Do we really get bad gas?

[Leo C.]

But when V-Power 97 came out a lot of us from Club Silvia tried it out and the consensus was our cars felt so down in power it was like we lowered our boost settings.  :dontknow:

That is very possible because as I mentioned before, octane is not only the factor in the fuel that controls the burn, etc. There are many factors in the engine that contribute to the burn / burn rate which affects the amount of octane needed. These are: cam timing, engine compression ratio, ignition timing, combustion chamber design, valve adjustments, sparkplug location, engine temperature, air/fuel mixture, etc.  Even the weather has a lot to contribute to octane requirements.

Another factor is altitude.  Air is thinner as you go higher above sea level. Less air going into the cylinders means less pressure at top dead center during combustion. It's like lowering the compression ratio of the engine and with this condition its ok to use lower octane rated fuels.
This is the reason why in the U.S., they sell low octane gas at high places.

The key word is "matching". You need to match your fuel with your engine to get maximum power because the highest octane rating is not always best.  The higher the octane rating, the slower the burn rate, which also affects power.  If V-power is good for the EVOs or other exotics, it might not be good for the Silvias. You have different engine specs to say the least.       

[niky]

But when V-Power 97 came out a lot of us from Club Silvia tried it out and the consensus was our cars felt so down in power it was like we lowered our boost settings.  :dontknow:

I think we talked about this before, yeah. Strange nga... pero we did our tests with Blaze and V-Power maybe two or three years ago... maybe two years after V-Power came out... they might have changed the formula since then. I haven't tried the current fuels on the dyno, but V-Power still runs better (given my crazy ignition advance... LPG loves advanced timing...) than SeaOil 97 whenever I actually feel the need to drive on gasoline (LPG is so cheap... hehehe...  :evilgrin2: )

[Zenki]

That is very possible because as I mentioned before, octane is not only the factor in the fuel that controls the burn, etc. There are many factors in the engine that contribute to the burn / burn rate which affects the amount of octane needed. These are: cam timing, engine compression ratio, ignition timing, combustion chamber design, valve adjustments, sparkplug location, engine temperature, air/fuel mixture, etc.  Even the weather has a lot to contribute to octane requirements.

Another factor is altitude.  Air is thinner as you go higher above sea level. Less air going into the cylinders means less pressure at top dead center during combustion. It's like lowering the compression ratio of the engine and with this condition its ok to use lower octane rated fuels.
This is the reason why in the U.S., they sell low octane gas at high places.

The key word is "matching". You need to match your fuel with your engine to get maximum power because the highest octane rating is not always best.  The higher the octane rating, the slower the burn rate, which also affects power.  If V-power is good for the EVOs or other exotics, it might not be good for the Silvias. You have different engine specs to say the least.       

But I think it also has something to do w/ the gas station. I once felt that 2 diff. gas stations have different kind of Vpower. The acceleration of the car felt different... that' why ever since I never got back at the "x" shell station near us. But w/ the other station, so far all of the cars I bring there, either mine, a friend's or a relative's they all liked the after effect.

[Leo C.]

But I think it also has something to do w/ the gas station. I once felt that 2 diff. gas stations have different kind of Vpower. The acceleration of the car felt different... that' why ever since I never got back at the "x" shell station near us. But w/ the other station, so far all of the cars I bring there, either mine, a friend's or a relative's they all liked the after effect.

In my first comment, this is what I referred to as "consistency" . It is very important that the fuel you use maintain its consistency regardless of what brand it is. Bulk fuel  tanks may have the tendency to produce moisture, this changes the consistency of the fuel. This is the reason why racers purchase fuel in sealed drums.
 

[Conan®]

But I think it also has something to do w/ the gas station. I once felt that 2 diff. gas stations have different kind of Vpower. The acceleration of the car felt different... that' why ever since I never got back at the "x" shell station near us. But w/ the other station, so far all of the cars I bring there, either mine, a friend's or a relative's they all liked the after effect.

Where is this Shell station located?

[Zenki]

Where is this Shell station located?

You got p.m. 

[MFB]

Actually... the knock count MFB mentioned will give clues as to which gasoline actually has the better MON or AKI... and, as many of us have testified, it seems that V-Power really is the best. In my experience on the dyno, in what MFB has posted, and what I've heard from owners of Evos and 911s... V-Power seems to be the most stable and best gasoline for cars requiring "high octane" fuel to prevent knock.

