07 Altima aero mods

[user removed]

Good battery test, turn on headlights. If they wont go an hour without killing the battery, the battery is on its last leg.

I have 20,000 miles on the Michelins on my VX and close to that on the Insight. Both sets of new tires when replaced took almost 1000 miles to wear the nipples off the center of the tire at 44 PSI side wall max.

I bought a Scion XB a few years back and the dealer took off the factory option wheels with those super low profile tires that cost $1800 extra. The problem was they inflated the standard tires to 65 PSI. Riding home I knew there was something wrong by the way the car rode. They were supposed to be 44 PSI.

That's 21 PSI over sidewall max or 50% overinflated. At the time I felt I was lucky they didn't blow right off the rims.

I monitor the tread wear on both of my cars and both are wearing perfectly evenly. At the wear rate the Michelins on my VX might last 100k. They have a 740 tread wear rating compared to the 200 on the factory Bridegestones they replaced.

As Vegas Dude stated so well, if the Police use sidewall max, I don't see it as an issue. Another benefit is when I carry a load, the pressures are already where they need to be.

regards
Mech

[99clipsgst]

Thanks Vega, I have to put new rotors on tomorrow so maybe I can get the from grill off to put an upper grille block on and pump up the tires some more. I have a 3 hour trip this weekend so it will be a good test to see if it works. Does any one know a good length to make the flaps in front of the tires? only the front ones have have little one in front and the back has nothing.

[99clipsgst]

Ok I pumped my tires up to 48 PSI and made an upper grille block out of cloroplast. and the results are in. having done the 1st 1/4 of a tank in mixed city highway driving and the next 1/2 tank on the highway averaging 70-75 MPG I got 26.29. not too bad but I wanted better. Right now I'm on the return trip fill up so Maybe this one will be better since its got more hw and less city on it.

[ecofreak]

Altimas would really respond well to an undercarriage cover, and some grill reduction plates. A kammback would have to be made with plexiglass, because of the already tiny rear window.

[COcyclist]

Originally Posted by ChazInMT

Am I the only one who wonders why the rear spoiler??

It seems like that would be adding drag. You may want to give consideration to losing that. I have never seen an ideal aero template with a spoiler on it. If it is creating downforce, it is creating drag, and if you keep your speed under 150 MPH, control shouldn't be an issue.

I could understand if you had some huge awful curving back end on a car (Think VW Bug, Audi TT Coupe) why a spoiler would help by detaching flow at a more beneficial place in the slipstream, but the Altima appears to have a nice thing going without the extra bump.

It does look cool, gotta give you that, and it probably isn't costing you a lot. Any guru's want to chime in on how I may be mistaken about this, I'd love to hear it. I have given this a lot of thought since driving a rented 09 Corolla S last fall for a month with a wing thing and wondering if it wasn't a drag load.

Chaz, Some deck spoilers may hurt, some may help and some may have no significant effect on fuel mileage. Post #8 indicates no real difference for this Altima. How could a deck spoiler help?? The Salt Flats racing Ford Fusion used an extension off the back deck to make the car's shape come closer to fitting the "aerodynamic template" found on this site. The half teardrop (Ultimate Aerodymnamic Car) is optimum but it can be stepped too. It is a compromise but this is why a pick-up has less drag with the tailgate up than down, even less drag with a tonneau, and even less with an aero Kammback.

Originally Posted by superchow

I would like to offer a different perspective from personal experience. While I am not advocating hyperinflating tires, pressures at or below the max. sidewall has always been safe for me. I got 60,000 miles out of my previous set before the tread on the edges was more worn than the center of the tread.

This has been my experience as well. I have run tires at or above sidewall pressure since I began racing autocross in the '80s with no problems. I will admit that there may be slightly less traction on hard acceleration but better cornering traction because the tire doesn't roll onto its outside edges as easily. Hypermilers may take corners at higher speeds to conserve momentum but don't typically do smokey burnouts. I have seen some treadwear in the middle but still usually get 60-80,000 miles from a set of tires. You may notice a slighter harsher ride and much improved coasting.

[ChazInMT]

Originally Posted by COcyclist

It is a compromise but this is why a pick-up has less drag with the tailgate up than down, even less drag with a tonneau, and even less with an aero Kammback.

Aero Kammback huh? I think I have seen this somewhere before.

GMC Aerocap

Thanks for the response, I see what you mean. I knew this too, I know the cost of the thing, or gain, is slight.