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-   -   Low boost - 2.5" or 3" exhaust? (i searched) (https://www.homemadeturbo.com/forced-induction-7/low-boost-2-5-3-exhaust-i-searched-1044/)

si_mekanik 01-12-2003 11:57 AM

Low boost - 2.5" or 3" exhaust? (i searched)
 
Hi, I searched with no results? And all i typed in was "exhaust"

Anyway, after monkeying around with the upteen T3 turbos, I decided I am going to buy a T3/T4 from this one guy. BTW this is the turbo, does it look ok in this pic?

http://members.aol.com/vtecingthismotha/turbo2.jpg

Will I be able to keep AC?

And back to my original Q, I plan on boosting 6-7psi with Fuel management with VAFC hack. Should I go with 2.5 or 3" exhaust?

TurboCIvic2000 01-12-2003 12:02 PM

Re:Low boost - 2.5" or 3" exhaust? (i searched)
 
It depends on when manifold and year car you have.
The bigger is better.

HMT-Admin 01-12-2003 02:42 PM

Re:Low boost - 2.5" or 3" exhaust? (i searched)
 
I use to have that same turbo, now beau has it... havent even tried it yet.

what is the a/r on the turbine side?

https://www.homemadeturbo.com/turbo/t3-t4/t34p2.jpg


https://www.homemadeturbo.com/turbo/t3-t4/t3turbo.jpg

It all depends on the manifold if it will work with AC. More than likly its going to have to be a custom manifold.

Jeff

HMT-Admin 01-12-2003 02:43 PM

Re:Low boost - 2.5" or 3" exhaust? (i searched)
 
btw, either exhaust will work 2.5 or 3.0 as long as you are not using a cat.

Jeff

PhoenixGSR 01-12-2003 02:50 PM

Re:Low boost - 2.5" or 3" exhaust? (i searched)
 
a 3" exhaust will make more power, but it will be a lot louder.. your choice

CivicSiR 01-12-2003 02:52 PM

Re:Low boost - 2.5" or 3" exhaust? (i searched)
 
Hey Jeff, why not use a CAT? Does it gets in the way? Or does it affects the way the exhaust flows?

HMT-Admin 01-12-2003 02:53 PM

Re:Low boost - 2.5" or 3" exhaust? (i searched)
 

Originally Posted by PhoenixGSR
a 3" exhaust will make more power, but it will be a lot louder.. your choice

He wont even notice a difference with 2.5 compared to 3.0 running 6psi. It hardly makes a differnce, You can make more than enough power than your engine can even support with a 2.5 exhaust system. But if you want room for improvement later down the road, just go with 3inch

Jeff

wildman 01-12-2003 03:12 PM

Re:Low boost - 2.5" or 3" exhaust? (i searched)
 
I read some conflicting info on this.. Well at least conflicted with my own belife's.
Something to understand is boost pressure isn't the end all be all. It is quite possible to have more power with less boost pressure on otherwise identical engines. A turbo which is forced to work outside its peak efficiency range is not going to provide as much power. This is why turbocharger selection is so important. It's all about compromises.
Problems

-Sluggish boost rise at low RPM's may mean the A/R is too large, while quick response which causes driveablility problems can be an A/R that is too small.

-Power tapering off at higher RPM's can be a sign of the extruder outlet being too small which is causing high back-pressure between the engine and the turbine. Or an improperly sized turbocharger that is working too hard.

What size exhaust pipe should be used? 2.5" ID pipe is plenty for street use, 2.75" ID at a maximum. Not much of a muffler is required as well, I would not recommend skipping the muffler for the street though.

this info from a page on turboing the bmw m10 can be found at http://320i.com/turbocharging.htm
:D

si_mekanik 01-12-2003 03:39 PM

Re:Low boost - 2.5" or 3" exhaust? (i searched)
 
The A/R on the exhaust is .48, and .70 on the compressor. This thing looks huge. As far as a manifold, I will be getting a DRAG or REVHARD or FMAX (which all claim to retain A/C. I just hope I don't have to cut in the block or get rid of AC for this monster.

