johnc

Is your calculation of the deflection number: 1. The total deflection of both arms measured at the link mount holes 2. The total deflection of both arms measured at some other standard point on the arms. 3. The amount of twist in the bar itself?

Yeah, I guess a turbo would be a slightly different story if your turbo takes a bit to spool up. The old 934 single turbo Porsches ran a wide ratio 4 speed with various rear gears (from 5.88 to 3.9x) to suit the tracks they ran. The drivers used to left foot brake while keeping their foot in the throttle to keep the boost up. Better have damn good brakes.

But, but, but... At the rear wheel it doesn't matter where the torque comes from. A rear end gear's job is torque multiplication. When you gear a car for a road race track, you start with a rear gear the gets you to your track or aero limited top speed at the end of the fastest part of the track. From there you make compromises in rear gearing (assuming you can't or don't want to change transmission gears) to get the fastest corner exit speed onto the start of that same fastest part of the track. Then you might make further compromises to keep from being in-between gears at other critical parts of the track. While you're doing this you are ALWAYS checking lap times and making changes to get the fastest lap. In a 240 its common to have to feather the throttle at 7,000+ rpm in top gear (1.1 on a 4 speed) at some point on the track because you've run out of gear. With a 5 speed and its overdrive you can probably drop you rear end gear one step. FYI... on my NA 3L I'll be mostly running a 4.11 gear with my .87 overdrive 5th. The engine has a soft redline of 7,500 and was built as a torque motor so its horsepower and torque curves are very similar to a 300 hp turbo motor.

At that price you've got nothing to lose. Get 'em as hot as you can in the burnout box and then launch with about 10 to 15% wheel spin if you can figure that out by comparing the engine rpm with the speed you're moving. There's also a tire traction treatment called Formula V that helps soften the tread a bit. It should work well for a drag racing tire.

From the numbers you listed (23 x 10 x 15) they sound like bias ply road racing slicks. Its my understanding from Trackside (the Yokohama racing tire distributor here in the US) that Yokohama has not made bias ply road racing slicks for at least 5 years. Anyway, to make then work best you need to get the tire temps up to around 200 degrees. I'm not an expert on drag racing burnouts but I don't think you can get the tires hot enough just by spinning them. Sounds counter-intuitive but the smoke from a burnout carries heat away from the tire. Hopefully someone else who knows more about this will chime in. Also, road racing slicks tend to harden after 6 to 10 heat cycles. Unfortunately with drag racing (assuming about 1/2 hour between runs) that will work out to maybe 10 runs down the track.

Was under a 2002 WRX last week and the rear R180 has a longer snout and a different front mount casting. Maybe the internals could be swapped into a 240 housing. BTW... just because Subie R180 is newer doesn't mean its better. The Hitachi "R" series hasn't changed much internally since the mid-1960s. All internal parts are still available new - except some of the more unusual ring and pinion ratios.

There isn't a racetrack in the states of California, Nevada, or Arizona where you would want to run a 3.54 over a 3.90, regardless of engine torque or horsepower (except maybe the California Speedway oval or the full tri-oval at PIR). A 3.90 is the PERFECT rear end gear for T-Hill and a 4.11 is said to be perfect for Sears. Now that I've said that, is the 3.90 you're talking about an R180?

Thought the Subies ran mostly R160s. I was under a 2002 WRX the other night and it has an R180 in the rear, but the snout is longer then the snout on a 240/260/280 R180. It also has a different front mount casting.

As the rear of your car slews to the left, the Christmas tree counts down and the green light comes on! You release the line lock and shoot forward exactly where your rear wheels are pointing... everyone else at the track now hates you because you took out the Christmas tree.

Search this forum on the word "bumpsteer". There have been LOTS of discussions about this exact topic.

Ooops! Tim is right, my design would require that the rod ends be disconnected from the spindle pin to adjust toe or camber. I guess my design would get a bit more complicated because the spindle pin would have to be replaced.

You should look at the internals of a Borla XR-1 Raceline muffler. That's basically what you're duplicating with your design. There is a perforated metal cylinder that's the length of the muffler and the same diameter as the inlet/outlet tubes. Between that and the muffler wall is stainless steel wool packing. Down the center of the perforated metal cylinder is another sheet of the same perforated metal that bisects the tube lengthwise.

