91 octane vs 93 - Changing tune

[dab86]

My car is tuned for 93. I moved out west and all we have is 91. I have two options.

1.) A couple gas station sell 100 octane fuel. I can fill up at the same pumps when I need gas and mix 100 with 91 to get 93.

2.) I can just retune the car for 91.

Question - If the car is retuned to 91 octane, will I actually lose HP? Is it something I will be able to tell? The car ran great on 93 octane and Im nervous about retuning it to 91

What would you recommend. Thanks!

[45thCAMARO 2SS/RS]

About 10-20hp loss with your current mods, it won't be omg difference but you will feel it. And yes to answer your question to retune for 91 octane, don't take the chances by mixing gases, just cam it and you'll forget all about it lol btw where did you move too?

[376LS3]

^^ Exactly what he said. I had my car tuned on 93, then put 91 in it and knocked pretty heavily. Got it retuned, and shes happy. Or run Torco Accelerator. A tune in the long run would be cheaper though.

[rberns]

Im kind of in the same boat. I can only find 1 gas station in my city that has 93 octane and it is any big name gas station. Most others sell 91 so I am thinking about getting mine dyno with 91 when I get my cam swap done.

[dab86]

Theres about 6 stations that sell 100 octane in my area. Rely not sure what to do

[VADER SS L99]

This comes down to a money and convenience issue. My area is the same way. There really is only 1 station within 10miles that has 93 but its at least a $1 more per gallon over 91. Then there is the possibility of being out of town and needing fuel. In this case I guess you could keep TORCO in the trunk. One thing you don't want to do is run TORCO 100% of the time. Every once in a while is fine for a track day but not for every fill up. Nothing is wrong with mixing high octane fuel with 91 to achieve 93 so long as it is normal regular unleaded. If you put 100 octane in for every fill up you would need 5 gallons of 100octane and 14 gallons of 91 or to be safe a 1 to 4 ratio.

[JD_Alaska]

One thing you don't want to do is run TORCO 100%

What's the reason you don't want to do this? Was thinking of using this product because the best gas we have up here is "90"

[lynxone]

If it were me, I'd just retune to be safer and way more convenient. There's lots of ways to make up the power loss (which isn't enormous). Where did you move to? Where I live, at elevation, 91 is all you can find also. Have you considered converting to e-85?


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[dab86]

Im in Vegas. I got it retuned today to 91 and to be honest....it drives GREAT! I didn't notice any powerless and it actually drives smoother. It was running a little lean and Sam from Sullivan Performance fixed it right up. What a great guy and shop I highly recommend him!

[VADER SS L99]

Originally Posted by JD_Alaska

One thing you don't want to do is run TORCO 100%

What's the reason you don't want to do this? Was thinking of using this product because the best gas we have up here is "90"

That stuff flat out works to raise octane but I just wouldn't trust it ALL the time for the duration of the car. Just my opinion but the deposits it leaves behind could have negative effects on the fuel filter (which is on the fuel pump), oxygen sensors, and spark plugs.

[JD_Alaska]

Well that sucks Vader, not sure what he heck else to try other than a tune at "90". Can't get any good fuel up here like "93" so bak to square 1

[JimE]

Originally Posted by JD_Alaska

Well that sucks Vader, not sure what he heck else to try other than a tune at "90". Can't get any good fuel up here like "93" so bak to square 1

Unless you car is modded and aftermarket tuned, it's not an issue and there is nothing to worry about.

[VADER SS L99]

Originally Posted by JD_Alaska

Well that sucks Vader, not sure what he heck else to try other than a tune at "90". Can't get any good fuel up here like "93" so bak to square 1

Some people have used it with every single fill up and have not reported a issue. I don't think there is any concrete proof either way that it will or will not give an issue over time. You could very well use it with EVERY single fill up and never have a problem. It's just one of those things with me that I would rather be safe than sorry. If it was just a fouling of plugs and O2 sensors every 50k or whatever then I think that would be fine but if it messes up the filter in the tank that will be lots of money or a royal PITA to fix. I have also seen pics of the deposits it leaves behind on the pistons and valves that don't look so good. That however could be kept in check with the right professional fuel system cleaning every once in a while. You could also mix some unleaded race fuel to get 93 octane like the VP C20. That however would be SUPER expensive.

Is E85 available in your area? If so that would be a viable option. The only thing though is that you will have to check the quality of the fuel before every fill up. You would also need a custom tune for it of course. I would think anything past mild external bolt on mods would also need a higher flowing fuel pump and injectors with E85.

[monstertodd]

I had the opposite. Lived out west and was tuned to 91 octane. Moved to the east coast and retuned for 93 octane. Just way more convenient to retune.