• Welcome to the Contour Enthusiasts Group, the best resource for the Ford Contour and Mercury Mystique.

    You can register to join the community.

gas question

E

elraido

I kant speel
Joined
Oct 28, 2004
Messages
15,657
Location
Northern MN
Ok, I have my SVT and it requires premium fuel, duh. My question is that around here we only have up to 91 octane. But it seems like there is two different type of it. regular 91 octane and nonoxygenated (says use for only car eligible for collector use, offroad, small engines etc). Should I be using the Nonoxy in my car or not? It is a little more expensive than the regular stuff but there is only one station that I know of that sells the regular 91 octane.
 
Why does the SVT require premium? Does it run a really high compression ratio that you cannot use 87? They are not boosted, correct?

What is the compression ratio on the SVT?

As for the gas, oxygenated stuff should be just fine.
 
If you want to run 87 octane gasoline you should add 1 or 2 more washers to the spark plugs to lower compression a bit and make it safer.
 
elraido said:
Ok, I have my SVT and it requires premium fuel, duh. My question is that around here we only have up to 91 octane. But it seems like there is two different type of it. regular 91 octane and nonoxygenated (says use for only car eligible for collector use, offroad, small engines etc). Should I be using the Nonoxy in my car or not? It is a little more expensive than the regular stuff but there is only one station that I know of that sells the regular 91 octane.
Click to expand...


use the regular stuff (91 regular) just based on the fact that it's more readily available.
 
First off, neither of you even addressed his question....he's asking if he should use NON-oxygenated fuel instead of regular 91 octane, and I'm pretty sure he didn't ask anything about using 87 octane. The SVT engine has 10:1 compression. Adding washers to the spark plugs is a) not going to reduce the compression a significant amount, and b) going to back the spark plug out of the combustion chamber and most likely reduce its effectiveness.

Elraido, as for using nonoxy, I think it's recommended for use in collector cars, small engines, etc because these engines aren't used as regularly and are more prone to moisture contamination, which nonoxy (no ethanol) gas resists. If you're driving your car almost every day, I doubt there would be a noticeable performance gain in switching. I think nonoxy also is slightly higher octane, but since the SVTs were designed for premium it again wouldn't make much difference.
 
elraido said:
Ok, I have my SVT and it requires premium fuel, duh. My question is that around here we only have up to 91 octane. But it seems like there is two different type of it. regular 91 octane and nonoxygenated (says use for only car eligible for collector use, offroad, small engines etc). Should I be using the Nonoxy in my car or not? It is a little more expensive than the regular stuff but there is only one station that I know of that sells the regular 91 octane.
Click to expand...

To me it sounds like the non-oxygenated stuff is for "off road use only" for whatever reason. Maybe it puts out more emissions or something.

They have non-tax diesel in Montana that is only for "off road use only" with a purple dye in it that is for farmer's. If they pull you over and stick a tube down your tank and it comes out purple, you get in a ton of trouble. Maybe it's got some sort of dye like that?

-----------------------------------------

And oh man, where do I start with these guys! :shrug:

boogieq said:
Why does the SVT require premium? Does it run a really high compression ratio that you cannot use 87? They are not boosted, correct?

What is the compression ratio on the SVT?
Click to expand...

SVT Contours are not boosted, but the compression ratio is high enough (10:1, btw) for Ford to warrant the use of ONLY premium fuel. Sure, you can get away with 87, but the high compression of the engine can ignite lower octane fuels before the spark even goes off. This means that the fuel is burning before the intake valve is closed, which, if you can imagine, isn't the best for the engine.

There is a knock sensor, but it's not as "giving" sort of say as my Sentra, which "recommends" premium fuel. The Sentra's knock sensor is very senstive in conjunction with ECU programming which allows running on 85/87 octane.

