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CITGO no longer NEX gasoline contractor?

Brett327

Well-Known Member
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Super Moderator
Contributor
Lets put this as a prime example.. On Christmas eve, I pulled a "Split Load" out of CITGO-Braintree.

I loaded:
4150g of 87 Octane in Compartment 1
1450g of 93 in #2
2650g of 93 in #3
3500g of 87 in #4

No valve/additive/nothing changes between compartments, other than the red hose for super on the fitting for 2 & 3 and the white hose for 87 on #1 & 4.. (89 is blue, used to be leaded if anyone cares)

Compartments 1 & 3 were dropped at the Shell station on US-44 in Plymouth, MA. Compartments 2 & 4 were dropped at "Tom's Gas" in North Carver on MA-58..

Same gas, one going to Shell, one going to Mom&Pop store, all loaded at CITGO. And this is the norm..

I've seen the same thing for other products. I toured a charcoal briquette factory in my youth and they were loading up bags from every imaginable charcoal brand right out of the same hopper. Parts is parts.

Brett
 

helo_wifey

Well-Known Member
Yep...I did QA/QC for Valvoline (Ashland) and the same product (obviously different weights) got put into no name brands, as well as the "Valvoline" label.
 

wink

War Hoover NFO.
None
Super Moderator
Contributor
My Dad used to own a gas station. I though I was fairly familier with the product transportation thing. So what about this retailer in my area that says he is going to sell gas that comes from U.S. sourced oil production. No A-Rab or south of the border oil for him. He claimed that Sinclair is the only gas retailer that sells product from U.S. oil wells. He is changing to a Sinclair franchise. There are no Sinclair stations within 200 miles of here, so he has a good marketing gimmick anyway. Does Sinclair only refine U.S. crude?
 

MasterBates

Well-Known Member
wink, with the way the retailing/distro works, he may BUY gas from Sinclair, which may only refine US crude..

But, liike what Snizo said, the way it works with refining and distro, I seriously doubt he can gaurantee where his oil comes from..

I will bet it comes from the same place he always bought it from..

AND often, say we would get a load from Sprauge... A distirbutor..
Normally Sprauge would come out of Sprauge Weymoth. But say you are on the North side of town, and the load is goign north (BOS does not allow gas tankers in the city limits unless it is a local delivery, so oftentimes its a 2 hour ride to go 10 miles because you have to go around ALL of boston)

You would pull the load out of GULF-Chelsea, since they have a reciprocity agreement with Sprague..
 

phrogpilot73

Well-Known Member
OK, so now I'm curious... In Jacksonville, NC (which I am finally free of!!) I used to gas up at the Trade-Wilco, only because I got better gas mileage out of the 93 octane than I did from other gas stations (driving conditions were the same, always driving north to MD is when I compared). If I gassed up at Trade-Wilco, I could make it to the Ft A.P. Hill exit off of I-95, but if I gassed up anywhere else, I would have to stop on I-295. Are they getting their gas from someplace else?
 

MasterBates

Well-Known Member
They may have been getting straight-gas for their 93.. Many stations will order gas that uses ethanol in the mix to boost their octane rating.

That would depend on their distrubutor. Without knowing exactly where their loads come out of, that's my guess.

Most of the additive packages (or lack thereof) are all the same, and even in the case of really good additives, they make more of a long term difference.

The one other, but this is more of a regional thing, is the base stock they are made from can affect the density of the fuel, which affects the MPG (even though the miles-per-pound would not change)

Think JP-4 vs JP-5. Normally, when you get a load of gas, you get a printout with Bulk Temp, Density, and Vapor Pressure. I can't recall the specific densities off the top of my head, but oftentimes when a new shipment of gas came in (be it from a different source or a seasonal blend change) the density would change.
 

A4sForever

BTDT OLD GUY
pilot
Contributor
Since this thread has gone this direction ... it's better to "fill 'er up" on a COLD day vice a HOT day, yes???

And I've noticed when I'm really, really, really, really trying to "fill" it ... as in a road trip ... I can squeeze more petrol into the tank by the simple expedience of gently "rocking" the vehicle back & forth near the end of the fill-up ... gets trapped air bubbles out of the tank (??).

At least it used to work on airplanes when fueling for a max-range mission. We used to rock 'em and get more fuel into the wings and fuselage ....

Standing by for laughter. humiliation, and derision. Are these 'Ol Wives tales or not ???
 

scoober78

(HCDAW)
pilot
Contributor
There really are alot of wives tails sourrounding gasoline...Guess that makes sense considering that nearly everyone in the nation buys it.

