Compressor surge $ Stock BOV
 

first, background: about 7 months ago in getting my car back fro RP in VA the turbos went to sh-t. Since I have had them rebuilt by BNR. Still have some rasping noise during full boost spool up and it seems I am losing more oil than normal, plus I have smoke on boost out the back.

Today: took the day off from work due to finally having the car back after almost a month at the body shop. Anyhow, I have had an inkling while it was away that I don't believe my stock BOV is operating correctly (no hiss or anything upon releasing throttle--and this is while I had the stock intake as well). So, this morning I took it off the Apex-i intake and vented it to the atmosphere (closed off opening on the intake and let the open end of teh BOV free). Well, I just warmed the car up and took it for a spin. Not ONCE did I here any sort of "blow off valve" sound that the riceboys love. I'll admit I was interested in hearing what it sounded like due to seeing it posted here often that it is good enough for sound, but regardless, I heard ZERO change in performance and no "pssshhhhh". I defintely got on full boost at near 11psi on the Commander. Not to mention it doesn't seem like I am getting a kick in the pants until the secondary at around 5k RPM. Oh....and one more thing...the "shift beep" that warns you to shift, that is going off at about 6200-6500 RPM....WTF???

Any chance my BOV is shot and maybe back when its results busted the turbos while it was at the shop? Your thoughts on this and the other things would be helpful, I'm stumped.

Have you ever messed with the bov's or the vacume lines that go to them? It sounds like your bov stopped working which is probably what blew up the first set and damaged the 2nd set. When the bov doest release the air it puts a tremendous strain on the turbos and with the stockers being fairly fragile it wouldnt take much to destroy them.

As for the rpm buzzer coming on at 6500, I'm not sure about that. Sounds like some electrical issues. That sounds totally unrelated to the bov issue

Before these 2 things started happening had you been messing with anything?

Look at the rpms on your PFC and see if its lines up with your stock tach. Could be the computer is getting a false rpms reading or something.

STEPHEN

I haven't messed with anything, however, Demetrios put the rebuilt turbos in, the intake, Greddy SMIC, and the PFC and tuned it a little over a month ago. And these twins are the ones that went to crap before, and I am thinking that the rebuild wasn't successful (hence the oil and continued "ssskkkkkk" sound). However, what got me thinking is that before I even had that work done I recall NOT getting any type of sound released during blow off. I remember when I first bought the car last year at this time that even with the stock intake and a DP I could here some kind of blow off release when taking the foot off the throttle.

God damnit, now the car is beautiful visually, and now the mechanics are still being a PITA. Why do we love these cars again???? :confused: :)

Nah, that was basically one spacific type of upgraded stage 3 twins that he got some defective parts in and that whole run of turbos was bad. The regular stock rebuilt turbos wouldnt have that type of problem cause they have different internals.

It really sounds like if your bov isnt venting that is the problem. No bov can definatly blow the turbos cause all the pressure vents back thru the turbo trying to make it spin backwards. I'd imagine what would happen it is would crack the thrust bearing which would make it smoke then when it gets worse it'll sound like a dentist drill when you get around 0 vacume and up into the boost. Or it could cause the shaft to bend which would make the compressor wheel get into the housing and make a metal on metal sound.

Its amazing how it always seems to be something small that screws everything up.

Bryan's a good guy, give him a call. I'm sure he'll take care of you.

STEPHEN

This is the sound I got when I first picked teh car up from RP after he told me "you'll need a rebuild soon, there is some shaft play" Then I got a few miles away in a traffic heap in DC and heard the horror once I boosted. First picture that popped in my head of what was occuring was the compressor or turbine wheel spinning and scraping the housing. Alas I got the rebuilds. For the money I have spent farting around with it I could almost have a single!

So for clarification, I should be hearing a typical BOV sound when shifting or releasing throttle?? If so, I need to get a new BOV because mine has shit the bed then, cuz I am getting nothing.

If there is excess air, yes it will blow off the rest.

