Hey all,

I'm running a 2005 Monte Carlo LT (non-supercharged) 3.8 V6. Mods Include U-Bend Delete Kit & K&N Air Charger Kit (CAI)

I'm looking for some advise on my next upgrade.I did the K&N first, and I love it, the car got more picking and runs alot stronger, but I felt backpressure, so I decided to look into the exhaust to equal out the air in versus air out. I did the U-Bend delete kit to improve the rate the exhaust got out of the system but still feel like I have back pressure in the system. SO! I have been doing research on the net regarding on where to go next. Obviously I want to increase to a 3 inch system to get better out flow.

My question is, I have the 3800 engine with no supercharger. I don't plan to supercharge the engine anytime soon, if at all.

So I don't really think I NEED to go all out and get Headers, because I don't think I'm cranking that much heat in the firstplace to call for it.

So what would you guys do? Go all out with the headers, or simply get the upgraded high flow downpipe w/cat, and then do a cat back system OR go all out and get the headers.

keep in mind it's NOT supercharged. Thanks!!

 

personally i wouldn't worry about the headers, but as for the rest of the exhaust i guess it matters on how much noise you wanna be making

 

I've got the K&N and added the DP and hi-flow cat with the SLP catback. I love it! Big improvement. Kinda loud inside the car but I've gotten used to it.

 

I'm looking for a quiet inside. The engine sounds great now with the K&N, and the U-Bend delete, I'm not looking to go overly loud, just want a low rumble, and some extra horsey's. I wrote the W Body Store and they tell me that the S&S Headers are the way to go. Mainly I'm looking to add a new downpipe and cat back system, but don't know if going with headers first will be the way to go....I hear Headers can always wait, but I don't want to invest the money in the cat back system and downpipe if I"m going to see no gain.

 

gotta get flowmasters super 40s for loud as hell, or 40 delta for the less interior resonance

 

ok you say you want it somewhat quiet. and you are not going supercharger or turbo....SO:

3" exhaust is too big. if you go 3" you will loose torque!

my recomendation is this.

-Headers these will increase tq. if they werent so expensive for my Z34 i would have them ($970 only one place to get them too)
-Downpipe 2.5" with highflow cat.
-Single Muffler. if you want performance do not get flowmaster. for performance your choices are Magnaflow, dynamax, Borla.. all of these have straight thru flow design.
-option of second muffler or glasspack.
- too keep the interior sound down. you will need to run the pipe to the rear of the car. with single or dual exit.

entire system is recomended to be 2.5" this system is perfict for Non boosted applications up to 300 HP after that you may see gains by going to 2.75 or 3". but most people are fine with 2.5" also 3" will be much louder!

hope this helps

 

i hate the prejudice towards flowmasters. Yes on principle they produce less outlet due to baffled chambers vs straight resonators, but the amount is negligible in these applications. Just like ram air for car, the only way ram air hoods work is at super sonic speed. Learned that **** in class(student for biomedical engineering), didnt believe it so I researched it. Wikipedia tears the ram air franchise apart. ****ers.

 

http://en.wikipedia.org/wiki/Ram-air_intake

found the link!

Ram-air systems are used on high performance vehicles, most often on motorcycles and race cars. Ram-air has been a feature on some cars since the late sixties, but fell out of favor in the seventies, and has only recently made a comeback. Modern parachutes use a ram-air system to pressurise a series of cells to provide the aerofoil shape.

However, Fluid Dynamics can support claims that only 3 % higher volume of intake air is accomplished at speeds attainable by high performance and race cars (and an intake on the side reduce the volume by 3 %). Forcing a large volume of air into a cone by motion alone is only possible at supersonic speeds (below that it reduces the volume)

so yeah, just because ram air sounds badass by principle, doesnt mean it really produces outstanding differences, just like the difference between flowmaster and magnaflow. Flowmaster is still a preformance brand, and many people swear by it. I see a lot of anti-flowmaster on this site and they base it on word of mouth and possible 1 or 2 hp cuts on a dyno. Id rather 248 hp than 250 if my car is gonna sound like *** on the 250. So if ya believe me--than sound is the only question, and its gotta be flowmasters.

 

Ok I have read before that -300HP don't go over 3inch, so perhaps 2.75 might be the right way to go. Still I don't know whether I will see the most gain by swapping to headers, or with a 2.75 down pipe and cat back system. The situation here is cash. I can only do one of these mods at a time so I'm trying to figure out which will be best to remove some of the back pressure in the meantime. I think the DP and the Cat-back will have a great effect only because they hold more exhaust than just the stock manifolds.

 

no he wants quiet, any 40 series flowmaster whether its delta flow or regular is insanely load, you dont want that at all

personally i didn't want a lot of noise coming out out mine, and i did the u-bend delete, high flow catalytic converter(3" universal) and removed the resonator and left the mufflers on, i'm very happy with the performance, and very happy with the sound, its just a little noisier than stock, i think you'd be happy with that