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mastiles · 11-10-2014, 09:09 AM

Has any one run the 105 without the velocity stack on the carb? And if so what kind of results did you have? I'm thinking bout doing it with my Trex 700n and was curious.

j bomb · 11-10-2014, 06:04 PM

About a year ago, I installed the velocity stack on my 91 speed which has the same carb but doesn't come with one. It seemed to run a little smoother in the midrange and a little easier to tune, but I didn't notice any additional power. Of course, this could have been the "placebo effect" for all I know. Anyway, it didn't make a huge difference.

Rob43 · 11-11-2014, 10:53 AM

Guy from whom I bought my 700N has the 105 with stack. Said he pitched his. Said getting rid of it improved tuning a great deal for him.

mastiles · 11-12-2014, 06:16 AM

The other night I pulled the engine to put a governor sensor in and while doing so I was looking at the shroud and on the inside it has plastic splitting the air flow. Some to the head and the other to the carb area. That got me to wondering about the stack. I am suffering from the over rich condition that some 105 owners have. It might be a stretch but y'all think maybe leaving off the stack might allow the engine to run more "normal"? By getting more air. Granted I'm not a engine scientist and know all there.but engines in simple term is a pump. I'm thinking in my shroud the carb is not getting enough airflow to it requiring you to lean it out, but you can only lean it so much. With it off it allows more air into the carb which allow you to run richer. More fuel more air. Less fuel less air. This is the first engine I've run with a stack in 30 years of this hobby and tuned many other helis and plank engines just fine. Busy at work now but I'm gonna put the engine back without the stack and post back my findings. Thanks for the replies.

dchekas · 11-13-2014, 06:04 PM

The purpose of the velocity stack is to INCREASE air flow into the carburetor by smoothing out the air entering the carburetor.

However, it does not have an enormous impact. You can run the engine without it just fine.

It will not resolve an overly rich condition in the engine.

Contact hobby services: http://www.hobbyservices.com/contact.html

They will provide you with a replacement main needle seat that will allow the engine to be leaned free of charge.

11-10-2014, 09:09 AM	#1 (permalink)
mastiles Registered Users My HF Map location Join Date: Aug 2011	OS 105 HZ-R Velocity Stack Has any one run the 105 without the velocity stack on the carb? And if so what kind of results did you have? I'm thinking bout doing it with my Trex 700n and was curious.

11-10-2014, 06:04 PM	#2 (permalink)
j bomb Registered Users My HF Map location Join Date: Mar 2007	About a year ago, I installed the velocity stack on my 91 speed which has the same carb but doesn't come with one. It seemed to run a little smoother in the midrange and a little easier to tune, but I didn't notice any additional power. Of course, this could have been the "placebo effect" for all I know. Anyway, it didn't make a huge difference. __________________ John Barta Michigan Whirlybirds Heli Club http://www.michiganwhirlybirds.com

11-11-2014, 10:53 AM	#3 (permalink)
Rob43 Registered Users Join Date: Oct 2008 Location: Midland, Michigan	Guy from whom I bought my 700N has the 105 with stack. Said he pitched his. Said getting rid of it improved tuning a great deal for him. __________________ = Rb43 =

11-13-2014, 06:04 PM	#5 (permalink)
dchekas Registered Users My HF Map location Join Date: Sep 2006	The purpose of the velocity stack is to INCREASE air flow into the carburetor by smoothing out the air entering the carburetor. However, it does not have an enormous impact. You can run the engine without it just fine. It will not resolve an overly rich condition in the engine. Contact hobby services: http://www.hobbyservices.com/contact.html They will provide you with a replacement main needle seat that will allow the engine to be leaned free of charge. __________________ Team Align Enterprise Hobby Facebook Align Part Finder YouTube Channel

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11-12-2014, 06:16 AM	#4 (permalink)
mastiles Registered Users Thread Starter My HF Map location Join Date: Aug 2011	The other night I pulled the engine to put a governor sensor in and while doing so I was looking at the shroud and on the inside it has plastic splitting the air flow. Some to the head and the other to the carb area. That got me to wondering about the stack. I am suffering from the over rich condition that some 105 owners have. It might be a stretch but y'all think maybe leaving off the stack might allow the engine to run more "normal"? By getting more air. Granted I'm not a engine scientist and know all there.but engines in simple term is a pump. I'm thinking in my shroud the carb is not getting enough airflow to it requiring you to lean it out, but you can only lean it so much. With it off it allows more air into the carb which allow you to run richer. More fuel more air. Less fuel less air. This is the first engine I've run with a stack in 30 years of this hobby and tuned many other helis and plank engines just fine. Busy at work now but I'm gonna put the engine back without the stack and post back my findings. Thanks for the replies.

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