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trackdom

Well Known Member
I built for my rv8 O-320 D2A a plenum...I kept former air intake. At take off colder cylinder is 320 F , cruising 280 F , descending 230 F . I am afraid I could stress The engine if I need to pull up. Do I need to reduce air intake surface or place a flap at the exit ?
Thanks
 
Good question!

Good question! After fighting high CHT's on my first flights in the summer, this winter my CHT's sometimes drop below 300 when reducing throttle for decent. :confused:
 
trackdom said:
I built for my rv8 O-320 D2A a plenum...I kept former air intake. At take off colder cylinder is 320 F , cruising 280 F , descending 230 F . I am afraid I could stress The engine if I need to pull up. Do I need to reduce air intake surface or place a flap at the exit ?
Thanks
Click to expand...

Sounds too good to be true. Typically we have high temperature problems. 1st thing I would check is to make sure the readings are true and correct. I would put one probe in boiling water & then check the reading on the gauge. IF the gauge reads 100 C or 212 F, then the reading you are seeing in flight is more than likely correct.

After checking instrument calibration and readings are still low, I would try a piece of metal or tape on the two front cylinders. The OLD baffle plans showed OPTIONAL temperature raisers that can be fabricated out of thin metal. The size can be reduce to increase temperature and enlarged to raise temperature.

Once gauge accuracy is assured and temperature raisers on front two cylinders did not help, I would start closing off the exit area because that will have the least impact on the look of the airplane.
 
Rv6 flyer,
It sounds good to Check the probes. They come from GRT , And I doubt all of them are failing...
I would like to reduce air intake if not too complicated...And I would gain some speed.
Reducing exit would be the easiest Way.
Mickey,
When coming to land And descending cht are low , I hav? to reduce speed And keep engine rpm...
Rv8 has an enormous problem! She is too fast...;)
 
Hi Dominique,
You are well within the Lycoming guidelines for CHT. This is from the 0-320 Operators Manual (bottom of Page 3-11 in my copy)

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After implementing a number of mods recommended by the experts here to increase the efficiency of the stock Van's cowling and baffles, the CHT's on my RV-8 are running 260 F average at 35 F OAT. So there's more work to be done to take advantage of the excess cooling.
 
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Wonderful, Wy Didn't I see that instruction? And decreasing temperatures less than 10 ?c by minute .
 
When I run LOP in the winter months, all CHTs are under 300; typically in the 280 to 295F range. That includes OATs as high as 45-50F. The only way I can get CHTs above 300 is to run on the rich side. That plenum really works!
 
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