{"id":263,"date":"2010-10-15T22:51:11","date_gmt":"2010-10-16T05:51:11","guid":{"rendered":"http:\/\/www.rhoadescamaro.com\/build\/?p=263"},"modified":"2010-10-15T23:23:18","modified_gmt":"2010-10-16T06:23:18","slug":"non-terminal-steelitis","status":"publish","type":"post","link":"http:\/\/www.rhoadescamaro.com\/build\/?p=263","title":{"rendered":"Non-terminal steelitis"},"content":{"rendered":"

Some cars are really good from the factory and need little help to be made made super good. \u00a0Other cars are not so blessed, and need lots of help.<\/p>\n

Something I’ve seen a lot of in modern performance cars, particularly turbocharged ones, is a proliferation of “magic little boxes”. \u00a0One of them is a manual boost controller. \u00a0Another is a turbo timer. \u00a0Then there’s the other one \u00a0to play with the A\/F tuning and cam timing. \u00a0Before you know it, there’s half a dozen little black-box warts all over the interior with their knobs and wires everywhere. \u00a0Yuck! \u00a0I hate that sort of clutter, magicboxitis you might call it.<\/p>\n

“-itis” is often used as a suffix to describe an inflammation of the -whatever, maybe it’s the tonsils or the colon.<\/p>\n

The thing I’ve seen happen with these old muscle cars is a sort of steelitis. \u00a0The answer to almost every problem is to bolt or weld in some beefy looking steel braces. \u00a0Subframe connectors, watts links mounts, additional crossmembers for conversion to 3 or 4-link, roll cages, and extra tubes and braces in the engine compartment. \u00a0Certainly, when done right using good straight paths, these things can be helpful and effective, but so often the cars end up like tanks – strong but heavy. \u00a0Leaving one to wonder if the car is really any faster than it would have been with a flexible chassis, minus the 200lbs. of steelitis.<\/p>\n

A big goal for this car is to keep the weight as low as possible – both in quantity and location :). \u00a0I’m going to be competing with better-balanced cars on the same size wheel\/tire (well, many of the BMWs run 255s, but it’s close), so I have to do everything possible to keep my weight in the same range as them. \u00a0The RX8s are 26xx with about 50\/50 weight distribution, the BMWs in the mid to low 2800’s also around 50\/50 and the Subaru WRX in the mid 2800’s, with AWD, but nose-heavy and on 245’s.<\/p>\n

I had a huge 33% (650lb.) weight disadvantage to the Civics when I ran the 240sx in STS, but I had some big advantages there too in bigger\/better tires and RWD. \u00a0I think I can get the Camaro’s race weight a lot closer to the BMW and WRX weight than people would expect. \u00a0Doing so will be critical as I won’t have any sort of tire or drive type advantage.<\/p>\n

To make it light, I will have to aggressively treat any steelitis flareups that occur, which is difficult because there are lots of pretty steel parts out there begging to be put on the car. \u00a0One slipped past my steelitis immune system today, the subframe connectors-<\/p>\n

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Actually I had made up my mind weeks ago to use these parts, and having them in hand was a prerequisite to the first big set of work I’m having done by someone else, which should be starting in a couple more weeks.<\/p>\n

ST allows for bolt-in subframe connectors, which these are. \u00a0From a design perspective, I like them for a few reasons – one is they tuck up nicely next to the rockers, which should make it easier to get a good middle point of attachment between the SFC and rocker panel. \u00a0It also reduces the ground clearance hit from the parts; the car is going to be very low, and with the limo like 108″+ wheelbase, the car is going to want to high-center getting on trailers and stuff. \u00a0They’ll also make it a piece of cake to jack up the car from the side.<\/p>\n

But man, the pair weigh 24 pounds!! \u00a0See, that undoes my 11lbs. of weight savings in rear springs, and another 13 pounds of savings from the HVAC system. \u00a0On the steelitis mitigating side, they are sprung weight, very very low in the car, fully between the axles so the “cost” of that weight is about as low as it gets, but still, ouch.<\/p>\n

A quick aside about chassis stiffness. \u00a0People tend to go overly gaga about chassis stiffness and torsional rigidity. \u00a0The new Ferrari has 1x,xxx ft-lbs\/degree of stiffness, the McLaren has this, that, whatever. \u00a0While important, I think it tends to be mostly overrated as a goal for people working with autocross cars, particularly those that won’t be running on big wide slicks. \u00a0The reason we need chassis stiffness is so that our suspension tuning \u00a0actually does something. \u00a0If we want one end of the car to offer relatively more roll resistance than the other, our tuning efforts will be stymied if our stiffening of that end gets absorbed by additional twist in the chassis. \u00a0If the car is responsive, has the balance you want, and is generally predictable to drive, then you aren’t going to find a ton of time in additional chassis stiffness. \u00a0In most cases, you will probably make the car slower, as the additional stiffness comes at a huge weight penalty when the car builder succumbs to terminal steelitis in the form of multiple strut tower bars, fender braces, 24-point roll cages, etc.<\/p>\n

One other thing to note in the picture above, the little white cylinders. \u00a0Those are delrin bushings for the front subframe. \u00a0Delrin is a hard and durable plastic that doesn’t really compress, unlike the rubber bushings used in those spots by the factory. \u00a0In conjunction with the subframe connectors, those little guys will do a lot to “lock” the front subframe to the body of the car, and add some stiffness to the overall structure. \u00a0 If our rules were more open I’d probably use aluminum in those spots because it’s a bit tougher, but we aren’t allowed to use metal bushings. \u00a0The Delrin should be fine really. \u00a0These bushings aren’t the whole subframe\/body interlock story, there’ll be more coming later, stuff I’m still working on.<\/p>\n","protected":false},"excerpt":{"rendered":"

Some cars are really good from the factory and need little help to be made made super good. \u00a0Other cars are not so blessed, and need lots of help. Something I’ve seen a lot of in modern performance cars, particularly turbocharged ones, is a proliferation of “magic little boxes”. \u00a0One of them is a manual […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[11],"tags":[],"_links":{"self":[{"href":"http:\/\/www.rhoadescamaro.com\/build\/index.php?rest_route=\/wp\/v2\/posts\/263"}],"collection":[{"href":"http:\/\/www.rhoadescamaro.com\/build\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.rhoadescamaro.com\/build\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.rhoadescamaro.com\/build\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/www.rhoadescamaro.com\/build\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=263"}],"version-history":[{"count":13,"href":"http:\/\/www.rhoadescamaro.com\/build\/index.php?rest_route=\/wp\/v2\/posts\/263\/revisions"}],"predecessor-version":[{"id":277,"href":"http:\/\/www.rhoadescamaro.com\/build\/index.php?rest_route=\/wp\/v2\/posts\/263\/revisions\/277"}],"wp:attachment":[{"href":"http:\/\/www.rhoadescamaro.com\/build\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=263"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.rhoadescamaro.com\/build\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=263"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.rhoadescamaro.com\/build\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=263"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}