Derek14

Hey guys that know thier piping sizes and thier benefits/downfalls.... I dont know whether to go with 3 inch or 2.5 inch piping for my catback. I was leaning toward the Thermal R&D 3" Turbo catback, but the price of $600 is staggaring and it would be loud for that it lacks a resonator. Here is my setup- 98 ek hatch w/ built 01' type r motor/tranny(81.5 mm bore, GE sleeved, JE 9.1, eagle rods, stock head internals, spoon cam gears), SFP manifold, DP, turbonetics t3/t4ob, NO cat. conv(using flexpipe/resonator combo), hondata s200b, RC550's...... I want to hit 350 whp and be in the mid-low 12's, but not blow my eardrums out when driving. Is it possible with 2.5 inch piping? or is the three inch definite? Which catback would suit me well? I know sometimes it s a personal preference, but im about the numbers, now preference . Search kinda helped but not enough. Ive seen a few custom made catbacks on here and they have great sleeper looks and thier owners say they are great sounding... and input?

grndcont

you spent alot of money everywhere else, whats another 600. and btw, the thermal unit is very, very nice, and well worth it. just go with 3", youll be glad later.

M.A.R.C.

you can always do a custom exhaust w/ a cheaper muffler. 3" mandrel bent piping with magnaflow muffler I paid $340 for mine installed at a local shop

b20turbojason

this is mine 2.5 inch pipe this is all i have ever had but i am using a full titanium muffler and it sounds perfect not loud not raspy. i am running a b20 and t3t4 turbo. the piping is straight down the middle till it bends at the subframe. right i have no clearence problems. i have coilovers at almost the tightest setting. i am going 3 inch mendrel bent piping.

Derek14

Would i be able to hit 350whp, and mid-;pw 12's with 2.5 inch piping? This unit will be tuned to hell, so keep that in mind...

J.R.

hit up kteller on pm he sells great exhausts.

dfoxengr

3" definately, short rule. with turbo, less exhaust is better= less restriction

Prod

My friend just dyno'd his gsr with the same turbo and a somewhat similar setup and had a hell of a time getting close to 300whp thanks to his 2.5 inch downpipe...I would go 3 inch all the way if you want 350whp from your setup

Derek14

****... so the 2.5 inch SFP Down pipe is gunna get me on the HP numbers? anyone else have input on the numbers? I'm going for about 1 bar of boost..... and its not ALL about the HP, I would like to have a decent torque curve as welll, the backpressure should help a bit there... cmon, spill the ideas

swlabhot

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Derek14 &raquo;</TD></TR><TR><TD CLASS="quote">****... so the 2.5 inch SFP Down pipe is gunna get me on the HP numbers? anyone else have input on the numbers? I'm going for about 1 bar of boost..... and its not ALL about the HP, I would like to have a decent torque curve as welll, the backpressure should help a bit there... cmon, spill the ideas </TD></TR></TABLE>

Sure you can hit that hp on 2.5" but this will def be your bottle neck at that power level. You will most def not going to be able to resist not turning that boost up for more powar at some point in the future and you WILL def need 3" then, so why pay for the exhaust twice? Do it right once, the 1st time will same you time and $$$, not to mention the benefits of 3" for your current setup already..

Derek14

My final goal is MOST likely going to be 350 whp and low 12's... I'm only 18 years old and have a life to live, and investments to make (real estate, markets. etc.) so I figure a CTR that can smoke 95% of the cars on the road will do me well enough ..... Can I make 350 whp with 2.5 inch piping from Turbo/catback using this setup? Hondata, wideband, etc, the good stuff..... no cheap **** is going on here... and i dont want to skimp on the exhaust, BUT, its a daily driver, and its gotta be somewhat quiet to avoid the police and authorities... Loud is bad to me lol ( I had JRSC 00' Si with straight pipe into 5Zigen muffler and it was WAY too loud for me)...Its all going on in a couple months (New England's spring) all is left to buy is Hondata, injectors and exhaust ....... Fill me in

Derek14

Here is the question that will answer my piping size need... Say I run a 3 inch DP into 3 inch exhaust... Will this produce less or more HP/torque numbers at low rpm's than a 2.5" DP and 2.5" catback? does that depend if im in boost or not?

Less restiction is good for turbo- faster spooling, more power...

On an NA, exhaust restriction can help bump torque numbers at low rpm's (and restrict them at high rpm's), but how about on a turboed motor when it is NOT in boost? Is it the same principal? More restirction when NOT boosted equates to better HP/torque? Or is that irrelevant due to the presence of a spinning turbo?

So to say, am I better off with 2.5 " when not in boost, and 3" when in boost? I feel like a newb transforming from NA to a boosthead, although Ive gone back and fourth

Keep in mind, its a daily driver, so i wont be in boost all the time, so I want to find a HAPPY MEDIUM, thats the best way i can put it.... and the best streetable torque curve...

If 3 inch will produce <U>same</U> low end and better top end, i will go with that... But, if 2.5 produces <U>better</U> low end and 350 whp, i would be satisfied...

Decisions, decisions.... Must... need... help

the-anti-crack

why dont you just run a smaller exhaust, and an e-cut out?

quiet when you want it to be, and open dp at the flip of a switch.

