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Speed,Combat,Scale,Racing => Rat Racing and Team Racing => Topic started by: frank mccune on January 20, 2020, 03:36:57 PM

Title: How much pressure?
Post by: frank mccune on January 20, 2020, 03:36:57 PM

           
     Hello All:

     How much pressure is generated by using timed and untimed crankcase pressure when using a pressure fuel system?   
     Perhaps the answers shoul be psi.

                                                                    Tia,

                                                                    Frank McCune

Title: Re: How much pressure?
Post by: Tom Vieira on January 20, 2020, 03:42:33 PM

I recently read an article by Bill Lee from an old magazine.  I believe it was about 1PSI with no check valve. 1.25 with.  Doesn't sound like much, but it's still an increase!  I may be wrong, however....

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Title: Re: How much pressure?
Post by: BillLee on January 20, 2020, 07:25:50 PM

Quote from: T.J. Vieira on January 20, 2020, 03:42:33 PM

I recently read an article by Bill Lee from an old magazine.  I believe it was about 1PSI with no check valve. 1.25 with.  Doesn't sound like much, but it's still an increase!  I may be wrong, however....

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That's pretty close, T.J.

What I wrote was

" ... a test stand to measure this and found that the tank
pressure from an untimed crankcase tap is about I.4
psi, or about 1.6 psi if a ball-check is used in the
pressure line."

Yes, this is  crankcase pressure, not timed pressure, but what most folks would use.

Bill

ps; this may be found on the NCLRA website at  http://www.nclra.org/TechTopics/UniflowPhysics.pdf

Title: Re: How much pressure?
Post by: Tom Vieira on January 20, 2020, 07:27:37 PM

Not bad for not going back to look it up!  Hahahaha!

Thanks for the correction!

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Title: Re: How much pressure?
Post by: bob whitney on January 20, 2020, 09:11:51 PM

I have never liked timed pressure .most times don't use a check valve

Title: Re: How much pressure?
Post by: BillLee on January 22, 2020, 09:26:46 AM

Quote from: Motorman on January 22, 2020, 09:15:34 AM

Timed pressure is allot more, so much it will make your needle valve very sensitive. I use check valves I make myself on un-timed pressure but they need constant flushing out with straight methanol. Any dried oil gets in there you're done. 


Motorman 8)

+1

Title: Re: How much pressure?
Post by: Tim Stone on February 04, 2020, 03:13:19 PM

Quote from: Motorman on January 22, 2020, 09:15:34 AM

Timed pressure is allot more, so much it will make your needle valve very sensitive. I use check valves I make myself on un-timed pressure but they need constant flushing out with straight methanol. Any dried oil gets in there you're done. 


Motorman 8)

   I have enjoyed your input over the years. Do you consider yourself a current competitor or retired? I have not seen you
at the Nats in my 32 years since re-entering and attending the C/L racing Nats
 .