Does this look like a good turbo? More pics are located at:

http://members.aol.com/vtecingthismotha

No cat? I planned on getting a high flow cat? You think I should get a testpipe? I don't want to be THAT loud! -

BTW: I paypal'd you $5.00 for donation AbaZ

HMT-Admin 01-12-2003 03:49 PM

Re:Low boost - 2.5" or 3" exhaust? (i searched)
 
thanks for the donation, appricate it! ;D

by "looks" you cannot tell if its a "good" turbo or not. I am sure it will work just fine, the one we have is a .70 compressor and .63 turbine, with a On center 4 bolt flange. It looks like that has a internal gate housing? with a 5 bolt exhaust flange.. hard to tell since you dont have any pics of that side.

Seriously, it will not be that loud without a cat, just use a resonator inline, and a straight through muffler, 2.5 and you will be very satisfied. If you dont like it, then you can put a cat on it.. But it will sacrifice performance.

Jeff





si_mekanik 01-12-2003 03:58 PM

Re:Low boost - 2.5" or 3" exhaust? (i searched)
 
He said there is no shaft play and whatnot. I think when I get it i'll clean it up and whatnot. Maybe even sleep with it.

I guess I'll go with 2.5" exhaust. I hear WRX's run over 10ibs. of boost and they have 2.5" exhaust. Oh well. We shall see!

Thanks

HMT-Admin 01-12-2003 04:15 PM

Re:Low boost - 2.5" or 3" exhaust? (i searched)
 
My gf made me put my turbo in the garage for sleeping with it for a week ;)

wildman 01-12-2003 04:31 PM

Re:Low boost - 2.5" or 3" exhaust? (i searched)
 
Sleeping with your turbo is the best way to insure it wont get ripped off! ;D

si_mekanik 01-12-2003 04:48 PM

Re:Low boost - 2.5" or 3" exhaust? (i searched)
 
Damn after searching on honda-tech, seems like everyone there swears on 3" exhaust!?! WHAT TO DO?!

shortyz 01-12-2003 05:16 PM

Re:Low boost - 2.5" or 3" exhaust? (i searched)
 
do the 3" then u can upgrade your turbo to as big as you want later...

HMT-Admin 01-12-2003 05:45 PM

Re:Low boost - 2.5" or 3" exhaust? (i searched)
 
Our D16z6 hatch runs straight 2.5 mandrel exhaust, with a 24in resonator, no cat and a Apexi-N1 exhaust, it sounds very clean.

Jeff

si_mekanik 01-12-2003 06:00 PM

Re:Low boost - 2.5" or 3" exhaust? (i searched)
 
Is $340 shipped a decent price for this turbo?

HMT-Admin 01-12-2003 06:03 PM

Re:Low boost - 2.5" or 3" exhaust? (i searched)
 
its not a steal, and its not a rip off..

so ya its ok.

Jeff

mr8 01-12-2003 06:20 PM

Re:Low boost - 2.5" or 3" exhaust? (i searched)
 
I can vowge (did I spell that right) for the power loss from a cat, I had a exhaust leak on the weekend, smoked a big ass rock and it bent the two flanges where the dumppipe connects to the exhaust and ended up wrecking the gasket and loosing the bolts that hold the two together. Ended up driveing around with open dumppipe and holy ---- what a performance gain, I am definitely putting in a test pipe when I get it made.

si_mekanik 01-12-2003 06:32 PM

Re:Low boost - 2.5" or 3" exhaust? (i searched)
 
Change of plans guys, an auction was just thrown up on ebay, and I had to BUY IT NOW. I'm going to take a chance and see what it's like, because i was afraid if i emailed him questions that it would have been BOUGHT BY NOW. SO i'll take pics when it arrives.....I got a killer deal on it.



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