cliffyk

It says '04 in the profile block...

JRad405

Mine shows up as '09 for the person Rain when you look under the avatar. I'm guessing you clicked into the profile thing? Probably should do some more due diligence in that case going forward.

MCxQubed

yes rain has an 09, but purp is saying that a cai is useless for our cars, but it is useful for s197's. So he's asking why rain recommended it

Shampue

Cliffyk is referring to GT24 (the OP) with the 04. Isnt that who this thread is about? Or did I lose track?

SteedaBrandon

Gears would be a good idea. Is this a daily-driver, street-only, street/track, or track-only vehicle? (if track, what kind? drag? autocross? etc.)

JRad405

Yes. I was answering purps question. Maybe I worded it improperly.

Then added my suggestion for the OP.

JRad405

Please read my last post. Im on my phone so I dont know how to multiquote but I was trying to point out that maybe Rain thought since '09s were 4.6 they all respond the same. Basically I was trying to get at the fact Rain is giving advice like that because his engine is a 4.6L. But he failed to recognize the differences in engines/model or however you want to say it.

Like I said I think I wasnt being too clear. I dont know if this helps you guys see where I coming from.

cliffyk

I was indeed referring to the OP, don't know why the '09 guy is giving advice in the '99 to '04 forum?

Anyway, here is my usual 2¢ worth re: "first mods":

First steps, in this order:

• Open up the exhaust, 2-1/2" from the manifolds back;
  
  Catted or not (it doesn't really matter from a power gain perspective) H- or X-pipe (an X will perform better at high rpms, however sound is the predominate difference with H-pipe = musclecar, X-pipe = NASCAR).
  
  
• Buy a tuner and load a premium fuel tune;
  
  The stock tune is very poor, with milquetoast spark advance, and going pig-rich at WOT especially with the '03 and '04 MY engines having the lavender 21 lb/h injectors;
  
  
• Then rear-end gears (use the tuner to fix the speedometer);
  
  3.73:1 and 4.10:1 are the most used choices. If you do a lot of highway driving (20+ miles a day) both will reduce fuel economy. But the good news is that a custom tune will increase fuel economy and take up most of the loss from 3.73s, and a lessen the loss from running 4.10s.

The only other bolt-on (leaving out power adders like f/i and nitrous that do actually "bolt-on") that will provide appreciable gain is to replace the upper plenum--which is the real weak link in the "pre-manifold" intake tract. Top that off with a 70 or 75 mm throttle body and you will have gone about as far with simple bolt-ons as will provide any significant power gain.

Parasitic load and rotational inertia reducing things like underdrive pulleys, aluminum drive shafts and lightened flywheels will not make palpable differences except under hard acceleration in the lower gears.

Long tube headers will make unmistakable improvement, however how a particular design affects the powerband should be studied. Those that provide the greatest peak HP gains may leave you with a car that is a bit doggy unless you always drive it like you just stole it. Keep in mind also that with most LT headers one or both will have to be removed to pull the transmission.

That said, now that I am retired and my '03 is no longer a true DD (I have put fewer than 400 miles on it since the beginning of the year) LT's are moving up my "to-do" list...