Not at all. The rod end setup would be the same as in the picture above except you wouldn't have the threaded end going all the way through what Beastz calls the main shaft(s). Another point I would like to make - rear toe is not something you adjust all the time. Even racing monthly I adjust rear toe, maybe, once per year. Nothing is impossible for a determined idiot. But with a minimum 2" of thread even a determined idiot would get the alignment so out of whack that the car couldn't be driven safely. He'll wreck before a rod end even has a chance of falling out.

I'm always surprised how simple things can be made complicated. All you really need to add the threaded rod ends to the main shaft is a simple threaded insert that fits about 2" into the end of the outer housing and is welded in place. You're just building a tubular control arm so why not use the same design as on TransAm and NASCAR stock cars for the threaded ends.

Quaife makes a 6 speed with or without synchros. Taylor Race Engineering in Texas has lots of experience mating Quaife transmisisons to L6 engines. And they ship all over the world. http://www.taylor-race.com/

Tim, The adjustment rods are threaded into a bushing (main shaft) that's roll pinned to the outer housing (what you can see in the picture). I think...

The most difficult position in a company to interview and hire is: Recruiter. We spent months trying to hire one and got some real wackos showing up for the interview including: 1. A woman who wore a minishirt with no underwear and didn't cross her legs - just plain scary despite how it sounds. 2. A man who wanted 1 month off each year, paid, to search for Bigfoot. 3. A man who claimed to be an ex-Dodger first baseman and insisted he played in the 1996 world series (Braves vs. Yankees that year). 4. A woman who asked to take a break to use the restroom and vanished. 5. A man that we hired who "forgot" to quit from his previous company and worked two jobs for about a week until we figured it out and fired him. Then he sued us.

The day Erik brought your parts to his shop was all-you-can-eat bad spagetti night. After eating our fill at Perry's Pizza Bryan, Erik, and I proceeded to inspect your Z parts until about 11pm that night. Something just didn't look right and we were bound and determined to find out. It appeared that the guy you bought the car from didn't do you any favors with the rear suspension. The only races he could have won with that were ones where every other car in ITS failed to finish. I think you'll be much happier and more confortable in the car when Erik get's it done. And turning a '33 at Willow should be easy.

I would try a chemical rust remover first (if the head is off the car).

Livewire got it right. But, in our interview/test process we didn't care if the candidate got the right answer. We just wanted to see how they went about solving a problem under pressure. We had about 50 engineering staff and about 1/3 got the answer wrong or missed the 30 minute deadline. The ones that got the right answer generally had the path to the solution pop into their heads after about 20 minutes of concentration. BTW... there was also a coding test that programmers went through first.

Mike, Could that be how your rear control arm got bent?

Depends on who builds it. I've got at least 200 ft. lbs. of torque from 3,400 to 7,500 rpm.

Yeah, I was pretty sure I had the math wrong after I made my post. I was trying to find the calculation in "Race Car Vehicle Dynamics" but I obviously picked the wrong one.

Just found this while cleaning out some old e-mails. I was one of a few guys that started and then sold a software company and we used to give written logic tests to prospective programmers to see how they went about problem solving. These tests were timed and we usually sat in the room and watched them try to work out the answer. Nothing like a little added pressure to see how people REALLY are. Here's one: ***** Five houses of different colors are in a row. Each is owned by a man with a different nationality, hobby, pet and favorite drink. The Englishman lives in the red house. The Spaniard owns dogs. Coffee is drunk in the in the green house. The Ukrainian drinks tea. The green house is directly to the right of the white one. The stamp collector owns snails. The antique collector lives in the yellow house. The man in the middle house drinks milk. The Norwegian lives in the first house. The man who sings lives next to the man with the fox. The man who gardens drinks juice. The antique collector lives next to the man with the horse. The Japanese man's hobby is cooking. The Norwegian lives next to the blue house. Who drinks water and who owns the zebra? Be prepared to explain (in detail) the reasoning behind your answer. You have 30 minutes. *****

If you do the math (ignoring the lever arm lengths): 1" = 25.4mm 25.4mm * .75 = 19.05mm 3.14 * (20*20*20) = 25,120 3.14 * (19*19*19) = 21,537 25,120 - 21,537 = 3,583 3,583 / 21,537 = 0.166 The 20mm bar is about 17% stiffer then the 3/4" bar. That's assuming I've got the calculations correct.