Engine choice-190 or 200 hp for 8a

[tomhanaway]

My new Superior io-382 is scheduled for Sept. delivery for my rv-8a. The 190 hp version is warrantied for low lead. The 200hp uses 100LL only. Where I live, l premium gas without ethanol is available at regular gas stations.

I'll be running a constant speed Whirlwind 74rv prop. The prop calls for a minimum 200 hp but Whirlwind advises that it should be fine with 190.

I'm trying to decide between the two versions.
Shortish fun flights with the fun of takeoff is my primary use. Occasional long cruises. I'm skipping the 3 blade prop this time around although I loved the acceleration.

So, my question is, how much would I be giving up by going with an engine rated at 190 hp vs 200 hp for an rv-8a?

[RV10inOz]

I am assuming a CR difference between the two, so the extra fuel burn per HP from the lower CR 190HP is going to affect range.

Go for the HP

Where are the specs for these?

[Low Pass]

Not enough info available. If I were you, I'd go with the unleaded option - *if* I had a reliable supply of non-EPA/ADM contaminated gasoline. The hassle would be worth the cost savings. 10 hp will not be missed. Especially if you've never had it.

This is a personal decision as much as performance, imo.

[Danny King]

If you were talking about the heavy angle valve I0360, I'd advise the lighter engine. But since weight is not a factor......In the words of Tim the tool time Taylor,......More Power! That said, experience has taught me that 9 to 1 compression ratio is as much as you should go. After that, it's more cubic inches.

[tomhanaway]

Specs on the io-382 aren't available yet. Will be on display at Oshkosh. Info is from discussion with Aerosport.
8.3 cr for 190hp. 9.0 cr for 200hp.

[rv7charlie]

Lots of upsides to no-lead fuel. Minimal to no plug fouling, potentially lower egt's (more of the fuel burns in the combustion chamber), oil stays cleaner longer, slightly higher energy content, etc, not to mention better 'PR' with the non-flying 99.6%.

Charlie

[Ken Martin]

The XP-382 spec sheet is posted here.

http://www.vansairforce.com/communit...d.php?t=111501

Originally Posted by tomhanaway

Specs on the io-382 aren't available yet. Will be on display at Oshkosh. Info is from discussion with Aerosport.
8.3 cr for 190hp. 9.0 cr for 200hp.

[Neal@F14]

Since an 8A has the extra weight of a nosegear up front, I'd rather have a 190-something HP parallel valve engine to help save some weight up front over a heavier angle valve engine. Just a personal preference, but my friend's RV-8 with a 192hp parallel valve ECI Titan IO-360 sure is a well-balanced delight to fly.

[cajunwings]

You didn't say for sure if parallel vs angle valve was in the mix but i suspect it is. After working on these engines for years my feeling is that with all other factors being equal the parallel valve motors have the edge on reliability and longevity. On the other hand if you'll never put more than 800-1000 hrs on a fresh engine (especially if it has real Lycoming cylinders) and you don't mind some added wt and cost go for it. 10 more HP won't change your life either way but it will climb better and probably use less fuel. YMMV

Don B

RV- 9. Rebiuld in Progress

[tomhanaway]

Additional info,
The io-382 is a parallel valve engine. Based on the 360. HP difference is solely from the piston compression.
Latest hp numbers from Superior dropped 5hp for the lower compression their S&F flyer. Either rating will have a counter balanced crank.