Best and most true freaking quote yet, lol. I love it. You sir, have a spot in my sig, haha

Good call on loading the 87 tune. Better to be safe than sorry.

 

A few have said to remove the 89 and fill with 93. I would like to know how he could drain his fuel tank. All late model cars have a device in the filler to prevent a hose from entering the tank and siphoning the gas.

I found this out the hard way after Hurricane Wilma when I tried to siphon some gas for my generator. I filled up both cars before the hurricane thinking I could use the gas... Doh!!!

 

Drain your tank and fill a bunch of glass bottles and you could have enough molitov cocktails for a small gang war?

 

LOL at all the responses, especially the one to return to stock AFTER the OP said he had a custom 87 tune.

That's one reason I have an 87 custom tune and carry the tuner in the car. I've said it before: You'll be on the road sometime and may only be able to FIND 87 octane. It's already happened to me.

This should have been a no-brainer for the OP. 87 octane on a 93 tune is bad. Duhhhhh.... Load the 87 custom tune. Duhhhhhhh...

 

Yeah, but he filled up with 89 not 87 and he doesn't have an 89 tune. That's why people were telling him to return to stock.
Duhhhhhhhh...

 

No crap. DUHHHHH back. He can safely run the 87 tune with 89 octane fuel.

 

You can use a higher octane with any lower tune but not a lower octane.

 

I haven't seen anyone mention what kind of tuner that he had. In the last Southeastern gas shortage I routinely had to fill up with whatever I could find. If you have a Diablosport tuner you can adjust your global spark timing pretty easily and re-apply the same tune with a tweaked spark profile.

If you remove 3 degrees or so of global timing for the 89 octane you shouldn't run into any issues. Plus most of the knock / detonation is going to happen at WOT and not general cruising.

If you have a diablosport tuner, go to install the tune, and edit it before hand, go to global spark parameters, remove 3 degrees, save, apply, should be fine. I can only assume that SCT has similar params.

 

It was 89 on a 93 tune Einstein. Glad I resolved this issue before you chimned in.

 

You DID say earlier in your post #7 that you had an 87 tune when you were still asking for help, "Einstein".

Yeah, I'm glad that you resolved it too.