Mixing Fuels With Different Octane
 

Recently came from Florida were 93 octane is practically everywhere, aaaaaaand now I'm in Colorado where I believe there isn't a single 93 pump. The premium gas here is 91 octane.

The power loss is extremely noticeable, and I can't take it anymore. Maybe elevation has a factor in to with the feeling.

I've been referred to add a little e15 to the tank. However this to me sounds sketchy. I have also been referred to add a little 100 octane to the tank.

I just want to at least match 93 octane again, nothing less. Whats the best way to go about this?
How would this work with tuning, considering every mix will be different.

Most pump gas nowadays is e5-e10 anyway. The only losses to octane would be pulled timing due to knock. You have a logging device to check timing?

The power loss is 80%+ due to altitude. Higher altitude, less air density, less oxygen, less boom. That's the drawback of NA for ya. FI or deal with it.

Edit, just saw mod list lol I'm dumb. Uhhh idk what's up then. Altitude still probably plays a part. Add octane booster? Turn up the boost?

Yea I'm JDL Turbo'd lol. I want boost to a minimum. I actually switched to the 5 PSI wastegate spring and it felt fine in florida. I figured it'd be the elevation but however comma, I did have some 93 left in the tank when I started driving in colorado and that still felt fine to me, I mainly felt it while staying on 91 for the first two weeks till now.

Add a little Blendzall 485 Racing Castor, it will slow the burn and give you a cool, racy smell.

Hey, Spuds ....... you wanna correct that statement ........;)

(or am I misreading it ..??)


humfrz

Nope.

So, are you saying that stock FR-S would lose 80% of its power at an altitude of 14,000 ft., compared to its power at sea level ..... ??


:confused0068:


humfrz

So do you have a way to log timing? Octane should only really affect knock compensation stuff right? If the ECU is pulling timing then yes, adding octane booster of some sort to every tank should help bring timing back up. 91 vs 93 octane has no more or less energy than the other.

So I'm not too familiar with how your blow off valve works, but if it's regulated by a spring, it's likely based on pressure differential to ambient. Ambient pressure at 5000 feet is about 2-3psi less than sea level under the same conditions. As far as your initial driving, pressure changes with weather so maybe that had an effect.

I think he is saying that of the power loss he feels he is missing - 80% of THAT LOSS is coming from the altitude. I think.....:thumbsup:

Not 80% of the overall power.

I would think that a car reduced to 34 WHP would be deemed more than "noticeable".

I do data logs and send then to my tuner, James Martin.... I have already updated the tune to this location and 91 octane...

I don't quite get your statement about psi and elevation. I am set to 5 psi spring, which usually goes to a maximum of 8 psi. You're saying that I'm actually getting 2-3 less of what my boost gauge reads?????

Well I would think your boost gauge would read absolute pressure but I really don't know how turbo stuff works lol. Hopefully someone can help you out.

Now, that makes sense. I reckon I was reading what he ( @Spuds ) said differently .....:bonk:


humfrz

It says it blends with premium gas. So you use this mainly as a safe factor or for driving feeling