Ok so I have a question. First, I got my car tuned at a very reputable shop by a very reputable tuner locally. Jr tuned at shift fast motorsports. So far the car is running pretty good minus a few hiccups in low rpms and made 405whp on their "low reading dyno" at 25 psi on an fp green and gsc s2's. I switched from e85 to pump and my concern is, I planned to drain the e85 when I got there but when I got there my fuel light was on and they said as long as my lights on I can just fill up with 93 over the top and I'll be fine. So I put in 10 gallons of 93 over the top right before they dyno tuned it. Just wanted to make sure that's ok. I believe they know what they are talking about. I'm just paranoid and scared that when I run through a couple tanks and it's just straight 93 it'll effect afr's when I do a wot pull. Thanks for the space and any input.

 

If your tuner says it's fine then it's most likely not gonna blow up on you.
Feel better now? :P

 

As long as they left the timing soft, it will be fine. So, as long as they there was still 4 gallons of E in it before they tuned, you'll be fine.

If they didn't know, that 4 gallons of E85 increases the fuel resistance to knock quite a bit, and if they ran max or aggressive timing for the fuel that was in the tank, you may run into issues with knock once you get straight 93 in the tank. It would also effect the air fuel ratio.

If you're concerned, I would talk to the tuner about it.