93 tune knock?
Thread Starter
2nd Gear Member
Joined: Sep 2008
Posts: 313
From: New York
93 tune knock?
I had a little under a quarter tank of 87 in my car, and filled up with 93. I switched from the 87 tune to the 93 tune, and drove it easy for a little, and then revved the engine at a red light a few times, not to high. I heard what sounded like a slight knock right before the engine revved up each time. Should I be concerned? Thanks.
Gentleman's Relish
Joined: Feb 2005
Posts: 13,189
From: AZ
Yep, always run a couple tanks of the right octane before switching your tune over.
The poor running was because the 87 fuel lowered the 93 octane most likely by a full point or more. When you are pushing on the higher Octane tunes, they have much less forgiveness for improper octane or crappy fuel in generally.
The poor running was because the 87 fuel lowered the 93 octane most likely by a full point or more. When you are pushing on the higher Octane tunes, they have much less forgiveness for improper octane or crappy fuel in generally.
6th Gear Member
Joined: Jun 2007
Posts: 16,182
From: PA to KY ('07) to IL ('09) to MS ('10) to FL ('11)
Also, higher octane fuel, IMO, is more suspect of being at or above the advertised octane than lower octane fuels. Just a gut feeling; I have nothing to support that. Add that to your 1/8-1/4 tank of 87...
3rd Gear Member
Joined: Sep 2011
Posts: 546
From: DE
You can always use higher octane gas than your car and tune is rated for. That is why you can run 93 in your stock car that calls for 87 octane. So long as you run high quality 93 octane in your car then you won't have to drop down to a 91 tune. But if you're filling up with poor quality 93 octane then you will hear the car knock. There are a number of high quality gasolines out there. Shell, Exxon, Sunoco are some here in the northeast.
6th Gear Member
Joined: Jun 2007
Posts: 16,182
From: PA to KY ('07) to IL ('09) to MS ('10) to FL ('11)