Design Notes/Goals for my 510 Project: Goals : Power weight ratio of 10:1
: I want exceptional acceleration. Many high-performance cars have a power/weight ratio of
between 10 and 12lbs per horsepower. Few are much beyond 10:1. Porsche 911 Turbo, Dodge
Viper, and the C5 Corvette are better than this, but the Acura NSX, BMW M3 and Mustang
Cobra, for example, are not. Incidentally, magazine test results of cars with a P/W ratio
of 10:1 run the standing 1/4mi anywhere from 13.3 to 13.8secs. Not world-beating, but
exceptional. Handling : I want a quick
car that could still take corners faster than the average Joe in his Mustang GT, Z/28,
etc. I think this will take the most R & D once the car is running. Efficiency : I don't want a
GAS HOG. I'm shooting for all-highway mileage of 28-30. Driveability : This will be
my "daily driver", once everything is sorted out. Grocery getter, commute to
work, etc. As such, it has to have a useable powerband, be reliable, and efficient. Cost : I do not have
unlimited funds, and therefore have to watch where I spend what. CAR - 1971
Datsun 510 A no-brainer. I'm a "510 guy" (and have all the quirks THAT entails). There are lots of cars that can be used to fulfill these design goals, as well as just about every motorcycle over 400cc. The 510 has the advantage of being fairly lightweight (2100lbs or so with the 4cyl), has 4-wheel independent suspension, and can share a lot of pieces with the higher performance (and therefore good aftermarket availability) Z-car. The year of 510 didn't really matter, I just happened to find a '71 2-door 510 for cheap. Engine -
VG30DE High output : This motor
develops 222hp in stock form in the 90-later 300ZX. With an expected weight of 2450lbs, I
therefore need 245hp to reach the 10:1 goal. the VG30DE with only bolt-on modifications
can even exceed this, and still maintain excellent efficiency. (This removed the VG30E) Weight : While the VG30DE is not the lightest engine with 220+hp, it's also not the heaviest. (This removed the V-8's) NISSAN : An unstated goal was to maintain as close to 100% Nissan as possible. The VG30DE has the second highest output of any non-turbo Nissan engine in the U.S. (This helped remove the V-8's, and the Buick, and Rotary) Efficiency : The 300ZX with this motor, which weighs more than 1000lbs more than the estimated completed weight of my 510, can get 25-26mpg on an all-highway drive. Aerodynamics is part, but so is engine efficiency. (This removed the rotary & the Buick) Driveability : While
developing 245hp, the VG30DE is not a peaky motor, it has a fairly flat, very usable
torque curve. (This removed the rotary and KA24) Transmission This is where I may have overlooked something. I did not realize the earlier 300ZX (Z31) transmission would bolt up. The earlier transmission WILL bolt up, as well as having the starter run forward from the transmission, instead of backward like mine. It is also cheaper, lighter and physically smaller - requiring little transmission tunnel modification. My Z32 has improved shift feel & accuracy, as well as a higher torque rating, although I feel the Z31 has sufficient capacity. I may go boosted (supercharger) at a later date, so at least I wouldn't have to upgrade later . . . Differential
- R180 1) Higher torque capacity : The R160 seems to be only factory installed in four cylinder cars with 100-120ft/lbs of torque, and I'll be running 200-220ft/lbs (about double). 2) It's 10-15lbs lighter than the even heavier duty R200, which I don't think I'll need as I know of a few V-8 Z-cars that have run the R180 successfully. 3) The tire size I'm running is about stock 510 in diameter (205/50-15), and with the 3.54:1 ratio will give me the exact same overall ratio as the 90+ 300ZX - meaning I'll shift at the same MPH as a Z car for a given RPM. So think of my car as a 2500lb 300ZX (and quicker than the twin turbo!). 4) I don't want to get a shorter (higher numerically) ratio to get additional torque to the real wheel for traction reasons. My power/weight ratio will be about 10:1 (10lbs for every horsepower), which is the superior to the latest SS Camaro (it's about 11:1), and I don't want to have severe traction problems when launching the car. One friend of mine has a 350 V-8 in his 280Z, and first gear is useless - too much torque, too little traction. Same for another friend with a turbo SOHC V-6. They are both running 3.9:1.
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