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Discussion Starter · #1 ·
Hey, anyone try to put premium in the crz? See if you get any punch to it? idk, crazy thought. Maybe a stupid question. My prelude took premium, and im so used to that. I know you cant put a lower grade in a car that requiers a higher grade. But what about the opposite. In this type of motor? Just curious. No hating on me for the question plz. lol
 

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higher compression motors require higher octane fuel... unless you had a JDM motor in the Lude you probably could've gotten away with regular as the compression on that motor is like 10.5:1... anything 11:1 or higher requires +91octane... the CR-Z is i think 10.4:1 (i think i read that somewhere)... the thing about these motors unlike the older Honda engines is they use a timing chain instead of belt and they also do timing adjustment on the fly whereas with the older belt-driven engines needed to be manually adjusted for advancing/retarding the timing to prevent engine knock...

since these cars only take regular... adding premium fuel won't hurt it but it probably won't be worth the extra pennies spent by using it either... at the same time, on these cars they instantly sense when the fuel is lower octane and instantly retard the timing... but for advancing the timing they usually will sense that by the 2nd or 3rd fill up... so what i'm saying is, even if you add premium today, you have to run through about 1-2 full tanks b4 the car advances the timing enough to see any gains...


sn: boosted cars usually add more than the 11:1 C/R so premium is required almost always on those...
 

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Higher octane is also hotter to burn. Unless you add forced induction, don't bother running it in car that only needs regular.

Anti-knock sensors retard the timing due to... knock. ;) Usually this is done on cars that run premium fuel in case it can't be found, or if the fuel is bad to prevent damage. Since an eco car wasn't designed for premium, I seriously doubt Honda would have advanced the nominal timing beyond the timing associated with the fuel that the engine was designed for.

I don't see how a knock sensor tuned for regular gas could advance the timing if you put in premium: there's no knock event to measure. From the perspective of the sensor if there's no knock, it would keep the timing mapped for good regular gas as opposed to bad regular gas.

Just my theory... I could be wrong.
 

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good theory... i know that's how it worked on the Si and that required premium gas so i guess i forgot this isn't the 197hp 11:1 C/R K20Z3 on the Si :D

but u never know, "Sport" mode might advance timing a bit and i'm sure the premium fuel might help in that regard :spinning:
 

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Discussion Starter · #5 ·
higher compression motors require higher octane fuel... unless you had a JDM motor in the Lude you probably could've gotten away with regular as the compression on that motor is like 10.5:1... anything 11:1 or higher requires +91octane... the CR-Z is i think 10.4:1 (i think i read that somewhere)... the thing about these motors unlike the older Honda engines is they use a timing chain instead of belt and they also do timing adjustment on the fly whereas with the older belt-driven engines needed to be manually adjusted for advancing/retarding the timing to prevent engine knock...

since these cars only take regular... adding premium fuel won't hurt it but it probably won't be worth the extra pennies spent by using it either... at the same time, on these cars they instantly sense when the fuel is lower octane and instantly retard the timing... but for advancing the timing they usually will sense that by the 2nd or 3rd fill up... so what i'm saying is, even if you add premium today, you have to run through about 1-2 full tanks b4 the car advances the timing enough to see any gains...


sn: boosted cars usually add more than the 11:1 C/R so premium is required almost always on those...
manual says 87 or higher on the crz. So I went premium. I feel happier putting in richer fuel. Maybe its in my head, but in the end, i feel better at when i go to sleep. Actually, on the lude it said premium only. Ill always put higher then it says if i can, but never lower. What's the point? But, actually, i filled the crz today. Only 25 bucks on premium, vs my usual 32 on the prelude. 7 bucks saved already. I'm loving it everytime i start it up and go! Gosh, sport..is pretty zippy. I was passing someone in sport omw from work. I was in 6th, then dropped to 3rd and that thing went! Put a smile. And come to think its only a 1.5 liter! *lol* :thumbsup: I think I'm getting the hang of this. When to use the modes I mean.
 

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yeah it's in your head haha... my friend is Haitian and they're raised with very strong minded parents and his parents got him to think that premium was required on EVERY car they drove... i finally convinced him it wasn't necessary haha...

