So I am thinking about entering the 370Z into the Mojave Mile coming up in October. Its a standing mile event, same thing as the Texas Mile, but in CA.

Mojave Mile: The Fastest Mile in the West

For those that don't follow my website/blog/facebook/etc. I have a series of posts about my automotive bucket list (click here to see the list). #12 on that list is to compete in a standing mile competition.

I am hesitant only because it probably wont be that cool in my 370Z which is completely bone stock as far as power mods go. There's a 370Z that ran the Texas Mile at 143mph and a lightly modified Nismo 350Z that ran the Mojave Mile also at 143mph so I figure thats right around where I will be with my 370Z. Going over 140mph is fast, but for me personally not that exciting, especially in a straight line. I go faster than that nearly every lap at most tracks I go to with the Berk Technology team and their time attack 135i. There are some tracks where I am entering turns in their car at 150+mph so 140mph in a straight line isn't going to make my socks roll up and down.

So if I were to go with the 370Z, the fun things for me will just be participating in the event, the atmosphere of the event, seeing some cool cars, and geeking out prior to the event trying to make little aero mods out of Home Depot materials that will give me a few more mph.

Has anyone ever been to a standing mile competition? If you have, would it be worth it to go with a basically stock 370Z or is it a type of event where you really need to have a fast car to have fun?

Nobody?

Well I asked the same question on my Facebook and another forum and the general consensus was to do it so I will....if my worn out Hankook RS-3 tires will pass tech. Gotta send them some photos and find out.

If they do ok the condition of the tires (its really just the outside edge that is worn) then I will get to work on some garage built drag reduction mods. Think I might set a goal of 150mph but that might be too optimistic. Step 1 is to get the tires approved.

I haven't, but it sounds fun. You don't have to win or be competitive at everything, just enjoy it! If we had one near here, I would.

No I would definitely be going just for fun. And I do have to be competitive with everyting, even if its just with myself haha. It's one of my favorite things about motorsports.

Exactly. The fun of it is competing against yourself. I'd love to do a standing mile event...especially with the HP I have. I just don't know of I have the faith in my car.

Whiteline sway bars on the way! WIN

Also got some more sheetmetal to make an attempt at some simple aero mods for the Mojave Mile event in a month. I looked through previous Texas Mile and Mojave Mile results from 2009 on and it looks as if the current 370Z speed record is 143.2mph. No idea what, if anything was done to that 370Z, but this is my goal...with a completely stock powertrain. If I am able to get tires in time and get everything else done in time for the event then the car will look like this come "race" day...

http://i129.photobucket.com/albums/p...mojavemile.jpg

Who does your graphics for you?

In real life, a company called 702 Graphics here in Vegas. In photoshop...me. :)

LOL, yes it was the real life part I was asking about :) Are they vinyl appliques? Just asking in case I manage to pick up some minor sponsorship.

Yeah just good 'ol stickers.

And I think 140 ish might be achievable if you can improve the car's drag a little. Assuming you can get to 100 mph by the first 1/4 marker you are now travelling 146 ft/sec and will have less than 9 seconds to hit 120 mph by the 1/2 mile marker. You are now travelling at 176 ft/sec and in 5th gear and will have 14 seconds to accelerate from 120 to 140 (assuming hitting 190 ft/sec [130 mph] before the last 1/4 marker).

A base might have a slightly better run than a sport with no spoiler, smaller wheels and open diff. The gearing of the auto might also be more favorable.

So - borrow and auto base model and give it a shot :)

taller tires? Might give a little edge. Maybe skinny ones too, since its a straight line?

I was actually thinking shorter tires. It would give a gearing advantage similar to running a different rear end ratio.

shorter would accelerate a little quicker, but taller would give a higher final speed. If going for top end, I would think that would be better. My speedo is 10% off with shorter tires. Would be interesting to see final straightaway speeds with stock sized vs. what I run.

I calculate top speed as 160 mph in 5th with stock tire size. A 10% gearing advantage would make it 154 but he'll run out of road long before hitting that. The taller tire would work if it eliminated a gear change and he was able to hit the target in 4th. This works to my advantage on a couple of tracks I've run, can eliminate 3-4 extra up shifts a lap.

As pointed out, I will run out of track long before I hit the top speed of the car so acceleration and aerodynamics are the focus here. The other focus, not spending much money since this is a one-time event. The eventual focus for my car is still the road course so things that would be good for the standing mile, like skinny front tires, drag radials, etc. are out of the question since I will likely only be using them once. The goal here is to spend as little money as possible and by that, I mean the only thing I am spending on is sheetmetal and spray paint from Home Depot...and a new set of tires, which I need anyway and those tires are being purchased with the road course in mind, not a standing mile.

So the advantages my car already has over an off-the-showroom stock 370Z are as follows...

