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Would an electronic boost controller solve my problem? Help please?

Discussion in 'A4/S4 forum(B5 Chassis)' started by B5QUAT, Dec 20, 2011.

  1. B5QUAT
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    B5QUAT Member

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    Since having my 1.8TQS remapped, on part throttle ONLY, as soon as boost goes above 5psi or so, it starts to oscillate up and down like you are kanagrooing on and off the throttle. On full WOT and below 5psi it is fine.

    It is getting rather annoying.

    I was wondering if I fit an electronic boost controller (set to the same boost level as the chip runs now) to replace the N75 (but leave it still connected electrically) would this cure the problem? I've fitted loads of EBCs to Subarus in the past but I suspect the boost control system on the Audis is different.

    I've also noticed that sometimes the boost maxes around 18psi but sometimes I've seen spikes of 21-22psi! I suspect an EBC would help make peak boost a little more consistent too?

    Any advice would be appreciated.
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  2. Jason.s
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    Jason.s Active Member

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    Probably just end up changing the N75..EBC`s are pretty pointless on a basic tune on a VAG car anyway. The only time you`d use anything like that along side the N75 would be a manual valve which you`d set at the same limit of what its mapped for to cap the spiking.

    The chip you have in there now at 20psi is pretty extreme anyway. Poor little K03 must be screaming lol.
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  3. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    The OEM ECU maps boost against throttle position. So for instance even if the engines capable of generating 18psi at 50% throttle, it wont. This gives much smoother drive/progression and you'll never match that with standalone devices.

    The chip just sounds ****. I never understand why people want to make further modifications to the car to try and fix something thats caused by crappy mapping. Fix the problem rather than trying to sticky-plaster around it!
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  4. B5QUAT
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    B5QUAT Member

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    Would you recommend having it rechipped again by someone else? Don't wanna spend another few hundred quid for it to be just the same but with a different chip. That's the problem, you can't try before you buy. I only did the chip as an interim measure anyway (impatience) until I get it properly bespoke remapped next year when I get a GT28 on. Already building up my parts bit by bit in the garage. Got the 3" MAF and the Saab Reds, gonna get a FMIC after Xmas, so should be fully GT28'd by next summer.
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  5. Jason.s
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    Jason.s Active Member

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    Go to someone that knows what they`re doing and you know will do a good reliable job in the first place is the key really. Im booked in at Rtech on thursday so i`ll report the outcome on here.

    Its worth traveling a good few miles just to go somewhere decent.
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  6. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    Why not go back to the folk that chipped it and ask them to fix it? They're the ones that messed it up?

    If they cant fix it then get it put back to stock and at least that way your not out of pocket.
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  7. B5QUAT
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    B5QUAT Member

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    Yeah let us know please how you get on with R Tech. Was thinking of using them for the GT28 remap so will be interested to see how they do with yours.
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  8. Jason.s
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    Jason.s Active Member

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    Certainly will :) The service they offer for the money is hard to beat. £250 for the map, £25 for the physical chipping. Free before and after dyno aswell as full health check and possible smoke test if they detect any leaks. Cant ask for more than than for the money you pay.
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  9. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    Seems good value, pity you havent got a hybrid on there!

    I want to go DBW on my car, but i'm thinking an Rtech map might be perfect for the missus car. Do you know if they have a 4wd dyno?
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  10. Jason.s
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    Jason.s Active Member

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    Yep they do. They have a 2000bhp 4wd dyno now! lol.

    Yeah tell me about it. Shame im not going to get much more than about 185bhp/190-200ft-lbs but that`ll still make the car completely different and make sure its not slow as sin anymore lol.

    Atleast when/if i put a k03-73 and relevant injectors/maf on it`ll be a smaller cost to adjust the mapping to suit
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  11. marktdisport
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    marktdisport Active Member

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    your from manchester right ?????? try awesome gti top place top job and always willing to help

    it sounds like a cacky job done to me......
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  12. Jason.s
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    Jason.s Active Member

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    Awesome wont chip and map. Been asked before
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  13. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator

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    When did they get one? I asked a little while ago, and he was using a tuner around the corner's rollers
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  14. Bradderz_1988
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    Bradderz_1988 Dont replace it, Upgrade it !!

