[leftcoastman]

So in my area, 91 octane is the normal "premium".

There is one station, 7-11 with an unbranded gas (normally citgo, but doesn't say so) that shows 93 octane on the pump. This is the only place I can get 93. To boot, it's cheaper than the Shell, which serves up 91.

Now, without getting access to a combustion engine designed to increase compression to test knock resistance, is there a method to determine if the advertised 93, really is higher than the 91?

What I do NOT want to do:

1) Pay $100 for a dyno
2) Pay $xxx to drag my car

Is there some data log that I can pull from PROcede or some homemade test that I can use to determine the true octane?

I can always resort to bugging my friend who has access to a mass spectrometer. But uhh, is there an easier way?

[Terry335]

Get scanning software and monitor the total ignition advance. If you're in CA I doubt its really 93.

[leftcoastman]

Originally Posted by Terry335

Get scanning software and monitor the total ignition advance. If you're in CA I doubt its really 93.

Hmm, will a crappy Autozone OBD2 scanner work?

[Terry335]

Originally Posted by leftcoastman

Hmm, will a crappy Autozone OBD2 scanner work?

No, it needs to feed live data. You might buy one at pep boys for around $200 and return it. Not all do timing advance though so it might take a few tries.

[leftcoastman]

Originally Posted by Terry335

No, it needs to feed live data. You might buy one at pep boys for around $200 and return it. Not all do timing advance though so it might take a few tries.

Terry - as you know, I think you are argumentative prick sometimes.

But on the same token, you offer your help even though you dislike me. Thanks bud.

[sambonator]

Terry doesn't dislike you lefty

BTW I wonder if anyone has access to something like this?

http://www.spiritpfc.com/shatox.asp

[leftcoastman]

Dude Terry - I am not like that. I'm sure you're cute and all...

But I like women.

[Black Chili]

You're paying for the quality of the base stock and the additive package, including detergents and other organic and inorganic compounds that (in part) help the gas resist pre-ignition and detination and the research and testing behind the over 100 different compounds in the gas that differ a LOT.

I can put a gallon of Xylol paint thinner from Home Depot in my tank and raise the octane by a few points- that makes the octane higher, not the gas any better.

I'd put 91 from Chevron before I put anything from a 7-11 in my tank.

To answer the original question, you don't have access to the items necessary to measure octane and a factory knock sensor is like substituting an etch-a-sketch for a laptop.

CALIFORNIA- yeah, 93 is possible but I've not heard of it- then again I can get 100 & 103 from pumps within 1 mile and 4 miles of my house.

[Tuned335i]

Originally Posted by leftcoastman

Terry - as you know, I think you are argumentative prick sometimes.

Holy crap dude!!! It's probably no surprise that I'm not a JB2 fanboy, but that was kind of harsh! I'm not saying you're wrong, but Jesus! LOL!!!

[OpenFlash]

For $200, I recommend this: http://www.torukumotorsports.com/pro...uctid=108&js=n

Since you already have a laptop, this software/hardware package will log just about anything you need it to. And with good sampling speed which is what you need if you want to log ignition advance.

-shiv

[Tuned335i]

Ok you 180IQ tuner guys. How does that equipment tell you the actual octane? Does it measure the amount of ignition you can run before detonation and therefore knock resistance and relative octane compared to a baseline known octane?

[OpenFlash]

Originally Posted by Tuned335i

Ok you 180IQ tuner guys. How does that equipment tell you the actual octane? Does it measure the amount of ignition you can run before detonation and therefore knock resistance and relative octane compared to a baseline known octane?

You'll basically have to come up with a controlled testing procedure. Like a full throttle 3rd gear run from 2000rpm to 7000rpm. Log RPM and ignition timing. Do this with the questionable gas in the tank. And then again with something familiar. Compare the graphs and see which datalogs show higher advance curves. Of course, get the ECU fully adapted to each gas before doing the test.

Shiv

[leftcoastman]

Originally Posted by JephryB

You're paying for the quality of the base stock and the additive package, including detergents and other organic and inorganic compounds that (in part) help the gas resist pre-ignition and detination and the research and testing behind the over 100 different compounds in the gas that differ a LOT.

I can put a gallon of Xylol paint thinner from Home Depot in my tank and raise the octane by a few points- that makes the octane higher, not the gas any better.

I'd put 91 from Chevron before I put anything from a 7-11 in my tank.

