Sorry Rudeboy for the confusion. I did this math long time ago before I made a difficult decision between Saito and MVVS. It is now so abvious for me, that I didn't explain properly.
ORIGINAL: Rudeboy
Why does a Saito 150 need an 8 oz mount? Are you using mild steel beam mounts or something?
Any big 2lb or more engine needs strong mount. Cheap nylon stuff will not hold long. I looked at Tower at any solid mount like Dubro shock absorbing (over 8oz) or Great Planes for 1.2 -1.8 (7 oz). Other don't show the weight but if it's less than that it is probably not strong enough.
ORIGINAL: Rudeboy
Why does a Saito 150 need a 22 oz tank for 15 minutes...?
Again it is from Saito information website stating a little less than 2 oz per minute WOT. I assumed 75% of that adding 2-4 oz for the fuel tank alone. My 11 oz tank weights 12 oz.
ORIGINAL: Rudeboy
Are you running 40% nitro through it in a pylon racer at WOT all the time? Mine does perfectly fine on a 14 oz tank for an aerobatic flight routine (10% fuel)...
From RCFAQ database where SAITO 150 turns 17 inch prop at 8600 rpm, you need full throttle a lot flying 3D with 11.5 lb plane. I know, because I fly it with 18 inch prop and it needs over 8k rpm to pull out of hover.
ORIGINAL: Rudeboy
The installed weight of an MVVS 1.6 is definitely more than that of a Saito 150... it may not be much more depending on the tanks and batteries you use, but it will be more.
The great benefit of MVVS is that I can have small fuel tank at CG far away from the engine. On Saito unless you install fuel pump the tank should be close to the engine. And because the tank is big it changes the total weight and the ballancing of the plane during the flight. Kind of PITA.
ORIGINAL: Rudeboy
Now, the MVVS on a tuned pipe is a different thing: it really comes to life on a pipe, and becomes a hell of a lot stronger than that Saito 150... on a pipe it turns 18" props with ease, while a 17x8 is about as far as you can go with the Saito in any case.
I didn't go with tuned pipe because the pipe is 8 oz heavier than the can muffler. I wanted to be lighter than more powerfull.
I hope this explains and clears the confusion.
RysiuM