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Old 23-01-2021, 03:04 AM
RICE RACING RICE RACING is offline
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Join Date: Oct 2003
Location: Utopia
Posts: 511
Exclamation Why we run water injection to stop this!



https://www.youtube.com/watch?v=yCwP76MbVko
(video link above)

Here is a longer term test on a 2.2lt 4cyl turbo engine running DONMEGA probes.
This was at ~550bhp engine power.
Fuel was petrol of low octane.
Run to test probes, knock control, long term durability and suitability of mechanical specifications.
This was 9.0:1 and not running doctored 'pump' petrol laced heavily with toluene

As some historical context for real racing engines.
Group A Ford Sierra (run at ~550bhp during a 1000km endurance race @ Bathurst) on same map see proof below, needed to run 7.0:1 CR (or lower) .


Contrary to the plethora of rubbish on the internet and online 'education' talking heads this is not detonation nor heavy knock, nor pre ignition, its rather what Renault F1 published in papers when developing their turbo engines referred to as 'runaway knock' its of a low order and easily confuses the knock control system as the absolute figures are on the lower spectrum but their frequency confuses the rolling average that sets the base to which the knock threshold then needs to exceed to pull ignition timing.

This engine had no associated damage to bearings, rods, head gasket, etc as you would typically associate with 'detonation' or excessive knock, but it did melt a piston and started to show signs on others of that eventually happening to more of them, took a long time to eventuate as well.

Hope this helps people out who are interested. The EGT probe is a very useful tool and I hope this first hand experience and detailed analysis shows that, any questions best to send me an email
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Water Injection Specialist
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