johnc

FYI... I recall that every 1 degree of Ackermann is the same as 1/2" of total toe-out. I don't know where that 1 degree is measured (at full lock, halfway, etc.) but it just shows that a little bit can be way too much.

279 hp to the rear wheels on my car and 275/45-16 Hoosier R3S03 track tires. It has the following: 1. Welded in 4 point roll bar. 2. Welded in rear strut tower brace. 3. Welded mounts and bolted in front braces that triangulate the front strut towers and the center of the firewall where the hood latch was. No rear c-pillar seam cracks, doors open and close fine, etc. after 11 years of racing. 3 years ago I did have to weld some stress cracks that appeared at the rear of the driveshaft tunnel.

I'm sure glad Laurel and Hardy put down the Sawzall when I showed up to buy the diff. FYI... (just to make you guys feel bad ) that R192 diff is now at $950 my cost for everything. The two bearings that had to be shipped from Japan cost $130 and $110, plus shipping.

Ackermann is the non-parallel movement of the front wheels as they are steered. Most people think that the front tires stay parallel (when looked at from above) when the steering wheel is turned. In fact, almost all cars have the steering designed to turn the inside wheel a bit more then the outside wheel when turning. The amount of difference between the angle of the inside and the outside wheel is Ackermann. Ackermann is used to make the car's turn into a corner more responsive. The front end bites better. But, too much Ackermann angle and the front tires start working against each other and you get understeer. A tiny bit of Ackermann also reduces the loads on the steering system and reduces tire wear on the front tires.

The following are just uneducated guesses on my part... There is a little bit of Ackermann built into the steering of an early Z as 7450LZ mentioned. Its probably there to counter some of the bump steer issues in the front steering. When autocrossing an early Z I've run as much as 7/16" total toe out to get the front to turn in. It helps but you end up with a push mid-corner that can be overcome with power. Being able to run that much toe out tells me that the toe out gained with the Ackermann in the Z is very small. Increasing the toe out gain via Ackermann would allow someone to run less initial toe out and get the same results. But you would also have to look at what happens to bump steer and the built in camber gain. It would take a lot of of measureing and trial and error to come up with something that works.

Z-therapy rebuilds include new roller bearing throttle shafts and bushings, matched dashpots and pistons, etc. They basically blueprint a set of SUs. The price is comparable to a blueprinted Holley 4 barrel sold be Demon and others.

A 100mm TB? They are obviously building an engine with a 500 rpm power band. Must be for drag racing. Both individual throttle bodies and a single throttle body can be tuned to provide good power and torque numbers. The benefits of a single throttle body is a tunable plenum which lets you make mid-range torque and high rpm horsepower. Ultimately it will have a little less top horsepower then individual TBs but you'll have a much broader power band. But, that's only true with reasonable sized components. Intake and exhaust velocity is critical to torque. A 100mm TB can only be used for high rpm horsepower so my guess it that they are building a drag motor of some kind.

Either one is fine and I would buy the unit that I could work the best deal on. Try and get a bunch of equipment thrown in for free. Ask for a Hornell Speedgals 9000Xi helmet (about $350). I have a Lincoln Invertec V205-T TIG and just love it. I use it 3 to 8 hours a day and it will work off 110V or 230V. For MIG welding I have a Miller 135 110V and love it for small wire welding jobs.

Which "Indy" car? Dallara, Lola, March, G-force? Some have push rod suspesnions, some have pull rods, some are built with a rising rate, some have equal length control arms, some have unequal length control arms. Are we talking about flat oval, banked oval, road, or street course setup? All have the suspesnsion arms travel in an arc (they have to) but they might be adjusting suspension arm length to achieve certain things depending on the track. With a banked oval track camber gain is less important because you get much less body roll, so the suspensions are adjusted to keept he tire vertical in bump. On a road course the suspensions are adjusted to gain negative camber in bump. And, remember, their suspension have, maybe, 4 inches of total travel so its hard to actually see camber change and the suspension moves. And one more thing to confuse the issue - aerodynamics. When a vehicle uses aerodynamics as its major handling component then suspesnion design and setup favors that more then what we traditionally focus on when all we have to work with is mechanical grip. Ride height, pitch, and body roll are much more important when running big aero then tire camber.

Camber does change as the front and rear suspensions of the 240Z moves through its range of travel. Both the front and rear suspensions are designed to gain negative camber as the suspension compresses. This is to offset the positive camber gain caused by chassis roll. An independent suspension that doesn't gain camber in bump is difficult to make handle well. The Ford Tempo and Mercury Topaz are fine examples of a poorly designed independent front suspension.

