tube80z

One thing that will help a lot is what Jon mentioned about raising spring rate. I would start with 400 lbs/in all around and this will reduce the amount of travel you are seeing and that will help a lot to keep you from seeing as much bumpsteer. Ideally you need to get your bumpsteer down to around a 1/16 of an inch over the range of travel. That will make a world of difference. The last batch of AZC knuckles I saw needed a large wheel for clearance. I can't remember if we had 15s or 16s but the wouldn't clear with the wheels and spacers we had. We ended up using a spacer to lower the outer steering arm pickup point. The amount will also depend on how much caster you have cranked in. From what I recall this spacer was about 1.25 to 1.5 inches. It had to be clearanced as Cameron mentions when running a 15 inch wheel. If I still have these parts (knuckles, spacers, bolts) I'll send them to you but I'm pretty sure they were on the car when it was sold.

The only issue is those rod ends are junk. The grease fitting is the giveaway. So add another $40 to $80 for higher quality units are call them to see if that's really the case. Cary

1.3 to 1.5 may be all you can get if the pavement is not really clean and rubbered. It may also indicate that your tires are getting too many runs on them. You'll need a clean surface and the tires up to temp to ever see numbers over 1.5. When a bunch of us used to run our cars in prepared classes in Medford, OR we found that most cars worked pretty well with 550s all round, which is assuming a weight of around 2K pounds. The higher spring rate will help put heat into the tires. I know there are many ways to skin a cat but that resulted in a FP car that took many TTOD and was top on top of PAX. To put that in perspective on the Fall Enduro course it would now lap in 44.75 seconds. Not sure if that helps if you haven't been there with how the car is currently configured. Cary

The only thing I will add to this thread is that I've been seeing a lot more counterfeit parts. So if you see a really low price for what are typically premium brand parts and they are new take a really good look. I got a set of low cost "GM" ls7 lifters that ruined an engine. Cary

There are parts listed in the rule group that are excepted that are contoured. Everything else needs to be a flat plate. Cary

Jon found on off the shelf spacer for the 280 spindle. It' this one if memory serves it's the legends one, http://www.drpperformance.com/resources/bearing-spacers-kits-and-tools-mini-catalog/ Cary

I tested 240 parts and found they would move a lot more than expected. 280 struts will be better but you can create a sheet metal gusset from the tube to the spindle housing. Jon did this on his car and I can dig up some pics I have buried somewhere if you need. You have to figure you are putting a lot of stress on your parts with bigger sticky tires, a lot more HP and torque, and now aero. Here's an image of a Ground Control modified strut. Note the gusset used to stiffen the spindle The next step is to build a custom housing but when you get there it's probably time to start seriously looking at an a-arm retrofit. I have been playing around with a simple design that uses Nascar and dirt track pieces. I can't decide if a 7 inch upper is long enough (allows for 3 inches of suspension travel) or a longer upper is needed. At 7 inches I don't think you have to put holes into the engine compartment for mounts. Cary

The bellhousing will fit based on my LS version that has a rear mount starter. You will need to cut into the tunnel to make clearance. My bellhousing took some hammer work to get the top to fit and the aforementioned starter clearance hole. For your clutch look at using a rally version (cerametallic that's thicker). Those are still severe but can be slipped a little. Cary

It was part of a lot of changes. Part of that was to reduce bumpsteer and have the arms closer to level when operating since the car was lowered. None of this was tested a single item at a time so take that into account for the lap time difference. The car was around a second faster on a 48 second lap (now 47). The bigger difference, as Jon mentions, is you could do that repeatedly and it wasn't so hard to drive. Cary

I've always had good and luck with Bilsteins. It sounds like Megan simply took a shock and inverted it to act like a strut and that is the root of the problem. There are people mixing and matching parts between bilstein and stance that might be an option too. If you don't need the adjusters I'd probably go for the bilsteins. I had a set that's been in three to four cars over the years with over 30K in kilometres on them. Hope that helps, Cary

My only feedback is you might ask about lift speed. A friend of mine has a bendpack 9K lift and it is much slower than my 7K 2 post lift. I know this sounds silly but it is amazing how long it takes to lift the car off the ground. Perhaps not an issue on the 4 post lifts. Cary

Funny thing, I have that crossmember in my shop right now and it's only raised 7/8s of an inch, not the indicated amount. Cary

Not trying to get too off topic but I've had a fusion in my lumbar area and I can tell you that it only should be a last resort. I ended up eventually having many side effects and now live with chronic pain and all the fun that entails. Seriously, only as a last resort. Feel free to reach out.