I don't think they put that programming in the SVT Contour, which is one reason why it says "PREMIUM FUEL ONLY" on the guage, manual, and fuel door. There's a reason why it says that, and other cars have "Premium Fuel Recommended" maybe in only one or two of those places. :ponder:

98TredSVT said:
If you want to run 87 octane gasoline you should add 1 or 2 more washers to the spark plugs to lower compression a bit and make it safer.
Click to expand...

I would definitely just use premium fuel than to do this :help:

-----------------------------------------
rollinstylee said:
First off, neither of you even addressed his question....he's asking if he should use NON-oxygenated fuel instead of regular 91 octane, and I'm pretty sure he didn't ask anything about using 87 octane. The SVT engine has 10:1 compression. Adding washers to the spark plugs is a) not going to reduce the compression a significant amount, and b) going to back the spark plug out of the combustion chamber and most likely reduce its effectiveness.
Click to expand...

Right-o!
 
Last edited:
elraido said:
Ok, I have my SVT and it requires premium fuel, duh. My question is that around here we only have up to 91 octane. But it seems like there is two different type of it. regular 91 octane and nonoxygenated (says use for only car eligible for collector use, offroad, small engines etc). Should I be using the Nonoxy in my car or not? It is a little more expensive than the regular stuff but there is only one station that I know of that sells the regular 91 octane.
Click to expand...

You can safely use either fuel. The added alcohol in the oxygenated fuel will probably not be noticed except in a very slight decrease in fuel economy.
 
boogieq said:
Why does the SVT require premium? Does it run a really high compression ratio that you cannot use 87? They are not boosted, correct?

What is the compression ratio on the SVT?

As for the gas, oxygenated stuff should be just fine.
Click to expand...

The compression ratio isn't much different. non-SVT is 9.8:1. Early SVT (until mid 99 with the returnless fuel system) is 10.0:1. The late SVT is 10.25:1. The problem is in the more aggressive ignition timing curve.
 
98TredSVT said:
If you want to run 87 octane gasoline you should add 1 or 2 more washers to the spark plugs to lower compression a bit and make it safer.
Click to expand...

You really shouldn't post when you don't know.

There are no washers on the spark plugs used on this engine. It is a tapered seat plug. Attempting to use a washer would really screw up how the plug fits, and if you did get it to fit, the heat range would be way off. The tip of the plug would run way to hot and probably melt.
 
I am happy you explained why the SVT requires premium fuel.. however, I DO know why premium is required in regards to compression and boost, as what occurs when using an octane that is not high enough for the application.

Thus my questions as to what the compression ratio was, and if SVT's ran boost * I have never investigated SVT contours *. Those two things being causes for requiring a higher octane.

And oh man, where do I start with these guys!
Click to expand...

I take some offense to that, but because the internet cannot convey how a question is posed and you do not personally know me, I won't automatically assume you figured I was a newbie. I have built 5 boosted cars that have all run low 13's with one running 12's. (3,600lb curb weight Grand Prix's and 4,000lb curb weight Bonneville SSEi) I am very familiar with boost and high compression. :cool: I was only asking for specifics on what was requiring the extra octane (compression ratio or boost) in relation to an SVT contour.

Anyway... back to your regularly schedualed thread.


Big Daddy Kane said:
To me it sounds like the non-oxygenated stuff is for "off road use only" for whatever reason. Maybe it puts out more emissions or something.

They have non-tax diesel in Montana that is only for "off road use only" with a purple dye in it that is for farmer's. If they pull you over and stick a tube down your tank and it comes out purple, you get in a ton of trouble. Maybe it's got some sort of dye like that?

-----------------------------------------

And oh man, where do I start with these guys! :shrug:



SVT Contours are not boosted, but the compression ratio is high enough (10:1, btw) for Ford to warrant the use of ONLY premium fuel. Sure, you can get away with 87, but the high compression of the engine can ignite lower octane fuels before the spark even goes off. This means that the fuel is burning before the intake valve is closed, which, if you can imagine, isn't the best for the engine.