One of my favorites is that higher octane ratings improve the performance of your engines...ie...higher horsepower output. I've heard numerous "import tuner types" say..."I'm going to get some AVGAS and come back and smoke that guy next week because it is 100 octane."

Use the lowest octane rating you can without knock...
 

insanebikerboy

Internet killed the television star
pilot
None
Contributor
There really are alot of wives tails sourrounding gasoline...Guess that makes sense considering that nearly everyone in the nation buys it.

One of my favorites is that higher octane ratings improve the performance of your engines...ie...higher horsepower output. I've heard numerous "import tuner types" say..."I'm going to get some AVGAS and come back and smoke that guy next week because it is 100 octane."

Use the lowest octane rating you can without knock...

Actually, for certain "import tuner types" a higher octane results in better performance. That's because they build their engines with a higher compression ratio which requires higher octane gas for better performance. With max pump octane ranging from 91-94, that doesn't quite use all the efficiency of the engine. Also in consideration is that most street racer types aren't able or advanced enough to make a variable valve timing engine effective in racing, so they can't use lower octane gas as effectively.

From back in the day of straight push rod engines, the rule of thumb was that an engine with a compression ratio of 10:1 needed at least 100 octane (which is possible with AvGas). Considering they had 104 octane leaded gas back then, that's why some cars were built to almost 12.5:1.

Nowadays most car manufacturers recommend what octane to use. However, that may not always be the best, and as scoob said, use the lowest octane available without knock. However, if you decide to do that, make certain you know how to check your spark plugs because some detonation can occur in your engine and you might not notice it, which could just snowball the problem. Plus, if you use a lower octane than the manufacturer recommends and you have resultant problems, you might be treading on warranty issues.

The plus side is that car manufacturers are furthering development on the VVT DOHC engines, which allows a higher compression engine to run on lower octane, which means the engine can get optimum performance out of lower octane than previously used, plus saves you money.
 

scoober78

(HCDAW)
pilot
Contributor
Actually, for certain "import tuner types" a higher octane results in better performance. That's because they build their engines with a higher compression ratio which requires higher octane gas for better performance. With max pump octane ranging from 91-94, that doesn't quite use all the efficiency of the engine.

Not saying that you are wrong...because I am no expert...but your explanation doesn't make sense to me. Engines are engines, and high compression engines don't require higher octane for better performance, they require it to prevent detonation at that higher compression....survival if you will. Ever look at the compression ratios of aircraft engines? Please elaborate.


Something else I would point out in this thread...this whole "Chavez problem", to me highlights yet again, our need for a coherent energy policy. While I applaud the consumer choice not to directly support a Venezuelan owned company, the action, almost certainly, is a paper tiger. For example, Valero, which has a huge refinery on Aruba, imports all the oil refined there from Chavez.

It's the commodity, stupid....we must find a solution.
 

Brett327

Well-Known Member
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Super Moderator
Contributor
^^ I think people get generally confused about the order of things WRT octane and compression ratios. Laypeople see high performing vehicles which require higher octane (because they have higher compression ratios & longer stroke) and equate the high octane with high performance. They then mistakenly put it in their lower compression ratio cars, thinking it will increase their performance, which it will not. IBB's posts are spot on WRT the issue, but could be confusing if viewed in the wrong way because of the terminology he employed. I guess you could reason than a high compression ratio engine that is using low octane gas (thus detonating) would be operating at a lower performance level than if it were using the right gas. I think that's what he means.

Brett
 

RHPF

Active Member
pilot
Contributor
For the higher rated gas.... The biggest problem against people getting an advantage out of it, is that it takes TIME for an engine to remap its advance settings. You cannot just switch the gas and have an instant gain. With that said, on really hot days (100+) we used to run 100+ gas at the track (I was not an import guy) to compensate for the retard.

As for the gas being the same... my grandfather owns a company that owns a bunch of gas stations in the Bay Area. He has always said that the gas is the same at the mom & pop stations as the Shell/Chevron stations.

The only thing I can think of is that perhaps some companies (Chevron) still add their additives (Techron) to the gas that would otherwise be the same. I know this is a possibility because the car I owned (same one from the track^) before had a known fuel pump issue. Almost every gas type would cause the tank to read empty even when it was full. The only solution was to use Chevron gas because the Techron additive would keep the fuel level contacts clean. It worked, and its a known thing within that car community.

Just my .0000002
 

Brett327

Well-Known Member
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Super Moderator
Contributor
For the higher rated gas.... The biggest problem against people getting an advantage out of it, is that it takes TIME for an engine to remap its advance settings. You cannot just switch the gas and have an instant gain. With that said, on really hot days (100+) we used to run 100+ gas at the track (I was not an import guy) to compensate for the retard.

