downpipe question

[bradcurtis15]

Okay so I'm getting ready to install my wide-band but before doing so I am stuck debating on using my 2.5inch downpipe or going ahead and upgrading to a 3inch... after my down pipe my exhaust goes to 3inch to the muffler... I am going to upgrade from my 14b turbo to a 16g, and 450cc injectors to 560s... I'm running 15psi right now with a 3inch intake and Im going to get a 3inch gm maf... should i be fine with my 2.5inch downpipe and just upgrade later if I continue do get more mods?

 

[Ppayer38]

Well some will say 3" and some will say 2.5"

I am running a 2.5" DP in belief that since the exhaust gases are hot they are moving fast enough to escape out a 2.5" DP without a problem... To big to early can be a bad thing from something ive read and people ive talked to say and you want to get the exhaust out as fast as you can so it is not left in the cylinder!

I know a pretty fast(9sec) civic hatch that only runs a 2.5" DP so I think it will do for your setup

I say since you have a 2.5" ready to go you should run it and save the money for something else... dont think you will make enough power out of a 16g to really see a difference between a 2.5" DP and a 3" but that may just be me!

 

[bradcurtis15]

Cool, maybe I'll just stick with this until I get more supporting mods...

 

[DSMunknown]

The 2.5 inch DP will be completely fine for your future setup. FYI, some trusted vendors who make their own downpipes (i.e. RRE) make their downpipes so that before the flex section the piping is 2.5 inches and after the flex section it's 3 inches. Unless you have a "large" turbo there is absolutely no need to have a full three inch downpipe.

As you so eloquently put it, there are better ways to spend the $ right now.

 

[miguelmcv]

I'm agree with (Ppayer38) as well, which going with a 3'' Down pipe you will end up having Boost Creep with your 16g. Unless you do some porting or going external wastegate.

 

[bradcurtis15]

Cool thanks guys i appreciate it, I plan on going with a Evo o2 housing so I don't think porting is going to be needed

 

[CheaCheaBoy]

I have a megan DP thats 2.5" into the 3" apexi full exhaust. the flex section of the DP had to be replaced because it was too big and started leaking, but now its replaced and running fine with a smaller flex. I recommend a good gasket. GL in game 7, BRUINS FTW.

 

[miguelmcv]

Keep on mind that if you are going with an evo3 O2 Housing.
You need to modify your Down pipe.
evo3 Housing has a light angle which will give a stress to the down pipe.
You need to install a coupler for the down pipe to accept the evo O2 housing. Or weld an evo3 Flange. to accept the 02 housing.

 

[DSMunknown]

^ Not if you go with an RRE "EVO style" downpipe. They accommodate for the angle difference.

If you have the upgraded EVO O2 sensor housing, order the EVO style DP. It comes with the larger EVO bolt pattern and is angled correctly for those cars running the EVO O2 housing

 

[bradcurtis15]

Keep on mind that if you are going with an evo3 O2 Housing.
You need to modify your Down pipe.
evo3 Housing has a light angle which will give a stress to the down pipe.
You need to install a coupler for the down pipe to accept the evo O2 housing. Or weld an evo3 Flange. to accept the 02 housing.

well this guy im geting this turbo said he will give me his evo downpipe and evo o2 housing so im assuming i can just slap them together and connect them to my exhuast and if not my uncle has a shop and ill do some cut,bending and welding if needed

 

[miguelmcv]

Ho.
Glad to hear that.
Then your will be good to go.

 

[boostNmetal]

As stated above, don't forget about boost creep. With my B16G with unported internal wastegate, I creep to 20psi in the upper RPM range regardless as to what my boost controller is set to. I run 21psi so it isn't an issue, but its something to keep in mind.