There is a knock sensor, but it's not as "giving" sort of say as my Sentra, which "recommends" premium fuel. The Sentra's knock sensor is very senstive in conjunction with ECU programming which allows running on 85/87 octane.

I don't think they put that programming in the SVT Contour, which is one reason why it says "PREMIUM FUEL ONLY" on the guage, manual, and fuel door. There's a reason why it says that, and other cars have "Premium Fuel Recommended" maybe in only one or two of those places. :ponder:



I would definitely just use premium fuel than to do this :help:

-----------------------------------------


Right-o!
Click to expand...
 
boogieq said:
Why does the SVT require premium? Does it run a really high compression ratio that you cannot use 87? They are not boosted, correct?
Click to expand...
While "require" might not be the right word, when the manufacturer says use/do something, I tend to follow their directives. If you've bothered to note any number of prior posts like this, you'd know that right on the fuel gauge in a SVT vehicle it says to use premium fuel. Does that mean that you HAVE to use it? No, but why buy a performance vehicle and then feed it an inferior grade of fuel so that it can't run the way it was designed to? Some guys have tried lower octane fuel in their SVTC's and have noted a marked reduction in performance. So, I'd say if you want the vehicle to run the way it was designed, you are required to follow the manufacturers edicts. Otherwise, you have no one to blame but yourself if things go wrong.
Karl
 
98SVTC said:
Does that mean that you HAVE to use it? No
Click to expand...

Unless you want problems, then yes, you do.

Lower octane = easier to burn = burns earlier in the cycle than engine is designed for + not a sensitive enough knock sensor = pinging/detonation = engine damage!

If you're comfortable with that, then go ahead :shrug:

Like I mentioned earlier, my Nissan has a wicked sensitive knock sensor, which adjusts the fuel delivery and timing before it will cause damage, hence the "recommended" label.

Not using the proper fuel grade is like using the wrong oil grade... manufacturer says this car takes 10W40, but damn, that 0w15 is cheaper, so yeah, I'll just use that... :blackeye:
 
Big Daddy Kane said:
To me it sounds like the non-oxygenated stuff is for "off road use only" for whatever reason. Maybe it puts out more emissions or something.

They have non-tax diesel in Montana that is only for "off road use only" with a purple dye in it that is for farmer's. If they pull you over and stick a tube down your tank and it comes out purple, you get in a ton of trouble. Maybe it's got some sort of dye like that?
Click to expand...

Red-dye diesel. Its for agricultural use only. And you're right -- if you're caught with it on I-90 on your way to the Testicle Festival in Rock Creek Lodge (founded by Rod Lincoln, the "Baron of Balls" -- he has a tattoo that states exactly that -- I am not making this up) and the Montana Highway Patrol decides to check you out, you'll be so late that you'll miss the wet T-shirt contest, dammit.

As regards gasoline -- do what FoMoCo says. Not only do they build great cars, but they put in millions of dollars and thousands of hours of R&D into ensuring that your car will provide strong, reliable performance. Heed their advice.

I'm a purist -- Ford says it, I do it; Ford makes it, I run it. My beautiful SVT is bone as* stock, and I love her that way -- the way Ford built her. At minimum -- follow the fuel recommendations -- use 91 or higher.

Should you decide to cheap out, you may experience some small power losses, in addition to running the risk of engine deposits from low quality or low grade fuels without the benefit of detergency.

Car and Driver's Tech Ed. Larry Webster sums it up thus: "In most cases, we're talking about very small horsepower losses, but if you want your car to produce all its beans, put in the recommended octane."

Two complete articles on fuel grades / quality and its impact can be found below:

http://www.caranddriver.com/features/3604/regular-or-premium.html

http://www.caranddriver.com/columns/9752/larry-webster.html

To address elraido's original question, though -- you sure can run the nonoxygenated fuel -- it will produce a slighly higher level of emissions, on balance, and will deliver better fuel economy, but since its not legal for public roads, you run the risk of ending up in hot water if you get caught. I'd run the legal stuff, and since ethanol is hygroscopic -- meaning it sucks up water like brake fluid -- run a bottle of drygas through every 10,000 miles -- keep the water -- and the rust -- out of your fuel system.
 
