Multiple MODS at once

Jake411

New member
So I have been buying parts over the last few months and now am starting to install them all on my 19 WRX.

TurboXS Catted J-Pipe, TurboXS BOV, Grimmspeed EBSC, Grimmspeed Intake, Perrin TGV Deletes.

Has anyone installed multiple upgrades at once? My biggest issue is because of all these upgrades, until I can get my AP mapped I can not start or run the car to see if there are any issues.

Also anyone have any recommendations on ProTune vs Brentune? I am under the impression Bren is going to do the same thing as a Pro Tuner only difference is I have to do the driving.

Thanks!
 

Grinder34

Track Monkey
So I have been buying parts over the last few months and now am starting to install them all on my 19 WRX.

TurboXS Catted J-Pipe, TurboXS BOV, Grimmspeed EBSC, Grimmspeed Intake, Perrin TGV Deletes.

Has anyone installed multiple upgrades at once? My biggest issue is because of all these upgrades, until I can get my AP mapped I can not start or run the car to see if there are any issues.

Also anyone have any recommendations on ProTune vs Brentune? I am under the impression Bren is going to do the same thing as a Pro Tuner only difference is I have to do the driving.

Thanks!

Welcome!

1) Start up a journal and ask lots of questions. The reason I say that, is I think you should do a bit more research before you start buying any more mods!!

For instance, a BOV is not really advised on these cars. And if your goal is more power, there are far better bang-for-the-buck mods you can do.

2) I had never heard of Brentune, but after googling...yes, it's just an e-tune. Same process as a pro-tune, just done via email instead of in person.

As far as Brentune-I'm not saying that they're not good, just never heard of them! There are lots of e-tuners out there with lots of experience with Subaru and a more established reputation.

3) Installing all the mods at once is the way to go. You'll save on tuning costs! But you're right about not being able to start it up easily on the stock map. But your tuner should be able to give you a base map for all of them that will allow you to safely start it up.
 

Alin

Diehard Car Enthusiast!
Welcome!

1) Start up a journal and ask lots of questions. The reason I say that, is I think you should do a bit more research before you start buying any more mods!!

For instance, a BOV is not really advised on these cars. And if your goal is more power, there are far better bang-for-the-buck mods you can do.

2) I had never heard of Brentune, but after googling...yes, it's just an e-tune. Same process as a pro-tune, just done via email instead of in person.

As far as Brentune-I'm not saying that they're not good, just never heard of them! There are lots of e-tuners out there with lots of experience with Subaru and a more established reputation.

3) Installing all the mods at once is the way to go. You'll save on tuning costs! But you're right about not being able to start it up easily on the stock map. But your tuner should be able to give you a base map for all of them that will allow you to safely start it up.
[MENTION=7279]Jake411[/MENTION] , I'll expound on what [MENTION=652]Grinder34[/MENTION] said.

1) Realistically, you should have been doing research before buying any car parts. I'm not saying you didn't, but from my point of view, I don't know if you did. If you haven't read the owner's manual, read it! If you already read it once, read it again! Ask any and all questions! This is the most crucial part during the ownership of your WRX as it is first and foremost free, and secondly, learning from others' mistakes giving you insight on what to avoid is imperative!

2) Regarding the BOV, I believe almost every single person on IGOTASTI will tell you to ditch it because it brings only negative experiences. These cars are designed with a BPV (bypass valve) for recirculating the air back into the turbo inlet to avoid spool loss. When you swap the BPV for a BOV, you're changing the entire spectrum of the tune with this one single change in a negative way.

3) The way you worded your sentence, I'm assuming you already have a Cobb AP. Did you research if the intake you purchased is one of the intakes that Cobb tunes for with their OTS maps? The TGV deletes aren't exactly what I'd consider a beginner friendly modification and I completely disagree with the BOV.

4) I've heard of Brentune and they seem to be reputable. An e-tune is better than just a standard Cobb OTS map as the tune would be tailor made to your specific car and the environment which it will reside in.

Unfortunately, your situation is a bit complex because I'm assuming you just want to throw parts on the car and get a tune. The issue resides in the fact that these cars are extremely sensitive to modifications, especially a BOV and TGV deletes. Since you're in Ohio, you're well aware of the winters we get. TGV deletes change an aspect of the car warming up. (I don't have complete knowledge on this matter, but I've seen in the past how cars run roughly during colder weather with the TGV deletes. You'll have to do your own due diligence on the matter.)

I hope you haven't installed any modifications on the car without a tune yet. Please tell us the following information:

-Is your car stock right now?
---If no, what modifications are currently done?
---If yes, are you running the stock tune or a Cobb OTS map?
-Are there any other modifications you've purchased aside from the ones you've already mentioned?
-How many miles are on the car?
 

Batmobile_Engage

Squirrel Meat Aficionado.
Staff member
Another word on #2. There may be a time in the future when running a VTA (vent to atmosphere) BOV might be advantageous. But for now, Alin is correct in saying that the vented boost charge should be recirculated back into the turbo inlet. However, it doesn't really have anything to do with turbo spool, but rather Air Fuel Ratio. In the factory setup, the MAF sensor is on the intake arm just downstream of the filter, thus the air coming in through the filter is metered very precisely. When your valve opens and dumps boost, that air has already been measured and the ECU has applied the correct amount of fuel to maintain your AFR. If you dump this air to the atmosphere, suddenly there is more fuel in the equation than necessary and you get a rich condition and momentary stumble when shifting gears. To avoid this, your boost tube and MAF configuration has to be physically changed to accommodate the VTA BOV -OR- a tuner can tune this out (to an extent) -OR- you can just route the dumped boost back into the turbo inlet pipe as originally intended. :lol:

This isn't saying that you can't use that Turbo XS BOV. You can, you just need to plumb the output back into the turbo inlet.
 

