Chapter 19, Figure 20, bottom graph, solid red line with square markers is called "7000 RPM PWR". At 11.76/1 compression it's showing 500 kW and at 6.94/1 compression it's showing 550 kW. That's 10%, no? Furthermore, the text goes on to say, "At 7000 rpm, there is only a slight penalty in power output at high compression ratios and late spark timing."
I checked them and they look correct to me. Figure 7, for instance, shows a peak motoring pressure of 28 bar. P2=P1*(CR)^k, so substituting you get P2=14.7*(12.16)^1.39=473 psi, or 32.2 bar. You'll notice an error, but the text goes on to say "The pressure inside the cylinder at the start of compression will be a bit lower than intake manifold pressure due to VE less than unity." Playing a bit with the P1 and substituting -2 psig yields 27.8 bar. As a test, apply the same P1 to the 6.94/1 case and you get a peak of 12.8 bar which is right in line with Figure 7. Next, the motoring pressure traces fall exactly on top of the fired traces right up until spark, which is exactly what you would expect. And finally, the motoring pressure traces match those in my model as long as the boundary conditions are set the same. I have found no reason to doubt the motoring pressure traces.
If this were true, then gasoline wouldn't have an auto-ignition temperature.
80 bar Pmax is not a detonation threshold. It is a structural limit (page 56). This is typical for modern engine designers and calibrators. Some run much higher on 91 octane even.
Are you saying that the CO2, H2O and trace other chemicals that remain after combustion is what detonates?
Correct and I did not say or imply otherwise.
There is plenty of room to increase manifold pressure. The ignition timing would just have to be retarded in order to achieve the Pmax boundary condition.
In figures 21, 22, and 23 he did not specify the IMP but I found that 1.5 bar fits his fired and unfired pressure traces. For figure 24 and 25, he states "lower engine speeds and boost pressure values". This implies that boost is being applied in 21, 22, and 23 and lower boost is being applied in 24 and 25 but he again did not specify a value. A boost pressure of 2 psig correlates with his fired and unfired pressure traces and matches his qualitative description at least. The increased ignition timing advance was required to reach 80 bar Pmax at the lower boost levels he described. This would be easier if he had included the IMP in the Figure descriptions.
Why would I do that when my boundary conditions are different than the ones in the graph?
That would sound like a good idea if I didn't know what I know about compression and combustion dynamics plus the failure rate of professionally "tuned" supercharged coyotes.
I re-read your sentence and I don't see where truncating it for brevity changed the meaning. Apologies if you feel differently.
Ok, which is just what I described in post 102: "...they did not appear to model the temperature of the unburned air/fuel beyond the flame front, which is where detonation occurs..." Your response was, "...You don't seem to understand this, detonation is in the end gases...."
Post up the proposal.
Just quoted me over the phone. He said it may go over
OP can have his block sleeved and shortblock assembled with rods and pistons for 5600..
