Has anyone every tried to put together a lower HP turbo tune for the Miatas that would work with 89 octane or is the stock CR too high ?

 

89 octane? they still make that?

 

are you planning on running WI with that?

 

I had a factory turbocharged Buick Regal that ran on 89 octane back in the 80's, I think it did 12 psi, it was incredibly fast for a grampa car .

 

I was thinking air-air intercooler, not for extra HP but for economy, the way the factories did it in the 80's.

 

you can do it, but you're giving up performance for compatibility.

 

It's like $2 more for a tank of premium than it is for mid grade. If you're that cheap, then you don't need to spend the money on a turbo in the first place.

 

^^^^ +1


Gas savings are minimal, especially now. The savings between grades is even less, especially considering you can actually get better mileage on higher octane fuel.

I've never understood why people insist on saving $2/tank to buy the cheap stuff. I go round and round with my wife on this...the Xterra gets 19mpg on high grade, and 16mpg with low grade. That's 19% more efficiency for less than 13% more cost. This happens because the low grade junk sets off the factory knock sensor, and the ECU pulls back timing. You will be doing this by hand with your economy "tune".

Also remember that bent rods aren't cheap either.

 

I bet the MSPNP base map can run 89 octane.

 

89 octane is typically priced $.10 a gallon lower then 91/92 octane. The most you could save is $1.00 using 89 octane even if you are bone dry. Not a significant savings, and in my mind not worth the effort.

 

You're probably right but I thought I remembered 91 octane being $.75/gal over 89 last summer? Gas will be right back up to $4/gal in no time.

 

No, gas won't be back up to $4/gal anytime soon, the price per barrel is at almost a record low and the economy won't support higher prices. I am a gas snob and only put Shell or Chevron in my vehicles, even in my Jeep. It might cost more, but I do see slightly improved mpg with the better gas. My dad used to tell me that years ago and I thought he was full of it, but I put it to the test and he was right!

 

+1

Stick with high octane, stick with name brands.

Be aware that the same truck that fills up the "Dave's SunMart" 89 tank then drives across the street to fill up the Chevron 89 tank.

High grade is usually a proprietary blend brought in on a seperate truck. Mid grade is a mix of the two.

To me this is one of those cheap things you should always do to take care of your car...like frequent oil changes, reading and changing spark plugs, and air filter cleaning/replacement. Sure spark plugs can last 2-3yrs, but for $8 I change mine atleast every six months, and I generally get great mileage to make up for it, as well as added performance and knowing what my motor is doing.

Run high grade, run the brand names with detergents, don't look back.

 

So did you ever figure out your wheel dilemma?

/threadjack