PDA

View Full Version : Boosting on stock Cat Back



Endoe
08-10-2006, 03:21 PM
As i discuss the invidia O2 housing in another topic....

I just installed Invidia O2 Housing and DC Downpipe on my 05 evo...there is a leak between the dp cat delete and the exhaust pipe with the second o2 sensor but will it cause my car to not hold boost...it felt much stronger when i had the stock exhaust dp and O2 housing....im also running the stock cat back--- here are my mods:

-HKS BOV ver.2
-Greddy Vspec FMIC kit
-Invidia O2 housing
-DC DP

-im running on vaccum boost at 15psi and it will hit 15psi but at 5K RPM you feel the boost starts to fall out and it only does that on the longer gears when it has to try to hold boost to redline..... Help anyone...

EVO GRIM
08-11-2006, 06:27 AM
Exhaust leak is bad.
Step 1 fix that.
Step 2 get rid of the Bov
Step 3 get tuned

wzcx
08-11-2006, 07:17 AM
Why would an exhaust leak make you lose boost? It seems that you'd be getting a "freer-flowing" exhaust for, um, free. But yeah, your other crap seems to be problematic, judging by your other posts.



Step 2 get rid of the Bov
Step 3 get tuned


+1
I don't know much except that a tune is worth more power than any thousand-plus dollars in parts.

Matz
08-11-2006, 07:36 AM
Why would an exhaust leak make you lose boost? It seems that you'd be getting a "freer-flowing" exhaust for, um, free. But yeah, your other crap seems to be problematic, judging by your other posts.


Marshall didn't say that you lose boost with an exhaust leak. He just said it was bad. :)

In general, exhaust leaks are bad because you can damage your parts. Have you ever had an exhaust leak in your manifold? Eventually, material gets "burned away" in the region of the leak, and eventually the only way to fix it is to replace the manifold / part completely, or get it removed and refaced at a machine shop. That's been my experience, at least.

Endoe
08-11-2006, 09:53 AM
seriously HKS BOV..not too great on holding boost.... but need a exhaust first..magnaflow anyone? any suggestions...

wzcx
08-11-2006, 10:42 AM
Marshall didn't say that you lose boost with an exhaust leak. He just said it was bad. :)
No, but Endoe did. I'm with ya, but I was phrasing it as a question. Endoe, if you're losing boost, I'd look on the intake side of the engine, not exhaust.