True, but much of that can be overcome by how we add the airdam, floor, and diffuser. They don't need to attached level with the car. Perhaps too into the weeds.

It's worth reading many more of Willem's posts at https://www.linkedin.com/today/author/187006218. While he has worked in F1 for many years he's also an avid hillclimber and has talked about his own car on many of the technical discussions. His post about power and control is quite good as are almost all the posts he shares. Highly recommended. Cary

Actually I'd argue you don't want rake, perhaps the opposite. Primarily because you're standing the windscreen up, which will add drag. Get the car low but perhaps run the tail down or at least try level and then nose down. Cary

I personally would use shocks with a lot of rebound to pull the car down, just like NASCAR. That will allow less air under the car and help with lowering the drag number. The bumpstops I talked to Keith about were actually linear bump springs. The idea being he could run softer main springs at a higher ride height but when running this event lower the car and use packers to engage the bump spring. This would raise the rate similar to running a higher rate main spring but you don't have the rougher ride when using on the street at normal ride heights. These springs can stack solid or be used in combination with other rubber or poly bumpstops when maxed out from aero load. Cary

I think it's cool they picked a Z. I'm disappointed that with all the professionals involved they didn't really do more. It would have been awesome to see this used to create some really cool one off parts that added more function than the flares. At least that was what I was expecting for SEMA. Cary

A friend of mine had and LS with the JCI kit and we built a brace that turned the standard crossmember into a k-member. This was made from 1 inch 0.095 square tube and had 14 gauge sheet metal welded to it forming a skid plate for the pan. On more than one occasion it took a hit big enough that would have probably cracked or damaged the pan enough to ruin a weekend of racing. If you look closely on the attached picture you can see it.

What is the distance from the stock pivot? I'm hoping to finally get all the pieces in place this week to drop all this is susprog. Cary

All manufacturers of hose will have limits for their products. These will lbe temperature limits, working pressure, burst pressure, bend radii, and vacuum for each hose family. Some of the newer high tech hoses can handle vacuum fine (Starlite, BMRS, etc.). But best to check your master catalog to know. If you need to make a sharp turn from the pump to the pan is another issue. So if either of these are the case then you'll need what's called AN hose inner support springs. You can find these at Jegs, speedway, summit, etc. Each manufacturer will have a special version for their hose if needed. The problem is that the pump generates considerable suction and when the oil heats up the hose it gets very pliable. These springs will keep it from momentarily pinching off. If that happens you loose oil supply and bad things happen. It's not as big an issue on the scavenge side but you still don't want a hose getting pulled shut. It all comes down to the pump and the hose rating. It's not whether or not the hose is any good. General rule of thumb is on any of the new high tech hose solutions the non-metal braided hoses will not have enough vacuum resistance to be used in a dry sump system. I'm using BMRS progold plumbing for my dry sump and section 1.2 of their master catalog lists AN 12 hose as being capable of withstanding 28 inches of mercury of vacuum at a minimum bend radius of 2.5 inches between -57 to 400 degrees Fahrenheit. At diameters larger than AN 16 these ratings drop quite a bit. Hope that helps, Cary

I think 10 or more years ago I took a racecar engineering class from ICP. It was two days in a shop for 12 to 13 hours each day. The topic of bumpsteer came up and the shop owner had one of the gauges above. Steve Lathrop said they were fine but there was a much cheaper setup that was faster to boot. His rig was a welded frame with two roller bearings that ride along the plate. He did warn it's best to measure near the actual radius of the tire so not to have error get out of hand. To use this setup you run the wheel up and down and watch the gap on the rollers. Make a change and note if things are better or worse. Repeat until the gap is very fine 1/16 of an inch was good enough for them. Done this way it should go much faster. I made an even cheaper version of this using 2x2s so I could get this done between races. This is more about process and less about tools. The longacre system is nice but unless you need to do this a lot I'd try a lower cost set up. Cary

And they shouldn't. Carol Smith would not be happy.

My guess would be they found it didn't work and went solid. Nice end they used.

Nice find. Having taken apart Bilsteins and my Penskes you can see a very big difference between the quality of the pistons compared to the BC shocks. Penske have a lot of pistons available in 46 mm that are available as castoffs on ebay from NASCAR teams. Swapping the pistons would be a nice performance upgrade. Cary