Question for my fellow 5 Star owners please.

I've got 3 sets of tunes: economy, performance, towing. All are for 87 octane fuel. I see a few posts here and there with guys running 91 octane tunes when towing or hauling. And I'm curious if there's really that much difference in engine performance?

I should state that fuel economy means very little to me, that's not the reason I'm considering 91 octane fuel. I am only interested in engine performance gains.

I have no problem plunking down the additional $100 (or whatever it is) for premium fuel tunes. But I don't want to risk just throwing that cash away if there's feedback from this group that there's really no perceptible difference.

If it matters at all, I have 3.73 gears, and usually drive in the 4000-8000 elevation realm.

Comments appreciated. Thanks.

 

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There are a few good reasons to run Premium fuel in my opinion. I also look to find 100% gasoline with no ethanol. I don't have a 5 star tuner but do have one from another outfit. Premium gas has better cleaning agents and burns more completely. When I changed my sparkplugs they all came out and none were crusted over with carbon. That is the reason they break or give people problems. When towing you are running the engine hard and 100% gas will give you more energy return on the gallon. That translates to better performance regardless of timing advance.


This is a hot topic and many will say that you are wasting your money. I will take their opinion under consideration and continue to do what I think is best. My truck still runs like new and I have run premium (91) in it since day one. Shell Gold is always my first choice but anything I can find that does not have ethanol will do for me.


I have towed 5th wheels and goosenecks for many of the miles on my truck and am very happy with the results. My v10 works very well with 91 gas.

 

If you're towing, and the engine is hot, higher octane can only help - with a tune, it'll get a little more power of it too.

How much? Dunno - but to get the most out of it, 93 would be required, I'd think.

Warning, no matter what the tune is, 93 octane WILL run slightly "cold" under normal driving conditions. You can feel it as you tip into the throttle. The engine will just feel "cold" all the time. If you're towing, it won't matter.

That "cold" feeling is the fact that the engine doesn't have the compression to fully partake of the high octane. But again, if you're towing, that's not a concern.

 

Below I have posted a portion of a post I made over a year ago answering another members question about the various tunes and the differences between them. My rig, of course isn't identical to yours, our Eastern mountains aren't as high or steep and much of my driving style involves some effort to get the best mileage even when towing heavy. But this info does show how the higher Octane fuels and matching tunes do improve the engine/trans performance under load. I my opinion the higher Octane tunes and fuel are well worth the cost if you want to get the most from your truck when working it hard.

As far as the different tunes and how they perform, I have not towed with my rig in it's current configuration (4.88 gears, 35" tires and 11k TT) with the factory tune. The last time I towed with the factory tune it was still on 31.5" tires and was only pulling 9.5K lbs.
On my rig when I loaded the 87 Octane Tow tune I found that it was very eager to downshift out of OD when climbing a highway grade, which would be great for someone looking to either be the fastest one to the top of the hill or someone who wants to maintain a constant speed on the hill climb no matter what. I'm not either one of those guys, I am willing to bleed some speed on the climb if it means that I can stay in OD to maintain the best economy that I can while not slowing down too much and holding up traffic flow. For my setup I have found that the Performance tunes (87 and 89 Octane) will allow me to hold onto OD with a higher throttle opening % than the Tow tunes did. This works for me, between the deeper gears and whatever amount of additional power the headers (and tunes) provide my V-10 has enough grunt to handle all but the biggest Interstate Highway grades here in the East in OD. As an example on a given hill at 65 MPH the 87 Octane tune will allow me to roll the throttle open to about 54-55% before it will force a downshift. That is a big improvement over stock which would drop down around 45%-ish under the same load. Moving up to the 89 Octane Performance tune (and 89 octane gas) on a similar grade at the same speed and towing the same load I can work the throttle opening up to about 65% before forcing it to downshift. That additional opening makes a noticeable difference in engine output that allows it to hold speed during the climb even better than the 87 Perf tune. For a real world example of the application of this operation here is some data from a trip last year towing home from Charlotte NC back to the Philly suburbs. The bulk of the trip was up I-77 and I-81 which is nearly all mountains (Decent sized Eastern Blue Ridge Mountains, and I think maybe the Smokies down by Charlotte). We were towing the 11,000lb TT with 6 adults onboard our EX for combine weight of about 19,000lbs. I was running a little faster than typical due to our time schedule and a stop to visit a forum member in VA, I was going 65 to 75 MPH as much as possible on I-77/81 but had to run with slower traffic around Baltimore and that extended area at evening rush hour. If I could hit the base a grade climb at 73/75 MPH and hold a throttle opening of 60/63% (was running 89 Octane tune/gas) it would slow to no less than 55/60 depending on the length of the hill, all the while staying in OD. On the few very steep climbs I would let it downshift to keep the speed up to the traffic flow, same if traffic wouldn't allow for the higher climb start speeds. The 565-ish mile trip finished up with a 61 MPH average moving speed (pretty good considering the Balto beltway crawl and our side trip on several miles of surface streets in VA) and 8.75 MPG.

