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Everything posted by johnc
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building a turbo header w/ sched 40 weld pipe
johnc replied to OlderThanMe's topic in Fabrication / Welding
Not to be nipicky, but why would a Stick weld be stronger then a proper MIG or TIG weld in this application? -
Aerodynamics DONATIONS NEEDED!!!
johnc replied to Mikelly's topic in Windtunnel Test Results and Analysis
I can check with Nissan Sport Magazine to see if they would be interested in publishing the results. That's if we want to go that route. FYI... I'll have some money to donate in December. Regarding the ITS/EP racers, in many cases they are not allowed to run aero mods beyond a front air dam. There will be some data that can help them but things like VGs and rear spoilers are not allowed. -
Tension compression rod T/C
johnc replied to z_webslinger's topic in Brakes, Wheels, Suspension and Chassis
Also, the factory nut on the TC rod is a metal lock nut. If your's is/was not that type, someone repalced it at some point in your car's life. -
Help w/ rear wheel bearing assembly
johnc replied to pete280z's topic in Brakes, Wheels, Suspension and Chassis
That may be true in theory but, having assembled at least a dozen rear hub sets, I can say that stub axle nut torque has a direct affect on how free the stub axle turns. Stub axle nut torque settings are anywhere from 185 to 240 in the units I've assembled. And I do use a fish scale to measure turning torque per the FSM. Remember, these are 30+ year old parts with bearings and seals from various suppliers. EDIT: To answer the original question, your hub set is too tight. Take it back and have them assemble the hub set per the FSM. -
If you can weld you should be able to build and paint it for under $200.
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Having built a 240Z that beat modified Vipers and C5 Z06 Corvettes on a road race track I can say that a $15,000 240Z will not beat a mostly stock Viper or Z06 Corvette on a road race track if the cars are on DOT-R tires and are driven by competent drivers. Look at the lap records for T1 cars on the tracks near you and then compare those times with the ITS lap records and see what I mean. Typical T1 lap times are about 2 to 3 seconds faster then ITS. FYI... there are few Hybrid 240Zs that can match the ITS 240Z lap times on most tracks. More are being built every day but that's still the standard by which fast road race 240Zs are judged.
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What I described above regarding the contact patch is the transition from grip to slide. Its how the contact patch is losing grip. The most heavily loaded part of the contact patch is just ahead of the trailing edge and that's the part that starts "letting go" of the pavement first as the tire reaches its grip limit. Where this process starts is typically at the point where the linear portion of the slip curve starts to flatten out and the contact patch has lost all grip and is sliding where the slip curve starts downward.
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You're better off not knowing. It has to do with cable TV repairmen, flannel shirts, and butt cracks. I'm interested in the AL block idea but the cost will probably scare me away. I do know of a pallet of L24 blocks (6 total) that have been bored and align honed that can probably be bought for cheap.
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Wider tires do provide more lateral and longitudinal grip then narrow tires. Why and how they do is up for debate and I have yet to read a convincing arguement for one point of view over another. I tend to lean towards the argument that: When a tire starts to breakaway and slide, that actually starts at the rear of the contact patch and propogates forward. With a properly inflated, properly cambered wider tire that propogation progresses more slowly due to the greater frontal area (propogation line) of the contact patch area beaking away. The breakaway shear forces are spread along a larger area and are less concentracted then if the contact patch was narrower.
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Please be clearer in what you're asking. A larger tire? Larger in OD, wider in width? LSR cars are concerned with aerodynamics more then anything else. A narrower tire has less frontal area given the same OD.
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Let's stop using the word FRICTION when we are really talking about GRIP. The above friction calculations are only somewhat approximate when a tire is spinning or sliding, they are completely irrelevant when a tire is not. A tire generates grip through "gearing" of the tread to the road surface irregularities and through molecular adhesion to the road surface. This grip process is the least understood aspect of tire behavior and is closely related to a tire's slip angle while generating lateral force.
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That's true in a very broad sense, but tire construction plays a part in contact patch size. The most extreme example: a 315 run flat tire vs. a 315 wrinkle wall slick. The run flat will have more pressure per square inch of contact patch because of the stiff sidewalls and a smaller area while the wrinkle wall slick will have more square inches of contact patch with less pressure per square inch. Maybe. A lot depends on a tire's construction and tread compund. It also depends on the slip angles that tire works best at. When a tire is working nears its "best" slip angle the contact patch is not a static thing that is stuck to the road. There's a wave pattern moving through the contact patch itself with the rear of the contact patch providing the least amount of friction.
