[hightower99]

Originally Posted by revetec

I made an error in my report and have amended it to remove the reference to port length effects. Thank you for your input.

Well that makes me happy. I thought you might have disagreed.

Originally Posted by Revetec

The top end of the LS1 is similar to the X4v2 and the gains are consistent through the tested range. If you are correct, the gap should decrease significantly as the revs increase. So your point is?

The only shared things between the heads of your engine and a LS1 is the fact that they are both pushrod operated 2VPC heads. Other than that I would wager that unless you based the total head design on the LS1 (which would be a bad move on your part) that the designs are not overly similar. First the tested range is only from 1250RPM to 3000RPM (Only a 1750RPM spread). The LS1 valvetrain is optimised at something around 4500-5000RPM and therefore is actually causing a loss in performance everywhere else in the RPM range. Furthermore I don't even know how you got torque ratings for such low RPM from a LS1 the majority of dyno charts I have seen start above 2200RPM. The gains are not consistent at all. As revs increase the gain is decreasing until about 2600RPM where your engine closes in on it's optimized RPM while an LS1 is still more than 2000RPM away from it's optimized RPM. It is plain to see that the torque curve of the LS1 is steadily increasing as revs rise.

Originally Posted by Revetec

It does matter when it comes to thermal loss. A shorter stroke engine dissipates less heat into the cylinder wall. But a conventional engine with a short stroke produces less torque than is practical in automotive use.

Yes but that aspect was not mentioned or even implied it is plain to see that in the context of the article you are referring to the fact that you are producing almost as much torque with a shorter piston stroke as if a shorter piston stroke should be considered a disadvantage (like it would be in a common crank system). This is mainly used as an excuse for the fact that the Toyota engine produces more torque for more than half of the shown range even though you claim an increase "anywhere up to 30%". You are making excuses for the apparent lack of any advantage.

Originally Posted by Revetec

The Lambda sensor measures Oxygen not fuel. If the desired combustion is achieved there is a trace of Oxygen in the exhaust gas. If the combustion is on the rich side, oxygen is reduced, and if the mixture is too lean a greater amount of oxygen is measured. The Lambda readings are a guide because we have proven independently that running a leaner mixture in the 2,000-4,000rpm range provided a normal lambda reading. This means that the desired combustion was achieved using a leaner mixture. Either that or we had a 50% restriction in the intake at 4,700rpm. Torque was good so I think there was little restriction.

Firstly I know exactly how a Lambda sensor works so lets assume it is a known for both of us. You cannot cheat or fool a Lambda sensor without doing so on purpose (by injecting excess air into the exhaust of by burning excess fuel in the exhaust). You apparently are forgetting that you fuel metering sensor system could also be defect. Explain to me how your engine can burn less fuel but still fool/trick the Lambda sensor into thinking that you are running 14.7:1? If you are burning less fuel then more oxygen will be present in the exhaust and the sensor will detect that and tell you that you are running lean. How are you fooling it?

Originally Posted by Revetec

Please go to Autospeed where they explain BMEP. BTW. We have used a Kesler BMEP plotter that has a sensor in the combustion chamber measuring and plotting pressure, so BMEP is not fictional. It is the average cylinder pressure over 4 complete cycles.

Unfortunately Autospeed doesn't do a good job of describing what BMEP actually is. They do however make one simple point: BMEP is a better value to compare different engines than Specifc Power. However BMEP has very little to do with efficiency. Think about it some of the most inefficient engines in the world produce extremely high BMEP figures while some of the most efficienct engines produce relatively low BMEP figures. However BMEP is even better suited for talking about the same engine. Because for the same displacement engine more torque requires a higher BMEP.

I suggest you read this: MEP

Notice where it says "It’s important to remember that the values produced by the formula are for theoretical analysis only, and do not reflect the actual pressures inside an individual combustion chamber."

Originally Posted by Revetec

In the right conditions? The dyno we have corrects to standards using air temp and barometric pressure adjustments.
For your Info the test conditions are as follows: Room temp (26.7 degC) Humidity (60%) Barometric Pressure (1010 mbar) Intake Temp (26.5 degC)

That is all important information that should have been in the article! The article says that the Dyno chart is raw output with no SAE smoothing which leads me to think that it isn't corrected to SAE standards for ambient conditions.

Originally Posted by Revetec

Look if I published everything and all data and calculations, it would take me a year to tabulate it. This report was aimed as an overview of recent testing. If we used the same technology as current engines and had a budget to optimise all the systems, then the result would be even better. We are currently making further upgrades and will better these figures soon.

the article is referred to on your site as a "Comprehensive testing report" it comes no where near comprehensive. I am not asking for a full on totally complete technical analysis of all systems and aspects, but I am certainly asking for actual data as opposed to your own interpretations of the data.