07 Altima aero mods

[99clipsgst]

I recently got a 07 Nissna Altima and I was looking for some Aero mods. Has anyone on here done anything to a 2007 - 2009 Nissan Altima? The underside looks pretty clean but I know it can get better.

[superchow]

The Altima is quite light for the size and it has fairly good aero already. A grille block (partial or full depending on season and location) and max sidewall tire pressures should get you going.

Is it MT or AT? 4 cyl. or 6 cyl.? Sealing panel gaps could be useful, but you have a great starting point already. Unless you go with extreme mods and add a boat tail, I'd stick to non-intrusive mods for now.

My mother in law got 40 mpg out of her 4 cyl. AT Camry driving to Oregon (from WA state) by just setting the cruise at 60 mph for the whole way. Just letting you know what's possible without any mods. Low hanging fruit!

[99clipsgst]

I have the 3.5L v6 with the CVT transmission. Right now I have a warm air intake, rear spoiler and some new Goodyear fuel max tires pumped up to 45 PSI.

[superchow]

The CVT should keep the engine revving quite low at highway speeds, right? Any manual control over the transmission? It would be interesting to manually keep the transmission at those low rpms and increasing the load without increasing rpms. Then you should reach a better BSFC "island".

That 3.5L V-6 must be a sweetheart to drive. I was eying a V-6 with MT, and Nissan is the only manufacturer of affordable family sedans to offer that combo. Well, when the Hyundai with the 2.0L turbo I-4 arrives I may have more options.

Do you do a lot of highway or city driving? In any case try manually "down-shifting" to use the engine to brake for you. Less brake wear and as an added bonus DFCO (deceleration fuel cut-off). Timing stop lights also helps a lot. I'm curious about your driving style/hypermiling experience at the moment, and how that all fits in with a CVT.

[user removed]

I would be wary of blocking the lower grille on a CVT equipped Altima.

If you restrict the airflow to the transmission cooler it could eventually damage the transmission. Nissan recently extended the transmission warranty on all of their CVT equipped cars to 10 years and 120,000 miles. If they find consistent overheating of the fluid, they might not honor the warranty. Since the transmission can not presently be rebuilt and replacement is the only option, costing thousands, I don't think the risk is justified.

Nissans CVTs will stay at low revs and keep the engine at higher BSFC points than just about any other transmission on the market. Our Rogue will do 60 at 1900 RPM. Thats 90 at under 3k RPM if the aero drag did not cause the transmission to allow the engine to rev higher.

I have seen 35 MPG in our 06 Murano which has about the same setup as the Altima, and another member here has done better than 40 MPG in a 3.5 Altima. I once managed 33.25 in the wife's Rogue on a trip for a whole tank, and a lot of that was in heavy rain. Probably could have hit 35 MPG. This was at 55-60 MPH.

I love the 07 and up Altima platform, same basic chassis as the Rogue. I'm considering a 4 cylinder Altima as a possible replacement for one of my cars, so the wife is more comfortable driving when we take my car.

I wonder what the CD is on a factory Altima?

regards
Mech

[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.

[titan8or]

Hey guys, I don't post very often and don't want to be a bummer here. I've read alot of postings and 1 of the things that really twists me is when I read about people recommending max sidewall tire pressure. I've seen alot of great ideas posted andsome innovative thinking, but the tire pressure thing shocks me. I've been in the tire business for close to 20 years so here's a few reasons NOT to increase tire pressure to max sidewall listing. Now it doesn't take a rocket scientist to know that increasing tire pressure will decrease rolling resistance but the more you increase it the faster you tires will wear in the center. So you'll save money on gas, but have to fork over money ALOT sooner to replace your tires. Max sidewall pressure is designed to increase the load capacity of your tires when carrying a heavier load. When you're not carrying the load, max pressure will typically cause belt separation and could lead to a blowout.Also increasing tire pressure, especially max pressure will reduce the amount of tire footprint on the road and decrease vehicle stability. I'm all for trying to increase the mileage in my vehicle, but not at the expense of costing myself more money on something else and certainly not at the risk of hurting someone else on the road.

Just some good info to think about.

[99clipsgst]

@Superchow the 3.5 Is a very sweet engine and with the CVt I can easily cruise around town without even cracking the 2K RPM mark. The CVT does have some manual control it has the option to lock the CVT into 6 ratios to simulate a manual transmission. However when ever i drive around using it my MPG drops so I tend to stay away from it.

@Old Mechanic it Cd listed for 2007+ altima sedans is 0.31 and the Hybrid is listed at 0.30. and as you pointed out the Altima 3.5SE and Murano have the same drivetrain.

@ChazInMT Igot the car without a spoiler and since putting it on I haven't seen a diffrence at all with the MPG. The spoiler dosen't have a gap between it and the car So i would think that it would help some with detaching the air from the otherwise rounded lip of the trunk.

