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S3 Hesitation (& DV)

Discussion in 'A3/S3 Forum (8L Chassis)' started by AL_B, Jan 29, 2003.

  1. AL_B
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    AL_B Active Member

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    Guys,

    Okay, I wasn't going to post about this for a week or two, but I can't resist. /ubbthreads/images/graemlins/smile.gif

    Those who remember the old site, may remember a post I made about my S3 hesitating around 4000 rpm when accelerating. Its like a split second of no boost. Then things kick-in again. Very bad if you are in an overtake situation. I can remember a couple of other people having the same problem.

    So the background is:

    - July 02 (2500 miles). Hesitation first spotted. Initial thoughts were "sticking OEM DV".
    - July 02. Fitted Forge DV006. Didn't feel right on the car. Car didn't seem to pick-up as good at low revs.
    - End of July 02. Removed DV006 after one week of use, and sent it back to Forge for servicing and weaker spring to be fitted.
    - End of August 02. Fitted DV006 again. Car was still hesitating, and pick-up just didn't seem right.
    - Sept 02. Fitted DV006 in reverse position (Forge suggestion). Car was even worse. Sent valve back to forge for further testing.
    - End of Sept 02. Refitted DV006. Seemed to be okay until hesitation was felt again. So removed it and went back to OEM valve.
    - Oct 02. Bought a brand new Bosch 710N, and Forge sent me a CL007P. The CL007P felt much more suited to the car. Did a back-to-back comparison with the 710N. Just subjective testing, 3rd gear pick-up etc from 2000rpm. In gear pick-up on the dual carriageway etc. At the time, the CL007P felt very close to the 710N, and I thought slightly faster to react, smoother and the car seemed to really hold boost. So I kept it on.
    - Nov 02. By mid november, there had been one or two instances of hesitation again under accleration. But I stuck with it, because it was less frequent than before.
    - Jan 03. Been a few more instances of hesitation. So at the weekend I put on the new 710N valve.

    Now I know its only been on a few days, which is not an adequate trial period really, but the car feels transformed!!! /ubbthreads/images/graemlins/shocked.gif There's instance response when the throttle is pressed in the 2000-3000rpm range and it seems to hold boost well, giving strong acceleration right up the rev range. Not had any hesitation from the car in the 4000rpm area either.

    The only down sides from the 710N valve are:
    - slight surging/run-on on light throttle e.g. in traffic;
    - car doesn't feel as smooth in traffic, as with the CL007P, but is more responsive
    - the feeling of smoothness when changing gear, a trait of the Forge valves, has gone with the 710N valve. But the car seems to get back on boost quicker with the 710N.

    Now, let me be the first to critise myself here, because when I first fitted the CL007P, it felt pretty good too! And I said so at the time. So now I'm totally confused.

    BUT, I just thought I'd share my experiences and feelings with you about these valves. And of course I'll let you know if any hesitation occurs with the new 710N valve fitted.

    Cheers

    AL
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  2. amoffat
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    amoffat Member

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    I was waiting for this /ubbthreads/images/graemlins/wink.gif knew it would come soon /ubbthreads/images/graemlins/grin.gif
    Anyways, as you (Al) know I have had similar problems, but I am too lazy to sort it out /ubbthreads/images/graemlins/grin.gif

    Now that you seem to have resolved your issue, can you tell me how much and where from for your new Bosch DV? Time for me to install one (well... get a mate to do it for me /ubbthreads/images/graemlins/tongue.gif)
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  3. Drystone
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    Drystone Member

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    This thread has got me thinking. When I'm really going for it in the Golf, ie revving upto between 5500 and 6500 rpm, then slamming it into the next gear and getting back on the throttle as quickly as possible, there is always a second or sos hesitation before the boost kicks back in and the car takes off again. This is very unnerving especially if you're in the middle of a (badly judged) overtake. Is this just normal lag or is my DV faulty? /ubbthreads/images/graemlins/confused.gif It's been like this since I got it from new.

    It doesn't seem to happen when you're not really rushing the gear change.

    Christian
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  4. Jazzedout
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    Jazzedout New Member

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    Having also checked the 007P, I have to report similar findings. I returned to the original bosch valve, but there is also another thing to try: A bosch valve (black plastic as the Audi original) made for the Porsche 911 (993) Turbo. Porsche part number 993-110-337-50. Costs around 50 euro but can not source it yet. Used by S3s and TTs to cure the failing dump valve issue, but mainain original look even in cars with more than 300hp.
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