Is the Viperhead worth getting for a YS 91 ST?

[Saint728]

Just wanted to know is the Viperhead worth getting for a YS 91 ST? Does it make a big difference on power or smoother running then the stock head? Thank you in advance.

Take Care,
Cheers, Patrick

[Splattt]

Patrick,

From everything i've heard and read about the viperhead it does smooth out the engine and increase power...More than anything I'm getting it just because of the redundancy of two plugs. smoothness is my next priority and the power is an added bonus.

My Viper head should be he by the middle of next week and I can give you a more accurate description of what it does for the ys 91...

I will be running a MP2 on it, but have heard that the best power and smoothest running combo is the ys91, viperhead, and sb16 combo...that supposedly is the best.

Let u know more when I get the new head.

[DavidH]

Patrick
I am using the Viperhead dual plug on a YS 91. Gear ratio 7.75 to 1.
Cool Power 25 %, Hatori SB 16.
I am currently using an Enya 3 and 4 plug in the head. I have used many different combinations of plugs and brands. OS 8, Enya 3, Enya 4, OS A3.
I could not really tell any difference in how different plugs made the engine run different.
Now changing from the stock YS head to the Viperhead.
I do notice that motor is smoother running in a hover. As for the power input, hard to say if it is putting out anymore power than the stock head.
The smoothness improvement is what I was looking for when I talked to James about making the YS Viperhead.
I did the prototype testing on the YS Viperhead last summer before OMI started producing them.

David

[Sluggo]

I found the same thing as David. The motor is alot smoother and doesn't change when up right or inverted now. I did notice a power increase though. Not so much in HP but in torque, the motor seems to be able to hold a rpm alot more then with the stock head.

I have also found the motor likes to run richer with the viper head over the stock head. I have also tried many different plug combos and they didn't seem to make any change in how the motor ran so I now use 2 enya #3 plugs in my heads. I also think gears has a little to do with how it may work for you. So far it is one of the best upgrades or add ons that I have bought.

Chris

[Saint728]

Thanks guys for the info, I will order one this week.

Take Care,
Cheers, Patrick

[iachia]

Hello guys, could you tell me if the vyperhead will smoth out the engine and increase power also on 15% nitro? or is it only for high nitro content?
thanks!

[Azdesertfalcon]

I would use 30% coolpower
you will not be disapointed
however if your not flying agressive then you might not benifit from that combo

[iachia]

The price of CP30 here is just crazy that's why I don't use it. :(
I brew my own fuel and I'm happy with it. Also the engine semms to like it and I was just wondering if the vyperhead would be a benefit or not at 15% nitro.

[bighands3d]

I'm sure you could shim out the head for the 15% I'm going to use 20% simply because I have 2 cases right now. I may have to play the shim game myself.

[G MAN]

have also found the motor likes to run richer with the viper head over the stock head. I have also tried many different plug combos and they didn't seem to make any change in how the motor ran so I now use 2 enya #3 plugs in my heads. I also think gears has a little to do with how it may work for you. So far it is one of the best upgrades or add ons that I have bought.

Chris -------------------------------------------------------------------------


The reason plug heat range doesnt make any differece is because the plugs should be side by side and not over each other. If they were side by side you would have one plug on the exhaust side which would require a colder plug and one on the boost port side which would require a hotter plug. it would require that you cut the fan shrould out and the plugs would be facing side ways and difficult to get a glow driver on them.

I think the main reason the motor runs smoother is because of the combustion chamber design,i always when using 30% nitro change the chamber by enlarging it and making round instead of flat top like most OS heads are. Too much compression makes the motor run ruff in hover,shimming the head will help but modifying the combustion chamber works better.DOUG