RedStarGsr

just curious, did a few searches, but nothing regarding WHY size matters. Hopefully the 14b will spool to 8grand, and should be at fool spool under three grand or so. Let me know what you guys think. later.

RedStarGsr

bumpity bump-

Snafu-Si

I've alwasy been told the bigger the better. The less back pressure for a turbo, the better, increases HP and spool time.

I've ALWAYS been told that.. I have NEVER been told to go smaller.

I've ALSO been told that it is more benificial when pushing higher boost.

WHat I mean is...Let's just say for the sake of argument that .. you have a 2.5 inch exhuast at 5 psi, and a 3 inch exhuast at 5 psi in the same turbo setup. The 2.5 inch is getting you oh say.. 200HP, and the 3 inch might get your 204HP or something... whatever.

But if you are running 15psi ina 2.5 inch exhuast, and 15psi in a 3 inch exhuast. The 2.5 inch at 15psi might be getting you 280hp, while the 3 inch will be getting your 300hp.

You get the idea???

This is what I have been TOLD anyway. Soooo.. I hope that helps you a little. I just felt bad cuase nobody responded.

Hell.. I'm only running a 2 1/4 exhaust, but I have a 2.5 test pipe.. seems to work okay for the time being, I plan on going 3 inch next summer when I have to money to do so.

turbod16y8

hey sup im running a 14b on my sohc with a 3 inch piping and i start spooling at 2k and full boost at 3k. 10 psi....

AlLMoToRvOtEr

When running boost go with the biggest exuast you can. I would just run open down pipe. BOOST VERY COOL

drjondurst

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jdmhatch138 &raquo;</TD></TR><TR><TD CLASS="quote">When running boost go with the biggest exuast you can.</TD></TR></TABLE>

thats what i've always read too

mamaboy

There was a great post from a Garrett engineer awhile back. If I remember correctly 3" exhaust was recommended solely for 250+ WHP and he recommended 2.5" for anything lower. Of course no exhaust is best for a turbo, but in the real world we need to drive longer then 10sec. I guess in the end its up to you if you want HP and give up comfort....or give up some HP for sound suppression. wheeeee!!!!!

RedStarGsr

thank you guys so much for your help

do you guys run a 2.5" downpipe or 3"? I guess I will keep my grreddy until I sell it and go 3"

also, how big is everyone's dumptube? I really appreciate everyone's help on this topic..still no one seems to be running the 14b on a dohc vtec..hmm... maybe i should put this project on hold until i can afford a t3 or something, but i'd like to stay internall wastegated. the thing w/ the 14b is that i already have it, and can have the manifold, downpipe, and dumptube all for roughly 350 plus shipping...not too bad...granted its a mild steel log style but i don't need any bling bling factors this **** is sleeper.

anyway, thanks for advice and keep it coming...

LEON

I would recommend going with the 2.5 inch exhaust. Why, because you have a rather small turbo, pushing low boost. I dont see the differenct between 2.5 and 3.0 being significant enought. I went from 2.375 to 3.0 on a GSR with t3/t4 and even though there is a diffence in power if I had to do it over again I would have gone from the 2.375 to 2.5 - 3.0 is too loud for me, but hey, it's up to you.

mamaboy

dumptube is 1.5" and you'll need the flange. If you want that **** sleeper you better run the dump tube into your downpipe......and run a few resonators.....because as the myth goes you run a turbo it gets quiet.....well with 3" not really it's still pretty loud.....it's true the turbo itself acts as a muffler, but i swear 3" ....i've heard it on a little d16 ...its too loud for my taste.....sounded like a tank rolling by

RedStarGsr

haha-- tank rolling by thats nice--

doesn't a dumptube free up the exhaust? will adding a dumptube (either into air , or back to exhaust) let the turbo spool up a little more free-er? im just trying to do everythign I can so it won't die out at high rpms (8000). Any other tips?

Should I just keep my greddy 60mm exhaust? Im running a 2.5" test pipe (w/ a jdm header now)

let me know what youguys think...

DB2

Dan if I can ever get this thing going on mine, I'll be running 2.5" and possibly a 2.75-3" DP, with a test pipe. BTW, this is Jordan. I mainly lurk over here, rarely post.

RedStarGsr

whats up jordan--

interesting-- what is your setup going to be?

DB2

Honestly, a simple Drag kit (can't live w/o A/C), looking to push 6-8 psi. I just want a little more, that's all. I'm not looking for something insane, more around 220-240 whp. Something fun and daily-driveable. A guy in my area is selling some JEs, Eagle Rods, Total Seal rings for a good price, so I'll probably scoop those up and then work on getting the actual turbo stuff together. I planned on doing this a long time ago, then got stuck on the debate of buying a second car and having the DB2 be the beater. Well, six months (and some more money) later, I'm back on the idea of boosting the GS-R. At any rate, you interested in the DSM SMIC I've got? If you want pics of it setup in our cars, check nosintegra92 (I think) on our boards. He's got a simple 5-7psi setup running the SMIC where the normal filter would be.

RedStarGsr

i already have the smic, but thanks anyway, i'd love to see pictures of how they get mounted in our cars though.

i agree 200-240 whp would be really nice, especially the 180tq that comes with it...ahh yes...torque, whats that? hahha

im just scared the 14b that i have now wont be enough to spool up to 8 grand, and still don't know if i wanna run a dumptube or not... grrr.

Full-Race Henry

just get an ecutout. I have some for sale. Check it out in my sig.

then you can run any exhaust you want and when you wanna race just flip a switch and you will be at open header.

MachAF

Bigger is not always better.

You want to have a high mass flow and a high velocity. Go too big and you get low velocity. Go too small you get low mass flow.

2.5 inche seems good to 300hp. Anyone more than 300 I'd go 3inch.

kommon_sense

bigger isn't always better.

Interesting because the neon srt-4 puts down over 225whp and has a 2-1/4" exhaust. I've also heard people say go big with turbo exhaust but the reading that I've done says that the exhaust should be 10% bigger than the turbo outlet (Maximum Boost by Corky Bell).

Another thing to consider is that in the import world, people seem to be obsessed with peak horsepower at the top of the rpm range. If a 3" exhaust will get me a few more ponies than a 2.5" at 6800rpm but the 2.5" gives me a little more down low, I'd rather have the 2.5". Less noise, and just how often do you really hit 6800rpm on the daily driver?

IMHO, a 2.5" may be the best way to go. 2.25" if you will probably be making &lt;200whp.