Grinder34

Track Monkey
I was trying to think through if the BOV was harmful to the motor, or just smoothness, but was feeling stupid this Friday afternoon. I really feel like I should a) know this already, and b) be able to work it out

It creates a rich condition--which is the safe one, vs lean. So it should be ok from that standpoint.
Mechanically, is there any shock to the system (compressor surge?) that causes harm?
 

Alin

Diehard Car Enthusiast!
Another word on #2. There may be a time in the future when running a VTA (vent to atmosphere) BOV might be advantageous. But for now, Alin is correct in saying that the vented boost charge should be recirculated back into the turbo inlet. However, it doesn't really have anything to do with turbo spool, but rather Air Fuel Ratio. In the factory setup, the MAF sensor is on the intake arm just downstream of the filter, thus the air coming in through the filter is metered very precisely. When your valve opens and dumps boost, that air has already been measured and the ECU has applied the correct amount of fuel to maintain your AFR. If you dump this air to the atmosphere, suddenly there is more fuel in the equation than necessary and you get a rich condition and momentary stumble when shifting gears. To avoid this, your boost tube and MAF configuration has to be physically changed to accommodate the VTA BOV -OR- a tuner can tune this out (to an extent) -OR- you can just route the dumped boost back into the turbo inlet pipe as originally intended. :lol:

This isn't saying that you can't use that Turbo XS BOV. You can, you just need to plumb the output back into the turbo inlet.

ppibd.gif


The recirculation hose connects the BPV to the turbo inlet. The MAF is attached to the intake, which is before the turbo inlet. Therefore, the BPV routes air into the turbo inlet bypassing the MAF (turbo inlet is post MAF).

oe61SUj.jpg


I don't have the information memorized, so I don't deny that it doesn't affect the AFR. However, I do know for a fact that it does help keep the turbo spooled (to an extent) in between shifts!





Edit: I took the initiate to shed us some light on the matter:

http://subaruidiots.com/bov-blow-off-valve-subaru-faq/
https://forums.nasioc.com/forums/showthread.php?t=1735302
https://www.wrxtuners.com/threads/blow-off-valves-101.13188/
https://forums.nasioc.com/forums/showthread.php?t=468038&page=4

What is the function of a bypass valve (BPV)?
To release pressure from the intake tract of a turbo car when the throttle closes. It is a vacuum-actuated valve designed to recirculate the air back into the intake before the turbo inlet, but after the airflow sensor.

A BOV/BPV is a valve on a turbo car that will stay shut when the car is under boost and it will open when the car is off of boost to let air pressure out of the system so that you do not back spin the turbo or rupture a pipe in your intake tract. The difference is that a BOV will vent the air to the atmosphere and will tend to be loud while a BPV will re-circulate the air around the back of the turbo to prevent it from being spun back wards.

If you have purchased a turbo?d Subaru of any kind, it has a BPV from the factory. The reason why it has this is because the Subarus are also equipped with a Mass Airflow Sensor (MAS). A MAS sits right after your air box and records the amount of air and the temperature at which it has entered the system. As soon as the air comes into the filter it is calculated by the ECU and an appropriate amount of fuel is ready for it once it gets in past the intake manifold. Your factory BPV will open when the car comes out of boost and it will re-circulate air AROUND the turbo so that it does not back spin it, but it still keeps it in the system so that when the throttle plate opens again, the air still in the system has already been accounted for and the fuel is there for it.


I found a good explanation that covers the richness and spooling aspects:

Once air flows past the MAF sensor, it becomes "metered", meaning that the ECU has measured how much of it there is.

When the throttle closes, the BPV takes pressurized air from after the turbo but before the throttle body, and circulates it back into the intake tract after the MAF sensor. Since the space between the MAF and the engine is enclosed, and all the air that fills it has been metered, the ECU knows exactly how much air is there. Since the ECU knows exactly how much air is going into the engine, it can calculate how much fuel it needs to inject. A BPV moves metered air around in your intake tract, but since it recirculates after the MAF sensor, the total amount of air between the MAF sensor and the throttle remains constant.

As you said, the ECU *doesn't* know when a blowoff or recirc event has occured. With the BPV setup, this doesn't matter, because a recirculation has no effect on the total volume of air in your intake tract. However, this is an issue in a BOV setup. Instead of putting metered air back into the intake tract where it belongs, a BOV vents all the pressure into the atmosphere, removing air that the ECU expects to be there. Since the ECU has no idea when this occurs, it continues to inject fuel for all the air that flowed past the MAF sensor, even though some of it has been vented. This is what causes your car to run rich.

Admittedly, it's not *that* big a deal that your car runs rich for short intervals, but it certianly doesn't help anything. Plus, BPV's decrease spool time, since when they actuate it eliminates the load on the compressor wheel, which causes it to remain spinning.

I hope we are all on track now with this refresher course! (I didn't know the recirculating air was considered already metered.) :lol: :tup:
 
Top