B5 S4 Questions

Discussion in 'OT Driven' started by Merli, Mar 29, 2003.

  1. Merli

    Merli gplus.to/merli OT Supporter

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    Okay... This car has really grown on me ever since I started trawlling Audi Forums and seeing pics like the one at the end of this post :)

    A few questions if you don't mind.

    1. What boost do they run standard?

    2. What boost can the standard turbos be wound upto before they step out of their efficiency curve?

    3. With Intake/Exhaust/Chip Mods, what kind of power would I be looking at?

    4. What is the usual modification path for these cars?
    e.g. Intake, then exhaust, then chip, then turbos? then ?

    4. What kind of intercooling do they have? twin coolers on each side of the front bumper? :dunno: How efficient are they? Do S4 owners usually replace them with a front mount? At what stage of mods would they need replacing (become restricitve or not efficient enough)

    Thanks guys! :)
     
  2. Merli

    Merli gplus.to/merli OT Supporter

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  3. bobo

    bobo Something Something....

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  4. GoGophers

    GoGophers New Member

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    Most chip/exhaust upgrades for the S4 will give you a little over 300 hp and 360 or so lbft of torque. If you wish to get more power (over 400 hp) you'll need to replace the turbos. Standard is to replace with K04's over the K03's. There are a few companies that have this kit. . . . APR as mentioned before. If you are to do the K04 switch the stock IC's really don't do a good enough job of cooling and you should upgrade to RS4 intercoolers. Also to make the most power from the exhaust you really should replace the downpipes and that is a lengthy and difficult task on the S4, if you are doing it yourself.

    Most people chip, exhaust, downpipes, then replace turbos, RS4 IC's.

    BTW Audi's intakes are pretty well designed and really don't require any more than an aftermarket filter. But those can be bad too if oil ends up getting on the MAF.
     
  5. Merli

    Merli gplus.to/merli OT Supporter

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    Legends...

    Thanks guys! :) Now to find a reasonably priced black S4 :yum:
     
  6. SnYpR808

    SnYpR808 Guest

    i've heard mixed reactions about the reliability of the S4. It's a great looking and performing car, but some people say the engines are unreliable. Anybody have input?
    As for the new S4...looks like a good car if you're not looking for something really fast and you don't intend to mod, but as far as i'm concerned... V6 biturbo S4 > NA V8 S4, when it comes to styling and modification potential. I heard it really took some work for Audi to shoehorn the V8 from the A8 into that S4, they even had to shorten the block of the motor by two inches or something like that.
     
  7. Laser Red

    Laser Red Guest

    the engines are fucking strong. its the stock KO3 turbos that suck ass.
     
  8. GoGophers

    GoGophers New Member

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    :werd:
     
  9. Merli

    Merli gplus.to/merli OT Supporter

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    Okay guys... Seriously, I think I have read every single post on AudiWorld and AudiZine in the relevant S4 forums ;) I prefer the 2.7L TT engine over the 4.2L V8, so I'll probably stick with the B5 S4...

    I've already carved out a mod path of:

    Stage 1:
    Turbo-back exhaust (downpipes, high flow cats, cat back), custom ECU, 1.0 Bar Boost.

    Stage 2:
    RS4 Intercoolers, K04 Turbos.

    Can I ask why people love getting off-the-shelf "chips" for these cars, and not a new ECU with custom tune? I have read a few complaints about detonation with these "chips", from various chip producers, and that's the exact reason why I don't want a custom chip.

    Also, it seems that boost is controlled by the ECU, seeing that you can buy chips that turn up the boost to various levels... Why doesn't anyone employ the use of a seperate electronic boost controller so they have more control over what boost they wish to run?
     
  10. Rev. Johnny Vegas

    Rev. Johnny Vegas Rectal Ventriloquist

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    First off, what you're calling Stage 1, is actually Stage 2+. Furthermore, your Stage 2 is a step past Stage 3, and frankly closer to a "Stage 3+". Typical Stage 3 S4s haven't had the intercoolers swapped.

    Also, why are you after a custom program on the ECU?? You're going to spend a lot of money getting that written and you're probably going to be way behind the GIAC and APR chips on power since they have so much development time.
     
  11. Rev. Johnny Vegas

    Rev. Johnny Vegas Rectal Ventriloquist

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    Also, if you go to Stage 3 and RS4 Intercoolers, expect to run into transmission problems. My former co-worker who did that had to upgrade his clutch, and is begining to have problems with the syncros.
     
