Getting on with my supercharged project and I'm pondering over what type of valve I should get for the system... Never run boost before so unfamiliar with the different setups.
Which is better? A BOV or a recirc valve..

Not sure what type of SC you're using, but if using a roots type (eaton etc.) then I'd stick with recirc. being as it'll be making boost all the time, having the BOV going constantly while cruising would be a right PITA!

Yes eaton roots blower, do i even need a valve at all???
Sort of considering a valve of some sort tho, my fuel pump only puts out 20psi to handle the 3-4 psi carbs need plus say 8 psi boost via turbo regulator. The blower might spike above 20 psi on overun and start pushing fuel out of the float bowls. a bov set to stop this might be a good idea...

[Edited on 9/10/11 by Craigorypeck]

Yes, youll need a BOV or Recirc valve when the throttle butterflies close.

Ive supercharged mine with an Eaton M45 - Soon to be swapped for an Eaton M62 that ive just bought.

When on idle, the BOV opens, which dumps the pressure, so it is quite noisy on idle. When revving however, this closes and gives a satisfying Ptshhhhh when the throttle closes again. Works a treat. Recirc will be a little quieter, but not a lot. Your MAP wont spike on overrun because the throttle bodies and BOV remove that risk.

You will need a rising rate fuel pressure regulator that connects to the manifold, as with the BOV.

[Edited on 9-10-11 by MakeEverything]

Where is you throttle body relative to the supercharger? If its before then you shouldn't need a blow-off valve.

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Originally posted by MakeEverything
Yes, youll need a BOV or Recirc valve when the throttle butterflies close.

Ive supercharged mine with an Eaton M45 - Soon to be swapped for an Eaton M62 that ive just bought.

When on idle, the BOV opens, which dumps the pressure, so it is quite noisy on idle. When revving however, this closes and gives a satisfying Ptshhhhh when the throttle closes again. Works a treat. Recirc will be a little quieter, but not a lot. Your MAP wont spike on overrun because the throttle bodies and BOV remove that risk.

You will need a rising rate fuel pressure regulator that connects to the manifold, as with the BOV.

[Edited on 9-10-11 by MakeEverything]

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Originally posted by matt_gsxr
Where is you throttle body relative to the supercharger? If its before then you shouldn't need a blow-off valve.

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quote:

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Originally posted by Craigorypeck

quote:

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Originally posted by MakeEverything
Yes, youll need a BOV or Recirc valve when the throttle butterflies close.

Ive supercharged mine with an Eaton M45 - Soon to be swapped for an Eaton M62 that ive just bought.

When on idle, the BOV opens, which dumps the pressure, so it is quite noisy on idle. When revving however, this closes and gives a satisfying Ptshhhhh when the throttle closes again. Works a treat. Recirc will be a little quieter, but not a lot. Your MAP wont spike on overrun because the throttle bodies and BOV remove that risk.

You will need a rising rate fuel pressure regulator that connects to the manifold, as with the BOV.

[Edited on 9-10-11 by MakeEverything]

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Yes I'm using a malpassi turbo regulator, same as on espirit and reno 5. I'm connecting it with a pilot tube as a boost reference.

Why you going for m62? what cc engine you have? I'm sticking my m45 on a 2.0 YB. geared at 2:1 crank speed.

Might get something like this and just vent to air with the option of plumbing it back into the inlet pre charger...

TURBO 1.8T RECIRCULATING DUMP VALVE BLOW OFF BOV 25MM | eBay

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