Last edited:
To address elraido's original question, though -- you sure can run the nonoxygenated fuel -- it will produce a slighly higher level of emissions, on balance, and will deliver better fuel economy, but since its not legal for public roads, you run the risk of ending up in hot water if you get caught. I'd run the legal stuff, and since ethanol is hygroscopic -- meaning it sucks up water like brake fluid -- run a bottle of drygas through every 10,000 miles -- keep the water -- and the rust -- out of your fuel system.

Drygas is alcohol and will do little or nothing to remove water from gasoline that already has alcohol.
 
Big Daddy Kane said:
Unless you want problems, then yes, you do.

Lower octane = easier to burn = burns earlier in the cycle than engine is designed for + not a sensitive enough knock sensor = pinging/detonation = engine damage!

If you're comfortable with that, then go ahead :shrug:
Click to expand...
I thought I explained quite clearly why premium should be used. This subject has come up many times before. A few guys have tried regular. It works but not very well and was probably only done in a pinch or by mistake. As I said, I wouldn't do it and the manufacturer doesn't recommend it.
Karl
 
I've avoided it on this thread but now I'll comment on octane.

Let me start by saying that I made my living for more years than I care to remember as a drivability technician with a hobby of hot rodding. I was the local "go to" guy to resolve tuning problems on modified engines.

Octane is nothing more than resistance to ping. If your engine doesn't need higher octane there is absolutely no benefit to paying more for higher octane fuel. The higher detergency is the only reasonable argument, but premium tends to create more carbon, especially in an engine that doesn't need it.

That said, I run 87 octane in my SVT. During it's life it has had maybe 20 or 30 tanks of premium if that. I have checked thoroughly and can say that there is absolutely no difference in performance or fuel consumption between 87 and 91 on my car.

Now I will add that I'm disappointed that Ford didn't tune it better.

I will also add that the car is very aggressively maintained so there is not much chance that there is much of any carbon built up in the combustion chambers and that probably makes some difference.

I will also note that in my drivability and hot rodding experience I have tuned many cars to run on premium and I certainly know the difference.
 
LauraSVT said:
To address elraido's original question, though -- you sure can run the nonoxygenated fuel -- it will produce a slighly higher level of emissions, on balance, and will deliver better fuel economy, but since its not legal for public roads, you run the risk of ending up in hot water if you get caught. I'd run the legal stuff, and since ethanol is hygroscopic -- meaning it sucks up water like brake fluid -- run a bottle of drygas through every 10,000 miles -- keep the water -- and the rust -- out of your fuel system.
Click to expand...

No emission tests done here, so I don't think I need to worry about getting "caught" running the non-oxy. I actually have never even heard of anyone getting caught for that around here. Like I said before, I have found only one station (out of 15 or so) that has plain jane 91 octane. So, I am just going to continue using the non-oxy since it is much more accessable and is the same price.

Only a few people I don't question at all when they post about things. Stazi, Demon, Big Jim, Ray, Tony, and (can't believe I am saying this) Steeda. And with Jim saying that these cars can run lower octane, I believe him. But, I am a wuss and am going to continue with what the gas guage says on premium. :laugh:
 
Only a few people I don't question at all when they post about things. Stazi, Demon, Big Jim, Ray, Tony, and (can't believe I am saying this) Steeda. And with Jim saying that these cars can run lower octane, I believe him. But, I am a wuss and am going to continue with what the gas guage says on premium. :laugh:

I should have added it works for me, but your results may vary due to different factory tunes and how the car is maintained. Perhaps I should have said "Kids, don't true this yourself at home".
 
You must log in or register to reply here.
Back
Top