 

WE3ZS: thanks for the info. Though our respective rigs, loads, geography, and driving styles are different, I appreciate you taking the time to weigh in.

I acknowledge that premium fuel often has more (better?) detergents so the conversation can move beyond a simple question of performance differences. Ideally, I would run only 100 percent gasoline (none of that crap-anol stuff). There are a handful of stations near my house where I can fill with non-ethanol. Away from home, though, I don't think I've EVER seen it along our usual routes to/from the mountains.

For an engine to fully take advantage of higher octane, the compression has to increase - I completely understand that. And tunes aren't going to alter compression ratio. Primarily, tunes will (I assume) alter timing a bit. I guess my hesitation to drop the cash on premium fuel tunes is higher octane fuel will burn slower, so timing can be advanced. But at 8000 feet, the density of air is greatly reduced. So the fuel/air mixture will burn *even slower*. And I have to wonder if the net effect at those altitudes will be actually poorer performance relative to 87 octane tunes?

 

My stock 2000 running around 19-20k gross does much better in the western mountains on 91. On 87 detonation would start at the very bottom of a climb, necessitating a downshift and throttle modulation or the pinging would resume. On 91 I could stay in the throttle much longer before any detonation and after the downshift I could keep my foot buried without pinging. 89 works well for me when towing east of the Rockies. Time for headers, Y, and tunes.

 

My altitude is roughly 1400 feet where I live so it may not be apples to apples for your situation.

The 91 perf / tow tune from mike is the best of the tunes I bought, by far. It does advance the timing to take advantage of it. If you remember the older distributor engines, advancing just a couple of degrees was noticeable.

I do notice slightly better mpg with 91 also. It actually was paying for itself when there was about a 50 cent spread or more to 87 octane. I don't care about it being worth it as the performance difference is noticeable. That is all that matters.

I have been running the 91 perf / tow tune since I bought it from 5 star...maybe 6 years ago? I have seen no reason to change.

The other thing that is noticeable is using ethanol free premium. I don't use it all the time but if it's handy I will get it for sure. Not as much difference in power but there is in mpg. Get it before a road trip and you'll notice it.

 

I just did a long run hauling my 4000lb slide in camper. I have an 89 octane performance tow tune. The truck runs fine using 87 octane fuel. It runs great using 89 octane fuel and it runs even better using 89 octane with octane booster added. These motors like octane, but don't need them!

 

I have 99 F350 drw 4x4 that I have programed for 91 octane from 5 star. I very much like the way the truck tows my 12,500# 5R. I have replace the 3:73s with 4:10s and between the program and ratio changes, this truck does very well. And by the way. I just crossed over 415K miles.

