91 vs 87, real difference?

turbosix

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Mostly it is q daily, not a toy. It will get what it needs to perform the most efficient (based on mileage, engine life, and cost). I don't care if it is fast, I got other stuff for that. It just seems a little odd how jeep jut it. Mostly if over 95 been getting premium. If pulling, definitely premium (those two instances are displayed in manual as a must I think).

When premium is within about .30 for it, premium. But some places want as much as a dollar more...then 87. It does get a majority of top tier gas for the detergent. When not top tier, definitely 91. It won't make up for the missing detergent, but hopefully a little less nasty build up if timing being used to full advantage.

I guess the curiosity is, how much timing is being pulled? And how much does that effect turbo (as again, first boosted car)? I know on my ls2, if timing bus pulled, it is a lot and I can certainly tell. On this, I haven't seen much. Maybe a bit more lag in the turbo, but I also wonder if that is in my head as I am looking for it.

P.s. grand national.... sweet ride.
Fwiw I come from forums where we kinda talk shit while also talking cars so sorry if I came off a little abrasive. I forget some other forums aren't that way.

Anyway if you have an obd tool we can test it. I am sure it pulls boost. I am not sure if my obd mx can log timing but i will give it a shot as I've wanted to see what kind of boost it makes. If I can log timing and boost on a similar 95-100 degree day (plenty here in Dallas) maybe I can see how it compares to yours on 87.

And yeah it's my wife's daily. Mine is now her old turbo mini and my s2000 is now the toy.

I've never owned a car that took anything other than premium so I have always just hit 93 and went on my way.
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Ksvette

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Kansas 93 is impossible to find, but 91 isn't. I broke my obd2 tool. Need a new one lol. I am sure it pulls timing too. But, does pulling a bit of timing have an increased effect with forced Induction?
 

BigGreen

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Like the manual states...........lower octane can be used with reduced performance.

Modern engines will retard timing and adjust to reduce the possibility of engine knock/ping.
How noticeable it is depends on driving conditions. A winter day with an empty jeep vs. a hot day pulling a camper with a loaded jeep you will likely notice a performance difference.
Along with timing, it should be able to pull boost too, with a max drop to whatever the waste gate is set to, probably around 10psi.

The first thing the motor will do is dump fuel to reduce temps. So mileage will also take a hit on this motor when using lower octane.
(inb4 anecdotal evidence against this fact)
 

BigGreen

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When premium is within about .30 for it, premium. But some places want as much as a dollar more...then 87. It does get a majority of top tier gas for the detergent. When not top tier, definitely 91. It won't make up for the missing detergent, but hopefully a little less nasty build up if timing being used to full advantage.
I don't think detergent or not is a factor with direct injection. There's no fuel washing the intake valves.
 

YYCSahara

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I only use 87 in mine. Tried 91 and didn't notice any difference. I will have to go look in my bundle I got with the Jeep but I recall seeing a separate piece of paper that was not in the manual that addresses the octane. Said to use 87, unless towing or driving in extreme heat.

Anyways, compression and forced induction don't automatically mean premium. Mazda has the highest compression engines out there and they are designed for 87 octane. They are 13:1 ratio.

Here is a test C&D conducted on 4 vehicles. It's highly vehicle specific. Some of them it made no difference some of them made a small difference in using premium vs regular.

should-you-be-buying-premium-comparison-1564776519.jpg
 

turbosix

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I only use 87 in mine. Tried 91 and didn't notice any difference. I will have to go look in my bundle I got with the Jeep but I recall seeing a separate piece of paper that was not in the manual that addresses the octane. Said to use 87, unless towing or driving in extreme heat.

Anyways, compression and forced induction don't automatically mean premium. Mazda has the highest compression engines out there and they are designed for 87 octane. They are 13:1 ratio.

Here is a test C&D conducted on 4 vehicles. It's highly vehicle specific. Some of them it made no difference some of them made a small difference in using premium vs regular.

should-you-be-buying-premium-comparison-1564776519.jpg
you are bad at math or you don't know much about cars. none of them made "little difference".

even the CRV made 8hp to the wheels more. do you realize people will spend hundreds of dollars on an intake or exhaust for 8hp to the wheels?

also, you're wrong.

https://msmownerassets.z13.web.core...blications/en-us/Jeep/2019/Wrangler/10390.pdf

Fuel Selection — 2.0L Engine 87 Octane Minimum – 91 Octane Recommended, 0-15% Ethanol.
Fuel Selection — 3.6L Engine 87 Octane, 0-15% Ethanol.

2.0L Engine This engine is designed to meet all emission requirements, and provide satisfactory fuel economy and performance, when using high-quality unleaded “regular” gasoline having an octane rating of 87, as specified by the (R+M)/2 method. The use of 91 or higher octane “premium” gasoline will allow these engines to operate to optimal performance. This increase in performance is most noticeable in hot weather or other heavier load conditions, such as while towing. While operating on gasoline with the required octane number, hearing a light knocking sound from the engine is not a cause for concern. However, if the engine is heard making a heavy knocking sound, see your dealer immediately. Use of gasoline with a lower than recommended octane number can cause engine failure and may void or not be covered by the New Vehicle Limited Warranty.

.... so... lol... it will run on 87 fine if you are just pussy footing around town. put a load on it and it will knock and pull timing/boost to keep itself from self destructing.

so... great. i mean you might as well just like unhook the wastegate puck so it makes 0 boost cause it will definitely run forever on 87 at 0psi.
 
