apex head flow data

[Turbor]

some local guys built a brp 1200 turbo and are building another one but with high hp goals. They claim the stock brp head flows 268 at 550 lift.
ported flows 300 at 550 lift . anybody have the stock numbers ? hurricane must have that, its ok if you dont want to give your ported head flow numbers, but id like to have atleast the stock flow numbers, to see if all the hype they are having is true. They claim the brp flows alot more than the yammi...

 

[HURRICANE]

They do flow better then the Yamaha with those #'s as there results.I going buy memory but it seems to me that the Yamaha flows around 180 intake at .300in lift.The Yamaha valves are small so we found that the flow #'s were the same at higher lift untill we went bigger valves.Our porting doesn't make the flow #'s bigger,it just make the low lift #'s ALOT better

 

[mulot30th]

Okay... but 268 at 550 lift is HUGE for a 400cc cylinder!!!!

Let alone 300 on the ported version.

 

[mbarryracing]

The Rotax 1200 flows alot of air...

 

[TWIN TURBO]

There must be a typo, you can't open a Apex/RX1 valve .550 lift. You would have to cut the valve guide out of the head and there's no room for valve spring at that lift.

 

[mbarryracing]

Greg,
They stated the Rotax opens .550 not the Yamaha

 

[Turbor]

yeah and i even asked for the yammy data at .500 as i was sure it would not open .550, so whats the max lift on the yammy head?

 

[TWIN TURBO]

Sorry my mistake, thought they were talking about a Yamaha. My educated guess is .400 lift max. on a Yamaha maybe with a different valve spring.