Ultra 94 Gas Details
06-15-2013, 10:19 AM
#1
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Ultra 94 Gas Details
Please move if this is a repost.
I know at the Niagara meet some members including myself was joking around about ultra 94 and how its a must have, and how that's all we pump religiously in our cars. In the article below, it gives you more insight to what we are actually pumping into our cars and explains a few things to us that some of us may or may have not known about. It's an interesting read and definitely worth your time.
http://ca.autoblog.com/2013/06/14/is...-shell-sunoco/
I know at the Niagara meet some members including myself was joking around about ultra 94 and how its a must have, and how that's all we pump religiously in our cars. In the article below, it gives you more insight to what we are actually pumping into our cars and explains a few things to us that some of us may or may have not known about. It's an interesting read and definitely worth your time.
http://ca.autoblog.com/2013/06/14/is...-shell-sunoco/
06-15-2013, 11:29 AM
#3
I use 94 in the type R. In Japan the octane rating is different as it said in the article. The K20 requires 100+ and so if you convert 94 it said it was 101oc. Meh, its not that much more expensive but I miss filling up with 87 for my daily.
06-15-2013, 08:32 PM
#4
Unfortunately the answers given in that link are generalizing too much. I'm not buying everything that rep is selling.
If you run 94 in a street driven 1993 1.5 litre Honda Civic ( with a relatively average compression ratio) it might put out less power than 87 , it is possible to lose power running 94 over 87 in some vehicles as 87 can have a better burn pattern over 94.
In order to gain power on a stock S2000 our engines have to be experiencing knock-based ignition retard, or they have an ecu that will advance ignition timing to the threshold of knock. I'm not sure we have either of those conditions.
In the aftermarket, obviously if you can control your ignition timing and boost then you can up the power output with 94.
I'd like to run a few tanks and monitor my ignition timing and see if the ecu will advance timing with 94 octane vs 91 , but it might be tricky replicating comparable driving conditions. I don't know if our engines experience much knock-based ignition retard while daily driving oem on 91 as these Honda combustion chambers are so well designed. I haven't seen any information either way, I'm just saying.
I'm open to experimenting though. I also wonder if the later ap2 models' ecu's are more sophisticated compared to earlier ap1's in terms of being able to adjust ignition timing relative to fuel octane levels? (adjusting ignition timing to the threshold of knock situation), as many of today's vehicles are being engineered to do that. I don't know if that was the case a few years ago.?
If you run 94 in a street driven 1993 1.5 litre Honda Civic ( with a relatively average compression ratio) it might put out less power than 87 , it is possible to lose power running 94 over 87 in some vehicles as 87 can have a better burn pattern over 94.
In order to gain power on a stock S2000 our engines have to be experiencing knock-based ignition retard, or they have an ecu that will advance ignition timing to the threshold of knock. I'm not sure we have either of those conditions.
In the aftermarket, obviously if you can control your ignition timing and boost then you can up the power output with 94.
I'd like to run a few tanks and monitor my ignition timing and see if the ecu will advance timing with 94 octane vs 91 , but it might be tricky replicating comparable driving conditions. I don't know if our engines experience much knock-based ignition retard while daily driving oem on 91 as these Honda combustion chambers are so well designed. I haven't seen any information either way, I'm just saying.
I'm open to experimenting though. I also wonder if the later ap2 models' ecu's are more sophisticated compared to earlier ap1's in terms of being able to adjust ignition timing relative to fuel octane levels? (adjusting ignition timing to the threshold of knock situation), as many of today's vehicles are being engineered to do that. I don't know if that was the case a few years ago.?
06-15-2013, 11:14 PM
#6
Our ecu's can only compensate for "bad" or lower octane gas. The compensation is calculated by the ecu over a period of time and a long term trim is applied. It will not advance timing on the fly. Nor can it be relied upon to automatically retard ignition timing in real time. I have done a lot of tuning on my ap2 using Flashpro, and can confirm this.
Further reading and explanation here:
http://www.hondata.com/help/flashpro...rol_tables.htm
Further reading and explanation here:
http://www.hondata.com/help/flashpro...rol_tables.htm
06-16-2013, 03:31 AM
#7
Our ecu's can only compensate for "bad" or lower octane gas. The compensation is calculated by the ecu over a period of time and a long term trim is applied. It will not advance timing on the fly. Nor can it be relied upon to automatically retard ignition timing in real time. I have done a lot of tuning on my ap2 using Flashpro, and can confirm this.
Further reading and explanation here:
http://www.hondata.com/help/flashpro...rol_tables.htm
Further reading and explanation here:
http://www.hondata.com/help/flashpro...rol_tables.htm
That is great information then, thanks for sharing. Based on that I would not expect 94 to offer that much of a performance benefit unless someone's S2K is having long term knock issues, but I still don't think that these cars are that prone to knocking in normal daily use.
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06-16-2013, 06:28 AM
#8
No problemo! You said it exactly right. There is no benefit unless someone has been using really shitty gas long enough for the ECU to have retarded timing. The good thing about the higher octane fuels is when you start tuning on a dyno. The higher octane will allow for more timing advance, thus more power.
Under WOT conditions, the stock map is not really prone to knock. However, there are still some areas that you can get the ecu to start retarding timing. I.e. heavy loads below 3000rpm during stop and go traffic in 30* weather. That's normally the most susceptible area for knock.
Back to that Ultra94 article... it seems like a lot of marketing jumble to me. Having said that, I still use 94 exclusively. If I'm in a pinch, I will use Shell V-Power.
Under WOT conditions, the stock map is not really prone to knock. However, there are still some areas that you can get the ecu to start retarding timing. I.e. heavy loads below 3000rpm during stop and go traffic in 30* weather. That's normally the most susceptible area for knock.
Back to that Ultra94 article... it seems like a lot of marketing jumble to me. Having said that, I still use 94 exclusively. If I'm in a pinch, I will use Shell V-Power.
06-16-2013, 07:49 AM
#9
Registered User
there is a thread going back some time where various octanes where tested on the s2000 on a dyno. iirc 91 octane performed the same as the higher ones. as explained above our ecu is tuned on 91. I can't see the logic of the OEM ecu trying to maximize ignition in case the driver wants to run 94, that would only open up a can of worms for the manufacturer.
your better off using dedicate high octane pumps and not the mixed type then worry about 94 octane on a stock ecu
your better off using dedicate high octane pumps and not the mixed type then worry about 94 octane on a stock ecu
06-16-2013, 06:32 PM
#10
No problemo! You said it exactly right. There is no benefit unless someone has been using really shitty gas long enough for the ECU to have retarded timing. The good thing about the higher octane fuels is when you start tuning on a dyno. The higher octane will allow for more timing advance, thus more power.
Under WOT conditions, the stock map is not really prone to knock. However, there are still some areas that you can get the ecu to start retarding timing. I.e. heavy loads below 3000rpm during stop and go traffic in 30* weather. That's normally the most susceptible area for knock.
Back to that Ultra94 article... it seems like a lot of marketing jumble to me. Having said that, I still use 94 exclusively. If I'm in a pinch, I will use Shell V-Power.
Under WOT conditions, the stock map is not really prone to knock. However, there are still some areas that you can get the ecu to start retarding timing. I.e. heavy loads below 3000rpm during stop and go traffic in 30* weather. That's normally the most susceptible area for knock.
Back to that Ultra94 article... it seems like a lot of marketing jumble to me. Having said that, I still use 94 exclusively. If I'm in a pinch, I will use Shell V-Power.