BROOD

Retaining backpressure after the turbocharger is not much of an issue on FI engines compared to retaining backpressure on NA engines. The larger the exhaust the more power you are possible...as well as being louder.
The 3" will be louder especially w/o the cat. It more or less depends on how much daily driving you do and how strict the law is on exhaust dB laws in your area....and of course what you are after higher HP or more live-able street driving.
I'm not a big fan of Thermal quality (poor past experience) so I would suggest to check out Kteller's mandrel bent kits. Great value
I have the 3" Kteller kit with a Spiral core resonator, Magnaflow rear muffler, and test pipe for now. With that and the 2.5" - 3" step up downpipe, the note is low tones but can be pretty loud at full throttle for most tastes. I like it alot but this is also not my daily driver.
Good luck on your choice


Modified by BROOD at 6:17 AM 1/7/2004

Chillinit

I was just gonna suggest the same thing but BROOD beat me to it....backpressure on a Force Induction ride is not benefical!! I don't think it will provide you with more torque!...go 3" man...u can't go wrong if you want that type of power...unless u have a 2 1/2" exhuast already and don't have that much cash to blow...in that case I would stick with the 2 1/2"...and turn up the BOOST!

Speed PHreak

Just go with 3", I had 2.5" on mine and then swapped to 3". The power difference between 2 is definately noticable ALL the time. It'll spool faster and make more power, downside it can be louder. I've got 3" mandrel bends and a 3" glass pack bought from JCwhitney.com and it's not loud during normal driving, but can get rather evil sounding when you're on the throttle hard.

This is not the N/A world where exhaust sizing is critical to squeek out to most Hp/Tq. The turbo itself puts an acceptable amount of backpressure on the engine to keep it happy, and restriction after the turbo is just that...restriction.

PM-Performance

i was making more thna that on 2.5 inch Apexi N1, i just recently sold it for 3inch from Kteller becuase the deal was sooo good and my numbers want to be doubled. i payed like $185 or so for the piping , thne another $200 on the 3inch N1, cant beat it man .

RedTegLS

I have had a tanabe racing medallion since boost day 1 and have wanted to upgrade to a thermal since that same day. Actually I just ordered one this morning. You can tell that the 2.26" piping is really holding back the boost. I can hear it spool at 3000rpms but it doesnt reach full boost till almost 5000! Larger exhaust piping will help in that department.

As far as Thermal having poor quality that is the first I have heard of it. Everyone usually raves about how nice they are. Well, I will let you know in a few days

Jstue

get the 3 inch'er!!, for turbo, bigger is always better

BROOD

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RedTegLS &raquo;</TD></TR><TR><TD CLASS="quote">As far as Thermal having poor quality that is the first I have heard of it. Everyone usually raves about how nice they are. Well, I will let you know in a few days </TD></TR></TABLE>

Yea, I know, I must be the only event of it. I had problems with a cracked midpipe due to a poor weld joint design..they replaced it no problems.......but my problem was burning out the "unburnable" packing....I sent it to them for testing and it was replaced...
It was not so much the product that was the problem it was how I was treated by customer service that killed it for me.

4U2NV

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Derek14 &raquo;</TD></TR><TR><TD CLASS="quote">Would i be able to hit 350whp, and mid-;pw 12's with 2.5 inch piping? This unit will be tuned to hell, so keep that in mind...</TD></TR></TABLE>

With my old set-up at 10.5-11psi I was able to put down 280 whp with 2.5" dp and Greddy PE2 exhaust which 70mm (2.75")...

So to hit 350, I would say you would almost have to go 3" dp and exhaust... Also the Thermal turbo exhaust really isn't that loud... It has a nice deep tone to it, and doesn't sound to raspy... Sounds much better and quieter than a Apexi N1 on a N/A car IMO... However, the weak spot on those Thermal's is the muffler... They tend to **** out fairly quickly, but all you have to do is weld on another...

30psi Teg

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RedTegLS &raquo;</TD></TR><TR><TD CLASS="quote">I have had a tanabe racing medallion since boost day 1 and have wanted to upgrade to a thermal since that same day. Actually I just ordered one this morning. You can tell that the 2.26" piping is really holding back the boost. I can hear it spool at 3000rpms but it doesnt reach full boost till almost 5000!
</TD></TR></TABLE>

Yeah I deffinitly know the story on those Tanabe's. My Racing medallion on my 2nd gen TEG wouldnt even let me spool up to full 15psi of boost the best I could get was shitty 12psi that took for ever to get. ran open DP and probably doubled the horsepower it seemed like.

Derek14

thanks for all the replies guys ... The police know me and my crew in town and nearby towns, so we try to keep the noise down.... What cop doesnt hate Honda's? I just dont want to give them a reason to pull me over...

Itr206... I cant wait to put the IC and piping in.. needs a small fab to make it fit into an Ek, But it will go in there..... What were your piping sizes of your old setup after turbo (DP, cat or no cat, flexpipe, catback system or custom). Im interested cause you said you hit over 350whp with that size pipe..... let me know

Anyone have any pics of a Kteller's exhaust?

And any pics of some E-cut out setups?

Derek14

up for pics

RedTegLS

http://www.accordinglydone.com...73_44