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Car 'hits a wall' in gears 4 and 5

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Old 08-24-2001, 02:03 PM
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RicoLU
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Post Car 'hits a wall' in gears 4 and 5

In gears 4 and 5, car seems to ‘hit a wall’ or limiter of some sort. It feels like a slight push on the brakes. This occurs around 4000-5000 RPM with the boost pegged at 2 bar. In gears 1-3 it runs perfectly. The car has the Autothority Stage II chips and banjo bolt. I posted this in the dedicated 951 forum with few responses and hoped somebody could offer suggestions.
Old 08-24-2001, 04:25 PM
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Tabor
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I am no turbo expert, but could be KLR be halting your progress because of an over-boost situation?
Old 08-24-2001, 04:58 PM
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Greg Hammond
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I think Tabor might be on to something here.

First of all, if you're running an Authority chipset, you're not supposed to be reaching full 2 bar, even with the smaller banjo bolt oriface. You should be running somewhere in the 1.9-1.95 bar range. You might want to get an accurate boost gauge to see what's really going on.

If you're over-boosting, the KLR will retard your ignition and instruct the DME to cut fueling - and this would definitely give you the "brick wall" phenomena you're talking about. Just because you've got chips and a boost elbow mod, doesn't mean the KLR is going to allow you to run whatever boost you're capable of developing. The turbo can crank 23 PSI if you let it, and that would be a bad thing in this case.

That's my best guess. At 2 bar, your factory gauge is already pegged-out. You could be running 2.1 or 2.2 bar for that matter, and don't know it - the KLR may be reducing your power to save your engine from self-destructing from an over-boost condition.

Greg



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