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Not to discourage the creativity here, but is all this bracing really needed? The chassis is seam welded and you've reinforced a lot of areas on the car already. It seems that a good diff/front crossmember mount would be more then enough. Again, not to discourage anyone's efforts, but sometimes when we have extra roll bar tubing and a new tubing bender, every problem now needs a new roll cage segment.
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Sure! Bob would be happy to get something to give to the kids.
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Here's are the units I've used: OEM clutch and pressure plate - worked great on stock L28 with SUs. Nissan Comp clutch (sprung center) and pressure plate - worked great on a 190hp BSP prepared L28 and on a similar powered L24 ITS 240Z. Nissan Comp clutch (6 puck) and pressure plate - worked great on a L24 ITS 240Z. Centerforce dual friction clutch and pressure plate - sucked on a L24 ITS 240Z. Lasted one weekend and took the 3 to 4 synchros in the transmission with it. Quartermaster 5.5" dual disk clutch and pressure plate - worked great on te Rusty Old Datsun.
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That would work. The stock 240Z tank is pretty good and I've autocrossed it as low as 1/8 of a tank without fuel issues.
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Crimminology is the study of stupidity.
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Some, please use punctuation and capitalization in your posts. Thanks.
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I do variations on what you listed. I also cut the roof off a 240Z for one cage and then welded it back on after I was done. Few customers want to see you doing something like that, even though its the best way to get everything tight. On the last couple cars I've done I was able to (after tacking the cage together inside the car) cut holes in the floor and let the cage drop about 4". I then welded the tops, pushed the cage back up, slipped in the floor plates, welded the plates in, welded backing plates on the underside covering the holes, and then finished welding the cage. FYI... TIG welding a cage inside a car required LOTS of cussing, throwing things, and general grumpiness. Most of my customers prefer a MIG welded cage for cost reasons - and most likely not having to listen to my complaints BTW... Nice bio and I like the Midget chassis.
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A lot depends on who the supplier is for McMaster in the size you're buying. The 122" x 1/2" blades I buy for my 16" band saw are made by Starrett. They last a long time unless I'm cutting stainless. I've found that DoAll and Starrett blades last the longest but they are around $35 each. I also make prodigious use of Tap Ease metal cutting lubricating sticks on my band saw blades. It helps longevity and the cut itself.
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Suspension, Wheels/Tires, & Brakes
johnc replied to trwebb26's topic in Brakes, Wheels, Suspension and Chassis
Did I say that? Must have been in comparison to the open 3" exhaust I put on my 240Z. With camber plates (any) you generally won't hear much noise from the front but the rears will transmit shock piston movement and road noise into the cabin. You can isolate the EMI Camber plates from the car by cutting and fitting a 1/8" thick sheet of urethane between the plate and the strut tower. -
I buy 3" cutoff wheels in boxes of 50 and I buy Norton or Merit. Cheap cutoff wheels just make dust. Abrasives and blades are one area where spending more money saves money in the long run.
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Welding cast aluminum automobile parts, especially old parts, is tricky. The two most important things are: 1. Identifying the cast alloy - look for a 3 digit number somewhere on the part. It might have an "A" prefix and would look like A319, A390, etc. Without identifying the casting, filler metal selection is hit or miss. If in doubt, use 5356 filler. 2. Cleaning - old automotive aluminum parts are dirty and they are dirty deep down. Running a wire brush over the surface isn't going to get the oils and oxides out. Hot tanking and/or pickeling the part is the best way to get it really clean. Then use a new stainless crimped cup brush on a hand grinder to really clean the areas to be welded. Set the balance on the welder 40% on (balanced toward cleaning) and expect to pull a lot of oxides off the material. Add in a lot of filler to try and dillute the oxide inclusions that are going to happen.
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There are bolts under the intake that hold the exhaust manifold and intake manifold on via thick washers that push on tabs on each manifold. Unfortunately, you'll most likely have to pull the exhuast manifold too because the combined intake/exhaust gasket will probably get damaged.