Disclaimer: saying my friend is Haitian was not derogatory b/c lets be real... everyone from the Caribbean does it haha... i'm Cuban so i guess i can say that and get away with it :pP:
 

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manual says 87 or higher on the crz. So I went premium. IMO, better is better.
How is it better? The engine wasn't designed to burn it. There's nothing to take advantage of it. You're just making your engine work harder and hotter. Talk to your tech at the dealership.

From a random article I googled... there's more out there. Just search for running premium gas.

Premium, in fact, sometimes is worse fuel than regular. It resists knock because it's harder to ignite than lower-octane fuels. As a result, some engines won't start as quickly or run as smoothly on premium, notes Gibbs, the SAE fuel expert.

High-test does have a potential fuel economy benefit. It is slightly denser than lower-octane gas, meaning there's a little more energy in a gallon. But the small difference is hard to measure in real-world use, and that same density can contribute to undesirable buildup of waste products inside the engine.

No data show that engines designed strictly for regular run better or longer on premium.

The Federal Trade Commission, in a consumer notice, emphasizes: "(I)n 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."

There is "no way of taking advantage of premium in a regular-grade car," says Furey.

"There is no gain. You're wasting money," insists Jim Blenkarn, in charge of powertrains at Nissan in the USA.

"No customer should ever be deluded into thinking there's any value in buying a higher grade of octane than we specify," says Toyota's Paul Williamsen, technical expert and trainer.
 

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Discussion Starter · #8 ·
i knew someone was gonna say something about me saying better. Shoulda chose better words. lol Anyway, It says 87 or higher, and not 87 only. If it didnt, i wouldnt have opted for premium this time around. So shouldnt hurt anything. Otherwise honda wouldnt put it the manual. I dont know, seems simple to me. Ill find out from driving anyway. If it sucks, then ill swap back to regular.

I think ill listen to the manual instead anyway. Plus, I already saved on gas over my prelude. I think ill live with 2 extra bucks. Plus, its all about experimenting. It's not like Im putting regular in a premium car guys. This whole car is an experiment to begin with.


Okay, plenty of cars that run higher octane that are not boosted. To say only boosted cars really utilize it is false. Higher revving motors like preludes,s2000, si's, rsx's require it becuz of the heat that is built up at those rpms. Richer, cleaner gas is required for those motors like an h22 or k20 or f22 to run effeciantly. I experimented and put regular in my prelude once. Boy did it run like shit. *lol* Never went back. Plus, it said premium only. So yea....about that. *lol* I would smack someone if I caught them putting lower fuel in a car that requires higher or has a minimum.

Anway, i'm not trying to be a dildo about it. Just saying, I want to see how it runs with it. Once is no big deal as far as i see.
 

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just make sure you're putting UnLeaded gas only... it's hard to find Leaded gas anyways... i used it in my H22'd Civic... sometimes i ran 110 Octane leaded... that car ran so nice with that stuff but it's hella expensive and really not needed for daily driving...
 

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i know 1 gas station down south that carries it... it's a Sunoco on US27 and like Sheridan Street... and of course you can go to a place with a dyno that tunes cars and they will probably have some laying around too...
 

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On the Honda website it says Required Fuel: Regular Unleaded

You can likely get away with running one grade up. Running it sporadically isnt that big of deal as there is some variation from tank to tank. One tank won't do bad things. However, going from 87 to 91 or 93 can be problematic if that's all you burn. I know a fellow at work who had major engine repairs due to just that. I don't recall the exact details, but it eventually messed up his sensors and caused the ecu to make bad choices for combustion. About $2000 in repair costs.

Talk to your tech at the dealership. Seriously. You're talking about spending pennies per gallon to potentially damage your $20k+ car over the long haul.
 

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Discussion Starter · #13 ·
On the Honda website it says Required Fuel: Regular Unleaded

You can likely get away with running one grade up. Running it sporadically isnt that big of deal as there is some variation from tank to tank. One tank won't do bad things. However, going from 87 to 91 or 93 can be problematic if that's all you burn. I know a fellow at work who had major engine repairs due to just that. I don't recall the exact details, but it eventually messed up his sensors and caused the ecu to make bad choices for combustion. About $2000 in repair costs.

