Hybrid C:B ratios
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SpudBlaster15
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Last edited by SpudBlaster15 on Wed Jul 14, 2021 4:21 pm, edited 1 time in total.
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jimmy101
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Well, a gasoline engine is basically an 8x hybrid with a 1:8 chamber to barrel volume (actually, I think it works out as a 1:7 chamber:barrel).
A 1:7 chamber to barrel ratio is a CB of 0.14.
This would be the CB that maximizes efficiency.
My Quad, 8X, full-auto hybrid "spud gun";
a 1990 Toyota Celica.
A 1:7 chamber to barrel ratio is a CB of 0.14.
This would be the CB that maximizes efficiency.
My Quad, 8X, full-auto hybrid "spud gun";
a 1990 Toyota Celica.
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sharpshooter
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This is just a guess, but here it goes
It would make sense to me if at a 2x mix, half of the optimal ratio of a normal 1x would be prime in the hybrid. That being said, i would also assume that the extra pressure should increase burn rate, therefore altering the results on that somewhat.
And then so forth... 3x=1/3 of 1x, 4x=1/4 of 1x
just my $0.02 worth
It would make sense to me if at a 2x mix, half of the optimal ratio of a normal 1x would be prime in the hybrid. That being said, i would also assume that the extra pressure should increase burn rate, therefore altering the results on that somewhat.
And then so forth... 3x=1/3 of 1x, 4x=1/4 of 1x
just my $0.02 worth
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boilingleadbath
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An interesting alternative strategy using the burnt latke data is to add in the energy lost due to atmospheric pressure, multiply by the mix, and then subtract the atmospheric pressure out again...
M(Ev+Ep)-Ep
Of course, I'm suggesting this because it's really easy for me to do the comparison, as EVBEC 1.4 and later already do this calculation (to allow modeling of hybrid mixes).
Such indicates that:
1x -> 1.43/1.66/1.25
1.5x -> 2/2/1.96
2x -> 2/2/2.4
3x -> 2/2/4.7
These are B:C ratios because I'm too lazy to invert them.
(no inter-data-point guesses; these are the fastest of the data points I could do the calculation for [only those that latke tested) - order is 2.5", 1.5", and .75" data.)
We note that the 2.5" data and the 1.5" data indicate that a C:B ratio of .5:1 is best until really high mixes. I don't think that's a valid result.
M(Ev+Ep)-Ep
Of course, I'm suggesting this because it's really easy for me to do the comparison, as EVBEC 1.4 and later already do this calculation (to allow modeling of hybrid mixes).
Such indicates that:
1x -> 1.43/1.66/1.25
1.5x -> 2/2/1.96
2x -> 2/2/2.4
3x -> 2/2/4.7
These are B:C ratios because I'm too lazy to invert them.
(no inter-data-point guesses; these are the fastest of the data points I could do the calculation for [only those that latke tested) - order is 2.5", 1.5", and .75" data.)
We note that the 2.5" data and the 1.5" data indicate that a C:B ratio of .5:1 is best until really high mixes. I don't think that's a valid result.
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Jolly Roger
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Sharpshooters right, all depends on the mixes it is at. If you have a chamber say 100cc on a 2x mix, and you want to achieve the same results from a 4x mix, you would technically make the chamber 50cc. Then you have the addition of the higher original chamber pressure which will also indirectly add to the performance. As boiling said, burnt lake will be able to calculate it for you, as almost everyones circumstances will be different. And an over-sized chamber shouldn't decrease performance, just efficiency.
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SpudBlaster15
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Last edited by SpudBlaster15 on Wed Jul 14, 2021 4:24 pm, edited 1 time in total.
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boilingleadbath
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Excuse me... but I'm fairly confident that a 2x (50cc) outperforms a 1x mix (100cc).
Anyways, jolly roger must be working from the fast combustion (displacement definition) standpoint. (which, assuming a high-bursting burstdisk, is essentially the case)
Anyways, jolly roger must be working from the fast combustion (displacement definition) standpoint. (which, assuming a high-bursting burstdisk, is essentially the case)
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SpudBlaster15
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