Regular or Premium

montecarlo31 · Aug 19, 2014

FordandPolaris said:
Google would have all of the proof you need. Higher octane is designed to allow for higher compression motors to run without early detonation. If you increase octane without increasing compression, no more power is made. Stick with 87.

Sent from the Pocket Computer

Not quite but thanks for playing. There is more to the equation then simply "compression" and google. If the engine can make more power on E85, which it does, it WILL make more power on 93, 95 etc. Remember these engines has the ability to adjust timing on the fly which is where the increased power comes from when running E85. There is no change in compression as you imply.

FordandPolaris · Aug 20, 2014

montecarlo31 said:
Not quite but thanks for playing. There is more to the equation then simply "compression" and google. If the engine can make more power on E85, which it does, it WILL make more power on 93, 95 etc. Remember these engines has the ability to adjust timing on the fly which is where the increased power comes from when running E85. There is no change in compression as you imply.

Just because the octane fuel changes doesn't mean the motor will automatically change it's timing. The only time it changes timing is if it detects knock, and then it will retard instead of advance. The timing is set somewhere around 10 degrees advance to meet fuel efficiency and smog regulations. It will not go more unless you upload a custom tune that tells it to do so. This is why Edge and SCT programmers make such a big difference.

If you believe that, run premium all you want. I run it in my sleds due to them running a high 11:1 compression. My truck runs 9:1 so there is no benefit to running premium. E85 equates to 105 octane (race fuel) but the only time you need to run race fuel is when you have race compression (11:1 or higher). Otherwise it's just a cheaper option to 87 pump gasoline.

Sent from the Pocket Computer

metaldrgn · Aug 27, 2014

montecarlo31 said:
Not quite but thanks for playing. There is more to the equation then simply "compression" and google. If the engine can make more power on E85, which it does, it WILL make more power on 93, 95 etc. Remember these engines has the ability to adjust timing on the fly which is where the increased power comes from when running E85. There is no change in compression as you imply.

Actually that's pretty much the entirety of octane ratings. How much they can compress before they autoignite. Of course the rating is the rms value of RON and MON combined. For regular gasoline generally the higher the rating, the slower the burn rate which is why it's usually better to stick with the lowest rating you can run. With a variable cam you can change the dynamic compression ratio which is pretty much the only reason you could see a performance boost from using a higher octane. E85 is a different animal since it uses ethanol. Ethanol can make more power because it has oxygen in the molecular chain but you have reduced fuel efficiency because of that and the fact that the molecular chain isn't as long as gasoline I believe.

You are right in the respect that it's more than the static compression rating.

keithnra · Aug 28, 2014

regular

montecarlo31 · Aug 28, 2014

FordandPolaris said:
Just because the octane fuel changes doesn't mean the motor will automatically change it's timing. The only time it changes timing is if it detects knock, and then it will retard instead of advance. The timing is set somewhere around 10 degrees advance to meet fuel efficiency and smog regulations. It will not go more unless you upload a custom tune that tells it to do so. This is why Edge and SCT programmers make such a big difference.

If you believe that, run premium all you want. I run it in my sleds due to them running a high 11:1 compression. My truck runs 9:1 so there is no benefit to running premium. E85 equates to 105 octane (race fuel) but the only time you need to run race fuel is when you have race compression (11:1 or higher). Otherwise it's just a cheaper option to 87 pump gasoline.

Sent from the Pocket Computer

If you are only getting 10* then something is wrong. I am getting more than that on a stock tune.

metaldrgn · Sep 2, 2014

montecarlo31 said:
If you are only getting 10* then something is wrong. I am getting more than that on a stock tune.

The baseline is set around 6 degrees and it advances more with rpm and load up to around 50 degrees depending on the engine and tune

01yellerCobra · Sep 2, 2014

metaldrgn said:
The baseline is set around 6 degrees and it advances more with rpm and load up to around 50 degrees depending on the engine and tune

That also depends on the load. 50 degrees of timing at high rpm and high load is a little much.

expydude · Oct 21, 2014

Why are some of you guys only getting 6 or 7 mpg with a 3rd gen? I haven't had that bad of milage since I had an 84 bronco with a 351 in it

Sent from my SAMSUNG-SM-G900A using Tapatalk

01yellerCobra · Oct 29, 2014

I think I may have found the reason for mine. Or at least a symptom. Over the last couple of weeks I've noticed a tapping sound. Started off barely audible. Thought it was just me. Now I can hear it sitting at a light and the truck is down on power. Back to the dealer she goes. I've seriously been considering trading it in. The warranty is almost up and I'm worried about future issues.

Am3ricanInfid3L · Dec 31, 2014

$45 gets me a full tank (using regular). I'm definitely loving the lower gas prices!!

Regular or Premium

Regular or Premium?

Regular

Premium

E85

Diesel

montecarlo31

Full Access Members

FordandPolaris

Full Access Members

metaldrgn

Full Access Members

keithnra

Full Access Members

montecarlo31

Full Access Members

metaldrgn

Full Access Members

01yellerCobra

Full Access Members

expydude

Active Member

01yellerCobra

Full Access Members

Am3ricanInfid3L

Full Access Members

Similar threads

Latest posts

Members online

Forum statistics

Share this page