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Discussion Starter · #1 ·
I have a godspeed uppipe and downpipe that I'm about to put in but I'm worried about how much louder it's going to get now.

Also, I'm running low on cash (like to pay for installation) so I was wondering if I should just remove the Skunk2 catback and sell it since it would help me to save some cash and also keep the noise down. BUT if the performance loss is going to be too great I probably will just keep them both and deal with it all.

What I would like to know is if anyone knows the difference in performance between modifying just DOWNPIPE ONLY and modifying DOWNPIPE AND CATBACK.

I have a feeling these 2 pieces will work GREAT together since the downpipe only brings the outlet down to 3 inches, and the catback keeps the 3 inches going back the whole way. Right now the 3" catback isn't really doing much since the flow is being restricted before it even reaches the catback section. The downpipe should really bring this car alive in a big way. That's why I would really like to know.... how important is it going to be to keep the catback on? How much of a hit if I took it off once the downpipe is in?

Also how's the reputation for the Skunk2 3" catback right now. Have you guys heard much about it? I'm asking so I can get an idea of how interested WRX owners might be in the catback.
 

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The catback on a decatted car wont help out too much, just make the car very loud. Since you are getting rid of all cats with the godspeed uppipe and downpipe, the catback will give you small gains of around 5 hp. I might consider putting back on the stock can and run a copycat "stealth-back". Hope this helps.
 

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Discussion Starter · #3 ·
thanks for the quick reply, 5hp is no big deal if that's true

the way i was figuring is that the de-catting and size increase at the downpipe will make the catback more valuable since air will be flowing harder and faster at the catback, and the bigger piping will handle it better..., though i just assumed that in my head, i never really heard or saw anything that would back that up


also i'm thinking now that once the downpipe is in i can probably cheaply have the catback on and off to try it out both ways since the catback isn't as hard to put on as the uppipe or downpipe

btw: the catback is 2 pieces, maybe seperating the pieces is an option? here's the pics of what i have right now installed:

http://www.owningyou.com/mywrx/9.jpg
http://www.owningyou.com/mywrx/b.jpg

those 2 should show enough but here's more angles
http://www.owningyou.com/mywrx/8.jpg
http://www.owningyou.com/mywrx/a.jpg
http://www.owningyou.com/mywrx/c.jpg
 

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The main reason that I know the hp figures will only increase around the 5 hp range is because I asked TurboXS and they said that running a high flow axleback with there decatted exhaust gains about 5hp. But with your cat back it gets rid of the resonator box which doesnt restrict the flow much at all. But if you could, I would use the first pipe that came with your cat-back, the one that is closest to the cats and then hook the stock axleback back up to it if it will fit, then you can have 3 inch all the way to the stock axleback, but if you cant I doubt it will make a huge difference, from what I hear the cats in this car are what rob the power. PS since your catback is in 2 sections, and if the stock axleback wont bolt to the half of your aftermarket catback, you will need another midpipe, your stock one w/ the resonator box if you still have it.
 

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I am also thinking about going with the godspeed downpipe, it seems like a good product with nice fit/finish, plus it gets rid of two cats, and its a bellmouth. When you get it installed tell me how you like it. Good Luck!
 

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Discussion Starter · #6 · (Edited)
I still have the stock stuff, but I'm still not sure what i'm gonna end up doing, though dropping the catback is starting to better than it did before.

im expecting nothing but good things from the downpipe and uppipe so i'll let you know how it goes. I'm getting them installed at subyspecialties so it should be trouble-free (mostly i worried about the uppipe), and if any trouble arrises i'm sure it'd be temporary.

having a loud catback is a love/hate thing really. if i do take it off i'll sure feel better when driving the car easily since it's not always rumbling everywhere i go... but i'll also surely miss it being loud when i want to rev my engine at someone or scare away children playing in the street :)

all is schedualed for this friday morning (30hrs from now or so)
 

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Discussion Starter · #8 · (Edited)
ok, i guess im pretty much stock other than EBC and catback, and the catback is the topic so it's just the EBC running at 14.2 (street) or 16.3 (track) psi usually

so is it considered close to stock still?
im probably dropping the catback anyways, im too broke to keep it

also not sure how accurate these are but it says here this exhaust should give over 10hp w/out any downpipe, but that could just be magazine hype
http://www.clubwrx.net/forums/showthread.php?s=&threadid=12781&highlight=skunk2
 

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I was thinking about getting the godspeed upipe and downpipe too! How much hp gains do you think you will get ?? Let me know how you like it when you get them on and how it sounds!!:D
 

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Discussion Starter · #10 ·
8 hours till they are in! my sig should read ebc/uppipe/downpipe/catback and the track run will hopefully be very low 8s in the 1/8th and very low 13s in the 1/4 now that i feel like i learned to drive it right

i decided to keep the skunk2 on the car until i can find a buyer (ugh back and forth with decisions), that way i can also let them hear how it sounds, and i can play with my nearly catless system (only the high-flow cat the skunk2 has will be remaining)

if only there was a silencer that i could attach to it that didn't rob it of so much horsepower as the one that comes with the skunk2 does. But right now i'll just deal with the sound and probably only put the silencer on to see how it runs silencered (i mean silenced (i mean silent)) along with the mods in place.
 

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can you please tell me the gains of uppipe, and the gains of downpipe? not together. I don't want my car to be too loud, and stink, by installing both of them.
 

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The catback systems typically add 4-5 hp- this is w/ the stock downpipe and uppipe- However, that same catback is probably worth close to double that when the uppipe and downpipe are opened up. Big difference!

nyxjf- uppipe and downpipe won't add much for sound- neither stink- don't know where you heard that. Uppipe typically gains 7-10 hp, but will also lower egts-good, get rid of the chance of a cat failing and disentagrating into your turb-good, get a ~ 300 rpm lower spool- a must do mod. Downpipe typically gains 12-15hp (and torque!). I can't think of any reason in doing only one of these. They both add good gains w/ no down side, plus doing them together saves time. Probably the two best power mods one could do.

Big Sky
 

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Discussion Starter · #13 ·
All has been installed. Gains are what I expected. Pulls harder everywhere. I left the 3 inch catback on and am now completely catless, though there is one resonator and one muffler to keep the sound reasonable.

all in all, the power im sure will bring my 1/4mile down by MORE THAN half a second for sure, im hoping low 13's now

sound is about the same when it's at idle, but when you step on it you can really hear it get THROATY AS HELL. I LIKE IT!

it's a sound that I can control, if Idont want it to be loud, I drive easy in a high gear, and it'll just sound almost like it did when I only had the catback. But now any time i step on the gas more than 1/4 of the way down it's either a little louder if just pressed down somewhat, or a lot louder if floored down.

I didnt think I'd like it but I might be able to work with it since it's controllable. Maybe later ill change my mind but this is just my initial review after having driven around all day
 

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If you dont mind ansewering . How much did you pay for your upipe and downpipe? Thanks
 

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I'm not very car savvy, but replacing both pipes removes all cats? I know cats are restrictive, but are there any drawbacks from removing them all? Besides emissions and possibly making your bumper by the exhaust black.
 

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Replacing the downpipe and uppipe remove two cats, and happen to be the most restrictive cats. #3 cat is in the front midpipe, the piece directly behind the downpipe. Where some confusion comes in, is that many aftermarket manufactures sell a "downpipe" that actually replaces both the downpipe and front pipe- and those units (w/o any hiflow cats added) would effectively remove cat #s 2,3.

If you don't have to worry about emission testing (or race sanctioning bodies ie SCCA) then there are really no sides to removing all the cats.

Big Sky
 
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