Hey guys I just installed the Greddy Type-S recirc valve for the EVO. Everything working great on it...more smooth between shifts...better response....and a decent sound. I have noticed one thing that I think I might need some help on. Sometimes when i shift from third or 4th at approx 5-6k rpm the car almost seems to either speed up...or when i shift rev alittle higher between shifts. I'm assuming it has something to do with the tension i have adjusted on the Valve itself....maybe i'm shifting different because i'm trying to hear the valve...but i don't that is the case...has anyone had any experience with this? Thanks for all the help in advanced!!


P.S. the car does not exhibit any of the "problems" during any other driving situation...and not even everytime at the RPM range noted above.....thanks again

 

I believe you are describing compressor surge and you need to reduce the BOV spring pressure or flip it around. And it is quite common with that BOV.

Hope this helps.

Speedlimit..

 

Speedlimit, Do you know of any BOV's that don't have or aren't known for compressor surge?

 

There may be, but I can't think of any right now with the exception of the stock one. The Greddy Type S is mentioned many times in search results on "compressor surge" and removing the small spring was a solution. Sorry I can't be more helpful.

It is not necessary to replace the stock one unless you want to increase the volume of the pssssssssssssssss sound or it is leaking. Other than that, there is no performance benefit.


Speedlimit...

 

My stock BOV is holding 21 psi perfectly. I was told I'll need to replace it when I go to an upgraded turbo like GT30R even if I'm still only going to run 21 psi because they flow a lot more air at 21psi.

 

Hey guys thanks for the info....perhaps it is compressor surge....I will loosen it a little more and see where that puts me...i did the single spring mod on the valve...the surge isn't bad and actually kinda rare..just wanted to see if ther was a way to correct it even more...thanks again!

I got the Greddy because my plastic unit was leaking...i also plan on doing future mods which i understand would increase pressure to 22 psi safely..

 

Then you are going to need a bigger BOV.

Speedlimit..

 

Why, if I still want to run 21 psi? Do they have the capacity to expel more volume?

 

this is kind of off topic... but would you guyz recommend the HKS SSQV or Greddy Type S? thanks!