car was quicker. But you're right that a number of things change and it's hard to pin it down to any one item. The other question I'd ask is whether the car performs transitions better with a passenger. That's also very important. And I agree that this is all really fun. I had a good weekend too and found out how well a splitter can work. Cary

In thinking about this some more I wonder if the wing is more about yaw moments rather than downforce. I could see that helping to make the car more stable in turns. Cary

Please keep this myth going. We've found that 35 MPH is about the point where you can start to see some aero advantage. At 45 MPH it's clear as day. Cary

That's pretty cool but I'm skeptical it works any better than when set at max downforce for autox. I'd like to see a back to back test showing speed and g traces. I could definitely see this working on road courses. Cary

We did a T10 conversion for a race car and used the quicktime bellhousing that sets the tranny forward and had to manufacture the special pilot bushing. Later found that the LS7 bearing is very similar. Now it looks like Mcleod has an offering too. I was pretty excited about the article when I got the magazine but that didn't last long. It read to me more like a advertisement for buying a Mcleod flywheel. If you want a light weight flywheel then you have to look at the above option using the LS style flywheel. They mostly glossed over the use of an annular throwout bearing info. It would have been nice if they would have discussed more options for clutch and pressure plates to use the lower cost chevy parts. Oh wait, if I buy the Mcleod flywheel I can do that too. I give it a half thumbs up. But most of the info already seems to be on this forum. Cary

For pressure we've been running 22 to 24 lbs. You may need to bump this a little for the track. Softer will heat up the tires more and maybe too much. If you run bias air pressure you'll probably lose the tire off the wheel (another oops that doesn't work moment). The camber has been used at hillclimbs and autox events. No track days yet. So take temps and make sure the tire looks good across the tread.

I totally agree, but what I was trying to get at and poorly worded as a flimsy chassis generally needs a lot more to see a change. Meaning you need to make larger jumps in bars or springs. Anyway, I think I'm digging a hole here .... Cary

The chassis torsion is just another spring. Even though you've stiffened the front it's hard to say if it really changed the overall chassis torsion. If that hasn't changed then you probably won't need a change. It's somewhat hard to say without some numbers to take a look at. But as a general guideline if the chassis becomes stiffer you can run softer wheel rates to get the same result. What you need to know is what is the lateral load transfer distribution on your car. In the spreadsheets at the top of this thread that's referred to as the magic number. One option that I've found that works for me is to setup the suspension to try and get equal roll angles front and rear. This minimizes the need for chassis torsion. It has a side benefit of making the tires last longer and that's a big plus for me. Cary

The hoosiers are a little bit of a different animal. What we've found playing with them this year is that they need similar levels of camber to the bias plies. But to make this work you really need to control roll. So I'd start out running what you have listed above and look for temps. They seem to like about 10 degrees hotter on the inside for us. These tires do not seem to like camber gain very much, which is a plus for us. We're taking care of roll and running the fronts at 1.5 degrees and the rears at 1 degree (all negative).

If it's an R180 you'll find it won't work.