Quote:
Originally Posted by Shamrock
Could a bad tune cause knock?
He has a dyno where he dettaches the rear wheels. Is this a rolling road?
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Short answer is yes.
Knock can be caused by too much ignition and adding spark advance and a pulling a bit of fuel to run closer to a true stoic-ratio is the common way of a tune delivering more power. Most OEM setup are very "safe" to cope with global fuel quality variability and vehicle operating conditions - they run fairly conservative spark advance tables to leave a wide safety margin and avoid engine damage warranty claims. What the "tuning" industry does to take your engine closer to the knock limit which will deliver more power.
Too much ignition advance will cause knock - guaranteed.
Using a "hub-dyno" which is what you describe is one form of "rolling road" - it has the benefit of zero tyre slip which can happen with tyres on rollers style of dyno, so yes, a hub-dyno will do the job perfectly well.