What exactly is the CRV , I mean what does the leters stand for and what does it do

 

its just a fancy name for the secondary blow off valve

 

Here is a copy & paste from the third page of this thread:
https://www.rx7club.com/forum/showth...hreadid=118780

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The CRV is the Charge Relief Valve.

It vents the charged air from the rear (secondary) turbo until 4500rpm. At 4500rpm the CRV closes and the Charge Control Valve (CCV) opens to allows the boost from the rear turbo to combine with the boost from the front (primary) turbo. If you didn't vent the secondary boost before the CCV opened, then the boost would push back on the secondary turbo and not allow it to spool very well.
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Here is a pic from page 2 of the same thread:

 

WTF?

The charge relief valve essentially serves as the wastegate for the primary turbo under 4500 rpm. It vents excess air and pre-spools the secondary turbo so the boost doesn't dip excessively when the secondary comes online.

 

I love it when Jonski uses visual aids

youre the man, man

-Ben

 

6.Charge Control Actuator:

When closed, this prevents Primary boost from going into the Secondary Turbocharger. This valve seals the air passage the same way as the throttle butterfly valves. This remains closed until 4,500 RPM AND Secondary boost pressure is the same or more than Primary boost pressure.

 

There is ALOT of bad information on this thread. I think too many people have gone non-seq or single and forgotten how the sequential system works .

It is difficult to understand what the CRV does without understanding how the entire sequential system works. It's really not that complicated, in theory. It is explained in the shop manual, and here:

http://www.autosportracetech.com/RX-...erOverview.htm

 

It's a Honda SUV.

 

Some of this info is good and some is bad. Let me try to explain it in a easy to understand format.

I'm sure you know that before the 2nd turbo comes online its getting prespooled. Its prespooled so that when it comes online your boost doesnt drop a ton then have to build back up. Its already up and running and creating boost so that when the gate opens up its already going. Well during this prespool process the 2nd turbo is creating boost.....well since the boost isnt going into the motor yet it has to go somewhere or else it would just build up and be hard on your turbo. During that prespool period the CRV opens up so the boost can have somewhere to go, which is back into the intake box. When the gate opens and the 2nd turbo comes online the CRV closes so that it doesnt keep leaking it all out.

Hope that helps some
STEPHEN

 

wow........

Good info Stephen, That cleared a lot up. Thanks

 

So, let me ask another question. If you get an aftermarket BOV, do you still retain the CRV? and how does the two work in conjuction?

thanks, Matt

 

You still keep the CRV with an aftermarket BOV. They work the same way the stock setup does.

 

How could you tell that the crv is bad, cause I keep on getting this annoying wind blowing noise when my Hks bov goes off.. It start doing this when I switch to a Greddy type s bov...

 

put a vacuum hose to the actuator nipple, suck lightly, have your girlfriend blow through the main hose, flow when suck, no flow when no suck, end up in the bathtub with can of whip cream... oops