johnc

You have to solidly mount the engine and tran, not just one. Also, nuts and bolts will tend to vibrate loose so check them periodically.

An 8" wide wheel sounds a bit narrow for a 245 width tire if you're doing track stuff. I was originally planning to run 245s on 9" wide wheels. There are some old pictures on this site of 245/45-16 Hoosier R3S03s on 9" wide Monocoque wheels. Search for posts with me as the author and the topic was probably MSA flares or something like that. I have no high speed stability problems (140+) running 275/45-16 tires on the front of my car.

LSD options for the R180 (that I'm aware of): Nissan Motorsports (and Nismo) LSD (clutch pack 4 pinion) $800. Torsen/Gleason (torque biasing) NLA but about $1,000 used if you can find one. Quaife (torque biasing) $895. Nissan OEM LSD (clutch pack 2 pinion) NLA but available outside the US in the 432 and other street Nissan applications. Of the 4 above, the Nissan OEM 2 pinion LSD will have the same basic weakness as the stock, open two pinion R180. The other units are very strong. Also, be aware of the two different ring gear ID sizes. The early 240Z R180s (through 1972 I think) used a 110mm ring gear ID. All later ring gears had a 115mm ID. The LSD has to match the ring gear.

Search the site.

I'm doing the basic fab and Erik's doing the suspension.

No. I have my own shop.

And Amir's car is in my shop now getting the braking system plumbed, the fuel cell installed, and the fuel system plumbed.

Is he stating that he's using Metric Grade 8.8 bolts to hold the cylinder head on this 700hp beast? BTW... Troll alert! Troll alert! Troll alert! Don't get sucked into posting.

Traditionally, a Petty bar (named after Maurice Petty, not Richard) runs from the top center of the main hoop to the right front floor area. Its designed to increase torsional rigidity and is very effective. With newer cage designs the Petty bar is lowered from the top center of the main hoop to a stress junction about shoulder or rib cage high behind the driver's right side.

Dynos (engine or chassis) are tuning tools. Race tracks and drag strips are comparison tools. Horsepower and torque numbers are marketing tools.

A good chassis dyno operator should be able to determine the drivetrain loss for any vehicle they are running on the dyno. SAE published a standard in 1996: J1263 "Road Load Measurement and Dynamometer Simulation Using Coastdown Techniques" that determines drivetrain and coastdown loads.

I think the point is that there is no such things as "American" or "Foriegn" cars anymore. That's an old concept the became outdated in the mid 1980s when the Japanese started building plants here in the US and US manufacturers started building plants in Mexico.

There is no number and you cannot compare nor extrapolate horsepower or torque numbers generated on a chassis dyno to numbers generated on an engine dyno. My engine/chassis combo is a perfect example. On Sunbelt's egnine dyno (which is tested and certified monthly) my engine repeatedly produced 305 hp. On a Superior Automotive's chassis dyno (which is calibrated at least monthly) my engine in my 240Z repeatedly produced 279 rwhp with Jim Thompson at the laptop. Both numbers are accurate as far as I'm concerned but they are not comparable. Either my 240Z has the most efficient drivetrain EVER installed in a car (with a 8.5% loss) or my engine gained 15 to 30 horsepower after being installed in the chassis.

UFOs are just spoiled rich alien kids buzzing the earth to freak out lower life forms. At least that's what it says in the Hitchhicker's Guide to the Galaxy. Remember, "Don't Panic."

FYI... for those on HybridZ that might not know, Krazik is Rylan, the owner of the Honda S2000 that *almost* beat Bryan and I at least year's Open Track Challenge. Rylan's team basically cleaned our clocks at the Northern California tracks and we returned the favor at the Southern California tracks. It finally came down to the last event at the Derek Daily track in Las Vegas and I think we had a set of tires that were less worn then what Rylan was left with. He's got a writeup here: http://www.rylan.org/otc03/index.htm

Forged center 3 piece 16" x 10" weighs in at 14.29 lbs. on my digital scale.

When I had Kodiak build my 10" wide wheels I specified a 5" backspace and ignored offset. The same was true when I ordered a set from Monocoque years ago and CCW years before that.

