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

    You can register to join the community.

Premium Gas

m3ta1head said:
I've always put 87 in my SE...I have the SVT duratec so I should be using 93. I never even realized this. :(

What exactly does pinging sound like? I'm not sure if I've ever noticed it.
Click to expand...


well that is a mixed bag. the engine should have premium because of the compression ratio. but if you are still using the SE PCM it doesn't have the same timing curves as the SVT PCM. So by the PCM you don't need premium .....

I am not sure that I can discribe the sound never believing I have heard it before put I believe you would know.
 
Have you ever driven in an older POS car, possibly a tiny little 4 cylinder neon or some junk car?

Ever notice that when you (or they) are accelerating very mildly the engine sounds... "smooth"?? like a normal engine, but if they get on it that the SOUND changes (not necessarily the acceleration in this case.. haha) to a more.. poppy, clacky, chattery sound? That's extreme pinging. Probably caused by lack of maintenance on the older engine, as it were.

Floor the engine on an older car that hasn't been maintained and listen for it. It could also be much quieter, and just sound like a card in some bicycle spokes (though muffled from being under the hood).
 
Last edited:
MapOfTaziFoSho said:
Wow, way to give advice on something you know nothing about...

I love these threads where the blind lead the blind. :rolleyes:


For premium fuel, don't forget that there is no sensor to "detect" lower grade fuel, there is only a sensor to detect knock. Knocking is BAD. In a pinch you can use 87, but using it on a regular basis means you will likely be hitting knock every time you get hard on the throttle, and then the knock sensor will trigger the timing to be pulled back. This means that every time the knock sensor pulls timing that some knock had to have occurred already for it to detect it. Is it going to blow up? no, but its definitely not helpful to the long term health of the engine. I mean for chrissake, you spent the money on a brand new car and you aren't willing to protect your investment...


Calculate your additional cost per year...it is going to be a $200 difference at most.

This was my post on Cobaltss.net
Click to expand...

I hate to say this, but you should follow your own advise and not speak to those things that you don't know about.

I have nearly 245,000 miles on my SVT. I bought it new. I run it to the rev limit at least once a day, often many times a day. I have had probably less than 20 tanks of premium fuel in it, as every once in a while I start to wonder if it really makes any difference. It doesn't. I cannot tell any difference in either performance or fuel consumption.

Higher octane does not provide more power in and of itself. The modifications that can be made to the engine to better use higher octane does. At least with my SVT, Ford didn't tune it aggressively enough to take advantage of higher octane. I'm VERY disappointed that Ford didn't.

The only disclaimer I'll make is that I do aggressively maintain my car, so there is probably very little carbon built up inside the combustion chambers and that might make a difference.
 
BrApple said:
well that is a mixed bag. the engine should have premium because of the compression ratio. but if you are still using the SE PCM it doesn't have the same timing curves as the SVT PCM. So by the PCM you don't need premium .....

I am not sure that I can discribe the sound never believing I have heard it before put I believe you would know.
Click to expand...

Please explain how the difference between 9.8:1 and 10.0:1 makes any significant difference in octane requirement. It is the cams, intake, exhaust modifications, and tuning (ignition timing maps and fuel maps) that move it toward a higher octane requirement.
 
TX00SVT said:
This thread comes up about once a month. Search on the subject, and you will find the answer. :rolleyes: You are driving a car with 10.25:1 compression (maybe a little less because it is a 98.5) compared with most cars out there that are at like 9:1. When it already cost $50+ to fill up your car, what significance is that extra $2 for premium once every week or so? Take your lunch to work one day a week, and you've more than made up for it. Your car should run better, last longer, and give you better fuel economy. Tests have shown that running premium in cars designed for regular 87 has no positive effects, however running 87 in a car made for premium DOES have negative effects.
Click to expand...

Compression difference is much less. Standard Duratec is 9.8 to one. 98 to early 99 SVT is 10:1. Late 99 and 00 is 10.25:1.

Just for comparison, a stock Escape 3.0 is 10:1 and is rated for 87 octane fuel.

On the SVT, it is not the compression that may drive the need for higher octane.
 
96FordPOS said:
Higher the octane the less the chance that combustion will occur at the wrong time, SVT's have higher compression so they need higher octane gas so combustion will not occur due to the higher compression. Basically the knock from putting in 87 happens because the pressure causes the gas to combust before the spark plug sparks (bad)

Diesel fuel is like 40 octane they want it to explode (combust) due to pressure alone (hense no spark plug)

So for those with non-svts putting higher octane in wont do :censored::censored::censored::censored: either. Higher octane fuel isnt better it can just withstand more compression.
Click to expand...

Diesel fuel is measured in Cetane, not Octane. They are opposites.
 
And what I hope is my last comment on this thread, I have heard my engine ping. Twice. About two years apart. It was on a hot winter day (something we sometimes have in southern California) with winter blended fuel that probably wasn't up to 87 octane. It was a light throttle and light load and instantly went away with a little more throttle, what would be called "trace ping". "Trace ping" is supposed to be a sign that your tune is optimal for the octane of fuel you are running. "Trace ping" does need to be avoided though is you are running boost. It is because of hearing "trace ping" that I wonder if my car's factory tuning included a functioning knock sensor.

What I have heard is certainly not enough to tell me that I have to run higher than 87 octane.

Other people with different factory tune and different maintenance habits may have different results.
 
You must log in or register to reply here.
Back
Top