Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Reed valve in intake = 'infinitely variable' cam timing

Logic · 10-06-2022, 04:41 AM

If you have a 'very hot' racing intake cam in your engine,
BUT
with a reed valve/s just behind it
then
You get self adjusting 'infinitely variable' cam timing...

Well not infinitely variable like Koenigseg's FreeValve system, but with a mild exhaust cam; pretty damn good!?

The Honda 500cc single cylinder 'Thumper' had/s such:

And Alfa Romeo (and other manufacturers) experimented with them, losing ~1kw in top end power for a vast improvement in drivability.
(35% more low end torque apparently)

In those days Reed Valves were made of spring steel.
That meant that if one broke; your engine was a goner.
You also lost some power due to the greater vacuume reqd to open the reed valve.

Nowadays we have carbon and glass fibre reed valves negating the above issues.

If your intake tract bolts to the head, it should be pretty easy to fabricate a bolt on Reed Valve Box.
A bit far from the intake valve, but much easier and simpler than the very beta open source Freevalve setup mentioned in the Freevalve thread.

Some discussion:
https://www.speed-talk.com/forum/vie...hp?f=1&t=42425

Reed valves on a 4-stroke.

I can see this making a big difference in low rpm economy..?
Has anyone here tried this??

10-06-2022, 04:41 AM	#1 (permalink)
Logic Master EcoModder Join Date: Aug 2022 Location: South Africa Posts: 423 Thanks: 135 Thanked 187 Times in 155 Posts	Reed valve in intake = 'infinitely variable' cam timing If you have a 'very hot' racing intake cam in your engine, BUT with a reed valve/s just behind it then You get self adjusting 'infinitely variable' cam timing... Well not infinitely variable like Koenigseg's FreeValve system, but with a mild exhaust cam; pretty damn good!? The Honda 500cc single cylinder 'Thumper' had/s such: And Alfa Romeo (and other manufacturers) experimented with them, losing ~1kw in top end power for a vast improvement in drivability. (35% more low end torque apparently) In those days Reed Valves were made of spring steel. That meant that if one broke; your engine was a goner. You also lost some power due to the greater vacuume reqd to open the reed valve. Nowadays we have carbon and glass fibre reed valves negating the above issues. If your intake tract bolts to the head, it should be pretty easy to fabricate a bolt on Reed Valve Box. A bit far from the intake valve, but much easier and simpler than the very beta open source Freevalve setup mentioned in the Freevalve thread. Some discussion: https://www.speed-talk.com/forum/vie...hp?f=1&t=42425 Reed valves on a 4-stroke. I can see this making a big difference in low rpm economy..? Has anyone here tried this??