 

Higher octane fuel does NOT have better detergents and does NOT 'burn better'
People need to stop with these fabrications.
The only time you need premium is when your vehicle is setup for premium. That usually means the timing is slightly different. This is where the 5 star tune comes in. So if you use an 87 tune, using higher octane is a complete waste of money.
Now, if you have a 91 octane tune, then you should use 91 octane fuel. Using lower octane fuel on your 91 tune could cause pinging/detonation.
Again, it does NOT burn better or have better detergents. Any fuel you buy today is already loaded with detergents. If you have any issues w your fuel, you need to look else where to solve it in most cases.
The only fuel I'd avoid is from that small gasstation in the middle of nowhere that hardly sells any fuel.It's likely old fuel. If it's an old station the tanks might be leaking and other crap is in the fuel. I've seen some dramatic diesel containment with water that make you wonder.

 

I have to agree with geekwithoutacause, except for one thing that might have been overlooked.

If you're running loaded, towing heavy, whatever, the engine will be locally hotter in the cylinder heads and pistons, which is why you might benefit from a slightly higher octane than what the tune (stock or aftermarket) calls for. It's good insurance in any case, to go from 87 to 89, or if you're running a higher octane tune like 91, to go to 93 when towing.

Without datalogging the knock sensor PIDs, you'd never know it's pinging and the PCM might be retarding the timing causing power loss (only 4 degrees, if I recall correctly, but enough).

But otherwise, totally correct. There is no difference in how well a particular brand and octane burns. There is only the octane rating, all other things being equal like brand. Too high an octane for the tune will not benefit you.

(I painted with broad brush here)

 

Just to nit pick a little, higher octane gas does "burn better" solely due to the higher octane allowing for a slightly slower burn, that's why it is less prone to detonation and knock/ping.
And some producers/marketers do use a different (better/improved/increased) additive package in their high(er) octane blends. I know for a fact that when my refinery was still owned by Sunoco and they still had their Ultra 94 Octane Premium gas it had a different additive package from their 91/92 blend which was different from the 89 and 87 blends. Now we are a private refiner and produce either raw stock for marketers to add whatever they choose downstream or we blend to a buyers recipe. But as has been said, even the lower octane blends contain enough additives and detergents to keep most fuel related gunk issues at bay. And I agree, pure gas with no corn liquor added is superior to what is at most pumps, of course finding it in some parts of the country can be a challenge. It's very hard to find in my area.

 

I know this is a year old. With all the 5Star tuning info on this site, only geekwithoutacause and Krewat actually had info I was looking for. Folks were saying this and that about the tunes, but never mention what octane gas they were using for what octane tune. Sort of an important apples to apples information that is left out.

I have a stock 2001 F250 V10. I do pull a modest 3 horse trailer with LQ. I do cross country driving with and without the trailer. I also occasionally commute to work with it. Towing performance is important with the trailer. When commuting, MPGs are also a consideration. With that, I have been getting 15-17 mpg commuting on 85 octane and wish there was an easy way to bump ignition timing a couple degrees. I am a bit of a hypermiler geek - don't judge me! With the extreme lack of octane gas used vs octane program used, this leaves me hanging on the tunes to get.

I usually stick with the lowest grade octane gas when DD, since it has the most complete burn. I go with mid-grade octane when towing since it has a noticeable improvement in performance with towing. I didn't want to start a new thread since this has been beat to death, except for the missing valuable information. I will contact Mike soon to discuss MY needs.

Thank you to both geekwithoutacause and Krewat for actually having useful octane vs tune info!

 

I have 5 Star tunes in 87 and 89 octane and use the appropriate octane gas for the tune.. I tow a TT loaded ~ 9000lbs. When I ran the 87 octane tow tune it did downshift sooner and I did experience pinging along with lower mpg's. I went to a the 89 octane tow tune(both tow tunes customized by 5 Star) and it tows soo much better. Holds gear longer and do not have the pinging as before. Also get a little better mpg's. I am probably going to get the 91 octane tow tune and see what improvements it has. 91 octane will be the highest octane I would use as some fuel station will carry 91 octane but not the 93.