I'm trying to decide on a downpipe. I'd perfer a 3" piece because i'm going to be turning up the boost eventually and will probably get a different turbo as well.

I'm looking at a racing beat 3" dowpipe but i am unsure if the presilencer comes in a 3" size as well. I need the whole downpipe resilncer piece to be 3" because i'm habing rotary performance in manassas,va weld up a mandrel bent exhaust for me from the pre-silencer/dowpipe on back to a single n1 muffler.

also anybody know of some aftermarket exhaust hangers so that sucker doesn't shake verywhere.


thanks guys

 

Get the RB Downpipe and have a machine shop weld you a 3" straightpipe. I have the RB DP, and Presilencer... the presilencer is pretty darn loud for a presilencer still.

- Kevin

 

Here's the problem. If you the RB DP & Presilencer you might be making too much boost for the stock fuel system. You may need a SAFC, etc. You're simple mod starts getting pretty expensive at that point. That's why I only went with the 2.5" Bonez DP. (installed today) I hit 7 PSI on a quick run, on a warm day. With a DP & MP on a cold day I think you'll go beyond fuel cut and will be running lean. My twin scroll actuator is sort of off/not working right now so I'm not sure which scroll was active...I think the one for higher RPM. Perhaps if you want the 3" system for later you should just do all or more of your upgrades at once.

 

i'm getting a fuel pump and will be porting the wastegate at the same time so i don't think i have to worry about overboosting.

 

don't waste your moeny on the RB DP. www.thunderfabrications.com makes a 3" DP/MP combo to cat-back . i would buy your own pre-silencer and stick it with your cat-back system. I didn't have any problems over boosting. I also have a S5 tuerbo with a Profec-B. 10 psi was a piece of cake. Much cheaper and the easy to install.

 

At what psi is fuel cut?

 

The Homemade FCD page says 8.6PSI is fuel cut, but he has a S4 so it may not be the same for the S5. http://www.teamfc3s.org/info/articles/fcd/diy_fcd.htm Since he designed the thing he probably knows what he's talking about.

RETed's page says around 1psi above max stock boost (5.5PSI S4, 7.5PSI S5), so maybe it's the same cut for both, Ted's the far and away the most knowledgable guy on the forum, so I don't know... http://fc3s-pro.com/TECH/FM2W/power.htm