Metered Air question

[marcelo_caz]

sup guys?

I have a Turbo Xs BOV (Type H-RFL) and I wanna to change it for recirclelating one.
I love the sound of mine, so I want to get one with the same nice and lound "woooshh".

I was thinking about the Turbo XS Hybrid Blow-off Valve (Vent & Recirculate), but i don't know anything about this BOV.

Is it good?
Do anyone have other BOV suggestions?

 

[95-TSI-AWD]

sup guys?

I have a Turbo Xs BOV (Type H-RFL) and I wanna to change it for recirclelating one.
I love the sound of mine, so I want to get one with the same nice and lound "woooshh".

I was thinking about the Turbo XS Hybrid Blow-off Valve (Vent & Recirculate), but i don't know anything about this BOV.

Is it good?
Do anyone have other BOV suggestions?

You noob... I want it to woosh louddd

Tell ya the truth yeah its nice Ive got the greddy type S its loud as hell when vented but the gas milage sucks. If your not worried about goin thru gas faster then go for it. Id personally go for the SSQV

 

[Boost92awd]

This is the BOV to be had right now. Its as good as a tail BOV but you can recirulate it. Also it will give you the sound your looking for.

Synapse Synchronic Blow Off Valve (BOV) - Group 5 Motorsport - A premier automotive performance store in San Diego


YouTube - Synchronic Blow Off Valve Turbo S2000

 

[MASMORE]

I like the Stainless look for sure, I can wait to hear how it sounds,
but the price is a bit to steep for me!

 

[TechBenchTony]

i have the Greddy Type-S recirculating, and it is still pretty loud.

 

[Tsi_User]

You noob... I want it to woosh louddd
Tell ya the truth yeah its nice Ive got the greddy type S its loud as hell when vented but the gas milage sucks. If your not worried about goin thru gas faster then go for it. Id personally go for the SSQV

Would you mind elaborating on why your gas mileage sucked becuase of your BOV? Hopefully you were venting it properly, or else that noob comment might come back and hit ya in the face

 

[blkwidow]

If you like that particular sound then you might want to look into a Greddy Type RS.

 

[marcelo_caz]

Mine never affacted my gas millage, it affected after I raised my boost and chenaged my fuel pump.

So the Greaddy type RS is good choice. what about the HKS one?

 

[DSM_6SL2 Power]

This thread should be locked........ Wow.

 

[blkwidow]

Any recirculated BOV will do.

 

[95-TSI-AWD]

Runs Richer

 

[silverbullett]

HKS SSQV sounds awesome recirculated. It was venting openly when I bought the car but I got tired of the check engine light so I bought the recirculation kit. It got rid of the C.E.L., stumbling idle, and improved my mileage by 1-3 mpg. I know there are some cars that run fine venting but, mine wasn't one of them.

 

[Turbo-n-Auto]

Yes I know its been covered a MILLION times, Im on a sube forum and its the same there. Just recently though I had to switch from my HKS SSQ to my stock bpv and I found myself with the opposite scenario people said I should be having. The typical things came out, VTA makes you run rich, metered air blah blah blah...But my car is running just as rich between shifts with the stocker and the idle is more rough.

My question is this, the sube guys are claiming that when you recirc your recirc'ing air thats already been metered for and the fuel has already been injected for as well. This seems to make sense. My problem with the theory is how does the air get back into the cylinders if the throttle is closed? And why does my car go fat rich when I release the pedal from any kinda accel while I have my stock bpv on? Its only momentary but from the theory proposed this cant happen.

After posing those couple questions everyone was stumped and couldnt think of a good answer either. I know you guys have been over this MUCH longer then we have, please point me in the right direction to some good solid answers

Thanks!


Edit: I should add, I reset the ecu when I swapped to the stock bpv. I also have drove the car almost 1K now with it on.

 

[kenamond]

First, I'm not a WRX guy, but based on your statements, I assume it has a draw-through airflow sensor setup.

Are you recirculating or not? Were you recirculating with the upgraded BOV/BPV? The way I read your first paragraph is that you were venting the upgraded BOV and having the typical VTA issues and that you switched back to the stock BPV and have similar if not worse VTA symptoms now. Is that the case?

What boost are you running, and what is stock boost on your car?

As far as your question about when the throttle plate closes under boost...the turbo will continue to pump air, the vast majority of this air will recirculate, thus sustaining the input supply to the compressor, and whatever is "left over" that has to go through jets or vaccuum lines to get into the combustion chamber will be replaced by air pulled through the airflow sensor. If you vent, the vented air isn't sustaining the compressor flow, so that flow gets drawn through the airflow sensor and the ECU dumps gobs of extra fuel.

Need more info about your situation.

 

[Turbo-n-Auto]

Ok, I need to read what you wrote a couple times and soak it in

Here's the backstory though for you:

I was running a HKS SSQ and running it VTA. My car ran smooth as glass, idle'd like a champ and ran fine otherwise too. No bog between shifts etc... The HKS dies on me It wouldnt blow off anymore. I tried cleaning it, taking it apart etc... Nothing worked. I installed the stocker on the car. Eventhough I have a 20g sitting here to go on the car, I didnt want to grenade the stock turbo backspinning it all the time.

