Highest Octane For Stock ECU??

semtex · 09-04-2009, 09:25 AM

Quote:

Originally Posted by wstar

Hmm so this XXX fuel thing is interesting. So the basic idea here, if I'm understanding correctly, is that it's a higher octane fuel which also has added oxygen - and this means the extra oxygen in the fuel is effectively leaning out the mix for more power, and the extra octane is preventing the knock that would otherwise occur if you leaned out the mix that much on pump gas?

That's how I'm interpreting it (not that I'm an expert on fuel by any stretch of the imagination lol). I mean, that's why I find this so intriguing. The idea that you can just pour some of this stuff into your tank and get an immediate 14whp gain -- how can that not catch one's attention? And if I'm understanding the video correctly, they poured it into a tank that already had some regular fuel it, so it was like a 50/50 mix. I'd like to see what would happen if you poured this stuff into an empty tank!

Hi-TecDesigns · 09-04-2009, 10:09 AM

To answer the earlier question about the ECU advancing timing...

Using a semi-closed loop system, The ECU will retard timing as knock appears, and it will advance timing back as knock disappears, slowly but surely until either knock appears or it is back to the default timing. The key here is once the ECU has advanced back to the default value, it will not advance any farther. If there is zero knock on 93 on a sunny day, you are getting the best performance out of the engine possible, and placing a higher octane will not increase power (not getting into the oxygenated argument here). Don't make the mistake that the ECU will continue to advance timing beyond the default until it starts to knock, always giving you the most power possible for each tank of gas... it doesn't work that way.

Modshack · 09-04-2009, 11:08 AM

Quote:

Originally Posted by Hi-TecDesigns

The ECU will retard timing as knock appears, and it will advance timing back as knock disappears, .

Just as an example (from a 2008 Corvette) there are High octane and low octane timing tables that are selected based on knock sensor output. Without tuner intervention, the high octane table is going to give you the most timing advance adjusted for commonly available gas octane, but no more. Tuners can and will build Very high octane tables to take advantage of 100 octane race gas. Usually the only differences with these tunes are the timing adjustments. More octane + more timing = more HP

High:

Low:

Read T · 11-22-2013, 07:29 AM

When I track my S14 I advance timing and throw a bit of 100octane in the tank. It seems to pull harder and doesn't knock.

Driftomodachi · 01-17-2014, 10:52 AM

You can buy 100 octane at the pump at certain 76 stations

old guy · 11-03-2019, 07:25 AM

Remember when Sunoco had custom blending at the pump ? You could go from 190 economy to 260 which was two notches above their 240 which was premium . You could select anything in between in increments of 10

MZ DAIZY · 11-03-2019, 09:21 AM

Quote:

Originally Posted by old guy

Remember when Sunoco had custom blending at the pump ? You could go from 190 economy to 260 which was two notches above their 240 which was premium . You could select anything in between in increments of 10

Yup, I also remember static timing, points and condensers!

Octane is not that big of a deal since the ECU made its way into cars.

physics · 11-03-2019, 09:44 PM

Quote:

Originally Posted by old guy

Remember when Sunoco had custom blending at the pump ? You could go from 190 economy to 260 which was two notches above their 240 which was premium . You could select anything in between in increments of 10

Oh yeah; the good ol days when GTOs, Roadrunners, Z28s and 442s roamed the streets.

Spooler · 11-03-2019, 09:56 PM

Quote:

Originally Posted by old guy

Remember when Sunoco had custom blending at the pump ? You could go from 190 economy to 260 which was two notches above their 240 which was premium . You could select anything in between in increments of 10

Noop, I remember fuel for under 50ct. a gallon. Self serve pumps just started being installed. Most of them were still full service. Getting the oil checked, added, etc. Front window washed.

old guy · 11-03-2019, 10:43 PM

Quote:

Originally Posted by Spooler

Noop, I remember fuel for under 50ct. a gallon. Self serve pumps just started being installed. Most of them were still full service. Getting the oil checked, added, etc. Front window washed.

That was my first paying job ( except for paper boy ) pumping gas at a full service Sunoco station. The economy grade 190 was going for 19.9ct. a gallon in 1972

Rusty · 11-03-2019, 11:55 PM

Quote:

Originally Posted by Spooler

Noop, I remember fuel for under 50ct. a gallon. Self serve pumps just started being installed. Most of them were still full service. Getting the oil checked, added, etc. Front window washed.

My first job was for Boron Oil at a gas station. I remember standing guard at the pumps with a shotgun during the 1973 gas crisis. Had cars lined up around 2 blocks.

My gas tank was always full.

09-04-2009, 10:09 AM	#2 (permalink)
Hi-TecDesigns Base Member Join Date: Jul 2009 Location: Glenelg, MD Posts: 146 Drives: 370 Rdstr AT7 BkChry Rep Power: 16	To answer the earlier question about the ECU advancing timing... Using a semi-closed loop system, The ECU will retard timing as knock appears, and it will advance timing back as knock disappears, slowly but surely until either knock appears or it is back to the default timing. The key here is once the ECU has advanced back to the default value, it will not advance any farther. If there is zero knock on 93 on a sunny day, you are getting the best performance out of the engine possible, and placing a higher octane will not increase power (not getting into the oxygenated argument here). Don't make the mistake that the ECU will continue to advance timing beyond the default until it starts to knock, always giving you the most power possible for each tank of gas... it doesn't work that way. __________________ http://hi-tecdesigns.com/images/pict...on%20Small.gif 2000 S2000 Brickyard Red Metallic w/ Romanesque Crimson Kandy, custom everything else

11-22-2013, 07:29 AM	#4 (permalink)
Read T A True Z Fanatic Join Date: May 2012 Location: Raleigh, NC Posts: 1,046 Drives: 11 Nissan 370z BC 6M Rep Power: 18	When I track my S14 I advance timing and throw a bit of 100octane in the tank. It seems to pull harder and doesn't knock. __________________ 2011 Nissan 370z Black Cherry Sport Pkg - Daily Driver, , 1960 Morgan +4 fun car, 1986 BMW 325ES, 1998 M3 and 1996 Spec Miata - Race Cars SUPPORT TEAM WINSOME RACING - WRL, CHUMP, LEMONS

11-03-2019, 07:25 AM	#6 (permalink)
old guy A True Z Fanatic Join Date: Apr 2015 Location: S.E. Michigan Age: 68 Posts: 2,711 Drives: 13 magma touring Rep Power: 2684370	Remember when Sunoco had custom blending at the pump ? You could go from 190 economy to 260 which was two notches above their 240 which was premium . You could select anything in between in increments of 10 physics and Rusty like this. __________________ I better walk before they make me run....

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01-17-2014, 10:52 AM	#5 (permalink)
Driftomodachi Enthusiast Member Join Date: Mar 2013 Location: Cerritos, CA Posts: 482 Drives: 2010 40th Rep Power: 14	You can buy 100 octane at the pump at certain 76 stations