Installed 3in catless down pipe past weekend and my friend told me I should go with three inches the rest of the way back to the mufflers what kinda gains if any will I get and would it make it sound any better cause the 3in down with res delete is rough sounding.?!

 

in theory, if you put a 3 in down pipe in, you should already have 3 in exhaust as I'm guessing you did this on a supercharged motor. The naturally aspirated 3800 motor's only have 2.25 in exhausts.

The debate on resonator's being deleted is endless, some say you get droning sound in the car and some say you don't, some say you get more power and some say you don't, it comes down to a personal preference, if you delete it, you can always put it back on.

Exhaust for our cars doesn't really give you much power gains, it is best to just do it for sound, by putting in the downpipe you have deleted the u bend and stock downpipe which are the most restrictive parts of our factory exhaust

 

Is the stock exhaust for 00'-05' really a 2.5 in exhaust from the factory?

Just curious because the 06 SS stock exhaust size was 2.25 in and I found it strange that those ones would have a bigger stock exhaust size than the 06.

 

No, you're right. The '00-'05 have the 2.25" as well.

 

00-05 Have 2.25 unless they're stock supercharged, then they're 2.5" back to the y-pipe, everything after that is 2.25".

3" on a n/a 3800 for a downpipe or the rest of the exhaust is WAY too much.

 

3" with a Y all the way to the mufflers is too much, unless you have a turbo or two.

 

It was a typo, I edited my original post

 

I have a stock 2004 supercharged intimidator and plan to install a 3" high flow cat downpipe from ZZP. I want to do a 3" resonator delete pipe back to the Y and 2.25 to 2.5 to my already installed magnaflow mufflers. Would I see gains in HP with this exhaust? Additional planned mods at the same time - 1.9 rockers, 180 tstat, autolite 104 plugs, CAI, 3.4" pulley drop and PCM tune by will@overkill. Any suggestions or comments will be appreciated.


Rob from Canada.

 

Installing the high flow cat and downpipe will yield you slight gains as it eliminates the restrictive part of the exhaust, the resonator delete will also slightly help, but will make the car louder for certain. You won't see much gain from the exhaust to be honest, but your car will be better. The rockers, T stat, pulley drop and tune will give you the best results. Make sure when you get Will to tune your car you give him the pcm after you have the mods done and let him know what all has been done so he can tune for the mods to give you the best gain

 

Rob:
FYI if you opened up your exhaust with 3" and then it goes back down to 2.25... Your kinda defeating the purpose of opening up the beginning of the exhaust/cat res delete etc.....especially with a supercharged motor.. its kind of a waste and defeats the purpose of trying to improve the flow. when the tail end of the system becomes more restrictive with the 2.25 Y pipe/mufflers... Ultimately you want to open the whole exhaust system to 3" to see any real gains.