Wow! You did something completely mechanical?

That is a pretty cool solution. I have some anti reversion ideas to try as well, but not down that road. But that is an inventive solution you came up with.

 

From the start I had always thought it had something to do with intake reversion, as cammed cars had it worse off than stock lobe'ers. I had toyed with a few ideas before this(you'd remember me using the Syncronic as a BPV and "wastegate" simultaneously) but started running numbers and figured that there was some serious surge happening on these cars above 19lbs during throttle modulation. Mainly due to how fast this damn 16g spools.

In any event, yeah I went mechanical and did the math for the antisurge on the 16 compressor wheel. Opted for a 4" inlet with velocity stack(not shown) with the BPV dump right up at the 3 to4" interchange. My thoughts were that the flow from the BPV going back into the tract would "disperse" better at that location and not cause as much flow disruption in the intake tube, as well as the antisurge effect of the housing.

Another great effect....Erics 16g pulls and makes power all the way to redline now, does not fall off like the typical 16g does. Stock port/valve head with 272's, intake, FMIC, ~24-25psi....somewhere I have the dynograph

-Adam

 

The first one prior to issues was the HKS Racing Suction intake (just the pipe - I had a Buschur filter on it instead of the HKS filter).



The one I put on where the issues started was the Buschur Racing intake pipe.

 

Adam- So your fix completely eliminated the issue, or just muted it?

To eliminate reversion from the BOV dump as a variable, I played around with the BOV VTA with the stock pipe, and I swear that the bucking went away. But then I came across another problem where, the car's momentum just dropped too fast when going VTA. I need to test this again though with the new piping.

EJ- Which side of the Buscher pipe is next to the MAF?

 

I would say eliminated it about 95%. I think Eric said it only occurs sometimes in 5th gear at very low throttle input, like cruising on the highway. Only he can verify it though. I don't think my antisurge ports are big enough to mute the low velocity surge that occurs at that level. I'd have to remove the compressor housing and machine them larger to test at the risk that I go too far and it start to get worse. Eric was extremely happy with it the way it's setup now so I figured I should leave it be before I shoot myself in the foot.


Burschur pipe positions curved end to MAF, but on his pipe I relocated the BPV dump inlet to the straight end of the pipe(~2" from the end) and capped off the inlet stub on the bend of the pipe(I cut tube off flush and welded a cover patch)

 

+1 What he said.

I can induce the surge on the highway (get mild boost acceleration going, then back off the throttle at a specific rate - slowly), but I have to try to do it usually for it to happen. But a 2 day session at Watkins Glen saw me surge-free this past August, which was the first time in nearly a year.

 

I have this bov and not sure if its all cracked up to be. There is constant air coming out of it which seems odd. Listening to my tuner which deals with tuning all the time and many cars especially EVO's sounds like I would rather go with the Tial bov which will be my next swap to see what the differences are. Best bov not sure about that can't believe everything on the net. But I will see for my self and let you guys know. It could be just the setup.

 

The valve itself is very solid. Issue I found, or actually CBRD found, was the way it mounts to the dump pipe. They found it wiggled somewhat, which would lead one to think it might leak. There is a gasket that seals the gap between the valve and the pipe, which it fits over. It just seems the small allen screw doesn't provide a lot of clamping power to keep the valve from rocking on that pipe to a small degree. I'm running a stock Evo IX valve now... and suffering from pretty bad idle/stall issues after my CBRD BBK Full turbo install, but that's another story.

 

I have this BOV with the Buschur intake and have no problems and is took away the jerkiness I us to get with the stock MR BOV.

 

Friend had this same problem and put lock tight on the allen screw and it was perfect after that

 

Thomas- It sounds like you are venting the BOV to atmosphere? It really needs to be recirculated to function properly on the EVO. And as far as always blowing air out, that is only under vacuum. What that actually means is that you are unloading the compressor = not requiring as much energy to spin the turbine = less load on the engine when it isn't needed.

 

So your saying if you VTA than you shouldnt buy this bov?

 

I think hes saying anyone running a pre-bov maf shouldn't run any bov vta.

 

He's saying that anyone with a MAF shouldn't run any BOV in VTA mode. And he's right. But if you must have that ricey whoosh sound every time you drive past a crowded movie theater, then you'll just have to deal with the occasional hiccup/stall ... or convert to SD.

 

lol, so just because somebody is runnin VTA means they want the ricey whoosh in front of a crowded movie theater. Thats funny since i have been running VTA since i bought my evo brand new in 2004. No problems. I was thinking on switching to this bov but with his comment about the bov not functioning properly if you didnt recirculate i wasnt sure. My question is for synapse not for those who think they are so cool to post up about what everybody already knows about VTA.