Spark knock....

[Venum29]

I am running the Diablo tune on my 2010 RAM 1500 4x4 5.7L Hemi. I have for the last 4 times getting gas I have used 93 octane Shell. I noticed a spark knock after getting on it and letting up. It has done it twice so far. Should I drop it down to 91 tune? I always use Shell gas and have never had any knock/issues with it. Could I have gotten bad gas? 93 octane Shell gas should be fine with the Diablo tune, am I right? The first time I put a little over 22 gallons in it. Since then I have put 4, 12, 19 and 7 gallons of 93 octane in it. All the 87/89 should be gone by now. It has been raining and humid for this time of year just south of Toledo,Ohio. might there have been some moisture build up? Can moisture cause spark knock? I do not know. I have let the RAM sit a few days over the past few weeks with out going any where, or starting it. Just want to make sure I am explaining and give all the info on my situation. Thanks in advance.

[Mike_Levy]

Its the Shell. Shell has zero knock retardation. Use Exxon/Mobil or BP.

Also, get a Catch can of you don't have one.

[Venum29]

Should I drop it down? I have a full tank as of now. What would you do? Like I said I have never had any issues with Shell gas. Why would it all of a sudden start this. Will dropping it to 91 change the knock at all?

[Mike_Levy]

You can drop it down. The 91 tune has 2 degrees less advance, so knock retard should drop by 2 degrees.

[Venum29]

Ok, thanks.

[Venum29]

I changed the tune on my RAM to the 91 tune. I have not had the KR so far. I did write Shel, I told them I had a 2010 truck, I had a tuner that called for 93 octane gas. I told them I had put over 60 gallons in it since my last time using 87/89 octane gas. I then asked them to explain to me how I had spark knock with shell gas and they wrote me back this response.

Dear Shell Customer:

Thank you for contacting Shell. All Shell gasoline is Top Tier certified and we have a Product Quality Assurance program that backs up our promise to consistently provide our customers with quality products. Be sure of the octane requirement of your vehicle and buy gasoline with the matching octane level.

We appreciate the opportunity to serve you in this matter and look forward to providing you with quality Shell branded products and service in the future.

Sincerely,
Shell Customer Care

[Venum29]

I am not saying that the tuner is bad, I actually love how much it has brought my RAM Hemi to life. The thing is I have used Shell gas 95% of my fill ups over the past 5 years. Never had an issue with any kind of KR. I have talked to a few buddies about this and they are at a loss as to the Shell gasoline causing this. Not until I installed the Diablo tune has this happened before. There has got to be (IMO) a setting not wanting to ack right, or something to that effect. Please help me understand this issue.

Thanks
Dave

[Mike_Levy]

Are you sure you never had the problem? Had you logged previously? Hemi's like to knock. We see it on stock ones too, and when you advance the timing with the tune, it just makes it worse.

Shells response is typical propaganda. They always pull the Top Tier crap. They aren't gonna admit to anything.

[Venum29]

I am positive I have never had a KR on any of my autos. That noise is unmistakeable. I have changed the tune to 91 and have driven it to see if it had any KR and so far so good.

[Mike_Levy]

If the knock sensors are working properly, you'll never hear it audibly.