Ive been playing with my HKS boost controller for some time now and I have got my primary turbo hitting a solid 10psi but on the transition I dip to around 7-8psi and dint reach a full 10psi until much later in the rev range. The problem is I don't hold that 10psi to 8k, more like at 6ish I hear something on the passenger side of the engine bay dumping a good deal of air. Would my assumption in my Charge Relief Valve is going bad and needs to be replaced? Or maby there is a setting in the HKS EVC 5 that I should look into.

 

It could be the CRV I believe you can switch it with the BOV and just plug the line for the BOV. This is assuming you have the stock BOV to switch it with. Or check the hose to the CRV that might be bad.


John

 

Hi Justin,
Thats usually a split/loose coupler at the y-pipe to crossover pipe connection. Sometimes the cross over pipe itself will develop a crach that's not noticable until it's pressurized or sees boost.

Typically if you're hearing dumped air it's a boost leak from that section but could be a split or loose connection anywhere but I'd start at the Y pipe.

 

I'll check the y pipe for any leaks. I'm sorry but what is the crv?

 

The CRV is the charge relief valve. It is the "second" blow off valve located towards the fire wall on the passenger side of the car. Looks just like the stock blow off valve just further back from it. If you view this link ( https://www.rx7club.com/showthread.php?p=8113663 ) on the first diagram look at the lower section by the turbos and the CRV has the yellow hose coming off of it.

Fritz Flynn, The reason why I did not sudgest the Y pipe coupler is because he has 10 pounds of boost on the primary turbo. So that indicates to me, it is not blown and the leak has to be behind the charge control actuator.


John

 

I had the same exact problem and sound as you describe. Full boost on the primary turbo but **** boost during and after the transition. Until i pulled the rear turbo's inlet pipe off to view the y-pipe connection to the secondary turbo and found that the y-pipe to secondary turbo bolts were almost off the studs. I bolted them down with thead sealer and i have'nt had any problems since. I know my problem is pretty rare but if your engine has ever been rebuilt its worth checking first. If i would have checked this first i would have saved months of obsessing over finding the problem.

 

I put the engine in his car quick and in a hurry because he wanted it ASAP and I'm sure every nut and bolt it loose hehe, just kidding Justin

On serious note most leaks you can hear will be a boost leak starting there and ending at the elbow.

Could be the CRV but I doubt it. Not something that usually fails and his car has about 50k miles or so on the engine and most accessories etc....

For the record it's common to make good boost with the primary and fading boost on the secondary when there's a leak in the system.

 

I had a similar problem, turned out to be the reference line going to the CRV was bad. So when I made boost the little line going into the CRV did not put pressure on the valve inside so it would pop open and dump all my boost. I found it by trying to apply a small amount of air pressure to the vac line on the top of the CRV (going towards the car) and found my problem. Also another thing to look into is a pressure tester for the intake. Arghx recommended one for my issues and I have found all my leaks and what not.


Mike



http://www.fighters-garage.com/rx7.html

Down near the bottom

 

I'm picking up another crv from a local member this week. I took off the coupler to the y pipe and everything seemed to be ok. I think this must be something to do with the crv or hose going to it, but at this point I'm believing it could be anything.

 

Did we ever end up with a solution for this? I'm going through the same thing and I'm leaning at a crv issue, or the charge relief solenoid possibly going bad and not applying boost pressure to the crv valve and thus dumping boost.

 

I needed to bring this back for a CRV question, I didn't understand the testing instructions very clearly. When testing the CRV with a mityvac, the "big" ports should not allow air to pass through the CRV until the correct amount of vacuum is applied to the smaller nipple. What my question is, when you apply vacuum to the small nipple to open the "big" ports, is the vacuum supposed to leak out of the small nipple, or is it supposed to hold?

I was under the impression that the CRV is supposed to hold the vacuum you apply to the small nipple. However I've tested now like 4 CRV's, and they all leak out the vacuum after I apply it with the mityvac on the smaller nipple. So idk which is right??