# stupid questions **URL:** \ **Category:** SON240sx Automotive\ **Created:** [February 3, 2008, 6:55pm UTC](https://forums.speedlife.net/t/stupid-questions/112911 "2008-02-03T18:55:42Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![hatchnessmonster](https://avatars.discourse-cdn.com/v4/letter/h/ce73a5/32.png) [@hatchnessmonster](https://forums.speedlife.net/u/hatchnessmonster)\ **Post date:** [February 3, 2008, 6:55pm UTC](https://forums.speedlife.net/t/stupid-questions/112911/1 "2008-02-03T18:55:42Z")
maybe a stupid question, is there a hp difference without a catback or oem, i mean one being stock exhaust and one being stock downpipe into a cat with nothing behind the cat ---
**Author:** ![sidewayz240](https://avatars.discourse-cdn.com/v4/letter/s/e99b99/32.png) [@sidewayz240](https://forums.speedlife.net/u/sidewayz240)\ **Post date:** [February 3, 2008, 7:09pm UTC](https://forums.speedlife.net/t/stupid-questions/112911/2 "2008-02-03T19:09:38Z")
Depends what application its on, in most cases it will result in a loss of power due to no/not enough back pressure. ---
**Author:** ![R33](https://avatars.discourse-cdn.com/v4/letter/r/5f8ce5/32.png) [@R33](https://forums.speedlife.net/u/R33)\ **Post date:** [February 3, 2008, 7:25pm UTC](https://forums.speedlife.net/t/stupid-questions/112911/3 "2008-02-03T19:25:18Z")
With a 3" catback ,u will loose a little low end torque … but u will Definately notice a big (+ve hp ) difference in the higher rpm i drove my car with just the stock header and was slow as fuck ---
**Author:** ![Solarian](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/solarian/32/5514_2.png) [@Solarian](https://forums.speedlife.net/u/Solarian)\ **Post date:** [February 3, 2008, 8:32pm UTC](https://forums.speedlife.net/t/stupid-questions/112911/4 "2008-02-03T20:32:19Z")
> [@Call Out: Addicted2Boost & Onyx Z32](https://forums.speedlife.net/t/call-out-addicted2boost-onyx-z32/15787/13): > > Depends what application its on, in most cases it will result in a loss of power due to no/not enough back pressure. Plz dun say stuff that dun make no snes. Kthx. ---
**Author:** ![khoolie](https://avatars.discourse-cdn.com/v4/letter/k/85e7bf/32.png) [@khoolie](https://forums.speedlife.net/u/khoolie)\ **Post date:** [February 3, 2008, 9:16pm UTC](https://forums.speedlife.net/t/stupid-questions/112911/5 "2008-02-03T21:16:49Z")
lol ---
**Author:** ![Chad\_Dugan](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/chad_dugan/32/5576_2.png) [@Chad\_Dugan](https://forums.speedlife.net/u/Chad_Dugan)\ **Post date:** [February 3, 2008, 9:28pm UTC](https://forums.speedlife.net/t/stupid-questions/112911/6 "2008-02-03T21:28:33Z")
wha was weird on my s14, when it was still ka 2 years back, i remember cutting just the muffler off and it was a torquey bitch, i did feel like it had more punch, but maybe it was just a noise illusion… but for na who gives a shit lol boost FTW! ahaha im kidding ---
**Author:** ![hatchnessmonster](https://avatars.discourse-cdn.com/v4/letter/h/ce73a5/32.png) [@hatchnessmonster](https://forums.speedlife.net/u/hatchnessmonster)\ **Post date:** [February 3, 2008, 9:42pm UTC](https://forums.speedlife.net/t/stupid-questions/112911/7 "2008-02-03T21:42:51Z")
is it true if u change ur stock catback to a 3 inch all it’ll do is add noise cuz the same airflow is comin down the downpipe to the cat, was never really clear about that, ---
**Author:** ![DegrassiJuniorHighFT](https://avatars.discourse-cdn.com/v4/letter/d/7c8e57/32.png) [@DegrassiJuniorHighFT](https://forums.speedlife.net/u/DegrassiJuniorHighFT)\ **Post date:** [February 4, 2008, 11:21am UTC](https://forums.speedlife.net/t/stupid-questions/112911/8 "2008-02-04T11:21:04Z")
_What?_ ---
**Author:** ![kimmerkaze](https://avatars.discourse-cdn.com/v4/letter/k/9d8465/32.png) [@kimmerkaze](https://forums.speedlife.net/u/kimmerkaze)\ **Post date:** [February 4, 2008, 5:28pm UTC](https://forums.speedlife.net/t/stupid-questions/112911/9 "2008-02-04T17:28:48Z")
rather than components, you should consider sizing. if you keep everything the same with the engine, the larger you go with exhaust the more volume you have, lowering the pressure within. this effectively lowers your exit velocity out of your valves, which bogs things down in the lower end. however, as you climb higher in the rpm band, your valve exit velocity will increase and you’ll notice an increase in power because the exhaust does not have as much backpressure buildup and does not restrict this high velocity, allowing your engine to basically breathe better. my piping’s stock 2" on an s13 but 2 1/4" axle back and i can confirm this effect. so recapping what i just said, if you changeover to catback or something, you’ll lose lower end but gain some at the high end. personally, i noticed that the car picked up a bit better than stock around 3500-3700 to about 4500. if you go catback i would expect this range to get pushed a bit higher. fyi.