tIANci

I ran in my engine today and with an APC 8.8 x 8.75 I am taching 18,600 RPM using Byron 15% semi synth. Is this what I should be getting? Its also hot and humid here so am not expecting extreme RPMs. I am looking at installing her on my Viper 500.

bob27s

My Feedback: (19)

Engine is new, correct?

Did you put some bench time on the engine with a run-in prop ??
I use an old 8.75x9W cut to 8" diamter as my tach measurement and run-in prop.

When it is hot and humid, that is when you have to adjust to the needs of the engine by changing a prop. You still want to see a ground peak around 19,500. So dropping to an 8.8x8.5 (especially on a new engine) is a good idea.

Are you using a bubble tank?

Did you beef-up the nose and firewall area on the Viper ?

tIANci

Bob ... The engine was running in, its done about 20 mins or so. I know it needs more bench time, could see it getting better today itself after another 10-15 mins of running. I think I need to be more patient. Shall also cut down a prop. Not using a bubble-less tank yet, I used a big 320cc tank on the bench and let the engine run to half tank only. The new Vipers have f/glass on the tank area and the firewall. I shall try to get the 8.8 x 8.5. Thanks for the info.

tIANci

Bob ... what amount of oil are you using in your fuel? I got some Klotz and would like to increase from the standard 16% lube in Byron 15% nitro semi synth. Is there a need to? Its hot and humid here so I thought perhaps it would be better to get a little more lube in. Thanks!

tIANci

Guess there is no chance of a reply on this query huh?

MJD

My Feedback: (1)

Maybe he's tied up. In the interim -

The information is on their website. I can't see why Bob would tell you anything different than what Dub Jett recommends:

[link=http://www.jettengineering.com/faq.html#faq5]Jett fuel recommendations[/link]

MJD

bob27s

My Feedback: (19)

hey there...

I didnt see the posts ...... sorry. I usually get email notifications when someone posts in here, but I have not gotten one in weeks. I will have to check with Admin and my settings.

Thanks for the help MJD

Fuel is fuel when it really comes down to it. Almost all of the commercial blends are good. Oil content ranging from 16% to to 20% is fine. At one time I was running 15% total oil, but only for one of the larger engines. I also use the heli-fuel from time to time that is overloaded with oil. The only time I bother adding oil, and its always a bit of castor oil, is when I am babying a new engine.

If you have decent fuel with a good lubricant package, there is no real benefit to adding more oil. Oil will not really help the engine run cooler. It might help protect in case of a lean run. Your best defense against that is to run the mixture slightly richer... error on the rich side a little bit.

Bob

MJD

My Feedback: (1)

Just so you know, one difference in what I said to tIANci is that my personal thought is that 18% - 20% was the desired range and that 16% was a bit low. If you say good 16% is good, then 16% is good!

MJD