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Discussion Starter #1
<BEGIN ANGRY RANT>

Here is the story...

Bought a month ago I mixed 1/4 tank 93 w/ 1/4 tank 100 from Sunoco (Unleaded)...

I vaguely remember getting in the car and telling some people, "The cars response seems much better, I feel like its making boost earlier!"....

Well, the 100 octane is now gone (After my horrible AutoX outing) and I am running 1/4 tank of the same 93 again (I always use costco)....

The car feels like crapp now... it seems to be very laggy on the throttle and seems to take longer to spool the turbo...

I'm not sure what effect 100 actually has on this car because I tell you what, when I had the 100 octane in it the car ran like a bat out of hell, I even had issues with the HKS SSQV blowing off becuase of too much pressure (I think it is unrelated, but I am not having any issues now)...

When i was at the AutoX on the 100 the car was screamin, and the IC heatsoak didn't bother it one bit...

So to all you Speed6 owners who have used high octane, did you feel a difference or notice less turbo lag?

And I need to add one more variable to the equation.... right before the end of the race gas I switched to 10W-30 Mobil1 EP Full Synthetic... exactly 5.7 quarts....

Could this be an issue?

<END ANGRY RANT>
 

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Ran 3/4 tank of 100 & 1/4 tank of 91 and I definately noticed increased throttle response and more power.

That was over Easter weekend and I paid $5.00 p/gallon - I can't imagine what it is now.

Sometimes I sort of wish I would have never tried it... now I feel like I always need it - kinda like crack
 

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As you probably know there are several people (5 plus) who have tried the 100 octane gas. I've tried it undiluted for several full tanks and I've carefully watched the responses of others who have done so. The guy who sold me the gas claimed that with regards our high compression ratio turbo charged engine - it would definitely "wake it up" - not necessarily make it faster - but more responsive. Most people agree that the car is flat out more responsive., which makes sense. Mazda says the car requires a minimum of 93 octane and this makes me think it probably runs optimally at an even higher octane than that. I plan on using a mixture of 100 octane 1/3 to 2/3 93 octane, but only because I dont drive too much. Its just too expensive otherwise. As another forum member once mentioned - it would be interesting to discover the scale of diminishing returns with regards octane and our engine performance.
 

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Discussion Starter #4
Yes I agree... and from what I read Japanese 93 is like American 100... so maybe... but man the car seems to be half asleep now until 4K...
 

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Yes I agree... and from what I read Japanese 93 is like American 100... so maybe... but man the car seems to be half asleep now until 4K...
[/b]
at buttonwillow raceway over the weekend, i ran almost the entire 2 days on 100 octane sunoco...

the car felt much more responsive... the car ran great all weekend... except when i was running low on fuel in the middle of a turn and the car cut all power for a second... THAT was a scary feeling... but otherwise, the car felt awesome on 100 octane... now on 91 cali gas... it's not nearly the same, but the car still feels good... obviously i'm not driving it as hard on the street as i was on the track
 

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Discussion Starter #7
I'm not the only one... yay.... now to take out a mortgage to pay for fuel for this damn thing...
 

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Yes I agree... and from what I read Japanese 93 is like American 100... so maybe... but man the car seems to be half asleep now until 4K...
[/b]

I do believe they use a different scale using MON and RON to rate the gasoline then we do - their 100 is about equivilant to our 93 octane. I am sure someone will correct me if I am wrong.
 

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You can find my posts about using VP racing fuel 105 octane / 110RON. 50/50 mixture with 94 octane.

The car felt completely different to me. Much more responsive. Pulled full on to red line. Felt more powerful too.

A local gas station is selling 103 at the pump starting this week. I plan to try it out again.
 

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Discussion Starter #10
I do believe they use a different scale using MON and RON to rate the gasoline then we do - their 100 is about equivilant to our 93 octane. I am sure someone will correct me if I am wrong.
[/b]
You are indeed correct...

As seen here..

So our gas is actually quite good... but 100 feels so much better...

You can find my posts about using VP racing fuel 105 octane / 110RON. 50/50 mixture with 94 octane.

The car felt completely different to me. Much more responsive. Pulled full on to red line. Felt more powerful too.

A local gas station is selling 103 at the pump starting this week. I plan to try it out again.
[/b]
Please let us know how it works out...
 

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At VIR, the Evo/Sti owners swear by 100 octane. They usually get another 5-10 mph in the main straight just by running 100 octane.

Of course in the sti's case, running 100 octane for significant periods (especially if you are also pushing more then stock power and running race tires) can cause damage to the drivetrain.

If I'm not mistaken, going from 93 to 98 netted something like a 20 whp gain and 30 something ft/lbs on an STI on 5th gear.

Here's a video clip I made of that section of the program for those interested.

Right Click and Save As Please!

BP Ultimate (if I'm not mistaken) is 98 octane.
 

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Most performance oriented modern turbocharged cars will produce considerably more horsepower when you switch from 93 to 100 octane. My MS6 producese signficantly more power when I run 100 octane compared to the 91 supreme we get in CA. I try to mix my tank with race gas and 91 octane if I get the chance. Just not a lot of gas stations carry 100 octane. None in my area.
 

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Discussion Starter #13
Yeah... well considering I put on about 100 miles a month (if not less)... it really only costs me $5 a week in gas to use 100... so im gonna stick with it i think...
 

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Yeah... well considering I put on about 100 miles a month (if not less)... it really only costs me $5 a week in gas to use 100... so im gonna stick with it i think...
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100 miles a month?!?!?

Thats like 3 miles a day - don't you think a speed6 is a bit overkill for a grocery getter?
 

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Discussion Starter #16
Well it gets driven about once a week, maybe twice... and I assure you it doesn't live an easy life...

I drive about 5-6 miles on it at about 60MPH.... get off the highway.... romp on in it for a few blocks and then park it at work :)
 

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I ran a tank of 101 octane through it a couple weeks ago. I didn't notice any difference at all. Power and response is every bit as good as when I run 91 octane.
 

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Yeah... well considering I put on about 100 miles a month (if not less)... it really only costs me $5 a week in gas to use 100... so im gonna stick with it i think...
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100 miles a month, eh? That's 1200 miles a year. You must love your insurance rate. You fill your gas tank every 3.5 months, and you change your oil every three years. That's incredible.

I do nearly 400 miles a week.
 

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I ran a tank of 101 octane through it a couple weeks ago. I didn't notice any difference at all. Power and response is every bit as good as when I run 91 octane.
[/b]
This engine makes substaintially more power on 101 compared to 91. You may have not noticed power increase, but it was there. I bet at minimum the engine puts out an additional 10 hp.
 

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This engine makes substaintially more power on 101 compared to 91. You may have not noticed power increase, but it was there. I bet at minimum the engine puts out an additional 10 hp.
[/b]
10hp is pretty tough to read on the old butt dyno. Hopefully someone will try this on a real dyno to note if there are gains.
 
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