Anyone already know the drag coefficent of a 510? I have a 68 that I just got a g-tech for and it needs to know the drag coefficent. (it is a 4 door)

I heard it's somewhere around .49

That seems a little high.

My subaru forrester is at .37

In the g-tech manual it has instructions on how to figure it out by decelerating from 60 to 50... I have not tried it out.

At worst use what they have listed as a honda civic. The difference will not be dramatic.

I use my mind to benchmark and test my add-ons so once you don't change the settings you can gauge increase/decrease rather than overall performance.

Newer cars have MUCH MUCH lower drag coefficients than older cars such as your 510.

I would wager that the .49 is decently close to the truth.

The Forrester will be lower and the Civic will be MUCH lower.

Agreed, even the 240z is horrible at ~.46. And not to mention the scary front end lift that occurs when speeds get a bit higher. My friend's 510 had the hood fly up from the lift at a track day. After he installed an air dam, he hasn't had that happen. I think a front air dam is almost a must on these older Datsuns.

yeah it's basically required.