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Discussion Starter #1
R18 is 10.5:1 compression, which would typically need premium fuel. BUT honda allows us to use reg. Is Honda wrong!?? it wouldnt be the first time.
Whos using REG and whos using PRE
anyonoe have dyno testing or MPG date that backs this up??
Anyone also hear slight pinging when in higher gear/lower speed and going from coasting to very light gas
I always heard it when using regular. am i alone??
REMEMBER the R18, is the only car in america that uses regular fuel that has a compression ratio of over 10:1. And the R18 is also a brand new engine design.
mods, please do not lock this thread.
 

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The R18 is designed for regular fuel. Honda made the engine in a special way allowing them to raise up the compression ratio without sacrificing its ability to use Regular Gas. Using Premium Fuel can give you a little more MPG but not enough to warrant the purchase of it all the time.
 

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I agree that our compression SEEMS a bit high to be using regular fuel but like the guy above me said, Honda has found a way to allow it to run on regular fuel, so just follow the manual and use regular gas. Using a higher octane may not be good for an engine that is supposed to use regular.
 

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Discussion Starter #5
Ok i understand that honda "designed" our engines to use regular fuel with a high compresion motor, however. Honda is not a god, and honda cannot change the laws of pysicis.
and 10.5:1 is very high, not a bit high for Reg fuel.
Anyone have any experiance with pinging under slight throttle in a high gear???
thanks!
 

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pks17 said:
Ok i understand that honda "designed" our engines to use regular fuel with a high compresion motor, however. Honda is not a god, and honda cannot change the laws of pysicis.
and 10.5:1 is very high, not a bit high for Reg fuel.
Anyone have any experiance with pinging under slight throttle in a high gear???
thanks!
You don't understand physics then.

Compression is but only one factor in the cause of pinging. Pinging is from too hot of a spark plug tip.

The R18 ivtec is a dual compression format. In the mpg mode the intake cam stays open to bleed off some of the air so the compression is less.

Now for the power vtec mode. The R18 uses oil injectors to cool down the piston.

Not sure what else the r18 uses but in general - piston shape, head shape, cooling ability in the head, igntion mapping, and spark plug design play a role in creating the heat that cause or prevents pinging.
 

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Sirdude said:
I hear a pinging sound when im in low gears at high rpms.

I doubt that you hear pinging at high RPMs. Pinging is hard to hear in an engine - even harder to hear when the engine itself is noisy. If you could hear pinging it would be best heared when taking off from a redlight.
 

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i do hear pinging when in a higher gear at low rpm. now that i tried using premium i dont hear the pinging at all and the car feels a little bit more responsive and as far as mileage, its the same. i stayed with premium, its only costing me about 2-3 dollars more.
 

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FYI- octane is not a measure or total energy. High octane fuel doesn't make it produce more power. The BTU's are the same or even LESS.

Example 120 octane fuel could have less BTU's and create less power and consume more fuel. Which is why E85 is kinda stupid to use.

High octane fuel will not damage the engine nor will it produce more MPG. It might produce more MPG "IF" the engine wasn't designed correctly and the ECU reads that the engine is pinging with low octane fuel.
 

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ryker said:
FYI- octane is not a measure or total energy. High octane fuel doesn't make it produce more power. The BTU's are the same or even LESS.

Example 120 octane fuel could have less BTU's and create less power and consume more fuel. Which is why E85 is kinda stupid to use.

High octane fuel will not damage the engine nor will it produce more MPG. It might produce more MPG "IF" the engine wasn't designed correctly and the ECU reads that the engine is pinging with low octane fuel.
Isnt octane also the rate at which the fuel burns? Maybe i'm wrong. But if it burns slower, wouldnt that cause detonation?

Or is octane JUST it's ability to be compressed more without igniting?
 

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Yes it burns slower allowing for the flame to burn all the way down.

And octane has a few different methods to test it. Techincal and I would butcher trying to explain it. But in general it is a number of how it resist pinging.
 

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The main reason you can run low octane on the higher compression of the R18engine is because of the exhaust gas recirculation (EGR) valve. Basically it reroutes exhaust gas into the intake manifold in order to take up space in the pistons with unburnable air. This allows for a higher compression with lower octane and not having to adjust timeing much giving good power for the small engine.

http://www.hondatuningmagazine.com/tech/0704_ht_r18_engine/photo_20.html

http://en.wikipedia.org/wiki/Exhaust_gas_recirculation
 

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Discussion Starter #16
Ok RYKER, i hear ya. But.... do you think the R18 can benifit from higher octane? That is the question..
I think it can , the reason why? because i get pinging! haha. And I know what pinging is, ive advanced many honda distributers in the past.
OR .... Is my civic the only one pinging???
 

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I use premium for my r18. I don't care what people say. I don't care if it's more expensive. I don't care if there aren't any reasons to put premium into an r18. I just do it.
 

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ryker said:
I doubt that you hear pinging at high RPMs. Pinging is hard to hear in an engine - even harder to hear when the engine itself is noisy. If you could hear pinging it would be best heared when taking off from a redlight.
maybe not a pinging noise but i defiantly hear a slight ringing noise
 
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