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Would A Knackered Turbo Make Different Boost


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On the March SIDC track day by boost dropped from peak of 1.45 to around 1.1bar. Subsequently pranged the car so as part of the repair I upgraded the Autobahn 88 FMIC to one of Harvey Smiths new Hybrid GT Spec numbers. Once all back together it felt like it was boosting properly but I never really got the foot right down with geometry etc still to be done.

Went for a mapping session with Andy a couple of weeks ago and got an AVC-R fitted. Tried for a peak of 1.5 bar but it would only peak at 1.38.

Question is - if the turbo gave up in March and boost dropped to 1.1 bar on the Autobahn FMIC, could it possibly rise to 1.38 on the mnore free flowing Hybrid?

Cheers

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I personally don't think the turbo is goosed but other thing needs to be looked at.

Also i'm surprised that AndyF couldn't see what the problem is.

Andy suggested the turbo should be checked for damage, he couldn't think of anything else during the mapping session as everything else appeared to be in order.

Another thought just crossed my mind, I was running 10% meth on track without being mapped for it (which I'd been told was OK) - could this have made it run on thre lean side causing excess heat and possible damage on the exhaust side of the blower?

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Ok first we need to know what your base or wastegate pressure is mate.

Do you know how to switch off the boost on your Avcr (if not I can explain how), if so do that and take it for a run with the boost set to off, then if you can monitor the max boost you see then watch to see if the boost is stable ie does it hold, increase or fall away if you continue to accelerate.

Let me know what you find and we can take it from there.

Cheers Iain

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Ok first we need to know what your base or wastegate pressure is mate.

Do you know how to switch off the boost on your Avcr (if not I can explain how), if so do that and take it for a run with the boost set to off, then if you can monitor the max boost you see then watch to see if the boost is stable ie does it hold, increase or fall away if you continue to accelerate.

Let me know what you find and we can take it from there.

Cheers Iain

Cheers Iain, I have the instruction manual for the AVC-R, or would you be quicker telling me?!?!

Thanks for the help mate

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Ok here are the basics,

Menu navigation uses all the buttons on the front of the Avcr

Prev = back 1 menu step

Next = on 1 menu step

Up = An up selection on the menu or Increase when altering any boost settings

Down = A down selection on the menu or a Decrease when altering any boost settings.

I will give you simple menu steps from the boost display screen.

1. Press Prev twice this should take you back to the MAIN menu.

2. Press Down once to put you onto the Setting [A] or (whichever is displayed)

3. If you now press the LEFT arrow this will switch off your boost and be displayed [OFF]

4. To switch your boost on again simply press the RIGHT arrow.

5. From the Settings [A]/ (which ever setting it was on when you navigated to this menu step leave it on for the next steps) line press the NEXT button this will take you to the SETTINGS menu.

6. At the top of the SETTINGS menu you should see BOOST DUTY press NEXT on this.

7. From this screen you should see your target boost and boost duty settings, please let me know what both your target duty and boost duty % are.

Go back to the SETTINGS menu (by pressing PREV) and navigate through all the other settings ie, NE point/ Scramble/ F/B speed etc and make a note of what they are all set to then let me know.

You should now be able to switch off your boost (Navigate from the main display screen by pressing PREV, until you see the Setting [A] or screen then navigate the highlighted bar onto the Setting [A] or line and simply press the LEFT arrow to switch your boost control off)

Navigate back to your Monitor screen so you can see the boost

With the boost control off take your car for a run and record what your peak boost is.

Does your main display screen just show you boost or does it show more that that ie Boost + RPM etc

I hope you are following this mate :driving:

Cheers Iain

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There is no issue with the wastegate pressure, preload or the AVCR settings. Even with 90% duty the boost will not achieve target.

Airflow readings are normal for that boost level which tends to rule out an airleak and there is no blowing from the exhaust.

Thats why I suspect turbo damage reducing the efficiency.

cheers

Andy

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I remember a mate of mine got his car mapped with Andy and with in 10 min Andy says there is some thing wrong

with your turbo. It turned out to be a Small bit of Debris had trapped its self in between the turbo blades, ones removed

all was well again.

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Thanks all for your input, Big D, hope I didn't waste your time with the instructions on the AVC-r - your help is much appreciated.

Will get the turbo off and through to you ASAP Andy.

Jac - a bit of debris would be a pleasant and cost effective resolution, fingers crossed.

Will report back....

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