- 21 lbs. of weight savings from the Odyssey Battery
- Better acceleration from smaller OD, lighter wheels/tires
- Better grip off the line with 10mm wider, stickier rear tires.
- Adjustable compression/rebound to aide in a better launch.
- Lower ride height = less air going under the car = less drag.

Again since it's a one-time event I don't really want to spend any money on it. I have spent a total of $80 at Home Depot so far. Here's all I have planned to help improve my speed...

- Sheetmetal side skirt extensions to reduce drag by blocking air from entering under the car.
- Sheetmetal front air dam does the same thing at the front of the car.
- Sheetmetal front/rear wheel spats block the spinning tires from the air flow and forces air around them reducing turbulance/drag.
- Fold in side view mirrors to reduce frontal area and reduce drag.
- Tape & seal all seams on exterior to create a smooth surface and reduce drag.
- Brake duct block off plates (if I have the time and energy I may do a series of plates that block off part of the grille opening again, to create a smoother surface area and reduce drag.
- Remove passenger seat saves weight to improve acceleration.
- Remove spare tire/tools saves weight to improve acceleration.
- Run with as little fuel as I can to save weight and improve acceleration.
- Run max tire pressure to reduce rolling resistance.
- Adjust suspension to move weight to the rear under acceleration for better launch/traction in the low gears.

I also may try one or two runs with the stock rear muffler section removed. I know this doesn't add much, if any power but it will shed some weight. I have a feeling that the gaping hole left where the muffler used to be will negatively effect the aerodynamics to the point where I will actually be faster with it installed. Only one way to find out though.

By my calculations, the car should weigh in at around 3,350 lbs. with me in it come race day. Power wise, as of now, the car will be 100% stock right down to the paper air filters. I can't really think of anything else to do to the car that is easily reversable and free but if any of you have more ideas, let me know!

how about practing your launch? not a natural act for TT / road race guys

I started as a drag racer back in 2001....shhhhh.... :wtf2:

I am not planning on doing a traditional drag style launch, but more of a roll off start instead. A drag style launch, done perfectly in a Z is tough, especially if your tires are aired up to a high PSI like mine will be for reduced rolling resistance. I think a drag style launch can hurt me more than it can help me if its not done absolutely perfectly. Plus the shock of a traditional launch is hard on the car.

... not that there's anything wrong with that! haha

okay, another possible easy add on idea... vortex generators strategically placed to help with airflow separation on roofline and rolling off the rear hatch

these just showed up at my house this afternoon, in fact... now that I have no aero restrictions will be going on the car

http://i656.photobucket.com/albums/u...909-1535-1.jpg

also, can you ditch the side mirrors for the event? maybe that's taking it too far?

Following back up on an earlier topic... I measured my camber at last weekend's event... sure enough, the SPC arms did NOT hold camber... left measured ~1 degree, right ~3 degrees... unfortunately opposite of what I needed for a clockwise event

The vortex generators might actually be something worth trying. Seems you can find universal ones pretty cheap online. Here's a link for a set of 10 for $20...

Amazon.com: Vortekz Universal Vortex Generators Black 10 Pieces: Everything Else

Which ones did you get?

As for the mirrors, I have to drive the car to and from the event (about a 3.5 hour trip each way from Vegas) so I definitely want them on there for that. Probably too much hassle for what its worth to do at the event or between runs but you never know. If I am within 1 mph of my goal then I may just be persuaded to take them off.

I splurged for the ones that are proven to work on low-speed aircraft...

STOLSPEED VORTEX GENERATORS from Aircraft Spruce

$100 pack is probably enough to cover 2-3 cars, so I'll have some left over... but won't know until I get my car back in a few weeks - otherwise I'd send you half

Those are super tiny! Wondering if bigger ones are usually used on cars because of the lower speeds or because they are usually positioned on the roof instead of on a wing. Hmmm... may have to try and speak with people who are smarter than I on this one.

Doing some quick reading, choosing the correct height of a vortex generator depends on the thickness of the boundary layer of air where you plan on placing the fins. You want the same height fin as thickness of the boundary layer. Wondering if the profile of a car creates a much thicker boundary layer over the roofline of a car than an airplane wing creates over the top of its surface. Furthermore, if these work on the top of an airplane wing, wouldn't they then work on the bottom of a car wing to increase efficiency? Can't say I have ever seen that done before...

my understanding... they are used on a wing to help when the AoA exceeds 15% or so... they keep the flow more efficient in that situation in particular... for that reason, i'm not sure how useful they'd be on the underside of our wings... a question for the more educated on this subject for sure

re small fins... what I plan to do is put them a little further afield in the airstream where the boundary layer remains thin...

... but it would be nice to have some data that helps us understand how high the fins should be

these are used on kit aircraft by the way... those things cruise at 150-175

Autospeed has quite a few aero articles related to this sort of discussion

Vortex Generator 4 part series (They specifically test the vortex generators on the underside too):
Vortex 1
Vortex 2
Vortex 3
Vortex 4
Also in that article they show some data from Mistu EVO tests that seems to suggest that 25mm high or so is best.


