GTP Competition Group

Just bought my first Grand Prix (going from driving a Cadillac for four years, the GP was a change!).

I've heard about changing the pulley (even heard it gives your car better mileage?), and am considering tinting out the windows a bit -- but I confess I know very little about cars and really can't keep up with the tech talk (anyone care to speak laymen for me =)

Also, put my 2 12's in the day I got my car; anyone notice a slight buzz coming from the passenger side (only during certain frequencies of the bass hits)?

Thanks for putting up with my ramblings!

-Roxie

Heya!
Welcome to the world of the grandprix! Sorry can't help with audio questions, but I'm sure someone will chime in soon.

Thanks a ton! I hope people here don't get too annoyed with my limited knowledge of...well...my car! =)

Congrats on your new car. The rattling you hear is probably something in the car vibrating at the same frequency as the bass coming from your subs.

The pulley won't give you better mileage, but it will definitely increase HP and torque by a very noticeable amount.

Welcome! I concur with my fellow GP enthusiasts. As Brian stated, the pulley won't give you better gas mileage. However, most people will see increased mileage with a better intake and exhaust system... which are mods people usually do at approximately the same time as a pulley swap.

As far as a buzz after putting in subs... crank up the tunes and start crawling around inside the car to find out whats buzzing. After that, try and figure out a way to make the offending part more stable. When I had a system in my Camaro, I use to use Fiber Fill (teddy bear stuffing... can be bought at WalMart) to fill in gaps of plastic panels and such. Just make sure you're not stuffing it in areas where mechanical parts have to move (i.e., window motors).

Marc

Thanks for the suggestions (and the friendly welcomes!)

Yup, slap the pulley on and open up the intake and you should be good for high 13's in the 1/4 mile all day.

What do you mean by open up the intake? CAI?

Either a CAI or get a 9" K&N cone and run it into the fenderwell.

Open up the intake means replacing some or all of the parts upstream of the TB (throttle body ). The filter box, filter and connecting hose are major flow restrictions and will increase pumping losses and thus reduce the potential top end power.

A CAI ( cold air intake ) normally uses a large conical filter from K&N, etc. which has much more filtering area than the stock filter element and reduces flow restriction. To be a real CAI it needs to bring air in from outside the engine compartment, which few actually do. Those that do either mount the filter in the fenderwell, or have a ( restrictive ) box around the filter which is vented to the outside of the engine compartment. However, actual underhood measurements indicate that after the car moves 50-60 feet from a stop the air sucked into the engine is only a few degress warmer than the outside air, so the advantages of the true CAI may be limited.

Hi Fluid,

Thanks from another layman for the CAI explanation there.

In response to your testing with paper vs. K&N, I've done some fuel economy testing. I noticed that with my K&N filter in, I saw an increase in mpg and a touch in horsepower (butt-dyno testing).

However, I also should mention that my car could have been passing the "break-in" period at this point.

But then, there are those who mention that there may not be a break-in period on new cars.

So, we're back to the first point with me saying that I get better fuel economy with a K&N filter over the stock paper one.

How many others have done actual testing to see about fuel economy with different filters?

Also, another tip for Roxie with regards to fuel economy -- it also depends how heavy your FOOT is!!


~Krishna