I moved to SoCali and started to use 91 **** gas. Anyways, i did not feel a big difference but specialy after i dynod the car and it gave me 238 whp and 260 wtq so i was happy. yesterday i realized that there is a race gas station right next my house selling 100 octane for $5.19 so i was like . i am thinking about mixing 3 galons fron 100 with 10 gls or 11 gls 91 octane to give me around 93 or 94 it will cost $45 for each fill up but i only drive my car around 200 miles a week so no big deal. However, the question is if this pump broke for any reason and i go back to 91 till they fix it will it harm my car??? then i go back again to my mix will that harm my car if done few cases, my ECU for example will it fail or something??? Is my mix ok 3 gls and 11 gls 91?? please let me know will i gain HP???

 

Putting in highrer Ocatne gas will not harm your car. It will not harm your ECU. You will only get a HP increase if you tune for it. If you are running stock I see no reason to buy the more expensive gas. However if you get a boost controler and bump up the boost or reflash your ECU then yes increasing the octane will make a big diference.

To find out the right mixture just just average out the octane ni yoru tank. For example to get 93 octane.... form a total of 10 gallons using 91 and 100 octane, you would need between 2 and 3 gallons of 100 octane:
gallon octane
1 91
2 91
3 91
4 91
5 91
6 91
7 91
8 100
9 100
10 100
avg 93.7

 

thnaks, i have a stock car for now so you are saying to stick with 91 until i get my works turbo kit

 

yes - that is just my opinion... The higher octance will help prevent detanition at higher boost levels but I see no need for it if you are stock. I assume that Stock the car will run fine on 91 octane. If you don't notice any knocking etc. then you are fine. Ofcourse you can always put in a little higher octane as a safety net but I just don't see the need right now. In fact, I have heard of guys in California running boost controlers set at 20 or 21psi and using 91 octane gas and not having any issues.

 

But youve owned a lot of turbo cars and therefore something like mixing your own mystery meat gas shouldnt be a problem.

 

insult removed

 

so you guys think i should stick with 91

 

Keep the insults for your Mom and your Boss. They don't belong on this forum.

Az3ar. If your car has detonation, most certainly try out a 100/91 mix. It won't hurt your car if you switch back and forth between 91 and a 91/100 mix. Your ecu will adjust.

Yes, you will see more hp on a 91/100 mix than you will on 91 only. This has been proven all over the place in this forum. At WOT, the ecu running on 91 octane pulls all kinds of timing near boost peak. Bumping up the octane will stop this and give you a few more hp.

SC~

 

thats all i needed to hear. how simple that was. thanks man

 

i wonder what Az3ar said hehe... secret chimp says "RESPECT MY AUTHORITAI!!!!"

 

I like to edit posts and threaten members.

 

Ok - I thought that just increasing the Ocatne did no good unless you were at detination and or you tuned your car for it. At stock I have to believe that he is not haveing detination issues and he has not increased his boost or anything or tuned the car to run on higher octane. How is he going to get more HP?

If I am incorrect please explain as I have done some research on this topic and that is my current understanding.

 

When I lived in VA, I ran 94 octane at almost every fill-up. Now that I am in CA and am forced to run 91, I can totally feel the difference.

In CA, many of us do see pulled timing (on our stock and modded cars) due to the 91 octane we are forced to use. This is documented by people with pocket loggers and not a seat of the pants diagnosis. This obviously will effect the hp.

If you are still skeptical, try filling your car up with 91 at your next refuel. You will notice the decreased smoothness. You will feel how the pull at 3500rpm's isn't quite as brisk as it is on 93-94 octane fuel.

As I have been told, the ecu can not only retard timing due to bad gas, it can advance timing for good gas.

SC~

 

Very interesting.... I will take your word for it... no sence putting in bad gas to prove a point...

I change my vote -- put in some 100 octane to be safe from seeing pulled timing -- which I did not think you would see Stock but now understand differently.

SC - thanks for the explination...

 

Might I ask you to disclose you source of this info? Do you think yourself this is correct?