Of course, every car is different as to where it's designed to fire, but I generally call BS on things of that nature. These are the same people driving around with $2000 spoilers on their Ford Focii. ;) Show me some evidence on a dyno and we'll talk.

Brett
 

insanebikerboy

Internet killed the television star
pilot
None
Contributor
Not saying that you are wrong...because I am no expert...but your explanation doesn't make sense to me. Engines are engines, and high compression engines don't require higher octane for better performance, they require it to prevent detonation at that higher compression....survival if you will. Ever look at the compression ratios of aircraft engines? Please elaborate.

The higher octane gas actually burns slower and can withstand higher compression ratios before self-igniting than a lower octane gas. That's why if you use 87 in a motor that needs at least 93, it'll burn too fast and possibly self-ignite (a.k.a. dieseling) causing the knock you were talking about.

Now, why it runs better is that it has to do with the thermal efficiency that occurs when using a higher octane gas. Higher compression makes better use of the energy stored in the air/fuel ratio. Think of it kind of like a spring. If you compress a spring halfway it'll bounce 2 feet up, but if you compress is 3/4 of the way, it bounces 3 feet up. Just imagine the compression ratio like that, and the spark plug is your finger that adds the ooomph. So, if with the higher energy potential in the mixture you use a fast burning fuel your just essentially bypassing the plus of having the higher compression ratio. You'll get power, but since you haven't used the mix very efficiently you're losing max power. Bringing in a higher octane fuel with it's slower burning tendencies and it's less likely chance of self-igniting allows the peak power curve to be stretched out further, thereby milking all of the potential energy out of the A/F mixture.

That's why I was talking about the spark plugs in my last post. If you use a higher than necessary octane gas (i.e. 93 when all it needs is 87) you'll just foul the plugs because not all of the gas will be used properly. The energy stored in the A/F mixture in a lower compression motor isn't sufficient to properly utilize the energy coefficient possible with higher octane gas. Let that build up over time and you've got a chance to drop a cylinder or worse yet crack something. If you use the manufacturers recommendations you'll 99/100 times be fine, where octane use matters is when you build your own motors. I worked on one back in high school that the guy would actually mix 89 and 93 to get the octane he wanted (91 isn't available in Tennessee).

As for the guys who say they'll go put AvGas in the motor, should've clarified. Using modern day AvGas is just stupid and dangerous for the life of the motor. With all of the additives in the gas it's worse on the motor. Back when planes were just high performance radials that used 100 or 105 octane gas, that would make a difference. The interesting thing is that the octane would provide a bit of a boost at the expense of eating away at the rubber seals common in automobiles back then.

Now, using a high octane racing fuel is different. That's a 100 (or so) octane gas designed to be used in cars, so it'll actually make a good jump in performance.
 

MasterBates

Well-Known Member
You people have me about to break out my engine design books and start teaching ME-340...(That would be Engine Design at GMI)

IBB is pretty much right on..
RHFP is close.. Depending on the system used to control mixture and intake timing..

There are 2 ways to control detonation that are easily workable, given fixed thermal load/atmospheric conditions and fixed compression ratio and a given fuel. Variable valve timing can affect the effective CR as well, but that is a variable we will leave for later.

Method 1- Retard ignion timing, so that by the time the plug ignites the mixture, the piston will almost be on the way down. What this does it keep the mixture from "detonation" by spontaneous combustion. This is caused when the fuel/air mix reaches a critical pressure. Basically, it gets hot enough to ignite spontaneously. The "rattle/ping" you hear is the two flame fronts colliding in the combustion chamber.

This is bad, because it rips the boundary layer that is keeping the 4000F gases off the piston top, allowing the piston to ablade (think meltng to a vapor).

Retarding timing works only to a point. At some point you have to back off on the load on the engine, or get better fuel.

Method 2-
Richen the mixture..
The first thing this does, it the heat of vaporization helps cool the charge, giving more of a buffer against spontaneous combustion. The other thing it accomplishes, is that the richer mixute is harder to detonate.

This hurts performance, if you go richer than about 13.5:1, you really fall off the backside of the power curve with this.. (for reference, 14.7:1 air/fuel by weight is the stoichiometric mixture, which is the "perfect" mix from a chemistry standpoint)

Also, emissions go through the roof, fuel mileage goes down, and if you go rich enough, it can "wash" the oil off the cylinder walls, causing abnormal wear.
 
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