To answer the original question, you don't have access to the items necessary to measure octane and a factory knock sensor is like substituting an etch-a-sketch for a laptop.

CALIFORNIA- yeah, 93 is possible but I've not heard of it- then again I can get 100 & 103 from pumps within 1 mile and 4 miles of my house.

My man, before you get all self-righteous, you should talk to your local petroleum industry attorney. My ex-gf's father is one - in many states (California included) the base stock is EXACTLY the same regardless of station. They all pump from the same loading station tanks. Additives are added later. Furthermore, often the station is not required to purchase from its namesake.

You are paying for the brand creation and maintenance - in other words, the advertising.

If you don't have access to an attorney, check google/abcnews/nbcnews/consumer reports/etc.

http://www.abcnews.go.com/GMA/Busine...2978563&page=1

Additionally, anti-knock/anti-detonation properties are measured by one thing and one thing only: Octane, which is just 8 molecules of carbon and a dozen and a half of hydrogen.



FWIW - Shiv has publicly stated that he has measured (via a dyno) considerably and consistently worse performance from Chevron gasoline than any other gas.

[M&M]

Say Shiv, what's the sample rate? And can it clear the detailed BMW faults? Does the dyno function use the Mass airflow readings to calculate power, or the rate of acceleration?

[leftcoastman]

Originally Posted by Tuned335i

Holy crap dude!!! It's probably no surprise that I'm not a JB2 fanboy, but that was kind of harsh! I'm not saying you're wrong, but Jesus! LOL!!!

Hehee - look at the next line. I'm beating on him like I beat on my little brother.

A good smack followed by some ice cream, lol.

[OpenFlash]

Originally Posted by M&M

Say Shiv, what's the sample rate? And can it clear the detailed BMW faults? Does the dyno function use the Mass airflow readings to calculate power, or the rate of acceleration?

The sample rate can be very quick if you reduce the number of logging variables. I don't know the actual max rate but it's perfectly adequate for tuning and monitoring. I doesn't clear BMW faults. Just OBD faults. I haven't used the dyno feature but i'm pretty sure it just uses rate of acceleration (dRPM/dt).

Shiv

[leftcoastman]

Originally Posted by Tuned335i

Ok you 180IQ tuner guys. How does that equipment tell you the actual octane? Does it measure the amount of ignition you can run before detonation and therefore knock resistance and relative octane compared to a baseline known octane?

Me ain't got no 180 IQ, but here's what I figure:

I run standard ass 91 octane. Do a 4th gear 1500-7000 rpm uphill run. Observe timing advance, however it's reported.

Fill it with my "93 octane". Do the same 4th gear run on the same hill in hopefully similar enviro conditions. Observe timing advance. If I see more timing advance, then my uneducated bumpkin ass would believe that it's higher octane gas than the 91.

PS - BTW, I am not looking to determine exact octane with high resolution. I only care about relative octane. If the advertised 93 is giving me the benefits of higher octane (more advance) compared to the 91 sold everywhere else, then I'm all over it.

[leftcoastman]

Originally Posted by shiv@vishnu

The sample rate can be very quick if you reduce the number of logging variables. I don't know the actual max rate but it's perfectly adequate for tuning and monitoring. I doesn't clear BMW faults. Just OBD faults. I haven't used the dyno feature but i'm pretty sure it just uses rate of acceleration (dRPM/dt).

Shiv

Jeezus Christ, you just gave me a flashback of college calculus. That little "d" was the bane of my existence.

That said, dRPM/dt is probably not that accurate, eh? You have to throw in weight, Cd, frontal area, estimates of tire drag, gearing, etc. to estimate hp.

It's probably accurate given the right inputs. But garbage in - garbage out.

[OpenFlash]

Originally Posted by leftcoastman

Jeezus Christ, you just gave me a flashback of college calculus. That little "d" was the bane of my existence.

That said, dRPM/dt is probably not that accurate, eh? You have to throw in weight, Cd, frontal area, estimates of tire drag, gearing, etc. to estimate hp.

It's probably accurate given the right inputs. But garbage in - garbage out.

Yep, you need to enter all those other variables in the software. One reason I never used that feature

shiv

[satinghostrider]

Originally Posted by shiv@vishnu

Yep, you need to enter all those other variables in the software. One reason I never used that feature

shiv

In my time zone, i have never seen Shiv at this hour posting!