We are getting some exhaust installed on my girlfriends 1999 3.4 V6 5 speed runner this week.
She has stock exhaust manifolds and catalytic converter.
She also has k&N cold air intake kit.
The exhaust wiil be from the back of cat to tail pipe with a 40 series FlOWMASTER. she likes'em loud.
Should i go with 2 1/4 inch pipe or 2 1/2 inch pipe?
What are the power gains or losses with the different diameter?
What do you guys have, or have tried?
What size is best. and yes we are sticking to the 40 series flow.

 

come on guys what kind of exhaust are you runnin

 

If you are going to keep the engine NA, then go with 2.25". If you plan on supercharging later, then go 2.5". The stock pipes are 2.25" INNER diameter, and something like 2.375" outer diameter. The stock tailpipe flares out slightly larger for the last 4".

I've had both Magnaflow with stock pipes and mandrel bent 2.5" pipes. I have the 3.4 V6 NA and I lost low end torque with the 2.5" pipes. With the Magnaflow and stock pipes, I didn't notice any differences in performance except for more noise.

If you are looking for sound ONLY, then I can say that the 2.5" pipes had a slightly deeper and more resonating sound (more annoying to me, but maybe perfect for you). From my experience, no aftermarket exhaust will give you any noticeable performance gains and if not done properly will most likely just hurt performance.

Also, I couldn't help but notice your eagerness to get a quick response. I have to say that this topic has been covered many many times and a quick SEARCH would have definitely gotten your question answered very quickly.

 

5" er

 

2.5" all day

 

I stuck with the 2.25" stock exhaust. I've heard many ppl actually report losing a bit of power with the 2.5". I don't think there are any gains from the 2.5".

 

just reuse the stock pipes

 

i have the stock 2.25 with the 40 series and a turn down right after it, i noticed a small increase in HP but i wake up my neighborhood when i come home from work at night and car alarms are going off.....

 

Thanks guys. i think we will go with the 2.25. we pull a trailer full of toys and i dont want to risk sacrificing low end power.
I guess i forgot about the SEARCH part of this site. i'll try to remember next time.