My ST 3250 with Perry pump and pump carb.
10% "normal" fuel.
32 deg F and 2700 ft ASL.
TNC tach

Stock Bisson pitts muffler
Menz ultra 20x10 6800 rpm
Biela 18x10 3-bld 6000 rpm

Bisson pitts muffler with the pinched ends cut off.
Menz ultra 20x10 7300 rpm
Biela 18x10 3-bld 6500 rpm

Turbo-Jett Muffler
Menz ultra 20x10 6900 rpm
Biela 18x10 3-bld 6000 rpm

Perhaps the Turbo-Jett is too small even though it falls within the size range for this engine.

I have a new ST 3250 stashed away for a rainy day. I would not have guessed that this engine was this strong, what a suprise.

You are running at about the limits of the engine. That is why the numbers are similar. That is a lot of prop. Impressive it is turning up at 7000 though.

The 3250 is not agressively timed, but usually gets a bit of boose from the turbojett.

From the rpm's you noted, it looks like you are running below a point where the turbo can do much good. The large engine version tuned range is in the 7500-8500 rpm area.

Hello,
Using a "mousse can" type exhaust system the following was noted:

Menz 20x10 ultra 7400 rpm
Biela 18x10 3-bld 6700 rpm

I want to run this engine in the 6500 to 7500 rpm range to keep it in a good power band and have reasonable rpm to fly with.
So far it appears to be turning right with the 40cc gassers.
I also reinstalled the "K" carb and power is the same as the Perry pumper.
I'll try some "ST" fuel next and note any differences.

Thanks
John

Hello,
I ran some ST fuel with 10% oil in it and found no significant increase in power.
I did get a much better midrange with both the Perry and stock "K" carb.
The "mousse can" exhaust is real peaky.

John

John, that mousse can looks to be too short for a 32.5cc engine. Probably better suited for a .60-.90 engine.