FM's the State of Play with empasis on Climb performance.

[Crumpp]

The reference to +12psi and an external bleed hole confirms that the boost cutout used by Pilot Wilkie is the type modified for 100 octane emergency power. Blocking the drilled bleed hole returns the boost cutout to it's original operation (giving direct throttle control to the pilot) and hence the ability to get higher boost pressure than +12psi (on 100 octane).

Not if you read the 1937 Flying Notes. It talks about this same modification independent of fuel. The boost override could allow the pilot to reach boost pressure which caused detonation and this a typical modification.

There is no way of telling from an anecdote the details of the engine modifications.

Using a bleed hole is a very common method to control boost pressures. This is the same thing that BMW took when increasing the BMW801D series to 1.58ata/1.65ata. They just drilled the hole on the other side of the diaphragm.

Crumpp in post #14 YOU stated "The Relative performance is about right and it looks like people are nitpicking IMHO" !!.

The closest I could get to the correct weight was 75Lbs LESS than that used in the RAE test. If you actually look at the test you would see that with the CLOD Spit at 75Lbs less weight its still under performing by a considerable margin. So who is nitpicking now ?

I am wondering what your expectations are here. Yes, the relative performance is about right. What is the issue???

The error looks to be on the order of about 10% which is not bad for climb performance.

You are asking the developers to correct performance to a standard day, too. They should be moving the opposite direction and modeling performance on a summer day.

Of course your climb rates are going to be significantly reduced at a high density altitude.

I would ask questions like:

"Why is my level speed matching performance corrected to standard on a high density altitude day?"

"Why is my radiator temperature hitting the upper limits in level flight on maximum continuous?"

"Why can I asymmetrically overload the airframe at 400 mph and nothing happens?"

There is a lot bigger fish to fry for the programmers than a small error in specific climb rates.