@titan8or the fuel max tires have a max PSI of 51. and I'm not planning on going past that. Sadly in the 45 days or so that I have had the tires I have yet to see a real diffrence in the MPG. The goodyears are supposed to have less rolling resistance and the also weight 5 Lbs less per tire over the stock wheels.

Right now I want to see if these is any thing to the underside of the car that will up the MPG. does anyone if the hybrid altima has aero mods on it that could be transfered over to my car? Like tire spats or a belly pan? Right now I'm saving up for a new Y pipe that should help with back pressure in the cylinders and up the MPG.

[superchow]

Originally Posted by titan8or

Hey guys, I don't post very often and don't want to be a bummer here. I've read alot of postings and 1 of the things that really twists me is when I read about people recommending max sidewall tire pressure. I've seen alot of great ideas posted andsome innovative thinking, but the tire pressure thing shocks me. I've been in the tire business for close to 20 years so here's a few reasons NOT to increase tire pressure to max sidewall listing. Now it doesn't take a rocket scientist to know that increasing tire pressure will decrease rolling resistance but the more you increase it the faster you tires will wear in the center. So you'll save money on gas, but have to fork over money ALOT sooner to replace your tires. Max sidewall pressure is designed to increase the load capacity of your tires when carrying a heavier load. When you're not carrying the load, max pressure will typically cause belt separation and could lead to a blowout.Also increasing tire pressure, especially max pressure will reduce the amount of tire footprint on the road and decrease vehicle stability. I'm all for trying to increase the mileage in my vehicle, but not at the expense of costing myself more money on something else and certainly not at the risk of hurting someone else on the road.

Just some good info to think about.

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. Now, this is a design particularity of the Michelin MXV4 Primacy tires we got. The tread depth is only about 50% along the edges of the tread compared to the full depth in the center of the tire. (I was very angry at this because it was a great tire except for not having a water escape route anymore when driving in the rain - which never happens here in the Pacific NW...)

Apart from a few tanks of break-in period at normal pressures, they were inflated to 42 psi (44 psi max sidewall) and sometimes they didn't even need rotating when getting oil changes.

Again, this may be because of the well aligned Civic I'm driving, or spirited cornering that may scrub the "edges" of the rubber more, or maybe because the Civic has negative camber in the back and none at the front. If the tire wear would have been uneven I would have reduced them to "safer" levels, but that never occured.

So if one is careful and slowly creeps up in pressures to one's safety comfort limit and is smart about adjusting your driving to that fact it can be a useful tool to gain a few mpgs.

[VegasDude]

Disclaimer: I've done a few small aero mods but I can't positively link them with my gains in FE since I radically changed my driving habits at the same time.

The most effective single thing you can do without changing the body much is probably a front air dam. I have not yet tried this myself.

I have a 2005 SE V6 5 speed manual and I put the front license plate flat against the grill (which is an aftermarket billet type.) This does two small things: eliminates the aero drag caused by the plate when it was mounted on the front bracket, and it acts as a partial grill block. I have driven the car in temperatures up to 118F and I have not seen an increase in engine temps. (I wasn't towing anything up a hill either.)
My other mods:
Wiper delete, passenger mirror delete, rear mud flap delete, WAI, max sidewall pressure. No acetone, just premium gas.

I have not seen any evidence that max sidewall pressure is a problem. I read a lot of comments from people in the industry that say it's a bad idea. I've also read of a lot of police departments that use the max sidewall pressure for better fuel economy and handling. From what I'm told, the tires flex less when taking corners at speed, therefore keeping more of the tread on the road and the sidewall off. We're not all Dale Earnhardt Jr, and you might care more about ride quality. There are also times you shouldn't do this, like driving on the beach.

Aside from that it's all in how I drive. I drive slowly and patiently. Coasting with the engine off when it's not necessary, timing lights, and keeping the RPMs low are the most effective things I do. I'm not sure EOC is possible with the CVT. I have read that it is a bad idea to do so with an automatic. Also, your car may not start unless it is in park.

My best tank so far has been over 40 MPG, but I have seen my tank averages creep up to 49 MPG indicated before turning the A/C on and driving on the freeway. Mileage is only 32-33 MPG at 65 MPH.

On my last commute I timed almost every light perfectly and saw (an indicated) 40.4 MPG to work and 70.0 MPG back home. (55.2 MPG average) Even though my return leg has a down hill grade of less than 1% on average, the engine is probably on 20% or less of the time. This can be a problem since the headlights are on and I need to be careful not let the battery get too low. This happened once before on a long return trip that carried me down over 1100 ft. The engine was basically off the entire way. I had to stop at a red light after a long EOC and tried to turn it on when the light changed but nothing happened. I pushed it into a 7/11 and pondered what to do until I realized I could just let it roll backwards and pop the clutch in reverse to start it.