bandit1-RCU

My Feedback: (17)

I need some input from somebody that has experience. I am in the process of building a Tempest FAI, and am trying to make an educated engine decision but I don't have any firsthand knowledge to draw off of. My options are the OS C Spec, or the YS 91. What do you guys think?

Diverig

Hello,

bandit1

I have a C-spec in a Vigor and thus far I really like it.

lots of power and very smooth power up.

I would defiantly buy another one

_BOON_

I have the same problem as I have just got my preditor max.
I'm leaning towards the YS91 because of the added pump on it.

Vigor1

I have a YS91 on my Fury Extreem with SB Pipe VERY NICE and powerful
Ray

Galifrey

if you are happy to run 30% then the YS if not and you are happy to buy a viperhead and cline regulator get a C-Spec..

chris elliott

This might be worth considering. I bought a OS91 c/spec pumped with twin viper head from [link=http://www.directrcengines.com]www.directrcengines.com[/link] and it's just amazing! Really really powerful and smooth and no matter what I do in terms of violent 3d manouvers, it just keeps pumping out the power. The pricing is good enough from these guys to put the engine close to the non-viper head version, so it might fit into your budget

Flyfalcons

I have a YS 91 and it is an awesome engine. It runs very smooth and has a ton of power. Just a great plug and play engine. I am using a Hatori SB-15 pipe with Magnum 30% fuel.

sharam

My Feedback: (2)

I have both; a 91 CSpec PS (Viperhead) in a Fury Tempest and a YS 91 in a Fury Extreme. YS 91 is my first choice by far. They both have about the same power - the YS is eaasier to set. The OS tends to lean out and I had to fiddle a lot with different fuels and needle settings to get it to run right.

syclic

The pump make both very good engines. I like the YS because they give the same performance and are very user friendly for less money.

P.S. The YS does NOT require 30% fuel. I have ran successfully (using various KSJ and Hatori exhaust systems) 12% heli, 20% heli and 30% heli from Magnum and 15% and 30% heli from Cool power. The main difference I have found is that the lower nitro fuels did not give as much top end power (actually the Magnum 20% is not that far behind the CP or Magnum 30%) and the low nitro ones (12 & 15) were a little more needle valve sensitive to altitude and temperature changes.

DrScoles

My Feedback: (18)

YS is much more user friendly motor... set the needles once and forget it... This year I have been to Houston and Louisiana for funflys, and back to cold Seattle, didn't touch needles... YS may lose the edge on outright power over the tricked out OS, but they are tough to tune... So, depends on your skill level, and how much you like to mess with things... YS is set and forget, and change the bearings each season..period.

Mike

wilkigmc

Another vote here for the YS91, I've got one in a Fury Extreme, with the CY Muscle Pipe 2. It's got about the same performance as my mates Fury with OS C-spec but the YS is more reliable and more consistent.

Flyfalcons

How does your YS like the MP2? I am in need of a new pipe for my YS and don't want to pay nearly $200 for another Hatori.

wilkigmc

The YS and MP2 are a great combination, even only running on Coolpower 15% its awesome!! It's not overly noisy either and I haven't touched the needles in over a year.

warthog-RCU

I absolutely love the look and idea of the OS 90 C-Spec. But, after having heard all the issues with the pump, and requirement to fuss with it in the pits, I'm somewhat leaning towards the YS for my next chopper. Too bad, cuz my other OS engines are great.

(just my two cents)

WH

ChrisK7

My Feedback: (14)

I just put a YS 91 in my Freya Evo 90. I had a YS 80 in it for the first flights. I love the YS engines. Super easy to tune and lots of power.
I ran 15% as well as 30% in them with no issues at all, just re-set the needles if needed.
I'm running a Zimmerman stainless muffler on the 91 right now and it is super quiet. I have a Revolution aluminum that I ran on the 80.
Both are super engines and mufflers in my opinion.