252 vs 231 with wastegate/intercooler

[StParkin]

Hello all,

I am planning to make my first aircraft purchase in the next couple years and am mostly looking at the M20J vs M20K models. I live on the west coast of Canada so there are large mountains going anywhere east, hence considering a turbocharger.

I have read about all the benefits of the upgrades that the 252 has compared to the 231, but the low useful load with that model gives me some pause. An Encore would be ideal but they don't seem to come to market all that often and when they do they come with quite a cost premium.

So, my question is whether there is substantial differences in performance and engine management between a 231 that has a wastegate/intercooler compared to a 252? I understand there are other differences (28V electrical, second alternator, etc) but I am just referring to engine performance and management. Is there a reason the 252 continues to seem to be so coveted despite the fact that many 231's now have WG/IC installed?

Thanks!

[Will.iam]

2 hours ago, StParkin said:

Hello all,

I am planning to make my first aircraft purchase in the next couple years and am mostly looking at the M20J vs M20K models. I live on the west coast of Canada so there are large mountains going anywhere east, hence considering a turbocharger.

I have read about all the benefits of the upgrades that the 252 has compared to the 231, but the low useful load with that model gives me some pause. An Encore would be ideal but they don't seem to come to market all that often and when they do they come with quite a cost premium.

So, my question is whether there is substantial differences in performance and engine management between a 231 that has a wastegate/intercooler compared to a 252? I understand there are other differences (28V electrical, second alternator, etc) but I am just referring to engine performance and management. Is there a reason the 252 continues to seem to be so coveted despite the fact that many 231's now have WG/IC installed?

Thanks!

Yes because the 231 turbo is still controlled by throttle and the 252 turbo is controlled automatically by a controller. I. E. The 252 you fire wall the throttle like any normally aspirated engine and the controller keeps the MP at 36 inches all the way to critical altitude (23~24k ft) where as the 231 you do not firewall the throttle and have to manage the boost yourself. Having said that it’s not hard to do but it is not automatic. Think stick shift compared to automatic transmission. Both do the same job but one requires manual intervention. Also when descending the 252 will automatically hold the boost at the set MP through the descent the 231 you will have to make adjustments like an NA airplane engine. The merlin wastegate controller is not an automatic controller. This commands a premium for the convenience. Whether that is worth it for you depends on if you have a choice to buy one in the first place. Mooney made far more 231 than 252 and even fewer encores. Good news is you can take any 252 and upgrade it to an encore and get 230 more lbs of useful load but it’s not cheap. Again what’s that premium worth for u. You can not upgrade a 231 to an encore and the company that used to upgrade 231 to 262 (a 231 with a 252 type engine) no longer exists but there are 262 out in the field. 

[PeteMc]

I can't speak to the 252, but I have a 231 with the Merlyn wastegate (no intercooler) and engine management is pretty straight forward.  You will see a bit if an increase in MP just after takeoff (I've always assumed to to increased airflow and a little better engine performance).  Then as you continue your climb above 10K you'll see a slow decrease in MP, both of which just require a minor adjustment of the throttle to correct. 

A J is a good plane, but I  think you're right that the 231/252 Encore, etc. might be better for you if you if you're constantly crossing the mountains.  And even when get east of the Rockies on a X-US flight, I am always still in the mid teens.  Usually you're above the Wx, better speeds and typically very little traffic, so you're not constantly getting call-outs from ATC or maybe even frequent vectors. 

 

 

[Slick Nick]

Where are you on the west coast? Don’t count out the J model. I live in Calgary but frequently take my MSE to our pace on the island, as well as the lower mainland with 2 people and 6 hours fuel. Does great and will happily cruise at 16-19k on 7gph. I mostly only fly IFR. One thing that you may want to consider is FIKI capability. Especially this time of year, ice can hang around for a few days and make it hard to fly if you really need to get somewhere. I work for an airline so it’s easy for me to just hop a plane if the weather isn’t ideal, but your needs may differ  

There are a couple decent 231’s for sale on the island, and a couple in Alberta that would make good birds if that’s what you’re set on though. A turbo would be nice, but there hasn’t been a flight yet where I haven’t been able to go because I don’t have one. 

Edited Saturday at 02:24 AM by Slick Nick

[hubcap]

Performance wise, I believe the 231 gives you more performance than any other model, for the money.
 

If you have the intercooler and the Merlyn along with a good EIS, management and temperature control are easy. The 252 is easier to manage but with a lower useful load and a price premium. Either will serve you well.

[Tx_Aggie]

I went through this same consideration 5 years ago. I ended up choosing a J as I wanted to make sure I could afford flying altogether. While I don’t live in the mountains I am at 3000’ msl and regularly cruise at 9-11k. The J has been perfect, routinely see 155-160 ktas. 
 

sometimes I do wish to have a turbo to get higher but the speed and range of these birds makes it east to circumvent building or established storm systems. 
 

also as onboard equipment wears out I’ve replaced with superior garmin equipment, at this point I would only sell/trade for something with equal modern equipment and a much larger power plant. I don’t think I’d make a move to the 231/252 as the incremental increase in spend only equates to getting there maybe 5-10 minutes faster and that’s not worth it to me. 

[Danb]

Our planes are marvelous when looking at the fleet as a whole, we have planes capable of 140-230 knots and 8-18 GPH alone with useful loads up to approximately 1150 lbs range up to 1400 miles. Entering prices between 90-650,000 dollars. Comparison to other fleets we’re hard to beat for 2-4 person planes. I’ve had J models a Bravo and Acclaim. If you don’t have a need for carrying much load want a sporty affordable plane stay here.

D

[Ethan]

I have a 231 with a Merlyn wastegate but no intercooler. I love it. Engine management is no problem. My useful load is 1000 pounds exactly, which is pretty good for any Mooney built after 1979, except for the Encore.
 

Some 252s have far less (hundreds of pounds less) useful load. My full fuel useful load is 568 pounds, that leaves me with room for only 3 (smallish) people and scant luggage. That’s pretty pathetic. Most of the time, my limiting factor is almost always useful load so I am happy to have my 231 rather than a 252.

[Pinecone]

You can convert a 252 to Encore specs and gain 230 pounds of useful load.

You need to convert the -MB engine to -SB, which is different RPM and boost limits (2700 RPM, 39 inches).  No internal changes.

You have to install the dual puck brakes.  And replace the control surface balance weights.

No STC, as it is two factory drawings, for the M20K, which they both are.

And the interior in the 252 is lighter than the Encore.