Talk to your tech at the dealership. Seriously. You're talking about spending pennies per gallon to potentially damage your $20k+ car over the long haul.
One time around shouldnt hurt. Hopefully. I just saw 87+ or higher. So, they've considered it im sure. But it's no issue going back to be safe. I prolly will at next fill up. Cheers!
 

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Does anyone know if that Spoon CR-Z require high octane gas?
If there is a tuning or ecu reflash that can take advantage of 91, I don't mind putting in 91.
 

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Okay, plenty of cars that run higher octane that are not boosted. To say only boosted cars really utilize it is false. Higher revving motors like preludes,s2000, si's, rsx's require it becuz of the heat that is built up at those rpms.
But those are high compression engines designed for high octane fuel from the outset. And what's the redline on the CRZ... 6500 rpm?

On an engine that is optimized for low octane fuel, unless you do something to the compression, timing, or induction, you're not going to see any advantage by running premium. It's quite possible that Honda set the engine up with some margin to take advantage of tuning as well as better fuel grades in the rest of the world. But without changing how the engine runs, it's not going to take advantage of higher octane fuel. A mass volume manufacturer tunes for the worst case scenario.

Read the article I quoted closely. Look at who is talking. If you don't believe me, talk to your Honda tech.
 

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But those are high compression engines designed for high octane fuel from the outset. And what's the redline on the CRZ... 6500 rpm?

On an engine that is optimized for low octane fuel, unless you do something to the compression, timing, or induction, you're not going to see any advantage by running premium. It's quite possible that Honda set the engine up with some margin to take advantage of tuning as well as better fuel grades in the rest of the world. But without changing how the engine runs, it's not going to take advantage of higher octane fuel. A mass volume manufacturer tunes for the worst case scenario.

Read the article I quoted closely. Look at who is talking. If you don't believe me, talk to your Honda tech.
Exactly...Your just wasting money buying premium gas for a crz
 

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What are these 87 and 91 figures? At UK pumps we have 2 choices of unleaded, 95 RON or 97 RON (premium). Is this different to what you're talking about?
 

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What are these 87 and 91 figures? At UK pumps we have 2 choices of unleaded, 95 RON or 97 RON (premium). Is this different to what you're talking about?
It's a different unit of measure, just like the US gallon is 1.2x UK gallons.

US octane is the average of two octane numbers (RON and MON).

UK octane is as you described, only RON.

Octane rating - Wikipedia, the free encyclopedia

Octane rating does not relate to the energy content of the fuel (see heating value). It is only a measure of the fuel's tendency to burn in a controlled manner, rather than exploding in an uncontrolled manner. Where octane is raised by blending in ethanol, energy content per volume is reduced.
Thus a gallon of regular gas has the same energy potential as a gallon of premium. The only difference is the resistance to pre-detonation. And if the premium octane was boosted by adding more ethanol, it has less energy potential than regular. (I say more, as most US fuels contain 10% ethanol.)
 

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manual says 87 or higher on the crz. So I went premium. I feel happier putting in richer fuel. Maybe its in my head, but in the end, i feel better at when i go to sleep. Actually, on the lude it said premium only. Ill always put higher then it says if i can, but never lower. What's the point? But, actually, i filled the crz today. Only 25 bucks on premium, vs my usual 32 on the prelude. 7 bucks saved already. I'm loving it everytime i start it up and go! Gosh, sport..is pretty zippy. I was passing someone in sport omw from work. I was in 6th, then dropped to 3rd and that thing went! Put a smile. And come to think its only a 1.5 liter! *lol* :thumbsup: I think I'm getting the hang of this. When to use the modes I mean.
Not trying to be a dick, but you should really research how octane effects the burn. The higher the octane, the slower it is to burn. You're going to get more carbon buildup on the valves with higher octane.
And it can reduce performance if it's not needed. :hi5:
 
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