I installed the stock bpv, connected the recirc hose up, and reset the ECU. Then I drove the car easy for awhile. It idle'd rough at first, but I thought maybe learning after a reset....Now its 1K later and it still idles a lil rough, nothing crazy but not nearly as smooth as the HKS. Im not trying to say one is better then the other, so lets please not start that up . Im just trying to understand the metered air thing and why it runs worse although people say that cant be.

Another note: Im having an issue with rich idle when the car warms up. I logged my car last night and my corrections are WAY off. I tried a new Maf this morning and reset the ecu. It idles less rich, but still rich. This was another reason to try the stock bpv, it was the first thing everyone said to do. My plugs are new and gapped correctly and the front O2 is new as well. I have a wideband in the car and its dead on with what my logger is reading. Another guy I talked to said to check for exhaust leaks, but this turned up nothing for me. The car runs perfectly fine otherwise, just idles rich. When it first started to happen it was occasional rich idle. Now it seems like everytime it warms up.....

Mods for the car are:
98 RS chassis, 02 WRX swap (ran fine for 15K now)
Invidia 3" catless DP
Custom 3" catless exhaust w/HKS muffler
Gutted Up pipe
Clutch Masters Stg4 clutch and light flywheel
Walbro 255 pump
GM BCS
Perrin Crank Pulley
Prodrive Y pipe
PNP TMIC elbows and TB
XPT stg2 map for gm bcs

My map is tweaked to 20psi tapering to 16ish. Im getting no knock and running a pretty conservative AFR - 11.3:1
Ive tried the stock map on the car and drove it for a lil while, taking it easy. Still did the rich idle

 

[kenamond]

Heh...it's funny how not knowing anything about a WRX gets in the way of my ability to think of possible culprits.

If you're rich at idle (well, your corrections have to remove fuel), then I'd say you're injecting more fuel than the ECU thinks you are (fuel pressure too high, injector issue, fuel map issue). The other way you'd run rich is if you were *losing* metered air which is kinda hard to do when the entire intake tract between the airflow sensor and engine is under vaccuum. I don't know what an up-pipe is and what gutting it does, but if it's anything like hacking a 1g MAF honeycomb, that can certainly affect the airflow reading. In our cars, there is a honeycomb section before the airspeed sensor that straightens the flow so that the sensor gets consistent airflow through the airspeed section of the MAS/MAF. If you mess up the honeycomb, the sensor doesn't read the same, and the translation of the sensor input by the ECU produces incorrect air speed (which, when combined with barometric pressure and air temps yields incorrect airflow). But our MAF/MAS is one unit that includes the honeycomb, so if you swap it out in a test (to see if your MAF/MAS is bad), the honeycomb goes with it and pretty much proves whether or not the MAS is the problem. If you have components that are separate from whatever you swapped out, the problem could still exist even after swapping part of the sensor "system". If I'm wild-guessing right, you should be able to replace *all* of the speed-density components and see if that helps/fixes things.

Again, I don't know anything about Subarus, so I'm having trouble translating my DSM knowledge to your situation.

 

[Turbo-n-Auto]

I appreciate the effort Someone mentioned I need to scale my maf but Im running all stock tubing and air box as well. The Sube MAF is a drop in one, not the complete unit. There is no honeycomb on eitherside of it actually. But Im def going to check the inlet pipe that runs under the Intake manifold now. Someone else had mentioned a torn inlet but being stock I didnt think that could be a problem. Im def going to inspect the intake track now!!

I did just install the pump recently and the problems have been since I did that now that I think back. Another thing to look into

Seriously, thanks for throwing ideas out there. The sube guys like to hate more then help sometimes

 

[kenamond]

With our cars, a Walbro255 FP will overrun the stock FPR: the FPR can't return enough flow to the tank, "backs up", and gives higher fuel pressure in the rail. With a 190 FP, it will overrun at low RPM but the overrun goes away once some of the fuel is able to flow through the injectors, and some are willing to tolerate that bit of low-rpm overrun. Maybe the Subaru has a similar issue with a 255 that our cars have with a 190. The solution in our case is to get an AFPR that flows more and doesn't get overrun.

 

[Turbo-n-Auto]

Im starting to think what youre saying is true. This sounds quite possible and I honestly do think this started after the pump install. Def another thing to check.

youve thrown out some excellent thoughts man, I really appreciate it

 

[turbo_punk]

I would have to agree get an AFPR and a wide band or something to tune your air/fuel ratio too and that might just be it, I would not even put a different fuel pump on my car without those and a good boost gauge...Good Luck!

 

[kenamond]

Im starting to think what youre saying is true. This sounds quite possible and I honestly do think this started after the pump install. Def another thing to check.

youve thrown out some excellent thoughts man, I really appreciate it

So now you can go back to sube forums and see if there are known problems like that related to a 255. Keep me posted if you would. I'm curious now.

 

[Turbo-n-Auto]

Will do

I have a boost gauge, wideband and EGT gauge as well. My car is tuned using OpenECU and if you read above Ive tweaked my stg2 map. I can change anything and everything about the car. I have tuned quite a few turbo cars so Im not a total noob. Not saying Im some kinda expert as I think its obvious Im not. But Ive been around this stuff awhile

 

[marcelo_caz]

So I decided to go with the GReddy Type-RS BOV.
Heard good things about it, and the FMIC that im getting, I can get with the Greddy BOV fit (with the HKS BOV fit will be more expensive).
So I hope im making the right choice.

thanks guys.

 

[Defiant]

Jesus, this horse carcass is putting out a stink.