VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.






VAF on Twitter:
@VansAirForceNet

  #1  
Old 08-07-2022, 10:47 PM
cjjohns79 cjjohns79 is offline
 
Join Date: Aug 2022
Location: Edmond, OK
Posts: 1
Default IO-390 vs IO-360

I知 new to the group and looking to buy an 8 in the near future. Can anyone give insight about whether there is a noticeable difference between these two engines in performance.
Thanks for the help!
Reply With Quote
  #2  
Old 08-07-2022, 11:30 PM
Mike S's Avatar
Mike S Mike S is offline
Senior Curmudgeon
 
Join Date: Sep 2005
Location: Dayton Airpark, NV A34
Posts: 16,607
Default Welcome to VAF

Chad, welcome aboard the good ship VAF
__________________
Mike Starkey
VAF 909

Rv-10, N210LM.

Flying as of 12/4/2010

Phase 1 done, 2/4/2011

Sold after 240+ wonderful hours of flight.

"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."
Reply With Quote
  #3  
Old 08-07-2022, 11:43 PM
Robert Sailor Robert Sailor is offline
 
Join Date: Nov 2018
Location: Nanaimo BC Canada
Posts: 176
Default

I suspect you値l notice a bit more speed but probably not a lot however the additional hp will really show in takeoff and climb.
Reply With Quote
  #4  
Old 08-08-2022, 11:45 AM
N82VM N82VM is offline
 
Join Date: May 2017
Location: VA
Posts: 242
Default

It will reduce the weight of your wallet about $12,000 more than a 180hp io-360
__________________
RV-8A Project
2022 Dues Paid
Reply With Quote
  #5  
Old 08-08-2022, 12:02 PM
Tim 8-A's Avatar
Tim 8-A Tim 8-A is offline
 
Join Date: Mar 2009
Location: Colleyville
Posts: 318
Default

Its a significant difference from my 8a I had with a 180, my 390 At 8500 ft. 68% power 175 kt. TAS 8.3 gph (22 m.p. 2400 RPM) your prop could change the numbers quite a bit.
__________________
Tim Blake
Colleyville, Tx
RV8a Purchased flying (many changes) Sold
RV-10 Purchased flying.. Panel upgrade complete.
G3X/Dynon/TT all new interior. Flyin like a dream. Sold
RV8a Purchased flying Let the changes begin

Last edited by Tim 8-A : 08-08-2022 at 12:07 PM.
Reply With Quote
  #6  
Old 08-08-2022, 12:03 PM
Ironflight's Avatar
Ironflight Ironflight is offline
VAF Moderator / Line Boy
 
Join Date: Jan 2005
Location: Dayton, NV
Posts: 13,308
Default

“I wish I had less horsepower!”…..said no pilot, ever!

But honestly, the difference in performance between the two (assuming you;re talking angle valve to angle valve) is going to be pretty small. And also honestly, I have heard a number of guys with LOTS of RV-8 time that built a plane with an angle valve engine muse that if they built another one, they’d just go with a parallel valve engine because it makes the nose lighter, which makes for lighter handling.

Van originally designed the -8 for an O-320, but very, very few build that way!

With my 180 horsepower O-360, dual P-Mags, I cruised to and from Oshkosh this year at 170 KTAS burning about 8.8 gph. that’s just a data point, not a recommendation - just to help quantify things.
__________________
Paul F. Dye
Editor at Large - KITPLANES Magazine
RV-8 - N188PD - "Valkyrie"
RV-6 (By Marriage) - N164MS - "Mikey"
RV-3B - N13PL - "Tsamsiyu"
A&P, EAA Tech Counselor/Flight Advisor
Dayton Valley Airpark (A34)
http://Ironflight.com
Reply With Quote
  #7  
Old 08-08-2022, 12:38 PM
Freemasm Freemasm is offline
 
Join Date: Nov 2017
Location: Orlando
Posts: 950
Default

Parallel valve:

Stroked to 370-ish CIs
better breathing sump
EI
etc.

The HP numbers are then very close to the 390 at less weight and cost.

Yes, you could do much of the same to the 390 but a more economical path to 205->210-ish HP. Just another option to inform and cloud the OP's mind.
Reply With Quote
  #8  
Old 08-08-2022, 01:28 PM
Gash's Avatar
Gash Gash is offline
 
Join Date: Aug 2009
Location: Goodyear, Arizona
Posts: 988
Default

Quote:
Originally Posted by Ironflight View Post
的 wish I had less horsepower!賠..said no pilot, ever!
That gave me a good chuckle Paul. So true!
__________________
Karl, Goodyear, Arizona (KGYR) ATP, CFII
RV-14A
Yak 50 Red Thunder Airshows
=VAF= donor 2023
Reply With Quote
  #9  
Old 09-03-2022, 09:24 AM
Lucmac Lucmac is offline
 
Join Date: Jan 2022
Location: OKC
Posts: 41
Default

Quote:
Originally Posted by Ironflight View Post
“I wish I had less horsepower!”…..said no pilot, ever!

But honestly, the difference in performance between the two (assuming you;re talking angle valve to angle valve) is going to be pretty small. And also honestly, I have heard a number of guys with LOTS of RV-8 time that built a plane with an angle valve engine muse that if they built another one, they’d just go with a parallel valve engine because it makes the nose lighter, which makes for lighter handling.

Van originally designed the -8 for an O-320, but very, very few build that way!

With my 180 horsepower O-360, dual P-Mags, I cruised to and from Oshkosh this year at 170 KTAS burning about 8.8 gph. that’s just a data point, not a recommendation - just to help quantify things.
Count me as one of those guys that built an 8 with an angle valve IO-360A1B6 that would re-build with a parallel valve, non-counterweighted crankshaft (but still with fuel injection) if I could do it over again. It was a plus when doing cross country with a person and full luggage. But I mostly flew solo and it was a negative for me when doing acro. Heavier stick forces than I like pulling through the bottom of maneuvers.

Last edited by Lucmac : 09-03-2022 at 09:26 AM.
Reply With Quote
  #10  
Old 10-04-2022, 08:51 AM
chaskuss chaskuss is offline
 
Join Date: Mar 2005
Location: SE Florida
Posts: 1,617
Default

Quote:
Originally Posted by cjjohns79 View Post
I知 new to the group and looking to buy an 8 in the near future. Can anyone give insight about whether there is a noticeable difference between these two engines in performance.
Thanks for the help!
Check your private messages.
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 04:46 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.