Contour Enthusiasts Group Archives Forums General Troubleshooting My wife put in 87 octane gas in my SVT!!!!!!!!!!!!!!!!!

OK so i take it down the road,the check engine light is flashing. I went down to the store to get some octane booster, but before I got there something popped from under the hood. Sounded like a intake back fire. Now it runs like its on three cylinders. BTW its about 92 degrees out but I drove the car gently to the store. Should I be looking into getting a new 3 liter block?

Check the spark plug condition....

I run 87 octane in my SVT all the time. I cannot tell any difference when I run high octane stuff, and I drive it hard. I suspect that you have something else happening. Was it an off brand gas that may have some water or trash in it?

Big Jim using 87 octane? I'm shocked to say the least.

Ever read your owners manual Jim? (j/k)

John

Yes, I have.

In my defense I'll mention that when I took delivery of the car I did not have an SVT supplement. When I did get the supplement and read that 91 octane or better was recommended I had already run about a dozen tanks or 87 through it. At that point I tried a few tanks or premium and found that there was no difference in performance or fuel economy.

During the life of the car it has had maybe 20 tanks of premium. It now has 131,000 miles on it. I have only heard a very light ping twice, both times on light acceleration on unseasonably warm winter days.

Also, I go out of my way to keep everything very clean in the engine. I clean the throttle body often, clean the injectors often, and change the air filter every 15,000 miles. Oil and oil filter every 3,000 miles. Annual coolant changes. If there were a bit of carbon build up in the intake ports or in the combustion chamber higher octane might be needed. Don't forget that the compression ratio isn't that much higher on the pre 2000 SVT. Non SVT was 9.8:1 and SVT was 10.0:1. The 2000 SVT may not be quite as tolerant since the compression ratio was raised to 10.25:1.

It may not work for others, but it works for me. Believe me, I know and understand the damage that can happen from detination from the wrong fuel and I would not be using the lower octane fuel if I felt there was any real risk.

My main point in my original post on this thread is that I doubt that his problem came from one tank of 87 octane fuel.

Same thing happened to my SVT; wife put 12 gallons of 87 octane in it. The major problem was that after I raised much hell with her and told her she could never drive it again, I couldn't tell the difference! Must have great knock sensors on an SVT! BTW, I didn't tell her that I couldn't tell the diff.

Don't forget Big Jim, the SVT has a more aggressive spark curve to go along with the compression bump. I'd be interested in seeing a dyno with your car on 87 and on 91. Not that I'm sending you the money to get that done. :p

Based on what I know about your automotive knowledge, I trust that you know what you are doing. I can't say I'd recommend it to anyone though.

For what it is worth, the SOP dyno can tell no difference. I know that isn't very scientific but it is useful. My SOP dyno could tell that there was a drop in low end power with the secondaries held open.

SVT says that the preferred octane is 91. They say you can run it on 87 and as mentioned above, the car does have sensors that keep the engine from knocking. But they also say there will be a performance loss.

That's grounds for a divorce