Glad we're all on the same page. haha    You just need to use more fuel to get the same amount of power. Then from that point, add timing and boost. Voila!   It just sounds easy to do.

Recently I went back to seaoil. The only reason being its much cheaper than Shell. Im using the same map and see some feedback knock on low engine load.  Its ok, will just use Vpower when there's a fun run.  :-)  Just be careful with Sea Oil stations, they're not all on the same level.  Shell seems more strict with quality control.

But when V-Power 97 came out a lot of us from Club Silvia tried it out and the consensus was our cars felt so down in power it was like we lowered our boost settings.  :dontknow:

Its because you need to tune for e10.  Make afr richer (10.5 to 10.7) and you'll see power come to where it was before. Then add timing and boost until you reach threshold.  Better give some allowance as e10 quality varies.  You need more e10 fuel to produce the same power as your favorite gasoline like blaze.  So putting it in just like that will make you feel like having a car in limp mode.

[niky]

Glad we're all on the same page. haha    You just need to use more fuel to get the same amount of power. Then from that point, add timing and boost. Voila!   It just sounds easy to do.

Recently I went back to seaoil. The only reason being its much cheaper than Shell. Im using the same map and see some feedback knock on low engine load.  Its ok, will just use Vpower when there's a fun run.  :-)  Just be careful with Sea Oil stations, they're not all on the same level.  Shell seems more strict with quality control.

I'm glad I don't have to put up with such issues... my engine is pretty resistant to knock (knock on wood), but I only use gasoline sparingly and drive mostly on LPG. When I want to have a little fun, that's when I switch back to gas.

I'm considering making an extra map for SeaOil 97, but I don't have the time.

[Leo C.]

Another thing is that conventional gasoline and e10 have different energy values (EV) even if the two have the same octane rating.      A 93 octane e10 has a lower energy value of around 110,000 BTUs  than the 93 octane conventional gasoline at 125,000 BTUs, so you will need more e10 to achieve peak horsepower.  The result is a higher fuel consumption when using e10 of around 5%.

[MFB]

I'm glad I don't have to put up with such issues... my engine is pretty resistant to knock (knock on wood), but I only use gasoline sparingly and drive mostly on LPG. When I want to have a little fun, that's when I switch back to gas.

I'm considering making an extra map for SeaOil 97, but I don't have the time.

Our knock sensor is just sensitive. I believe I see false knock at times. Subaru even compensated (added timing) on cylinder 4 to "magnify" if ever there would be knock. Better safe this way I suppose.
If you add more boost and timing, knock will be a consequence as there will be a limit to all this especially with the fuel we have.

What car do you have? It seems to be NA due to you using LPG.  I previously researched on a turbo powered LPG set up but was advised not to go this route.
Post Merge: June 09, 2010, 10:44:51 AM

Another thing is that conventional gasoline and e10 have different energy values (EV) even if the two have the same octane rating.      A 93 octane e10 has a lower energy value of around 110,000 BTUs  than the 93 octane conventional gasoline at 125,000 BTUs, so you will need more e10 to achieve peak horsepower.  The result is a higher fuel consumption when using e10 of around 5%.

Yes, that's more or less around what I see in my LTFT when I compared Blaze and the e10 fuels (Shell V, g5).  When you adust to a richer afr, that's where the advantage of having e10 comes in. I know of some who tune for e0 and can accomodate e10 as well. I just dont like that you cant maximize e10 with that set up.  Conservative around 3  degrees total timing more per cell and around 3 psi. (depending where your boost is currently at its max in relation to VE)

[Leo C.]

Have you heard about Eth-Guard fuel additive? They say it improves the energy value of e10 among other claims.

[MFB]

Have you heard about Eth-Guard fuel additive? They say it improves the energy value of e10 among other claims.

Ok, google usually delivers the info.  :-)

www.e10gasadditives.com/product_ethguard.html

Is this available locally?

[Leo C.]

I don't know. I only heard this from a friend in the states. Maybe I'll try importing some, seems lucrative. 

[MFB]

I don't know. I only heard this from a friend in the states. Maybe I'll try importing some, seems lucrative. 

No real info on the web. Its their company posting on some forums especially those of boats.  I sent them an email and asked for data (engine logs). Also want to know what benefits that are measurable can be seen from a before and after scenario.

[Leo C.]

Great! I'll be waiting for all the infos!