RON vs CR

[moshpit21]

hi guys,

how to know minimum number of RON of fuel u should use with ur car?

is it true it depends on ur engine compression ratio (CR)?

if it is, then how much minimum RON to run properly our VTEC engine at 10.4 - 10.8 CR ??

sorry newbie question.. :_:

thx in advance..

-peace-

 

[maxgil05]

I just know that turbo cannot run on high ron like Shell's V Power, if u fuel the turbo car with Shell's V Power and the engine is hot, combustion might just have at early stage (maybe stroke 2) because of the heat that is produces by turbo.

Higher ron means it can burn faster, but u must tune ur car not burn at cycle of stroke 2.

But i dont know anything about higher ron on a high compression ratio car. :regular_smile:

Please correct me if i am wrong. :regular_smile:

 

[shiroitenshi]

hi guys,

how to know minimum number of RON of fuel u should use with ur car?

is it true it depends on ur engine compression ratio (CR)?

if it is, then how much minimum RON to run properly our VTEC engine at 10.4 - 10.8 CR ??

sorry newbie question.. :_:

thx in advance..

-peace-

This is not noobie questionlah moshpit..

Okay, for starters, this is a bit of a gray area for me.. I think I know, but I cannot say that it's a 100% sure thing.. There are many variables that affect knock resistance, so I won't go into that.. since I'm still learning those stuff.

The RON number is something that ranks how much the fuel resist autoigniton (something like detonation).. Many standards depending on how ppl test the fuel or calculate... some are MON, and PON (PON is the usual US rating.., that's why you see their fuel rating is lower)

If you want a clearer idea, I think you can google up sources for it.. I give simple version (as I see it lah)

The higher your engine compression means how much your engine compress the air. If 10:1, means that 10cc is compressed to the space of 1cc before it's ignited by the spark plug. In a B16A, one cylinder roughly pushes something less than 400 cc into the space of something less than 40cc (That's where you get the 10.5 CR on B16A)

One thing about doing that is that the air+fuel heats up by a lot when compressed... and if given a low octane fuel, it will ignite without needing a spark from the spark plug.. This is what causes the detonation/knocking you always hear about.

So one way is for tuners is to tweak the ignition timing so that it fires just before the fuel and air auto-ignite. This prevent's the detonation from happening, but also decreases power if went to the extremes.

Too much igntion advance is also similar, because the fuel air mix did not result in peak combustion chamber pressure just before the piston starts going down it's stroke (That's how power is generated in engines.) so to achieve that, we need higher compression, so the peak combustion chamber pressure is reached faster, and higher too. It also can result in knock, if the fuel + air mixture autoignites before the spark plug fires.

So you can use 92ron on your B16a, if you detune the ignition and accept the lesser power output.. but that's a step backwards isn't it?

The B16A is recommended to run on premium fuels like the 97RON (I think the requirements was like maybe 95 RON? (anyone has the original fuel tank cover sticker to be sure?)

 

[moshpit21]

:shocked:

feel like i ask question on proffesional website "ask shiroitenshi" :_:

never know it will get that complicated(at least for me)..

anyway thx for the info, which mean i cant really escape myself from ron97 huh? :X-:

-peace-

 

[shiroitenshi]

:shocked:

feel like i ask question on proffesional website "ask shiroitenshi" :_:

never know it will get that complicated(at least for me)..

anyway thx for the info, which mean i cant really escape myself from ron97 huh? :X-:

-peace-

Nolah.. this one is not professional info.. basic information of how petrol driven combustion engines work only.. a bit of something that I will need to know when I get around to tuning my own car.

If I don't know these basics to make power.. how do I know how to mod for power?

Like chris says in the 1.8 peak hp thread (or at least something like it).

Installing one part is something.. making them perform well together is quite another.

 

[zaki]

realtively speaking, lower RON burns faster than higher RON

 

[hattech-v]

RON stand for what aaa?
PON pun..

 

[shiroitenshi]

realtively speaking, lower RON burns faster than higher RON

Hmm.. burn rates faster? From what I know.. it's harder to ignite than lower ron.. not sure if the burn rates is slower though.. you might be right.. I'm actually wondering about them myself.

Maybe I should go read it up.

Mie,

RON=Research Octane Number

MON=Motor Octane Number = different test method.

PON=Pump Octane Number (used by the US)

PON = (RON + MON)/2

 

[zaki]

Hmm.. burn rates faster? From what I know.. it's harder to ignite than lower ron.. not sure if the burn rates is slower though.. you might be right.. I'm actually wondering about them myself.

Maybe I should go read it up.

Mie,

RON=Research Octane Number

MON=Motor Octane Number = different test method.

PON=Pump Octane Number (used by the US)

PON = (RON + MON)/2

correct, the higher the octane the harder to auto-ignite. generally speaking this characteristic will determine the burn rate. it is usually slower than lower octane. but, there are high octane fuel that can burn faster and burn longer than lower octane. this is due to the additive added.
turbo car shouldn't have problem using V-Power. From what I know, V-power is rated at 97RON (source from a fren who has a shell station). the only difference is the additive.

PON = AKI

 

[V8_nutter]

Both are right.:regular_smile:

 

[shiroitenshi]

Both are right.:regular_smile:

Hmm.. boy.. thermodynamic and all that math is scary.. :P

 

[zaki]

Hmm.. boy.. thermodynamic and all that math is scary.. :P

what math? who's math? i fail math....


p/s: bring us MAN UTD!! there shall be no all english finale....:regular_smile:

 

[hattech-v]

correct, the higher the octane the harder to auto-ignite. generally speaking this characteristic will determine the burn rate. it is usually slower than lower octane. but, there are high octane fuel that can burn faster and burn longer than lower octane. this is due to the additive added.
turbo car shouldn't have problem using V-Power. From what I know, V-power is rated at 97RON (source from a fren who has a shell station). the only difference is the additive.

PON = AKI

then this what? Z-PON? = ZAKI?

 

[J101]

since vtec came factory from japan, prolly 100RON :p

hi guys,

if it is, then how much minimum RON to run properly our VTEC engine at 10.4 - 10.8 CR ??

sorry newbie question.. :_:

thx in advance..

-peace-

 

[shiroitenshi]

what math? who's math? i fail math....
p/s: bring us MAN UTD!! there shall be no all english finale....:regular_smile:

Hahah.. takkan basic maths oso fail..

Thermodynamics is mostly physicsler.. and mostly basic maths..

But still, the amount of stuff.. scary! :P

 

[moshpit21]

thx for all the info... so another question.. hee hee

what RON number r u using now for ur vtec engine?? :)


-peace-

 

[shiroitenshi]

thx for all the info... so another question.. hee hee

what RON number r u using now for ur vtec engine?? :)


-peace-

97.. cincai any petrol station that is nearest.. shell is usually the one though.

I think 92 would cause knocking on the B16A... anyone tried?

On another note.. what determines the fuel that you can use is the ignition timing.. retarding it allows you to run high CRs, but at the expense of power..

Another factor is the cam duration, esp the overlap and the intake closing timing..

Big cams require high comp due to this fact.