Fuel is not simply "lifted up to the venturi" at WOT for anything resembling an engine speed of interest.mk e wrote:No, but the energy required to lift the fuel up and into the venturi does change with SG...the higher the SG the lower the flow rate.... not a lot less but less.nitro2 wrote:
In an engine, the head generated by the engine does not increase with increasing fuel density, so .......
toluene to up octane rating
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Re: toluene to up octane rating
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Re: toluene to up octane rating
There is an energy loss in lifting the fuel, not a big loss but it is not zero or setting the float bowl height wouldn't change the mixture.nitro2 wrote:Fuel is not simply "lifted up to the venturi" at WOT for anything resembling an engine speed of interest.mk e wrote:
No, but the energy required to lift the fuel up and into the venturi does change with SG...the higher the SG the lower the flow rate.... not a lot less but less.
But to your point most of the energy available is used to accelerate the fuel and overcome viscous flow loses which is why knowing the viscosity is prety important.
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Re: toluene to up octane rating
Tuner is right, aromatics have a destructive effect on fuel system polymers.Tuner wrote:BP of Toluene is 110.5 C ...... BP of Xylene is 138.9C
In spite of the high octane of Aromatics, the drawback of blending fuel with Benzine, Toluene or Xylene is they attack the rubber and other soft parts of the fuel system. The percentage of Aromatic content in Avgas is limited by regulation for this reason.
Specifically they attack:
ABS
polyethylene
polypropylene
buna n
silicone
neoprene
EPM
natural rubber
In order to use high concentrations of aromatics in fuels, the system component polymers must be changed to nylon or viton.
Re: toluene to up octane rating
Pump fuel has a high % aromatics in from the start.
You're only increasing the % a little bit with additives.
So..decoy statement.
No different from when leaded pump fuel got phased out.
The % or aromatics increased........fuel system leaks got blamed on the new fuel.
When diesel got upgraded to be low sulphur, same thing happened.
A lot of slippery diesel mechanics made a lot of money replaceng seals on injector pumps.
You're only increasing the % a little bit with additives.
So..decoy statement.
No different from when leaded pump fuel got phased out.
The % or aromatics increased........fuel system leaks got blamed on the new fuel.
When diesel got upgraded to be low sulphur, same thing happened.
A lot of slippery diesel mechanics made a lot of money replaceng seals on injector pumps.
Re: toluene to up octane rating
Ignoring viscosity, because 2 fuels could have the same viscosity, and more to the point this is a density discussion for the moment, you know that when the head is constant and the density changes a significant amount, the velocity also changes a decent amount, such that the net mass flow change is not equal to the density change.mk e wrote: But to your point most of the energy available is used to accelerate the fuel and overcome viscous flow loses which is why knowing the viscosity is prety important.
In the Kinsler test which is not representative of an engine, because the head changes proportional to the density, in that test the mass flow change is equal to the density change, all else being equal.
Last edited by nitro2 on Mon Dec 05, 2016 3:28 pm, edited 1 time in total.
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Re: toluene to up octane rating
On the subject of fuel lines...........there's a very serious problem with the quality of most of the aftermarket EFI hose. OEM is the only way to go , from the junk yard too.
Even though it might have the correct spec written on it, it's not much good for anything over 2 years. It goes hard and cracks and is totally unfit for purpose.
But if you're like Stevie Wonder, you wouldn't know.
Even though it might have the correct spec written on it, it's not much good for anything over 2 years. It goes hard and cracks and is totally unfit for purpose.
But if you're like Stevie Wonder, you wouldn't know.
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Re: toluene to up octane rating
Where can I find this Kinsler bench test you all are referring to?
Thank you.
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Re: toluene to up octane rating
I am wondering how the bulb in the hydrometer differs from the float in the carburetor... The float in the carburetor will change the head proportional to the density of the fuel as will the bulb.*
Is an assembled and dressed long block, sans a carburetor, an engine?
* The bulb is designed, though, to be submerged sufficient to allow portions of the cylindrical shaft to be the linear variable in displacement versus the irregular shape of the float. This is similar to the non-linear volume markings on a carefully prepared sump dipstick as most sumps do not vary linearly in volume versus height. So the gedanken experiment will neglect this deviancy in linearity but retain the concept of proportionality.
Is an assembled and dressed long block, sans a carburetor, an engine?
