Octane question

[TRZ06]

Given that the compression on our cars are 12:1, do California drivers get screwed out of a little HP & TQ since we max out at 91 octane?

Luckily, here in the Bay Area, there is a 76 station that offers 100 octane. Would I see any increase in performance from mixing half/half of 100 and 91?

[dogears]

yes.....

In fact, Pencil Geek dynoed his M3 with 100 octane. With no other mods, the car picked up something like 30+ hp!

His thread is in the engine section

[montreal red]

here in montreal, its rare to get anything more than 91. shell, mobil all only have oct 91. sucks for us.

[M3 Montreal]

Originally Posted by montreal red

here in montreal, its rare to get anything more than 91. shell, mobil all only have oct 91. sucks for us.

Montreal red... Im stalking you tonite !

That's why I always fill up at Petro-Canada for the only 94 octane in Quebec !

[caveboy]

Where in the Bay area is that Union 76 gas station?

[bmwpowerf1]

in australia. 91 octane is not recommended and could damage your engine. it says 98 octane minimum should be used

[TRZ06]

Originally Posted by caveboy

Where in the Bay area is that Union 76 gas station?

In San Jose, off Foxworthy and Almaden Expressway, after exiting hwy 85 it's about 1 mile past the Classic Car Wash.

[1MOREMOD]

call 1-800-345-0076 and they can direct you to the closest 76 competition 100 dealer. Unfortunatley for me its not in my state at all. I tried 101 trick fuel and that seemed to give me that extra 35hp as tested by my butt dyno.

[Cab5er]

Originally Posted by TRZ06

In San Jose, off Foxworthy and Almaden Expressway, after exiting hwy 85 it's about 1 mile past the Classic Car Wash.

How much more expensive is the 100? What was it per gallon last time u were there? Thanks

[TRZ06]

Originally Posted by Cab5er

How much more expensive is the 100? What was it per gallon last time u were there? Thanks

I want to say $4.50ish, but don't quote me on that, I used it occasionally on my 335I w/ SSTT

[Cab5er]

Originally Posted by TRZ06

I want to say $4.50ish, but don't quote me on that, I used it occasionally on my 335I w/ SSTT

Thanks

Originally Posted by PencilGeek

Here's a list of others:
http://www.davebarton.com/Unleaded_R...ral_and_NorCal

woooooo, there one 10 minutes from my house. Looks like gas expense might be on the rise for me.

[TRZ06]

Originally Posted by PencilGeek

Almaden Expressway & Foxworthy -- San Jose. 100 Octane is usually about double normal prices.

Here's a list of others:
http://www.davebarton.com/Unleaded_R...ral_and_NorCal

Hey PencilGeek, nice to see another local. I have a couple of questions for you if you don't mind.

1. I see you have the HRE P40s, I just ordered mine and should be here in about 4 weeks. Did you go with the 255/35/19 F and 295/30/19 R? If so, how is the handling? Any noticeable under-steer from going 3 sizes wider in the rear and 1 size in the front?

2. How much HP & TQ should I pick up by going 50/50 with 100 and 91 octane.

We should get together sometime, I am in S. SJ

[TRZ06]

Originally Posted by PencilGeek

I got 20x9 in the front, and 20x10.5 in the rear. 245-30-20 (front), 295-25-20 (rear)




I don't like guessing...that's why I dyno.



I'm in Morgan Hill. Come to my poker tournament.

I might need to do that. Hows the handling with those sizes, I dont know if you push your car around the on-ramps but do you notice any understeer with those wider tires?

[TRZ06]

Originally Posted by PencilGeek

Yes, I push my car pretty hard. It's still pretty neutral...seemed to shift just a tad towards understeer...but it's still in the oversteer territory.

But then again, I haven't had my car since October...so who knows what it handles like! Hopefully that will change this weekend...when I pick it back up again.

Well that is a relief, I was really worried about messing up the neutral balance of the car with going 255 F and 295 R

Where has your car been?

[TRZ06]

Originally Posted by PencilGeek

Car went to SEMA show in Las Vegas. Since then it's been getting the motor rebuilt to the 4.6L stroker motor from RD Sport. Should be done this weekend.
http://www.m3post.com/forums/showthread.php?t=169232

SWEET!!!!

Look forward to hearing about that

[VanM3Lover]

Originally Posted by bmwpowerf1

in australia. 91 octane is not recommended and could damage your engine. it says 98 octane minimum should be used

Different rating systems. Just do a search.

[Splinter4784]

I go to the 76 on San Vincente and Bundy, they sell 100 octane racing fuel and last time i checked it was 8.00 a gallon

and thats around 128 dollars for a full tanks worth of gas, its definetly worth it twice a month

[J08M3]

PG, how many tanks of 100 octane did you have to run before the ECU gave you the extra HP?

[TRZ06]

Originally Posted by J08M3

PG, how many tanks of 100 octane did you have to run before the ECU gave you the extra HP?

It should be immediate, or at least within a mile or two, as if there is any timing being pulled, it will give it back as it senses higher octane.

However I don't think you need to run 100% 100 octane, the ratio is 12:1 not 14:1 or 15:1, a 50/50 mix is plenty to advance any timing that might be pulled. I think running 100% is a waste of money.

[dcstep]

Originally Posted by Splinter4784

I go to the 76 on San Vincente and Bundy, they sell 100 octane racing fuel and last time i checked it was 8.00 a gallon

That's about what I pay in Colorado. I only use it for dyno runs and competition events.

Dave

[ersin]

Originally Posted by PencilGeek

" natural state of spark advance "

Could you elaborate on what that means?

[niqui]

Originally Posted by M3 Montreal

Montreal red... Im stalking you tonite !

That's why I always fill up at Petro-Canada for the only 94 octane in Quebec !

same here, 94 at petro canada.