new os 91hz-ps 3d

[3d_willz]

i will be needing a new 90 engine and thought i would look on the os website b4 i ordered my new os and there is a new os 91 on their site.
i dont normally use the pumped engines but what was the 91hz pumped engine like. the new engine is called 91hz-ps 3d ring. the regulator is horizontal now. heres a link
O.S. Engines .91HZ-PS 3D Ring

so was the old hz ps any good or do you all use the standard one like i do.
if the old one was good i will wait for the new one to come out.

mark

[gazza]

Never owned one myself but a few of my mates did & they were nothing but trouble and a nightmare to tune

Which is kinda why I never owned one myself

[Aidi]

If you can hang on a while longer, the OS 91 regulated engine is due out anytime now. Some good reports on it so far from those testing it.

As for the pumped, as gazza says, majority of users are not too favorable about them. If you are going to get an 90 sized engine right now, the 91HZ is the one to go for, or alternatively the YS91SR which is also a top motor.

[3d_willz]

iv think the one im talking about my be the new one as it says it is on the website. i had so much trouble years ago when the c spec first come out but i thought that was just them engines i thought it was all sorted now.

[simm0]

We have a hz pump and its a nice engine,but we like the sz as it seem good for us and a revy little devil
i heard the new os was going to run on back plate pressure like the ys sr instead of silencer pressure.i would prefer the os to work like the ys with no silencer pressure but i do like the hz
regards craig simmons/uk 3d cup-3dx

[leckylee]

well i've got the C spec viper and i can't fault it, i do know that te guy who had it previous to me made a bigger shim for the head.

[Bruinbear]

Yeah, correct shimming of the head for the fuel you're running makes a big difference.
Can't see what difference the horizontal reg makes on the new OS, surely it will be in what ever orientation that you happen to be flying ?