: 2006 STS Cold air intake

08-21-10, 11:13 AM
Hi, I just bought my first 2006 STS V8. Love the car, Drives like a dream, except the gas mileage. I do mostly highway and I don't have a lead foot. I only manage to get 20 MPG. I changed the air filter too. I am wondering if anyone has put in a cold air intake and if they say any improvements. I had a 99 cobra and I got 20 mpg with that. I figured the north-star engine with VVT technology would give me a little better, especially on the highway. I mostly have it on cruise at 75mph and I live in a flat area. Anyone have any suggestions on if the cold air intake would help? Thanks for any help.

08-21-10, 12:02 PM
Volant makes a CAI that can be fitted. I don't think you'd see much improvement; the OEM system is pretty good. The 2007's get the 6-speed transmission which helps us some in that car. My AWD is another matter. :) What RPM's do you turn at 75?.

Do you burn Top Tier 91 octane gas? Ethanol can be expected to hurt mileage.

If your car runs acceptably on Regular and Premium costs $.20 more as it does around here, you need a 7.5% improvement in mileage for Premium to pay off (given a price of $2.69 a gallon). On a road trip several years ago, we got 25MPG @ 75-80MPH (2k RPM) driving from Indy to Alabama in our 2007. That tank was pure regular unleaded gas.

08-21-10, 12:55 PM
Its a heavy car with a 4.6 V8 what did you expect? Honda territory?

08-21-10, 06:39 PM
Everyone is forgeting about TIRES, what size tires are you running, STOCK Size ?
and what pressure, I get 24 on the road, NO lead foot driving.
I run 32 when on the road, all around, and you should be running 2 K on the tach,
as mentioned before, at 75-80 MPH.
If you tires are NOT the stock size, your speedometer is reading wrong, and calcs are wrong.
Good Luck !

08-21-10, 07:00 PM
A lot of owners with one CAI setup or another report getting repeating MAF codes because the intake airflow is disturbed by mods.

08-21-10, 08:59 PM
Honestly I never had a maf or any engine light with my mine and I have the volant. I will also say other than more noise I seriously would be hard pressed to prove any gains.

08-21-10, 09:07 PM
Everyone is forgeting about TIRES, what size tires are you running, STOCK Size ?

While tires will make a real difference, they don't really affect the validity of comparing the calculations of differing conditions. For example, if different fuel or driving style has an x% improvement, that's valid.

Oversize tires will make the calculated mileage worse than actual. (You're going father than the odometer records!) You can adjust based on tables showing percentage variation or keep an eye open for a 'watch your speed' setup that many communities put out.

Tire pressure adjustments raise a very interesting dynamic. You can improve mileage but life's too short to endure a harsh ride (IMHO).

06-16-12, 03:02 PM
From what I have read, GM engineers picked all the low hanging fruit way back when. What the car comes with provides all the air flow needed, I may add a Volant, for looks though.

06-16-12, 07:23 PM
Way to dig up an old thread for no reason other than to chime in hahaha

06-17-12, 08:15 PM
At 75-90 MPH I get at best 20.5 MPG. Intake manifold tight, tires at 32 front, 33 rear, 89 octane.

06-20-12, 11:00 PM
To optimize Northstar mileage, stay within 2k rpm. Good luck!