  12. Merli

    Merli gplus.to/merli OT Supporter

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    Thanks for the response...

    As I mentioned, I've been reading AW and AZ for the last few days, and it seems that the stock intercoolers were at their limit with an agressive chip, so I thought I'd have to change them for SURE if I were to upgrade to K04s... Is this wrong?

    re: the custom program... Basically I've never liked the idea of a "generic chip" for all cars. Every car is different, and a custom ECU tune will extract the most out of your modifications. In Australia, it's generally accepted that "generic chips" suck ass :)

    I'd get an ECU installed for about US$600, and each tune after each modification for about $200 a pop. That way, I'm guaranteed an optimal program for my car and it's mods, without ever fearing detonation.

    Plus most of the chips you guys seem to have are tuned for 91 or 93 octane... We feed our cars a regular diet of 98 here in Australia :p
     
  13. Merli

    Merli gplus.to/merli OT Supporter

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    Interesting... Thanks for the heads up... I'll give that second set of mods a good think before embarking on it then...
     
  14. Rev. Johnny Vegas

    Rev. Johnny Vegas Rectal Ventriloquist

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    As I said, the Stage 3 kits generally do not include RS4 Intercoolers ($800 US from APR if memory serves), but I'd definitely do it if you Stage 3 the car. My co-worker did it (after much badgering from me) and is very glad he did. Basically, you're upgrading your turbos, but if your Intercoolers are overmatched (i.e. too small), you're not going to make optimal power. Furthermore, since the Stage 3 swap requires the engine be pulled, and therefore the Intercoolers as well, swapping them isn't really any extra work. If you're going to all the work of a turbo swap, I think you'd be stupid not to do the Intercoolers.

    I still think doing a custom chip is overkill, but whatever. Virtually nobody in the US has wasted their time on custom chip software for the S4s (Will had to work with APR to rewrite the Stage 3 program, and I know 1 guy that is having a custom program written, but he's going to be running a S4 racing engine that he got from Istook on the street so he'll have to). The GIAC X-Chip and APR chip are highly researched and extremely well tuned, and I've never run into anyone that has experienced severe detionation problems with those chips.

    As for the octane, just run the 100 octane program and you'll be set. The APR Stage 2 chip has programs for different octane ratings (as does their Stage 3 chip).
     
  15. GoGophers

    GoGophers New Member

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    Is that 98 octane RON? RON is what most European gasoline is labeled as which would be closer to SAE 93-94 for our measurements.
     
  16. Merli

    Merli gplus.to/merli OT Supporter

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    Thanks for all that, I'll reconsider buying an off-the-shelf chip when the time comes... I'll send APR an email and see what they say about my concerns about different fuel, and taking each individual modification into account when tuning a car...

    Also, it seems that boost is controlled by the ECU, seeing that you can buy chips that turn up the boost to various levels... Why doesn't anyone employ the use of a seperate electronic boost controller so they have more control over what boost they wish to run?
     
  17. Merli

    Merli gplus.to/merli OT Supporter

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    Well SAE is just an average of MON and RON, with MON usually being slightly lower than RON, making the SAE rating a little lower than RON...

    Basically, as you probably know MON is just like the RON test, but with the fuel heated to 300° F and the intake air is heated to 100° F. The test engine is a single cylinder 4-cycle engine that is run at 900 rpm... It's employed to simulate race conditions...

    If the fuel is good, the octane rating (which measures resistance to detonation) shouldn't differ much in MON to RON, as temperature of the fuel shouldn't affect it's ability to burn...

    So if you guys get good fuel, MON, RON and SAE ratings should all be very similar, and not MON = 88, RON = 98 and SAE = 93 like you're proclaiming...

    It would be more like MON = 94 RON = 98 and SAE = 96
     
  18. GoGophers

    GoGophers New Member

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    Good info, I'm by no means educated about the differences in gasoline. I just know that in my manual it says to use an octane rating of 91AKI (SAE)/95RON or higher, so wouldn't 98RON be like 94AKI?
     
  19. Merli

    Merli gplus.to/merli OT Supporter

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    Quite possibly, yes...

    If they have printed something like that, then they have probably done tests on your petrol to come up with those figures...

    But this doesn't answer my questions about the S4 :o
     
  20. GoGophers

    GoGophers New Member

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    lol, I know, I was just responding to the issue of which program to run on as mentioned before. You definately wouldn't want to run a 100 octane program on your fuel, if that 100 octane is our rating.
     

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