87 Octane in a Gen III SHO?

[5.0stang]

I'm looking at buying a '96-'99 SHO as a daily driver, but I know Ford "recommends" premium.

As a daily driver, has anyone actually seen problems running 87 Octane? The 10:1 compression isn't although much different from a lot of cars that run '87 octane.

Curious your experience if you actually ran '87 octane and for how long.

 

[Nuke]

Ran 87 in mine plenty. No adverse effects, except it is as slow as all get out. No pinging, no knocking, no issues. But I am being serious when I say I swear my bone stock Accord 2.2 non VTEC 5 speed would have out ran it.

It will run just fine. Mine had no issues. I just got sick of it running slow. If you don't care how it performs, run the 87. It is a good way to save money. Hope that helps.

 

[RonPorter]

FWIW, the first four stock Gen 3s that ran in the high 14s about 15 years ago all did it on 87 octane. All stock Gen 1-3 SHOs, that don't have mechanical issues, will run fine on 87 in virtually all situations. We learned this way back in 89:

 

[98SF19]

My main experience with premium is that it yields better fuel economy. I remember years ago reading an assessment on the topic that the premium essentially burns "slower" (IE more evenly and completely) than the 87 or mid-grade, and that the higher price should not be paid with the expectation of better performance, but more efficient energy conversion and a cleaner engine. Ron's account of the fastest SHO's running on 87 is well known among SHO veterans, so I guess the 87 is quicker-igniting with the upside being a higher rate of available energy and the downside being lower efficiency over the long haul and more by-products.

 

[RonPorter]

My main experience with premium is that it yields better fuel economy. I remember years ago reading an assessment on the topic that the premium essentially burns "slower" (IE more evenly and completely) than the 87 or mid-grade, and that the higher price should not be paid with the expectation of better performance, but more efficient energy conversion and a cleaner engine. Ron's account of the fastest SHO's running on 87 is well known among SHO veterans, so I guess the 87 is quicker-igniting with the upside being a higher rate of available energy and the downside being lower efficiency over the long haul and more by-products.

No, it burns at the same rate. Higher octane is more resistant to igniting, but the burn rate is the same. From published tests, including dyno runs, over the years, and with personal experience, 87 works better for performance and economy. Higher octane than the engine needs has been shown to have the very minor effect of very slightly retarding the ignition timing with the delayed fuel igniting.

There's have been SHO folks over the years that swear that their cars run and perform better on higher octane. We've told them that, apart from the psychological effect, they could be using octane to cover an operating problem with their car. As the Bedard article above points out, a healthy running SHO under most driving conditions has no need for the octane.

 

[RonPorter]

Another thing. If you can find 87 octane straight gas without any alky in it, you will get the BEST mileage and performance. Getting really tough to find gas without the 10% ethanol, though.

Another thing to keep in mind is that every additive added to pure gasoline drops the BTU level, which is why pure gasoline runs better than 10% alky gas. And also higher octane gas, apart from the 10% ethanol, will also have a lower BTU level from the octane raising chemicals, as well as the extra detergent that companies like Shell advertise to try to suck you into buying the pricey stuff.

 

[98SF19]

Higher octane is more resistant to igniting, but the burn rate is the same

Ron, this seems like a contradiction to me, but maybe I'm misunderstanding what you mean. Also, I observe a clear difference in fuel economy between 87 and premium, in my SHO and the wife's minivan, with the latter giving about 5%+/- more miles per tank than 87.

 

[98SF19]

Actually I think I get the quote - it's analogous to static friction vs dynamic, with the static being the "resistance to ignition" and the dynamic being the burn rate?

 

[RonPorter]

Burn rates don't change, it's the resistance to ignition. Never noticed any mileage nor power difference across many cars, including a half dozen SHOs. Only difference is in pure gasoline versus ethanol fuel. Technically, running higher octane in engines that don't need it should reduce mileage and power.

 

[stephen newberg]

Well, nice to see you posting, Ron. Actually, this is the first time in a bit that the posting section has worked right for me, and in addition, I am not even getting a virus warning every time I go to a new place on the site. So I guess Bizzy has managed to find and, at least for the moment, **** off the problem. Anyone know what it was? Regardless, nice to be able to use the site again without problems.

pax, smn

 

[RonPorter]

Bizzy doesn't own the site anymore. I don't get out here very often, and when I tried it on the work PC with AVG, I got a security warning on every page. Norton here on my laptop seems to be fine with it.

I see a C4S in your sig. Nice!!

 

[stephen newberg]

Who does run the place now, do you know, Ron?

I was getting that warning from my AV, its called ESET NOD32. Showed up a couple of weeks ago and after a week or so went away for a couple of days and then was back for another week or so, but now appears gone. I think they were having some sort of problem.

Yes, the C4S is a very fine machine. Picked it up about 3 years ago now, as it came in off a 2 year lease. Under 10k on it but it got me 40% off the list price. Very happy with it and drive it year round. some of those full winter high performance tires from the Europeans have gotten really remarkable.

On the SHO, I find I am starting to get some smoking from the valve covers gaskets, which I guess have over the years started to dry out with the car only being run once a month or so. I have never had that sort of problem before. Do you know if replacements are even still available? I seem to recall hearing they were no longer in the supply chain.

Good to hear from you.

Best,
Stephen

 

[SHOdded]

Jordan, by the handle jordanr, runs the site now. Very responsive and helpful person.

 

[E1]

Jordan, by the handle jordanr, runs the site now. Very responsive and helpful person.

Thank you for this useful information. Is it in a 'Sticky" anywhere?

 

[98SF19]

Stephen, I did my VCGs a few years ago and I think someone had posted a link to new ones as I was asking the same thing, but they may be gone now.
Paul says just soak your old ones in lacquer thinner just until you see them start to swell. I wound up just buying a set from him! But I DO still have my originals.

 

[SHOdded]

Thank you for this useful information. Is it in a 'Sticky" anywhere?

There's this thread:
http://shoforum.com/index.php?threads/news.127756/

 

[stephen newberg]

Stephen, I did my VCGs a few years ago and I think someone had posted a link to new ones as I was asking the same thing, but they may be gone now.
Paul says just soak your old ones in lacquer thinner just until you see them start to swell. I wound up just buying a set from him! But I DO still have my originals.

Thanks Ryan, I will pull them off and give it a try. If you run across the link to the new ones, or where they used to be, point it out to me, but its not a big rush of any sort. I really do only run her up once a month or so.

pax, smn

 

[98SF19]

http://shop.rocketracingshop.com/Ford-Sho-34_c33.htm
BOOM

 

[stephen newberg]

Excellent! Thank you.

pax, smn