1DayIllBFast

I went in for a tune yesterday at 9psi and at the top of the dyno the graph started to level off and get rough. the tuner said its because i have a high flow cat, resonator, and 2 1/2" exhaust. my question is if i went with straight 3" from my dp back how much HP could i possilby gain and does it change the sound of exhaust drastically because right now i love how quite and deep my exhaust is. my set up is

Stock Jdm Gsr
Skunk2 intake manifold
Peakboost Ramhorn kit
T3/T04e 57trim
650cc
255lph
3"dp to 2 1/2" exhaust
hondata s300

288whp and 208tq at 9psi

trickeng

at 288whp you don't need a 3" exh. it will help you spool a little quicker but its overkill for that power level. it will also be WAY louder. not worth the money right now in my opinion.

narfdanarf

At that low of boost levels/power, the gains wouldn't be all that much. Probably spool better and you might make 20hp or so. With that being said, there is nothing in the world that would get me to run anything less than 3" on a personal car.

civic-r11

i do agree about 3". when it comes to turbo honda's 3" i think should be a must. but i did have 2 1/2 exhaust on my car.. and i did like it a lot, but i am more function over sound and looks.. i don't care how loud my car is or how ugly something looks, if it benefits my car.. i will use it..

honda_teggy

the 3" is actually a good help, like they said spool is better and honestly is not loud. depends what kinda tip your using. i had a straight 3" EBAY exhaust and my **** was a badass deep sound! i loved it. but i was also tuned for 20psi, so for me it helped. why are you only on 9psi? its a gsr! bump it up!

My set up:

-Bone stock B16A2
-EBAY turbo kit
-Precision 750cc injectors
-AEM fuel rail and pressure regulator
-255lph
-hondata 4-bar map sensor
-3" dp and full exhaust
-Tuned on Hondata S300 for 20psi By: Turbo Ric out of San Antonio,TX

Only bad thing is we did a street tune so i don't have any numbers to post. i loved my car! my engine never blew up, never knocked, overheated or anything!! i know you can put out more on that GSR... well, if your tuner can do it. thats the most important deal, but i'm sure you know that since you actually got a tune done...

but back to your subject... just get a 3", better flow, better sound and 20hp gain is better than 0hp gain!!

1DayIllBFast

i am normally all for extra HP especially est. 20hp which would put me over 300whp on 9psi. but i just dont want it to be to loud and sound all raspy.

da_dude

I switch from a 2.5" catback to a 3" and it sounded the same to me. Straight throw with no resornator or cat.

goefyourself

i have a fully built poor mans type r turbo and a 3" downpipe and its f n LOUD! but it deff helps with spooling

1DayIllBFast

well i have a 3" downpipe but i have a high flow cat resonator and 2 1/2" exhaust. so i think if i replace all that with 3" all the way it will change the quiet deep sound that i like to loud crap.ha but if i knew it wasnt loud on everyday driving and only loud when im getting on it then i would be fine with it.but i guess ill never know unless i do the change

playap07

go with the 3in option. i have a 60mm right now and im upgrading too the 76mm skunk2. the 3in mod will help out with that good breathing and the sound should be deep... i dont really hear my exhaust at all just my damn wastegate!

1DayIllBFast

well i wont buy a catback system ill just get some mandrel bent 3" if i do it. but right now when i get on it all i here is my turbo and intake and it sounds mean so i like that but who knows. better spool, more power ill prob end up doing it.

pauld

Just did a 3" full mandrel exhaust on my b20/vtec turbo crx. It was somewhat louder, but not very much. All I ran is a dynomax ultraflo 3in/out, no cat or resonator. Really isnt loud. If you want it quieter, just stick a resonator in the mid pipe area - should be plenty quiet. Really helped with spoolup! I had a head bolt issue, so I cant tell you much about power gains, though. A big plus in my book!

Tjabo

I just did this exact upgrade today (well, finished today anyway), and the sound difference isn't much, but the motor seems MUCH happier!

Here's a little writeup if you're interested:

http://forums.neons.org/viewtopic.php?f=47&t=348562

redline760

hey 1day are you running stock gsr cams on your setup. And why not go 3" when you already have a 3" dp my opinion.

1DayIllBFast

yes i have stock gsr cams. and i dont know why i didnt ha. but i prob will end up getting it now since lots of people are saying its not much difference in sound and spools quicker and like 20+hp.

redline760

thats pretty good numbers 1day im also thinking of getting the same kit. Is it the ftw kit or the other kit. but i was thinking of running smaller injector maybe some 440 or 550 ill be running about the same boost level as you are.

ceeza187

you could also get a QTP Electric Exhaust Cutout, it would free up ur exhaust at the flick of a switch and jus flick the switch again 2 go back into quiet mode , do a web search and give it a quick look see

1DayIllBFast

It is the FTW series kit. you can look at my garage to see pics of it. but bro dont go with the 440's they are only good to 300whp tops and you will want room to grow man.

EARLdaSQUIRREL

honestly at your power level it wouldnt make much of a difference..

do you have the dyno graph to show the "rough" portion? hell i put down 400whp on a 2.5" exhaust and my tuner put down almost 500whp on 2.5"

1DayIllBFast

yes i have the graph just not loaded so ill try to do that tonight and post it up. but i also have a high flow cat and resonator. wouldnt those two be holding me back also?

EARLdaSQUIRREL

i had a high flow cat, resonator, 2.5" exhaust and a apexi muffler and although it cost me a little bit of power id rather raise the boost to make up for it than have a loud *** car

1DayIllBFast

look at the horsepower line and compare the old one to the new one. the old graph is a lot smoother than the new one. the tuner said up top around 6500rpms is where my exhaust starts to hold me back. old graph[IMG][/IMG]
new graph[IMG][/IMG]

redline760

hey 1day hows the driveability do you daily drive it. I know its pretty hot out in hawaii does it affect the turbo performance.

1DayIllBFast

yes i daily drive it but i dont live but 5 miles from work so its not to bad. i dont feel like it affects anything

1DayIllBFast

any ideas on the dyno graphs? looks like at 6500 the exhaust holds it back some? thats what my tuner said it was doing.