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Since the R has this "advanced" engine knock sensor and the ECU seems to cut back before knock presents itself. I wonder if the situation can actually be felt or heard when driving the car.

Sometimes with high ambient temperatures, about 95°F, 21 psi of boost and 93 octane gas, the engine seems to fail for just a moment, like the ingition misfires or the fuel is cut, but I can not hear any knock or pinging like I could with small block V8s, and then the engine runs well again. Is this engine knock or the ECU preventing it, none of the above?
 

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when i had my saab running 22psi on the stock injectors, i experienced some severe knock. it was pretty obvious because i lost a substantial amount of power. i couldn't "hear" anything but i knew it was happening. i wouldn't be quick to mash the throttle with 21psi of boost in 95 degree temperatures, especially if you are only running 93 octane. if you are going to be doing that kind of high-boosting, you might consider using some sunoco ultra or something similar.
 

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Re: (phuz)

Quote, originally posted by phuz »
if you are going to be doing that kind of high-boosting, you might consider using some sunoco ultra or something similar.

Unfortunately Sunoco Ultra is now 93, and premium is 91.

BOOOOO. http://********************/smile/emthdown.gif
 

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oh you know what...i didn't mean ultra, i meant the race octane...the 104 stuff
 

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Re: (phuz)

I believe that this is normal. I have the same thing when it is warm out(90 plus degrees) The explaination I got from the tech in my region was that the engine is pulling back prior to dtonation. This keeps the car from having catostrophic failure... due to detonation on a regular basis.
 

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Re: (Mash)

If you can truly hear "knocking" or "pinging", its probably too late!


(At least from what I remember from my Porsche tuning days).

That being said, when timing is pulled back and added in hot weather, you may be able feel somewhat of a surging feeling but it should be fairly mild (IMHO).

Regards,

Derek
 

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Re: (bb vign)

hell, i never could physically "hear" it happening...and this is what happened:

WAY too late!!

 
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