John's built a few dozen sets of wheels for Zs so he should know.

Same as what you started with most likely. Manifolds by themselves, like most bolts ons, don't add much (if any) horsepower. They have to be matched with other modifications to deliver real horsepower increases. At some point we should probably not allow topics like this ("How much horsepower do I have?"). There's no way to post an intelligent repsonse.

Why are you posting on this old Datsun site Mr. Honda S2K? FYI... I didn't notice any vids of the Rusty Old Datsun in the Supercar section...

Or the small fact that somewhere before 3,000 mph the Z would basically vaporize with only the engine block (minus all ancillary components) as the remaining recognizable part, just before it too disintigrates as it hits the sea surface.

A good friend of mine years ago worked cats on the Ranger during the Vietnam war. They shot bunches of stuff (including cars) off the carrier using the cats. And once or twice a year they would screw up and "cold shot" a plane off the deck - meaning they computed the wrong aircraft weight and the catapult didn't get the plane up to speed. About 50% of the time the pilots would save it.

I'm not a trained engineer, more a monkey-see, monkey-do engineer if there is such a thing so take my statements for what they are worth... I think the shape and orientation of the static contact patch remains basically the same (an oval or an elipse, wider laterally for a low profile tire, wider longitudinally for a high profile tire) and that basic shape is determined by tire construction. An exception to this is when the tire is severely underinflated and has run out of tread width. The total square inches (the size) of the contact patch varies by inflation pressure and load but the overall shape remains an oval or an elipse. Dynamic contact patch shape, pressure differentials across the patch area, etc. are a whole 'nuther thing. My experience has been different when racing on shaved street tires, DOT-R and slicks. On Hoosier R3S03s I'm running tire pressures 5 psi below what Hoosier recommends and the lap times, temps, and life have improved considerably. Same is true when running Kumho V700s and Hoosier 45 slicks. My example is different because I can get whatever camber I want and I adjust to get good tire temps across the tire. For a street car that is limited in camber adjustments you can't drop the pressures anywhere near as much. But, you DO want to drop (or increase) the pressures until you get scuffing to the tops of the triangle shaped wear indicators. In Brian's example where he was running 20 psi, the tire was underinflated. So, SCCs recommendation is true because he needs to increase his pressures. If the tires on his Z were inflated to the recommended 28 psi they are probably still low for best handling on his car. I guess if SCC is assuming that everyone is driving around underinflated, then their statment is true.

God help the 40-something, middle age crisis, recently divorced males. They are going to kill themselves in droves - like Lemmings to the cliff.

While I can't argue pneumatic theory (if the is such a thing) I think the relationship is pretty close because the math matches the recommended inflation pressures for my 1977 Datsun 810, 2000 F350, 1964 Lincoln Continental, and my 1970 240Z. While I agree that the 780 lbs is pushing down on the ground through the contact patch, the vehicle is being supported by the air in the tire acting on all surfaces within the tire. In essence, you have 780 lbs pushing down through the contact patch and an equal and opposite force of 780 lbs pushing back up through the air chamber in the tire. That pushing up force is spread out over a large area so the force per square inch of tire is pretty small. That's why you get a contact patch to begin with. Increasing air pressure in the tire increases the force per square inch and reduces the contact patch size (rubber in contact with the road). I think that's just a rephrase of what you said. Given the above, more tread rubber in the contact patch increases traction until we get into tire overheating, contact patch distortion (from excessively low air pressures), or exceed the optimal slip angle. I don't have Miliken's book here at the shop, but they have lots of math to backup this statement. Now, there are exceptions to this - 335 tires on a 1500 lb vehicle would not stick very well because the tires would never get warm. If we are going to make general statements (as SCC does) then lower tires pressures increase grip until the tire starts to roll over. Due to sidewall flex you might see a decrease in responsiveness but now we're getting into a more detailed statement that must take into account the type of tire: DOT-R tires have stiff sidewalls to counter the reduction in responsiveness from lower tire pressures. I guess I'll have to remember to get Miliken's book from the house to respond in a more intelligent manner.