New Guy and an M20F with RayJay Turbo

[Shadrach]

55 minutes ago, N201MKTurbo said:

Mine reaches critical altitude at about FL210 with a fixed wast gate that isn't closed all the way. It has the same turbo and the same engine. The only difference is the inter cooler. I didn't think it made that much difference, but apperently it does.

Are you limited to ROP as well?

[N201MKTurbo]

I always run LOP 30 in 2400 9.3 GPH TIT 1500

[Shadrach]

6 hours ago, N201MKTurbo said:

I always run LOP 30 in 2400 9.3 GPH TIT 1500

Any bootstrapping issues? I wondering why the Rayjay with a manual WG would suffer from this.

[N201MKTurbo]

Mine goes open loop above 21000. The manifold pressure will change with pitch changes or anything that changes the load on the engine. Manifold pressure cannot exceed 32 inches in my installation, but it will wander around a bit.

I've only been up there a few times and it's been a while. 

[M20F]

10 hours ago, N201MKTurbo said:

Mine reaches critical altitude at about FL210 with a fixed wast gate that isn't closed all the way. It has the same turbo and the same engine. The only difference is the inter cooler. I didn't think it made that much difference, but apperently it does.

The turbo is the same but everything going to it/from it is different. 

[cliffy]

Every system will have its own a critical altitude where, by design, the system will not maintain max MP anymore. 

It usually is found in the POH. It is usually defined as where the wastegate closes fully but with a fixed wastegate the function is the same.

When testing the actual altitude where the MP can not be maintained MAY vary some (a couple thousand feet) due to normal wear, atmospheric conditions, etc.  

But if the CA is way lower than called for that starts the investigation as to why. Bad turbo, bad wastegate, system leaks? 

BTW a little Mouse Milk squirted on the wastegate linkage and valve axle once and awhile does wonders in keeping them free and working. Old trick I learned decades ago on Navajos. 

 

[garytex]

I still don't understand how/why a 231 with no intercooler would be 20 - 25 kts faster than the RayJay F.  Are they that much slicker? 10 hp sure isn't going to make that speed difference. Must be lots slicker, either that or maybe the comparison is 'book' vs 'real world' speeds.