[Biturbos4] Turbos Reliability & Replacement Cost (was: 2000 S4 Running Hot)

[j y]

>"I highly doubt the stock exhaust and dp's are going to flame out the K03's any faster than they will already with the additional strain of the boost from the chip." 
 
No they won't - but YOU won't get the benefit of quicker turbo spool up. Believe me, it's evident when u open up the exhaust. The stock exhaust and DPs are restrictive. If he opens up the exhaust, he will gain additional HP above and beyond the chip. 
 
Yes, the chip is the biggest bang for the buck. But, you don't want to COMPROMISE those $hitty K03 turbos either. Better intake and exhaust flow is ALWAYS a good thing for turbos. 
 
In fact, it's pretty well known that The GIAC-X puts strain on K03 turbos. The new version is supposed to be kinder, but I haven't tried it - so I can't speak from experience. I DO have version 8 of the GIAC-X (the latest release of the previous version) and it produces significant boost spikes (1.4 -1.5MBAR) which will over-spin those turbos. 
 
If you open up the back end (via a bigger exhaust and modified DPs), you'll have much less back-pressure which can help. But, like I said before, it is also possible to over-spin the turbos by having the less restrictive exhaust - it's a fine line - depends on what side u want to walk.
 
In my opinion, you can do the exhaust or chip, regardless of the order. An exhaust upgrade (by itself) will not yield huge HP gains until you add a chip. I think you are splitting hairs.
 
With regard to "piggie pipies", I don't know about your "90%" claim (do u have dyno nbrs comparing piggies to LeBree or AWE DPs)?, but try and find a shop that will do this mod - it's ILLEGAL in the USA! (Canada?), because you are asking a shop to "gut" the cats. 
 
Ok, a work around would be to send your DPs to Piggie, and if your S4 is your daily driver, you are SOL until piggie sends them back. In addition, there will be  a big GAP between the turbos and the exhaust system - and your S4 will be NOISY as hell. Good luck driving any S4 that way. 
 
That's why I bought LeBree DPs and had them installed (in one loooong (6 hr) day) by a shop. Yes I paid significantly more for them (than piggies), but then I could drive my S4 the SAME day. Plus, the LeBree DPs separate wastegate and turbo exhaust flows (supposedIy reducing the risk of turbo over-spin and enhancing spool-up). In addition, I didn't have to wait for Piggie ( to make a return shipement) and the UPS man (to make a delivery) to make my S4 whole again. 
 
Regarding CELs, very infrequently have I gotten DTCs (never tripped the CEL) from the O2 sensors on my LeBrees. When I get them, I just use VAG-COM to clear the fault code.
 
The argument about whether a 3" exhaust is superior to duals (or vice versa) has been debated over and over again on AudiWorld. In my opinion, that's a toss-up.
  

docwyte at comcast.net wrote:
Can't say that I agree with this.  The chip is definately the best upgrade and should be the first thing you do.  I highly doubt the stock exhaust and dp's are going to flame out the K03's any faster than they will already with the additional strain of the boost from the chip.
 
A true dual isn't going to outperform a single 3" system like the Borla, you'll just have a lighter wallet.
 
I'd do a chip first, then exhaust, then piggie pipes.  You get 90% of the hp/torque gains with the piggies and don't spend the $1600 that aftermarket downpipes cost.  You also don't have to worry about fitment issues or CE lights.
 
-josh
 
-------------- Original message -------------- 

> Rohan, 
> 
> Depending on your $$$....I would upgrade the exhaust (look at AWE, Milltek, 
> etc.) to a TRUE dual. The stock S4 exhaust is a bottle-neck - even for K03 
> turbos. I would then consider a chip (if u haven't done this yet). If you 
> purchase the chip first - the turbos will be spinning so hard (especially with 
> GIAC-X) that you will defintely get too much back pressure and potentially cause 
> K03 (turbo) failure. 
> stinfo/biturbos4 
		
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