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YOUR RESEARCHEngine knocking w/ GIAC chip
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Use different octane and fuel mix than cali
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Suggestion · Original poster
I am hearing the noise now in Seattle and I'm thinking we likely use a different octane and fuel mix than Cali.
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I posted up a thread earlier describing this click noise I was getting when getting on throttle in a non-aggressive manner in 2nd gear and in 1st. Intermittent, usually happens after the car's been driven around a bit aka fully warmed up. Never happens when driving in a spirited manner.
I performed a search on Rennlist and the 997 guys seem to be having this issue even when stock.
I bought my current C4S in San Fran and the previous owner had his car flashed at Sharkwerks with the EVOMS intake and GIAC flash as part of their "Stage 2" kit.
I didn't hear this click noise when I was driving around in the Bay Area. I am hearing the noise now in Seattle and I'm thinking we likely use a different octane and fuel mix than Cali.
I've called S Car Go and some other GIAC shops and they say that knocking of this nature is quite common even on 996s (stock or flashed) and should go away if I drive aggressively. I don't want to accept this for now as I don't want to always drive aggressively especially since my car is a street 911 that I take extremely good care of.
I'm wondering if any of you have this knocking noise (click) whether you are on the stock program of GIAC program. I want to remain flashed, but maybe I need to get a WA State flash program v. the Cali program?
I am very new to this area of chipping as I've never chipped my cars before since I'm not big on spending $ on N/A cars and I only drive N/A cars period.
I just want this noise gone. No knocking.
Ben,
While I don't have this issue you should be able to isolate if it's really a timing issue with the flash by finding a station that sells 110 octane unleaded gas and putting a 1/2 tank or so in your car. If this makes the noise go away then it's def. timing related and likely based on the GIAC.
The weird part about it is that usually you'll get spark knock under heavy load at low RPM when the throttle is agressively applied at low RPM...not with a more gradual application of the throttle.
Andy
If I shift at a high RPM (5K shift point) say from 1st to 2nd, then I usually never hear the knock.
If I shift at around 3K from 1st to 2nd, I sometimes hear the knock or the metallic click noise.
And the noise is really not even a knock... it's a light metallic click. One click, sometimes two clicks.
I suggest you get a hold of Garret Lim, the owner and programmer for GIAC and tell him about your problem. He my be able to reflash you car with a less aggressive profile to remove the knock. I had the same problem back in 1995 with a VR6 Jetta with his chip and he gave me a new program. I still made power, just without the knock.
