Project84

I know the 2nd Gen is 0.31 and 0.29 for the sports package. What about the 1st Gen? Any wind tunnel info available on that? I did do a search and all I found was that the 1980 car was 0.38. Where others years and models different?

Thanks guys

Rx7carl

I bet the later cars had a lower CD than the SA's due to the more contoured front bumper/air dam.

82transam

iTrader: (18)

According to "Cars: A celebration" by Quinten Wilson a FB has a .36 drag coef. In reading through that book I've found numerous inaccuraces so I'm not sure how reliable that number is. Sounds about right though.

racermike

I seem to recall 34. But not sure,

rotor vs. piston

I think the color history of the Rx-7, it says .32 for the FB and a higher number for the SA, I just can't remember what. And too, in this book I've found misinformation.

racermike

36, 34, 32, do I hear 30? 30 going once, twice,,,,,

82transam

iTrader: (18)

30

fatboy7

I've also heard most of those, but using a simulation that I built using the equation for drag, I found that 0.32-0.34 gives a pretty close estimate for the posted topspeed. (using 1.895 m^2 for frontal area)

fatboy7

Actually the drag forces on a 1st gen and 2nd gen are really close, the 1st gen has a higher coeffecient of drag, but less frontal area.... this tends to balance things up a bit.

racermike

I was thinking the 1st gen was 34 and the second was 33,,,,,but surely someone has the factory (or sales) numbers!

error402

This is what I found in "RX-7 Mazada's Rotary Engine Sportscar" by Brian Long

Prototype -
"A final prototype being tested in the wind tunnel. The Cd was a highly creditable 0.36, or 0.35 if a rear spoiler was fitted."

SA -
"The clean lines and steep windscreen angle promoted a Cd figure of 0.362 - better then that of the Datsun 280ZX of the same vintage, and about the same as that quoted for a Porsche 924; the optinal rear spoiler not only dramatically reduced lift at the back end, but further enhanced the coefficient of drag, lowering it to 0.352."

FB '81 -
"The highly-specified UK cars came with a moulded rear spoiler (which dropped the Cd down even further, to a quoted 0.32)."

Manntis

"In JARI's wind tunnel the P642 [Mazda's designation for the car we call the SA- Manntis] attained a drag coefficient of 0.36.

P815 [Mazda's FB designation] appeared in August 1980with extensive styling changes. A new urethane covered front bumper/airdam helped lower the drag coefficient to .34, equivalent to a gain of 5 horsepower, and reduced the front-end lift coefficient from 0.18 to 0.12"

Source: J. Yamaguchi

purple82

What values are you using for power? Tire drag? Driveline drag?

fatboy7

I've been using a 15-17% drivetrain loss, if I'm trying to guessitmate the power curve. Of course there is enough dyno-charts lying around, I've just been using some of stock ones to make the torque curve that includes drivetrain losses...

Project84

So its pretty comparable to the 2nd Gen. The 2nd gen's CD is 0.31 (0.29 on with the sports package.)

error402

Yep.

-Error402

Zulu

I show a .31

rx7gslse

"Rx7 Sportscar History" John Matras...

SA22C .36 equal compared to the 924S
headlights raised it to .38

81+ front dropped it to .34, and adding the spoiler further dropped it to .32
- note, lift coeficent dropped to .12 compared to .18 for the 1980 model


2nd gen,
base model, .31
w/ aero package (spoiler, front air damn, and rocker panel deflectors) reduced it to .29

88 vert, .33 top up, .38 top down

no mention of change for the S5 cars.

Project84

I show you this

Its on page 9. .29 with sports package.

Thanks for all your info on the first gens guys.

damusto

Guys and what about rear end lift ?

DivinDriver

iTrader: (15)

42?