Well how unlucky am I? When was the last time anyone saw one of these fail?

The plastic fragments that came off the plunger resulted in damage to my brand new twins.

Just putting it out there, now may be the time to replace these as a precaution.

 

yikes

 

Thanks for the heads up. I am sorry to see that happened to you.

 

I know!


Thanks! I seem to be on quite a roll with the twins

 

Sorry for the paranoia everyone.........I just do not want anyone else to be in this situation.

Perhaps if someone finds an all metal direct replacement for these, this modification might be one of the reliability mods along side replacing the stock plastic AST.

 

That really sucks. I know I would be super po'd about that.

Pettit and a few other companies sell blow off valves for our cars, but I'm not privy to what materials they use internally.

I haven't seen any aftermarket relief valves yet. I just installed a new Mazda relief valve and the pettit bov and called it a day.

 

Yeah it does suck. I was planning to replace the rear bushings & pillow ***** this winter but that money will more than likely be needed to resolve this situation.

As for alternative BOV/CRV it looks like BLUE TII is investigating, if he finds a suitable substitute it will be great news for us all

 

Pettit uses a 1" BOV, while our cars use something like a 19 or 20mm or 3/4 inch bov. So you'll need a hose adapter at least.

Options are pretty limited in the stock size. Maybe you could use a 90* Kompact Turbosource 1-way recirculation valve for the CRV.

Last I heard you could buy NOS OEM BOVs. You'll probably want to make double check some aftermarket CRV is working well with the stock sequential system.

And, there are some solid aftermarket options for the stock BOV from GReddy and HKS.

 

I feel this in my heart and I'm sorry this happened to you. Really, I feel this.

as far as the bov goes, you can always go with an aftermarket one and get a flange welded on to your pipe somewhere. No problem. As far as the crv, functionally is the same as the bov just in reverse. I don't see why replacing it with an aftermarket bov and then recirculating it wouldnt work. Or of course buy a new one if they're still available. I guess with our cars getting up there in age, stuff like this will keep happening with oem parts from when the cars were made. I'm sure everything is well past it's expected service life. I think we're all just waiting on the clock at this point

 

There is a solution that is easy to do and will prevent any future problem with sucking debris into the turbos. I did this 15 years ago. You simply take the hose from the CRV to the airbox off and replace it with a smaller hose with a small air filter on the end. This prevents any of the broken pieces from getting to the turbos. No connection to the air intake. Also, if a new one should fail, the pieces would be blown into the short hose and against the small air filter. Easy to clean up and change. I put the air filter on the end just in case some air is sucked backwards into the turbo outlet during normal operation. I have I never understood why Mazda designed it this way anyway. Who would want to dump hot air into the airbox and suck it back into the engine to make the intake air even hotter for the turbos. Just dump the hot air under the hood.
Mike

 

Thanks for the sympathy, it's a shitty situation.....,,especially as I am still trying to help the bank account recover after the engine build!

If I do keep the twins, I will for sure be deleting both the stock BOV and CRV (as I am non sequential) and just relying on my HKS SSQ IV....which I REALLY wish had been the case in the first place.

 

Oh..... you're non seq..... well then lol you don't need either of the stock valves then. Just the ssqv is sufficient

 

I think this was just good old bad luck. The stock BOV/CRV is very hardy and it's VERY rare I've ever seen one that has failed.

This isn't the plastic AST that's a time bomb, this is a VERY rare incident. Everyone doesn't need to panic and start replacing BOV's .

I would get with Bryan at BNR Supercars and see if he can fix those turbos for you. Very possible he can replace that damaged wheel, get them re-balanced, and good as new.

Dale

 

So you have two BOVs and a CRV on a non-sequential car? Thats a big red flag. It makes no sense. Who set this up?

Also, if you're non-seq you should just go single. There's no point in being non-seq. Non-seq twins are just a very inefficient single turbo.

 

Yeah, if I keep the twins, that will be the plan.



Turbos are on their way back to the engine builder as per their request, will see what they can do. Thanks for the reminder about Bryan though!



The engine was built by Force-Fed Performance Turbos & Tuning - they do quality work so I guess I need to ask why those valves were left in place. I am no engine expert hence paying them and I assumed that if they were left in place that there was a good reason.

Going single is an option I am currently costing out.........sucks if a brand new set of twins just became worthless though

 

Emissions! Not just air comes out when things get a bit of mileage, leaky twins and 5 cent quality oil injectors the culprits for these stupid things. If you have them venting externally here, pulled over and asked to open the bonnet, nasty man in blue tends to have his way with you.

I can see where the charge relief might be more of a problem, virtually operating continuously below 4k(?) and taking out you secondary turbo in this case with a downhill run straight into the compressor outlet.....I'd expect damage not just at the compressor face. Charge bypass has a more convoluted path and should see positive pressure most of the time. Can't see the diaphragm, is the spring still above the "washer" or has it fatigued too?

 

The diaphragm are both there and in good shape, under vacuum it moves as you would expect. But for whatever reason the plastic on the plunger just decided to give way.

I can cut open the top and post a photos for curiosities sake though

 

Pettit makes a billet OEM replacement:
Blow Off Valve Upgrade Kit RX7 FD

 

 

No, I did not, but who knows what the previous owner(s) might have done.

That's why I am replacing EVERYTHING in this car with new. Which is why I am so annoyed this happened, the BOV and CRV should not have been left on my car when the engine was rebuilt as they were redundant. However I did not realize that until I took the turbos out and understood the work that was done to convert them to non sequential.

Unfortunately the engine build got out of hand towards the end and I expect that these two parts where overlooked when they shop reassembled everything. I am chalking it all up to bad luck as they do really good work and have a great reputation, so I am sure it was an honest mistake.

 

That looks promising.
Forge Motorsport once offered a kit to replace both BOVs with their recirculating valves. That was a number of years ago though and no longer listed on their web site.

 

Is it possible to replace both the ABV & CRV with 2 Pettit aluminum BOV kits???
One kit to replace each valve?

I replaced my ABV with a pettit BOV kit but not my CRV, thinking they are two different type of valves.
So my CRV is still plastic and brown and it bugs me how old and ugly it is.
My local rotary tech asked me why I didnt just replace both blow off valves. I was like uuuhhmm... lol
Are they functionally the same? Are they piped the same? Are the internals of the CRV and ABV exactly the same mechanically?

 

The valves size and plumbing wise are identical. I believe the only actual difference is the spring pressure inside, I think one opens at a lower pressure differential than the other. They do have different part numbers as well.

I don't foresee any problems with using the Pettit valve to replace the CRV.

Also I believe Turbosmart has some BOV's that would probably work to replace the stock ones as well.

All that said, I have the original stock BOV's on my car at 132,000 miles. Zero problems. They work great and are super responsive and not obnoxious.

Dale

 

I also think that the only difference is that the CRV might just have a higher pressure rating before it closes (second staged sequential turbo comes on at a higher exhaust pressure?)

And I agree, as said in a previous comment, that these OEM valves are pretty durable. I think it was a rare failure that was experienced by the OP.

Personally, I just wanted to upgrade to a black and metal version for aesthetics and long term reliability, if at all possible.