Gearhead
07-24-2007, 07:28 AM
Pump Gasoline variations –
Just something that I thought performance boaters should be aware of, especially when pushing and tuning boats to the limit on pump gasolines. Pump gasolines are not the same in every geographic location and their characteristics and formulations may change during the year.
Some areas of the country utilize “conventional” gasolines while many metropolitan areas are required to have “reformulated gasolines” (low emission fuels). The reformulated gasolines typically have lower pressures and have been known to make less power and lower fuel economy.
Also, we see “climatized” gasolines in many parts of the country. The formulation of the gasoline may change during the year. One of the components of the “climatized” fuel is a change in RVP (reid vapor pressure). For example, some states and counties may have a 9.0 RVP during winter then drop to a 7.0 RVP during the summer months.
One proponent of the aftermarket racing gasolines is consistency of product. The RVP is consistent; the formulation is consistent along with lead availability. In the last few years oxygenated racing fuels have come on the market, which really assist in performance during summer months when the air is hot and humid which results in less oxygen content atmospherically available to the engine.
The main reason I have posted this information is I have read where several folks have damaged their engines with pump gasolines. One of the contributing factors could be the change in the fuel quality or formulation from the time of their base tune-up.
Please refer to the information available on RVP in your area and you may also want to see if your area has “conventional” or “reformulated” gasolines. Another new buzzword is “Top Tier” fuels. Top Tier fuels are certified to meet the standards of several large auto manufacturers. All available “street” pump gasoline is not the same.
See these websites for additional information on RVP and Top Tier fuels.
http://www.epa.gov/otaq/regs/fuels/420b07007.pdf
http://www.arbca.gov/fuels/gasoline/gasoline.htm
http://www.toptiergas.com/
For pump gasoline, we have had good results with the Shell V-Power Premium 93 octane gasoline. Of course even this fuel has a change in RVP during the year. Generally on higher compression engines running pump gas require a richer (lower) air to fuel mixture ratio for peak power on the dyno. Also with higher cylinder pressures, running the engine cooler can help reduce detonation tendencies.
IÂ’m sure others can add information to this post with their knowledge and experiences. Please do so :)
Just something that I thought performance boaters should be aware of, especially when pushing and tuning boats to the limit on pump gasolines. Pump gasolines are not the same in every geographic location and their characteristics and formulations may change during the year.
Some areas of the country utilize “conventional” gasolines while many metropolitan areas are required to have “reformulated gasolines” (low emission fuels). The reformulated gasolines typically have lower pressures and have been known to make less power and lower fuel economy.
Also, we see “climatized” gasolines in many parts of the country. The formulation of the gasoline may change during the year. One of the components of the “climatized” fuel is a change in RVP (reid vapor pressure). For example, some states and counties may have a 9.0 RVP during winter then drop to a 7.0 RVP during the summer months.
One proponent of the aftermarket racing gasolines is consistency of product. The RVP is consistent; the formulation is consistent along with lead availability. In the last few years oxygenated racing fuels have come on the market, which really assist in performance during summer months when the air is hot and humid which results in less oxygen content atmospherically available to the engine.
The main reason I have posted this information is I have read where several folks have damaged their engines with pump gasolines. One of the contributing factors could be the change in the fuel quality or formulation from the time of their base tune-up.
Please refer to the information available on RVP in your area and you may also want to see if your area has “conventional” or “reformulated” gasolines. Another new buzzword is “Top Tier” fuels. Top Tier fuels are certified to meet the standards of several large auto manufacturers. All available “street” pump gasoline is not the same.
See these websites for additional information on RVP and Top Tier fuels.
http://www.epa.gov/otaq/regs/fuels/420b07007.pdf
http://www.arbca.gov/fuels/gasoline/gasoline.htm
http://www.toptiergas.com/
For pump gasoline, we have had good results with the Shell V-Power Premium 93 octane gasoline. Of course even this fuel has a change in RVP during the year. Generally on higher compression engines running pump gas require a richer (lower) air to fuel mixture ratio for peak power on the dyno. Also with higher cylinder pressures, running the engine cooler can help reduce detonation tendencies.
IÂ’m sure others can add information to this post with their knowledge and experiences. Please do so :)