Aero Testing 5 part series:
Aero 1
Aero 2
Aero 3
Aero 4
Aero 5

Underflow 2 Part Series:
Under car 1
Under car 2

thanks for the links... 1" vertical fin is the takeaway huh?

if true, wonder if there's any use for those 0.45" vortex generators I bought?

Who knows, maybe our boundary layer is thinner because our cars are so slick. :rofl2:

Feel like doing some tuft testing?

Awesome articles Chips! Thanks for the links!

Now, if we could only find some wind tunnel photos of a stock 370Z...

fun reading... don't know if you guys actually read through all those links but I'm going through now... friday night for married guys! any event, you'll notice from the excerpt below that the 15mm height when using a delta wing style vortex generator is within ~10% of the coefficient of lift benefit of the 25mm height... in other words, the VGs I bought should work fine... clearly on the EVO this test came from it was the right decision to go with 25mm... and I'm curious what 35mm would have looked like - unfortunately they didn't test it... but 15mm gets me 90% of the way there

I suspect we also have a tighter boundary layer vs evo, given our less steeply slopped windshield and overall better aero, which would just reinforce the choice to get a smaller VG than used on the EVO

Just finished reading all of the links myself. Very good stuff in there. Making me re-think my front air dam now too...

I do think that the Z's shape can probably get away with a shorter VG, but now I am wondering if the VGs are even going to make any positive difference at all.

even more disturbing... our car is a wing! look

http://i656.photobucket.com/albums/u...ingoverlay.jpg

I'm kidding with that last post btw!

Some of my (poorly educated) theories

- nissan was right to put the spoiler lip on the back... exactly because of the picture above... if they didn't there would be a lift effect of higher pressure below car vs above

- my car has a rear diffuser... I actually want the air to stay "attached" on the rear deck lid and to then flow under the rear wing... it will theoretically then "re-attach" with the high speed air coming from the rear diffuser and the air coming out of the rear diff cooler box... I want all that to be as laminar as possible to minimize drag... I also want all that to hug the surface of the rear deck lid to avoid having turbulent air come in contact with the wing... that part I can be certain of... goal is to get high speed 'clean air' to the wing and keep all the turbulent air associated with roof and boundary separation 12" below the wing

- therefore I need VGs at the rear roof

- therefore I need VGs on the rear decklid

What I don't know... do I need VGs on the front wind splitter? do I need VGs on the leading edge of the rear diffuser?

You may have been kidding, but you've hit the nail on the head haha. All cars are shaped like wings....the airplane kind that generate lift. Any object that has more surface area on one side vs. the other will create either lift or downforce, the side with the less surface area sees the pressure. If you flattened the surface area of the top of a car it would be much much longer than the bottom surface area which means pressure builds under the car and pushes upward creating lift. An airplane wing is designed the same way where the top half has a longer surface area than the bottom. An automotive wing is basically flipped upside down so the pressure is a downward force.

That being said, sticking the laminar air flow to the back of the car for a longer period of time actually creates more lift. So there's a trade off at some point. In one of those links they use the example of a modern VW bug which is a perfect example of aero fail despite the laminar flow of air over the rear sticking all the way to the license plate basically. As far as the rear diffuser goes, the vertical fins are basically VGs. Going back to the length of the surface area thing, rear diffusers slope upward and the fins help air stick to the surface creating a longer surface area on the bottom of the car so it better equals the top of the car basically producing negative lift, not so much downforce.

right makes sense... in fact, I've been thinking about extending my rear diffuser out another 6" now that I don't have aero restrictions... I'm also, as I pointed out on my journal, going to try and craft an under-tray... I'm sure that will be a lot of trial & error!!

btw, I'll point out for folks that are interested in this topic, the author of the previously linked articles wrote another article three days ago... here

AutoSpeed

hey one more thing sticking in my head... I head a world-known PhD in aerodynamics look at my car believe it or not about 1 year ago... he told me to try and minimize the boundary gap coming off the rear deck and keep it attached so that it would join the air coming off the diffuser... he said it would make the diffuser more effective... obviously runs counter to the car as upside down wing theory, but I remember he was adamant about it... brain hurts!

Mike, when doing the actual run, how about running without the air filters?

Also the rear quarter window I always wanted to have someone make a subtle duct for that area and channel it to the vaccum ducts in the trunk!

like these?
http://i656.photobucket.com/albums/u...amCLI_5513.jpg

and some you can buy here
http://www.uniqueautodepot.com/Nissa...dy-p/13020.htm

What are these trunk vacuum ducts you speak of?

I am sure there is an exception to the general rule I just don't know what it is. I would go with the experts. I am guessing the benefit of doing that would outweigh the negative. If there's one thing that I have learned in my very short and very basic gathering of aerodynamic knowledge is that there aren't many things out there that don't have some sort of trade-off.