Guesses on Cd?

[Vman455]

The Nissan Titan "Triple Nickel" land speed racer, unveiled today at SEMA:



Lowered, salt-scraping air dam, solid wheel covers, and looks like a full bed cover.

[kach22i]

The extended cab with wind tunnel tested roof arc might make the need for a roof wing or aero-shell less critical. However, they seem to be missing out on a lot by preserving the typical pick-up truck looks.

A Practical Guide to Pickup Truck Aero-mods


To make an accurate guess, look at another similar truck.

I could not find a Cd number for the two examples I looked into.

I mean they didn't even do a grille block and side skirts like this Ford below.

http://www.trucktrend.com/cool-truck...f250-scorpion/

The truck’s final evaluation was done at Lockheed Martin’s 200-mph wind tunnel in Smyrna, Georgia, before the Super Duty was shipped to Bonneville.

[darcane]

Originally Posted by kach22i

I could not find a Cd number for the two examples I looked into.

I mean they didn't even do a grille block and side skirts like this Ford below.

That's because they gotta play by the rules to race.

I'd have to double check my rulebook, but IIRC, /DT largely follows the rules for the /GC (Gas Coupe) category. /GC is not allowed any streamlining other than removal of mirrors and trim, lowering, air dam, and wheel covers. I think /DT specifically allows tonneau covers.

It looks like Nissan has done all that and stopped there. I am a little surprised that there is so much wheel gap up front and the windows are rather unusual, but otherwise it looks clean. My official guess: Cd = .300

[ByDesign]

I'm guessing the truck is in the current form for the show, and will be modified further for an actual attempt per the quote "additional safety equipment and more – will be added within the next few months as the truck is developed with an eye toward setting new class speed records."

Several other little do-dads are already made but removed for the presentation. Gotta glitz it up for press!

[Cd]

I'm going with .27 - I would have gone lower, but Kach pointed out the open grille.

As far as the open wheel wells, and lack of side skirts, I keep thinking back to the HotRod 1980 Camaro, which achieved a verified .201 Cd with nothing more than an airdam, a plugged grille and headlight assembly, a simple shelf spoiler, lowering, and moon disks.
No side skirts, no belly pan ( later added, but not present early on when tested ) etc.

( And that .201 figure is with the giant scoop on the hood !

Amazing.

[Vman455]

That Camaro test also demonstrates how much of an impact seemingly-minor details can have. Raising the rear by 1.5" increased Cd to .227. They also tested three different hood scoops, with the final version same Cd as no scoop.

[kach22i]

Originally Posted by darcane

That's because they gotta play by the rules to race.

I'd have to double check my rulebook, but IIRC, /DT largely follows the rules for the /GC (Gas Coupe) category. /GC is not allowed any streamlining other than removal of mirrors and trim, lowering, air dam, and wheel covers. I think /DT specifically allows tonneau covers.

It looks like Nissan has done all that and stopped there. I am a little surprised that there is so much wheel gap up front and the windows are rather unusual, but otherwise it looks clean. My official guess: Cd = .300

You gave me something to look into - thanks.

Originally Posted by ByDesign

I'm guessing the truck is in the current form for the show, and will be modified further for an actual attempt per the quote "additional safety equipment and more – will be added within the next few months as the truck is developed with an eye toward setting new class speed records."

Several other little do-dads are already made but removed for the presentation. Gotta glitz it up for press!

Yea, the Ford I showed was in a situation just as you described, one look for "show", and another look for "go".

From the original article:

with the truck competing in the D/DT class (current record 191 MPH) as well as the FIA class A-III-9 (record 115 MPH).

Looks like qualification for two classifications, and I suspect correspondingly two different aerodynamic packages (and looks) will result.

FIA World Land Speed Records | Federation Internationale de l'Automobile

CATEGORIES

There are many different types of World Records which are divided into four main categories (A, B, C & D) and then several Group & Class sub-divisions within those categories.

Definitions of these Categories, Groups, and Classes can be found in Appendix D through the link below.

I have to get going, but for now will assume the images posted of the Titan are for the lower speed class or closer to street stock class. This appears to be the lower speed number posted in the article, FIA class A-III-9 .

[Vman455]

Interesting--class A-III-9 is FIA, and breaks down to Automobiles (A--as distinct from "Series Automobiles B"), diesel engine with supercharger (III), 3.0-4.0L displacement (9)--but the Titan has a 5.0L engine. Nissan isn't telling all in that press release, apparently.

D/DT looks like an SCTA diesel pickup class that doesn't allow changes to bodywork. That's probably what we're seeing in these photos.

[Cd]

Originally Posted by Vman455

That Camaro test also demonstrates how much of an impact seemingly-minor details can have. Raising the rear by 1.5" increased Cd to .227. They also tested three different hood scoops, with the final version same Cd as no scoop.

Makes one realize of fickle that air is. One moment you have a vehicle with a Cd of .25 or so.
Then suddenly, a butterfly crosses the road, instantly sending your Cd number skyrocketing to .30

[Cd]

So what is the official Cd quoted at ?