Datsun Z aeromods wind tunnel testing

[tasdrouille]

Never seen this posted here. It's good stuff

Windtunnel Test Data - HybridZ

[Otto]

Am I reading the data incorrectly, or does it say those mods made very little difference?

I'd have thought the headlight covers, side skirts, windshield and hatch fairings, etc. would have done more to reduce drag.

[Figjam74]

Those cars are fairly decent already for aero, but it in both cases, blocking off the openings at the front of the car made a significant improvement. ~10% reduction in required HP.

[tasdrouille]

Well, there's a 13% difference in Cd from the stock car to the best iteration tested, but they kept adding, combining and removing stuff.

[Daox]

Sorry, but I gotta comment. A stock Cd of .45 is not decent at all. Thats about as good as a truck. Just because it looks slippery doesn't mean it is.

[Figjam74]

I mis-spoke(typed). You're right of course, I should have said CdA. The frontal area of those cars is absolutely tiny, and manages to compensate quite a bit for the efficiency of it all. If my math isn't too far off, it's about the same as the current VW Beetle.

[evolutionmovement]

They look fairly efficient, but I had a 240 and a 260Z and the aero was terrible. You could actually feel the wind resisting the car and they had all kinds of stability problems at speed. Much like a truck, actually. I find it interesting that the ducktail I had on the 260 decreased drag—I thought it just helped keep it from wandering so much. I'm also surprised the headlight covers didn't do more as much of the wind resistance and wandering seemed to come from that area. Never drove one with the covers, but I guess there's little difference according to the wind. The flared fenders actually decrease drag, which is amusing as the wheel wells were such an aero disaster that I guess just keeping some of the air out of there is worth the penalty in frontal area.

[aerohead]

CAR and DRIVER did some aero mods to a Z-car in 1974 after their success with the Pinto.They did not achieve as dramatic results as with the Pinto.A beautiful composite nose,with headlight covers was soon offered on the market.I'll post the article next Saturday.

[bondo]

That is the A2 windtunnel in Mooresville, North Carolina. Great bunch of folks there.

Somebody dropped a bunch of money running that many tests on different configurations for the Datsun Z.

Bondo

[aerohead]

Al Glidewell is pretty swamped with work and I don't think he'll be able to do the scans.------------ Here's a synopsis of the C and D 240-Z mods: for best economy,a rear spoiler of aluminum sheet,about 8-inches ( 200mm ) angled up at 30-degrees gave best MPG for downforce ( 110-lbs ) and 0.20 mpg.------------ The front air dam allowed 3.6-inches of ground clearance,hung basically straight down,canceled 85-pounds of lift and added 0.8mpg at 70mph.-------- The G-Nose,offered on Nissan's 240ZG,with grille block.added length,and covered headlights allowed a 1.2mpg improvement at 70.top speed 5-mph higher and 95-pound lift reduction.Headlight covers by themselves were good for 0.2 mpg.Total for C and D mods: 1.2 mpg @ 70-mpg,from 22 mpg,to around 23.5.