Mods for 04 Impala Police Package

[pipes1243]

I'm going to get a 2004 Impala Police Interceptor this fall from the local police auction. It has a 3800 series II engine, and if I'm correct, a Grand Prix transmission for quicker acceleration. I'm planning out what to upgrade on it now, so when it comes, I can get right to business. The list of things are as follows, feel free to say what you would change. I'm looking to spend less then $3000, and I'm installing everything myself, so try to keep it simple upgrades

-SLP Performance Parts Coated Exhaust Headers w/ high flow cat (or would buying a separate down pipe w/ cat instead work better with the cat-back system?)

-Corsa Performance Cat-Back Exhaust System for 00-05 Impala

-K&N Cone air filter (I don't want cold air because of slush and winter in Wisconsin, so what would be a good intake system?)

-Reprogrammed PCM (I don't really know how to set this up because I don't want to use premium fuel because of ridiculous gas prices)

-SLP Performance Parts Thermostat 180 degree.

So in short, what is the best way to set up the exhaust, what intake should I get, and what is the best PCM set up without the premium fuel.

Thanks for the help

(If I ever get money enough money, I'd want to supercharge it too.)

[mcgrath]

You would be amazed by the gains from just smoothing out the runners of the LIM; it wouldn't cost you more then a few gaskets and 1-2 dremel attachments.

Ed

[wagoner2]

Go fenderwell intake, ditch the cat all together, use premium gas ( I know it sux but it is what it is! ), most important get a scan tool to moniter your knock!

[wagoner2]

oh yah check out intnenseracing.com for your pcm.

[pipes1243]

I really can't ditch the cat, it still has to pass emissions, so should I buy the down pipe, or use the cat that comes with the headers? When I smooth the runners, can I leave the LIM to do that? If I set up the PCM for how the car is tuned, almost nothing changes, would it even be worth it to send it in?

[Rogue]

If you supercharge the car at some point, you will absolutely need premium fuel. Until then you might consider some higher ratio rocker arms which will add some power to the car, increase horsepower to weight ratio and probably up your crusing MPG a bit . We also offer a great reprogrammed PCM based on years of dynotuning that will be sure to unlock the potential of your car

As a side note, I'm suprised the Police interceptors weren't supercharged to begin with.

[12.99someday98]

Originally Posted by Rogue

As a side note, I'm suprised the Police interceptors weren't supercharged to begin with.

^^^ I agree with him, however that might give them a leg up on catching you when you fly past them at 110+... With a faster car you think they would keep chasing you instead of giving up. I'm no genius but i'm sure i wouldn't dremel my lim while it was still on the car just in case something gets in the motor. See how easy it is to switch to E85 for that car also so you can run a lot of timing an wake the na monster up.

[pipes1243]

If I were to get higher ratio rocker arms, how difficult would it be to install them, and if I get the chip, and use regular fuel, what would happen to the car? With the new rocker arms, the WOT shift points could be moved up to 6000, with everything else internal stock?

[12.99someday98]

Originally Posted by pipes1243

If I were to get higher ratio rocker arms, how difficult would it be to install them, and if i get the chip, and use regular fuel, what would happen to the car? If I would get a supercharger I could always move up to premium right?

I'm about to install 1.95 rockers this weekend and from what i've read its not the easiest thing to do but its not hard maybe a 6 out of 10. As far as my knowledge goes a chip just increases timing, i don't know if you mean an already programmed computer? If you get either and they increase your timing then you have to use premium to be safe, don't let an extra $3 or $4 per fill up steer you away from being safe, its not THAT much of a difference to cry about. However if they (chip or computer) increase the timing in your car and you run regular i'm assuming the computer will account for what it can to keep your car from blowing up but with enough knock its inevitable. I converted my car to E85 and its 3.55 a gallon and i only lost 3-4 mpg's and its not even tuned for good gas mileage. I have 105 octane all time and run more timing on a 100 degree day then i did with premium on a 20 degree day. Instead of a blower which would cost roughly $1200 you should save up and get the $3000 non-intercooled turbo kit. Way more power and easy to install. They say 6 hours and its done, and yes definitely would require premium fuel... Sorry for the long explanation hope that helps a bit. -Mike