First I should tell u its an 05 MR and my mods. I have all the bolt ons, APS TBE, ebay O2, BC 272 cams, Bushcar Air Intake, 255 warlbro, RNR race core, HPF lower intercooler pipe, tuned by TT it put 357 awhp and 347 tourqe on 22 psi

Ok I have had the Forge RS and now the Greddy Rs and either way i am really unhappy with these BOVs. No matter what i have done wether it is with changing the springs in the Forge or tighting the screw on the Greddy. I still get that partial throttle flutter that everyone talks about. If your on the highway and your just at that right speed at partial throttle u hear a continous fluttering from the BOV. Its like the piston doesnt know whether to open or close. If you go full throttle the flutter goes away and u can tell the BOV piston is closed. I had this problem with the forged and that is why i bought the greddy but the problem doesnt change. I have a friend that had the EVO 9 BOV on his 8 and doesnt have this issue and his hold to 24psi without a problem.

I have read that it seem this all goes away if you go back to stock or if you go to a JDM MR or Evo 9 bov. IS this true I know i cant use my stock 05 MR bov bc its plastic and they leak apparently.

I would really like to put a Tial on the car bc that is what i really want. Will this go away with the Tial or will it be the same problem i am having? I have heard on an 05 u can vent to the atmosphere and not have a lot of the issue that other evo 8 had. What are the disadvantages of venting to the atmposhere as long as ur car doesnt stall?

Any help or light into my problem would be good thanks guys

 

Firstly, our Type RS valve does not use multiple springs for tuning.

Our other valves do, but the RS only uses a singular, conical, progressive rate spring.

I don't know where/why/how you have different springs to use in the RS valve, but you shouldn't be changing the spring in it. Period.

Secondly, partial throttle flutter is a completely normal occurrance, and there is very little to be done about it. OEM valves don't do this because of a pressure equalizing channel up the back side of the valve that is not a feature easily incorporated onto aftermarket valves which offer the significant benefit of higher and adjustable boost retention.

Please read this thread for a better understanding of what causes fluttering and why it's not a problem.

https://www.evolutionm.net/forums/sh...d.php?t=209640

Our RS valve, has the least amount of partial throttle fluttering of any valve that we offer.

 

Mike I have the Forge Motorsports BOV with the 3 different springs that u can interchange. I came to me brand new with the middle spring in the BOV. I got tuned and it seem to be worse so I tried the Red spring and that made it even worse then it was with the Green spring in it. So i went back to the Green for a couple days and then bought the Greddy RS and that does nothing for me either. So this is just normal and i have to deal with it?

Can i vent to the atmosphere and put a tial on the car?

 

Ok, for clarification then, you do not have our Type RS valve. You have our direct replacement valve which is part numbered FMEVO15.

At 22 PSI, I would recommend using the Blue colored spring in our valve.

One thing that you might want to try, is reversing the orientation of the installation of the valve. This means switching the orientation of the two larger ports of the valve. When this is accomplished, the pressure will be entering the side port of the valve and recirculating back into the intake through the bottom port. This may help improve airflow through the valve such that it will help to minimize the partial throttle fluttering.

You will always have SOME fluttering at partial throttle when using an aftermarket valve, again, due to the inability to incorporate the pressure equalizing channel along the back side of the valve that OEM valves use. You will be able to minimize it a great deal, however.

 

Thanks for the help mike.

Im also wonder guys can u vent to the atmos on an 05?

 

Mike, may be an old thread, but I am confused...
If I do as you suggest, and reorient the BOV...
So what actually opens the valve then. The boost would push down pressure on the piston in the valve this way?
Is the Vacuum pressure what opens this valve entirely, or does the combo of the boost pressure and vacuum pressure cause it to open?

If it is the second method, then would not the suggested senerio of reversing the valve cause an issue?