* The bulb is designed, though, to be submerged sufficient to allow portions of the cylindrical shaft to be the linear variable in displacement versus the irregular shape of the float. This is similar to the non-linear volume markings on a carefully prepared sump dipstick as most sumps do not vary linearly in volume versus height. So the gedanken experiment will neglect this deviancy in linearity but retain the concept of proportionality.
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Re: toluene to up octane rating
Contact VP Fuels (?).statsystems wrote:Where can I find this Kinsler bench test you all are referring to?
Thank you.
http://www.ebay.com/itm/like/4008093729 ... noapp=true
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Re: toluene to up octane rating
You can play with the float all you like, on a running engine the total head is obviously not just the difference in height between the fuel and the venturi, (but it is on a non-running engine)Kevin Johnson wrote: The float in the carburetor will change the head proportional to the density of the fuel
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Re: toluene to up octane rating
http://www.tfxengine.com/index.html
Give them a call.
I suspect this window into the engine will allow the serious racer the ability to optimize the tune of their running engine following a change in fuel.TFX Engine Technology Inc. has been a leader in cost effective, race proven, turn-key, in-cylinder pressure analysis for the past 15 years. In-cylinder pressure sensing is the long sought after window into the engine, allowing the ultra high speed in-cylinder processes to be recorded, viewed, and analyzed in detail, at one's leisure. No simulation, just the hard cold facts.
Give them a call.
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Re: toluene to up octane rating
yes, in my mind for most carburetors, however, if you are only in the vintage american v-8 stuff then it may not be true, but if so, then the carburetor is relying on other means for full range metering, such as power valves, high speed enrichment sprayers, variable needles, progressive barrels, and so on, in which case predicting the response may or may not be simpler, but in any case as usual, can get it right WOT changing just main jets, but may require a lot more to make it right through the full range, is what I was thinking as I read though the discussion. I am aware pump gas today can have up to 25% paint thinner and that may vary, and the discussion got me thinking about the implications of that variance.jmarkaudio wrote:
Air jets bigger than the fuel jets?
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Re: toluene to up octane rating
Explain to me what carbs have air jets bigger than the fuel jets. Be careful, I have just a little knowledge of carbs...modok wrote:yes, in my mind for most carburetors, however, if you are only in the vintage american v-8 stuff then it may not be true, but if so, then the carburetor is relying on other means for full range metering, such as power valves, high speed enrichment sprayers, variable needles, progressive barrels, and so on, in which case predicting the response may or may not be simpler, but in any case as usual, can get it right WOT changing just main jets, but may require a lot more to make it right through the full range, is what I was thinking as I read though the discussion. I am aware pump gas today can have up to 25% paint thinner and that may vary, and the discussion got me thinking about the implications of that variance.jmarkaudio wrote:
Air jets bigger than the fuel jets?
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Re: toluene to up octane rating
Kevin Johnson wrote:http://www.tfxengine.com/index.html
I suspect this window into the engine will allow the serious racer the ability to optimize the tune of their running engine following a change in fuel.TFX Engine Technology Inc. has been a leader in cost effective, race proven, turn-key, in-cylinder pressure analysis for the past 15 years. In-cylinder pressure sensing is the long sought after window into the engine, allowing the ultra high speed in-cylinder processes to be recorded, viewed, and analyzed in detail, at one's leisure. No simulation, just the hard cold facts.
Give them a call.
Thanks for the plug Kevin, , but to be honest the density question/answer doesn't require anyone to have ever seen or heard of an engine pressure analyzer, let alone purchased one.
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Re: toluene to up octane rating
The ones that don't have tiny discharge nozzles. If you took a survey of all carbs on earth I think that would be a majority.jmarkaudio wrote:Explain to me what carbs have air jets bigger than the fuel jets. Be careful, I have just a little knowledge of carbs...modok wrote:yes, in my mind for most carburetors, however, if you are only in the vintage american v-8 stuff then it may not be true, but if so, then the carburetor is relying on other means for full range metering, such as power valves, high speed enrichment sprayers, variable needles, progressive barrels, and so on, in which case predicting the response may or may not be simpler, but in any case as usual, can get it right WOT changing just main jets, but may require a lot more to make it right through the full range, is what I was thinking as I read though the discussion. I am aware pump gas today can have up to 25% paint thinner and that may vary, and the discussion got me thinking about the implications of that variance.jmarkaudio wrote:
Air jets bigger than the fuel jets?