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    Awesome directed me to Wayne @ chip wizard as they dont have 4wd rollers and dont chip them iirc.

    Have you checked the wastegate actuator and piping did it start right after the map or has it developed ??
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  15. Bradderz_1988
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    Bradderz_1988 Dont replace it, Upgrade it !!

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    I found these on eBay last week and going off there description I think they would be worth a shot here's there item number 290645767766.

    There based in Stockport so not to far from yourself and myself, I work in stockport so would be less hassle traveling and that so I think I may go withs these guy anyone heard of them ???
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  16. Jason.s
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    Jason.s Active Member

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    No idea i was under the impression that they didnt have one. Not that it concerns me being FWD but i was looking over the website when i decided to go with them and noticed it said on the main page that they have a 2000bhp 4x4 rolling road.

    "We can offer you the best of both worlds with a fully mobile UK nationwide service, or take advantage of our Bosch LPS and 2000bhp 4x4 dyno-com rolling roads"
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  17. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    Bradderz: That unicorn motorsport is run by a guy called Rick over on AudiSRS. Seems to know his stuff, i've been chatting with him a bit about my ME7 conversion, and i'd certainly be looking to him as an option when i come to get some serious mapping done.
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  18. B5QUAT
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    B5QUAT Member

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    Yeah it was fine until just after the map was done. I'll check the piping tho (thanks) as it may just be coincidence. I had a Subaru that had the same problem and it was down to a dodgy boost control solenoid. Maybe my N75 is goosed an the chip has just made it worse?
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  19. Bradderz_1988
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    Bradderz_1988 Dont replace it, Upgrade it !!

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    I'd also check over the DV while your at it.

    If you want to borrow my home made boost leak adapter your more than welcome, you will just need a bung for where the pancake valve is and a compressor and tyre inflator. Oh and if your on stock air box you will have to remove the maf as it goes on the end of the maf when the little trumpet is removed.

    I also have a 'modded' n75 that you could try as well.
    Last edited: Dec 21, 2011
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  20. B5QUAT
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    B5QUAT Member

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    Cheers for that. Think I'll swap the OEM chip back in first and see if it still does it, just to rule out that for starters and if I need anything I'll give you a shout.

    Can't see it being a boost leak tho as it peak boosts perfectly on full throttle, it's when you are on part throttle it doesn't like it.
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  21. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    Its worth ruling out boost leaks ofcourse.

    When i first put my saloon back together i had a weird issue where the boost would fluctuate massively between 15 and 10psi as the turbo first spooled up at full throttle, and you could feel the surges of power as boost came and went. Needle on the boost guage would jump around like it was having a fit. Once up the revs a bit, the problem went away and the boost settled down.

    I at first blamed it on the Turbo (hybrid turbo on a standard car) not playing ball with the map, however i later noticed some compressor stall type noise driving around town making me suspect the DV was faulty.

    I replaced the DV and the crazyneedle went away.
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  22. Bradderz_1988
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    Bradderz_1988 Dont replace it, Upgrade it !!

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    If your on stock DV and running 20psi I'd be looking at that as its probably screaming out to be replaced lol
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  23. B5QUAT
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    B5QUAT Member

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    Hmmm interesting ideas. It's not the standard dumpvalve BUT it was a cheap (£35) one off ebay with a range of uprated springs (I fitted the hardest one). I wonder if that might be the issue as the symptoms aragorn describes are exactly what I'm getting. Below 5psi it's perfect but from 5-15 it's up and down like a bride's nightie. Above 15 or so it's ok too. The dumpvalve worked great before the remap but I'm wondering if it can't hack the extra boost maybe?

    I might just get a proper Forge jobbie and eliminate it as a cause.
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  24. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator

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    So you have a socket fitted to your ECU? Unusual if that's what they did
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  25. B5QUAT
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    B5QUAT Member

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    Yeah. They soldered in a socket and then plugged the new chip into it.
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