You should be able to build about 4 PSI of boost while revving the car at idle. That is more than enough to sound off the BOV (if everything is working properly).

Did that too before going for the spin, revved her a couple times to hear something...got nothing but the sound of the engine :p:

someone wanna come kick me in the balls too? hahahaha

does anyone have a pic of which vacuum line goes to the BOV? i recently had my UIM off and am wondering if I connected the wrong one to the BOV cause mine is not working either. thanks.

victor

And you verified you were getting some amount of PSI?

As originally stated, if you are building boost, check the vacuum line running from the BOV to the UIM. Make sure it's not kinked or damaged. As a test only, you can swap the CRV and the BOV just to see if the same thing happens.

it comes off the passenger side of the UIM, next to where you would hook up a boost gauge.

there are two that come off there right? one is the CRV and the other BOV? which goes to which? thanks.

victor

http://www.scuderiaciriani.com/rx7/boost_gauge.gif

Nope, the CRV does not come off that location. If you have two vacuum lines on the passenger side of the UIM, one is for the BOV (usually closes to the front of the car), the other is either capped closed or used for your boost gauge (which is closest to the cockpit).

apply some vac to the port and try and blow through it and see what happens

If your getting pressure on your gauge then when you let off you dont hear the bov they are not venting, we KNOW that is the case. Also, we know that will destroy the turbos and its probably what destroyed the first set if you didnt have bov then either. What you need to do from this point is find out what the problem is while the bad turbos are still on the car so you can trouble shoot and test with them instead of good ones. Then when all the bugs are worked out call Bryan and talk to him about repairing them, more than likely the shaft was bent. Its very common with bov failure, especially with the stockers cause they have thin shafts that bend very easily. More than likely they were hooked up to the wrong nipples or solenoids at some point in time.

Like I said, once you get the bugs worked out and the bov's are operating correctly call Bryan, he's a super nice guy and I'm sure he'll take care of it for you.

STEPHEN

If it turns out you need another BOV, I have one that you're welcome to... and I'll be in your neck of the woods on Saturday.. (going to the Manor Races) PM me if you need it.

The current turbos on the car are already rebuilt, they are not damaged from the incident I have spoke of. And I have only driven the car a couple times since they were installed, therefore I don't think the non-functional BOV has destroyed them for a second time. Rather, I have JUST come to the realization that my BOV might not be working and may have caused the initial damage.

I'll let you know if I need ti NewBern, but I am going to be away this weekend.

hey bob. i have a stock bov u can have if i can find it. or you can buy my blitz if ya like the sound. just swap another stock bov in and see what happens. it gives me an excuse to come and look at your ride. kvn

Does the Blitz need to be welded on or does it attach to the stock hoses?

Alrighty, update:

fd3virgin brought me his old stock BOV and I swapped that on. However, I took out the car and I am still not getting any sound. Could I just not be hearing it? My car isn't that loud, I have a RB single tip exhaust!

The hose coming off the Y-pipe is not kinked and and the vac line is a new silicone line coming off the UIM. My vac at idle is about -450 on the PFC and around -600 when cruising and I let off throttle.

Any further ideas besides that maybe fd3virgin's stock one is busted as well?

What is your boost pattern? What did RP do? Have you checked/replaced vacuum lines? My guess is that a line or two might be mis-routed.

Demetrios and BNR has since fixed RP's problems supposedly. They did the LIM gasket and silicone hose job, and FPD. However, I am currently wondering why I am getting no air release, hence why I vented the BOV to see if I could here it.

I'm getting 11psi boost, but not much on the primary I don't believe. I really think that the primary was not rebuilt to its potential, it still makes noise.

bob do you want to try my BOV still?

Actually, yeah, but I think we should vent it on your car first, then go for a spin. Then we'll know what it sounds liek. Then slap it on my car and see what the outcome is. Should be a good test.

i still have the stockers on mine, i vented them one time and it got aggrivating dont remember wut my exhaust is but it is loud as hell and i can still hear my bov like it sitting in my car with me.

bob, just let me know when ya wanna do it and i'll try to make some time