.035 wall 304 or 321 stainless exhaust with a Borla XR-1 Raceline muffler will be the lightest you can run. Probably cost about $1,200 complete.

Wow! I didn't notice. I guess this gets our "HybridZ Back From the Dead" award.

NASCAR and most of the Circle Track race cars run a solid rear axle because the rules require it. They do not run a solid rear axle because of better handling. A properly setup IRS compared to a properly setup line axle will: 1. Allow better braking into corner because of better rear compliance. More braking load can be shifted to the rear. Ever hear of a NASCAR driver complaining about rear axle hop under braking when running Watkins Glenn or Sears Point? When that happens they tend to spin and go off track. 2. Allow better transition into and out of corners due to less rear unsprung mass. The chassis (shocks mostly) doesn't have to be tuned to control that additional weight. It can be tuned to provide better transitory response. 3. Allow better power application in corner exit because of better rear compliance and a separation of torque effects from the suspension. Circle track cars have to have the rear suspension tuned to control pinion windup during accleleration even to the point of letting the pinion move to soften the rear and get more grip. That pinion movement takes power away from the rear tires and affects acceleration off a corner. Look at the top level series where rear suspension design is not limited to a specific type. IRL cars on ovals all run IRS. CART on ovals all run IRS. IRL, CART, F1, ALMS, etc. all run IRS on road courses. NASCAR engineers and designers have to run a live axle because of rule requirements, not because its the best choice.

What happens is that folks don't completely remove the peened over portion of the nut before removing it. That tends to damage/strip the last few turns of thread on the end of the stub axle. Then, when they try installing the new nut it gets cross threaded and they can't tighten it to the torque spec and have to throw the stub axle away. Buy a thread guage and a thread file and spend some time cleaning up the threads on the stub axle.

That's so true! I had to work in Houston for a few months and on my first day I went to step off an elevator and an older gentlemen put his hand on my chest and said, "Son, here we let the ladies step off first."

The 8610s are not street shocks so you probably won't find anyone doing a review like they do for the Tokico Illuminas. The 8610s work with spring rates from 225 to 350. Anything out of that range and they are not as effective. The 8610s are a much better shock for racing then the Illuminas, but they are NOT a street shock.

Exactly. That's how "stock" cammed L6 engines are making over 200hp with unported heads, stock pistons, and SUs.

Two weeks ago at the FastTrip in Arvin, California (southeast of Bakersfield on 223) unleaded regualr was: $1.2499 and Diesel #2 was 1.0999. Seems like the Californians living in the big cities are the ones getting screwed.

Scary thought! That's like saying every welding shop does machining.

The V8 has two cast iron cylinder heads up high, the L6 has an aluminum cylinder head up high. The V8 mounts the intake manifold and carb up higher then the L6s intake system. FYI... I'm comparing where everything is realative to the crank centerline, not the bottom of the oil pan. Remember, the L6 is a deep skirt deisgn. Compared to an L6 in the stock location, yes it does. But, move the L6 back and down the same amount as the V8 (as in my 240Z) and the CG is better. Just think about the weight distribution if the V8 was mounted in the stock L6 location.

I know at least a dozen 240Z ITS racers running the 8610s in 240Z strut tubes.

V8s have more weight up high then the Nissan L6. If you move an L6 back and down the same amount you can with a JTR V8 install you can get a 46/54 weight distribution and a lower CG. The only way to beat the L6 is to run an aluminum block and heads on the V8.

Well... since you're installing a roll bar for safety why wouldn't you want to build it to the specs specified by the largest and oldest racing association in the US? A poorly deisgned roll bar is much worse then no bar at all. A customer of mine did just what you suggested and I was able to "remove" the roll bar from his car with a 5 lb sledge hammer. In an accident all that tubing would have come loose and banged around inside the car. I figure I saved the guys life with my little sledgehammer.

If the pipes are aluminized you'll have to sand/grind the aluminizing away from each joint - at least 1" on each side of the joint, maybe even more. If you're TIG welding, buy a couple pounds of ER70S-2 .045 or .040 filler. If you're MIG welding buy a 5 pound spool of ER70S-6 .035 or .030 filler. Use a shielding gas (Argon for TIG and C25 for MIG) and practice on some scrap tubing before welding the real thing. Be sure to limit penetration inside the tube. That disrupts airflow. Depending on how complex the IC tubing is, $350 is a reasonable price to pay a professional welder. I would expect the parts to be nicely TIG welded for that price. I would guess that a lot of welders refused the job because of the aluminized pipes. That stuff is pretty nasty and really requires a separate air source for the welder when it starts smoking.

If your engine is stock, then I would go with stock parts.