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  #21  
Old 11-07-2018, 01:00 PM
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DanH DanH is offline
 
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Quote:
Originally Posted by KeithB View Post
It looks like there are differences between the original (Lycoming) and the clone (Superior). The XP400 is stroked an additional 0.25Ē. Whether or not that is material is beyond my pay grade.
Yeah, that's a Superior-only crank, currently out of production. It was used in the 382 and 400.

I doubt additional stroke changes the CHT vs advance relationship in any meaningful way.
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  #22  
Old 11-08-2018, 03:27 PM
Nova RV Nova RV is offline
 
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These were my numbers yesterday at 2500 feet and OAT 61F running 24" and 2450rpm. IO390 and 2- PMAGS timed at 20 degrees.

Full rich oil temp 189
#1 235
#2 196
#3 231
#4 233

leaned to about 20 degrees rich of max EGT oil temp 191

#1 259
#2 220
#3 252
#4 251
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  #23  
Old 11-08-2018, 04:56 PM
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Carl Froehlich Carl Froehlich is offline
 
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Am I wrong or does the data showing excessively low CHTs scream of too much cooling drag? Is this opportunity to clean up the RV-14 cowl inlet/outlet to gain a little speed?

Carl
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  #24  
Old 11-09-2018, 06:00 AM
Nova RV Nova RV is offline
 
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Carl,

Yes they do seem to be very low. I started this thread because of it and also because I noticed there were no posts that I could find about high CHT issues in a 14. Based on the posts here it seems to not be an issue but I agree mine seem very low and I wanted some other data than mine before I start pulling things apart to run some tests. My setup is the stock CHT thermocouples that come in the Lycoming kit from Garmin, I have the correct thermocouple wire from the sensors to the GEA24 pins and no dissimilar metals connectors or solder in between. When I was assembling, I did some tests using the stock sensors and different wire from the sensor to the GEA24 unit and did get some interesting errors vs. OAT when I used different (non thermocouple) wire.
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RV-14A kit # 140243 (flying as of 11/18)
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  #25  
Old 11-09-2018, 07:12 AM
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At 85-95deg F (Alabama Humidity) between 4500-5500 mine are consistently 340-360 at 85%, 320-330 at 75% but I generally lean out a bit to bring them back up to 340-360. Oil temps started at around 225 but as the hours went by the settled to around 185.

The manual states:

Quote:
For maximum service life, the Cylinder Head Temperature (CHT) must be maintained below 435ºF (224ºC) during performance cruise operation and below 400ºF (205ºC) for economy cruise powers.
But doesn't really give an optimal operating range.

For oil:

Quote:
The maximum permissible oil temperature is 235°F. (113°C.). For maximum engine life, maintain desired oil temperature is 180°F (82.22°C).
As a noob, I'm always looking for advice on how to manage my engine.
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Last edited by bkervaski : 11-09-2018 at 07:22 AM.
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  #26  
Old 12-03-2018, 11:33 AM
Bavafa Bavafa is offline
 
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Just wondering what folks are getting for their top speed on their 14/14A.

My numbers so far has been encouraging... it has been cooler weather here so I lucked out. During the engine break-in, the two hours of full power, I was seeing 340-350 CHT and 204 oil temp. Yesterday, on my 6th hour of flight already seeing lower oil temp and CHT.
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  #27  
Old 02-07-2019, 06:45 AM
Nova RV Nova RV is offline
 
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Just to update this for anyone collecting data, yesterday I did a boiling water test on all of the CHT probes and found #2 to be reading 20 degrees low (10% error) and the rest read 209-215 degrees (cycling around 212). This low #2 seems to corroborate the data from earlier with #2 always being lower. I also pulled all of the spark plugs and #2 were no different looking from the others so I'm sure it's firing correctly and that the one CHT probe is just off.
As to why the CHT numbers seem low from some others, no idea really. One difference from stock is that I have a Vetterman exhaust (4 into 2) which could run cooler or the exhaust opening at the rear of the cowling is larger than stock because of the extra cut outs to accommodate the dual pipes. One other difference is that I had the exhaust ceramic coated which could make a difference temp wise but I really have no way to claim this without any before/after data.
One interesting note is that my friend has a nearly identical setup in his 14A (Thunderbolt, Whirlwind prop and a ceramic coated exhaust) but his exhaust is stock and his CHT numbers are 30+ degrees higher than mine.
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  #28  
Old 02-07-2019, 08:26 AM
rvbuilder2002 rvbuilder2002 is offline
 
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Quote:
Originally Posted by Nova RV View Post
As to why the CHT numbers seem low from some others, no idea really. One difference from stock is that I have a Vetterman exhaust (4 into 2) which could run cooler or the exhaust opening at the rear of the cowling is larger than stock because of the extra cut outs to accommodate the dual pipes.
That explains a lot.

I haven't seen a Vetterman installation on a 14 but if additional openings are added to the cowl, an increase in cooling flow would be expected.
That alone might make a Vetterman exhaust not a good choice unless the builder is willing to do other experimenting to modify the stock cooling exit.
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  #29  
Old 02-07-2019, 10:30 AM
KeithB KeithB is offline
 
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Verterman 4 in 2 on Superior XP400 - the cutouts donít have to be very dramatic. However, obviously the entire tunnel is outflow.

I have also since added small deflector extensions trimmed almost parallel to the airflow.
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  #30  
Old 02-07-2019, 10:53 AM
Nova RV Nova RV is offline
 
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Quote:
Originally Posted by rvbuilder2002 View Post
That explains a lot.

I haven't seen a Vetterman installation on a 14 but if additional openings are added to the cowl, an increase in cooling flow would be expected.
That alone might make a Vetterman exhaust not a good choice unless the builder is willing to do other experimenting to modify the stock cooling exit.
Scott, I'm not questioning your analysis but how are lower CHTs bad unless they are so low the cylinders can't "expand" properly and not allow it to break in properly or cause increased wear? Lower temps within reason was always told to me as being a good or better thing.

My cut outs are similar to Keith's although slightly larger.

Thanks!
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