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YYCSahara

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="turbosix, post: 803419, member: 35851"]you are bad at math or you don't know much about cars. none of them made "little difference".

even the CRV made 8hp to the wheels more. do you realize people will spend hundreds of dollars on an intake or exhaust for 8hp to the wheels?

also, you're wrong.

https://msmownerassets.z13.web.core...blications/en-us/Jeep/2019/Wrangler/10390.pdf

Fuel Selection — 2.0L Engine 87 Octane Minimum – 91 Octane Recommended, 0-15% Ethanol.
Fuel Selection — 3.6L Engine 87 Octane, 0-15% Ethanol.

2.0L Engine This engine is designed to meet all emission requirements, and provide satisfactory fuel economy and performance, when using high-quality unleaded “regular” gasoline having an octane rating of 87, as specified by the (R+M)/2 method. The use of 91 or higher octane “premium” gasoline will allow these engines to operate to optimal performance. This increase in performance is most noticeable in hot weather or other heavier load conditions, such as while towing. While operating on gasoline with the required octane number, hearing a light knocking sound from the engine is not a cause for concern. However, if the engine is heard making a heavy knocking sound, see your dealer immediately. Use of gasoline with a lower than recommended octane number can cause engine failure and may void or not be covered by the New Vehicle Limited Warranty.

.... so... lol... it will run on 87 fine if you are just pussy footing around town. put a load on it and it will knock and pull timing/boost to keep itself from self destructing.

so... great. i mean you might as well just like unhook the wastegate puck so it makes 0 boost cause it will definitely run forever on 87 at 0psi.
8 hp means nothing. People spend all sort of money on mods for many reasons. As is shown in their data 8 hp won't make any difference in acceleration and no one would be able to feel that. Each vehicle in that test made about 5% more hp going from 87 to 93.

I used to be into import tuning in my younger years I know what it took to get a 16s integra to a 12s car. That car would only run on 94 octane so I know when to use good fuels and when not to. My jeep never knocks on 87. It could be my environment (3600ft and usually under 80F in summer), I don't tow.

I tried 91 like I said and there was no difference. I will try it again once I have more miles on the Wrangler.

Here is the slip I was referring to. This was a sheet that comes separate from the manual. I interpret this as 87 is what this engine should run on just fine, unless you're towing, or high heat. The box at the bottom only shows 87 octane. My experience has been positive with 87 so for now I won't waste my money on 91 unless something changes with the way it runs.

IMG_5277.jpg
 

turbosix

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8 hp means nothing. People spend all sort of money on mods for many reasons. As is shown in their data 8 hp won't make any difference in acceleration and no one would be able to feel that. Each vehicle in that test made about 5% more hp going from 87 to 93.

I used to be into import tuning in my younger years I know what it took to get a 16s integra to a 12s car. That car would only run on 94 octane so I know when to use good fuels and when not to. My jeep never knocks on 87. It could be my environment (3600ft and usually under 80F in summer), I don't tow.

I tried 91 like I said and there was no difference. I will try it again once I have more miles on the Wrangler.

Here is the slip I was referring to. This was a sheet that comes separate from the manual. I interpret this as 87 is what this engine should run on just fine, unless you're towing, or high heat. The box at the bottom only shows 87 octane. My experience has been positive with 87 so for now I won't waste my money on 91 unless something changes with the way it runs.

IMG_5277.jpg
8hp means nothing meanwhile Chevy's performance exhaust on the c8 adds 5hp for $1200 and they will sell them all day long.

Also, relying on motor trend for 1/4 mile times is hilarious.
 

smithrd65

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turbosix

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Using 91 or better in the 3.6 is a waste of money.

But take note: the recommended gasoline for most cars is regular octane. In fact, in most cases, using a higher octane gasoline than your owner's manual recommends offers absolutely no benefit. It won't make your car perform better, go faster, get better mileage, or run cleaner.
Paying a Premium for High Octane Gasoline? | Consumer Information
https://www.consumer.ftc.gov › articles
This thread is a little above your pay grade bro
 

Punkindave

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I've run a few tanks of 93 and IMHO there is no real difference in performance, MPG, or "smoothness" (whatever that is) that would justify the $0.40/gal cost difference.
I've seen a lot of rediculous claims on every one of these threads, but have never seen any dyno data to back anything up.
Run good quality fuel and drop a 20oz bottle of Techtron every 5k and you'll be good.
 

Fizzlepop

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The important question hasn't been asked.

What's the upper limit in regards to the timing adjustment of the ECU? Can it advance enough to take advantage of 95 octane? 98? 104?

E85 does wonders in turbo applications, if its tuned for it. I don't believe that the 2.0L is an e85 vehicle, but 3 parts 93 1 part e85 would put ethanol around 30% and octane rating at what, 98? MPG would be kaka but can the injectors push enough fuel and can the ECU advance enough to make use of the extra octane?
 

Thill444

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It's not even about throwing these on a dyno and measuring HP/TQ numbers. You would want extensive data logging, especially under load, to monitor knock, air fuel ratio, if timing is being pulled, etc.

I have been in the tuning scene and turbo engines for many, many years and I have found that higher octane fuel is always best when it comes to performance, knock, AFR, etc. I data log my ND Miata (tuned) and only run 93 octane gas, it's rather silly to spend this much on a JL Jeep and cheap out on gas.
 
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