Can anyone help. I have 300 miles on my car and installed the Blitz BOV yesterday. Today the Service Engine Soon light came on while I was on the highway going about 35 or so (San Francisco traffic). I read some info about BOV's that release to the atmosphere causing excess fuel to be pumped during low boost which could cause the catalytic converter to overheat. I understand that the recirc port is blocked and that the ECU still reads the air flow as actually going to it. Would reducing the spring tension on the BOV possibly help this ? I reset the light by disconnecting the battery for a few minutes and I am going to see if it comes on again. If it does I am going to take it to the dealer. Will they tell me it's my fault for installing the BOV ? The one I bought is supposed to be for the EVO VII and even came with directions specific to my car although they are completley Japanese. I just went from the pictures. Is there anywhere that has the directions in English or should I just call Blitz ? Any help would be immensley appreciated.

Thanks

Rich

 

Rich,

I am not familiar with that blow off valve, but reducing the spring tension should make your current situation worse, it will vent more air at part throttle making the engine run even richer. If anything you might want to try increasing the tension, that will help the part throttle venting. If the tension is to tight you might start getting surge which can cause the MAF signal to run lean, especially noticable when comming to a stop.
I would try slowly increasing the spring tension until you find what works best. I have seen a couple of people adjust AV BOV's so that they seemed to work reasonably well. They stumbled ocassionally but not to bad, you have to really want that sound.
An ECU or even a fuel controller like the AFC could help also.

Good luck, let us know how it goes,

Eric

 

Silver, thanks for the info man. I went ahead and removed the valve completley and reinstalled the stock one. Modacar took the part back and refunded my money without any hassle. I did not need to blow something in my engine with only 300 miles on the car. I got the engine light to go out by disconnecting the battery. I have driven another 100 miles and light has not come back on so I am sure the BOV was the problem. Thanks again for the info. I think I am going to look at the recirc BOV from Forge. I have read a lot of good things about it. They say it fixes all the leaking problems of the stock unit. The sound of the VA BOV was cool but not worth the risk.

 

Din't really read the whole 6 pages of info, but have to say this was a learning experience reading what I did, thanks for the info.

I installed a HKS Sequential and have to say it has been perfect right out of the box, never made an adjustment. I could tell the stock valve was leaking, and with the new one the amount of pressure/vaccume vented when I shift it much lower. I am venting to intake and the install only took around 20 min.

 

Guys,

I have an APEX'i twin chamber BOV in my Evo 7. During high-speed runs and when on half-throttle, the BOV leaks. I tried tightening the spring but it still leaks. But I only experience this when running above 80 km/h (about 50 mph) at half throttle.

Do you guys have any same experience? Or anyone using the same BOV brand that I am using and experience the same thing?

A shop here told me that the only way to eliminate leaking in my BOV is to change to a different brand like HKS or SARD.

ttiscio: Did you need to put an EIDS for your HKS BOV? I also heard that without the EIDS on an Evo7, the engine will die after releasing the air. The Rpm will just go straight down to zero!

Thanks.

 

please excuse my ignorance...what is the difference in performance between a recirculating valve and a atmposphere BOV? Does it bog when the atmospheric valve blows off? Thank you for your help....

 

Here is what I experienced. The Evo has a recirc type valve from the factory. I bought a vent to atmosphere valve from Blitz and installed it. The car started to almost stall when coming to a stop and surged sometimes. The Service engine light came on during the second day I had it installed so I took it out, reset the light and it has not come back on. The ECU and the Mass Airflow Sensor see the air before it leaves the BOV and assume that it will be recirculated as with the factory valve, so it adds more fuel for the air that is suppose to be there but no longer is. This causes the engine to run rich for a moment(surge or stalling) and can load the catalytic converter with fuel and overheat it, hence the engine light. If you do this long enough the catylitic converter will eventually fail. From what I have read you can try to adjust the vent to atmosphere type to get it to run correctly but I did not want to risk it with only 300 miles on the car. The sound of the VTA type is very cool but not worth an engine problem. Good Luck

 

So if I am reading this thread correctly, the stock bypass valve has a spring that is a bit soft for high boost (even in the stock lancer), while aftermarket bypass valves have springs that are too hard, which causes compressor surge at low boost. It sounds impossible to get both bypassing at low boost and high boost as well...am I getting this correct?

 

Actually you are comparing apples to oranges here. What I was saying is that the stock valve is a recirc type which takes the excess boost pressure and puts it back through the engine. The Vent to atomosphere type blows the excess boost pressure into the atmosphere (obvious, I know). Since the EVO's computer is set up for the recirc type you encounter the surge or stall when that excess pressure is not sent back to the engine when using the vent to atmosphere type of blow off. You can purchase an aftermarket recirc type that will work better than the stock one. The problem that has been encountered with the stock valve is that it can leak at higher boost pressures due to it's plastic construction. I have heard the Forge makes a very good replacement for the stock one that eliminates all the leaks. You just don't get that cool woosh sound unless you open up the intake system with an open element filter. Hope this clears up what I was trying to say.

 

THank you. I am clear on the atmosphere vs recirculating bypass valves.

As for my last post, I was just trying to paraphrase what the whole thread concluded to. Was I correct in my paraphrase? THank you for all your help.

 

The stock valve does not leak due to spring pressure. The leak occurs because it is made of plastic and cannot handle high boost and high temps very well. Some people have not had any problem with them at all.

Most of the aftermarket units have a variety of options to adjust them. Almost all have a way to adjust the spring pressure and some have kits you can purchase to change the spring from soft to hard or vice versa.

If I am not getting what you are trying to say then I appologize if I am being condescending.

 

I see...thank you fo clearing up the subject.

 

i had stalling issues with my forge motorsports vta, until i put in a LIGHTER spring. now it makes little whistles at 0 or little boost, but doesn't stall.... whereas when i had the blue spring in, (compaired to green) i stalled constantly.

the only problem that started yesterday was the fact that, when i let off the accelerator, the valve isn't opening right away, so i'm still under boost for a split second, so basically i'm still accelerating, even when the pedal is not depressed. i think i need to take the valve apart and re-grease it.

 

Having bought and installed the Forge recirc dv I also experienced a little engine stutter when letting off the gas at slower speeds. I gather from reading this post that some of you have had success by changing the spring (to the green one?) Can you confirm this for me before I go buying the sprng and installing it to fix my problem. and BTW Silver Surfer, nice write-up. Thanks

 

I have an HK$ SSQBOV in my Eclipse. For $20 you can get a little metal tube from that allows it to be recirculated, but you have to loose the little noisemaker (awwwwww...). The main problem I had with this BOV was breaking 3 pair of snapring pliers trying to get the damned snapring on the flange.