Demonstrated Performance of Bf109T

[Kevin J]

supercharger was damaged, worn out or had some other technical issue, a /trop modification does not cause this significant power loss.

A /Trop mod affects the rated altitude of the engine at which maximum power / speed can be achieved, so a Spitfire Vb/Trop had about 20 mph less speed than a Vb temperate version, likewise a Bf 109G-2.
Have a look at table 4 in the Kurfurst link for the 109G-2 and G-2/Trop.
Kurfürst - Bf 109G/trop Middle East trials: Dimesnions, Weights and Performance
and table 3 in the Spitfire link for the different variants of the Spitfire V,
Spitfire (F) Mk.VB W.3322 Report

 

[parsifal]

It could be a number of reasons, but facts are the tropicalized version of the Bf109F did not, in and of itself suffer huge losses performance compared to other types.

Possible reasons for the reported low performance could include....as stated missing or malfunctioning supercharger, excessive engine wear, incorrect fuels, not pushing aircraft to full design limits. misreporting of report (error in translation). There are probably more...

 

[Shortround6]

That may depend on the air intake/filter.

With the doors open there should be little loss of ram effect into the supercharger. With doors closed there will be a loss of ram.

Other engines (or installations) may not have had as good a provision for altering the inlet to suit the conditions.
P-38s did. They drew air in from inside the wheel wheels and unless changed over to the outside scoop would show a considerable loss of RAM (total?)

 

[Denniss]

A /Trop mod affects the rated altitude of the engine at which maximum power / speed can be achieved, so a Spitfire Vb/Trop had about 20 mph less speed than a Vb temperate version, likewise a Bf 109G-2.

Tropical filters on Spits were rather bad, causing a significant loss of speed and rated alt. AFAIR this improved in 1943 but I'm not sure about this.

 

[Kevin J]

Tropical filters on Spits were rather bad, causing a significant loss of speed and rated alt. AFAIR this improved in 1943 but I'm not sure about this.

I've modified my post to add some table data if you look at it again.

 

[swampyankee]

It could be a number of reasons, but facts are the tropicalized version of the Bf109F did not, in and of itself suffer huge losses performance compared to other types.

Possible reasons for the reported low performance could include....as stated missing or malfunctioning supercharger, excessive engine wear, incorrect fuels, not pushing aircraft to full design limits. misreporting of report (error in translation). There are probably more...

And the possibility the data are valid.