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bov on ea82t


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13 replies to this topic

#1 87hatchbackturbo

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Posted 05 April 2005 - 02:45 PM

how do i install a bov on a ea82t i have no intercooler yet but my car is still faster then alot in the pensacola area (high doller rice rocks) and i want them to fear the suby whooooooooooooooooooooshhhhhhhhhhhhhhh.

#2 subyrally

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Posted 05 April 2005 - 03:03 PM

just do an intake on it and it will sound like its got a bov, at least mine did.

#3 calebz

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Posted 05 April 2005 - 04:57 PM

Dril a hole in the intake plenum, figure out a way to mount the BOV, the install and enjoy the sputtering and richness between shifts that venting to the atmosphere causes.

Enjoy your rice

PS. There is no performance gain to be had by putting a BOV on a stock EA82T.. Just rice.

#4 Steveman09

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Posted 07 April 2005 - 10:04 PM

The only Atom. Blowoff valve that doesnt affect drivability is the HKS SSQV which is what I purchased for my EA-82-T project thats allmost done :)

I also have a WRX intercooler which will be its new home, mmm I cant wait to spool up the new TD04-13G :)

#5 XSNRG

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Posted 08 April 2005 - 08:26 AM

PS there is no performance gain to be had by putting a BOV on a stock EA82T.. Just rice.


Pleas explain.

#6 calebz

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Posted 08 April 2005 - 08:58 AM

Pleas explain.



1- A BOV, by definition vents to the atmosphere. Venting to the atmosphere on a MAF based car can cause a number of niggling little problems. None seiously major, but all resulting in a loss of performance and economy

2- A BOV/BPV's purpose is to release pressure between the TB and the turbo between shifts and such. That is so the compressed air doesn't go slamming back into the turbine, potentially causing damage over time. A stock EA82T has a couple of things going in its favor. First is a relatively low stock boost. Second is, without an intercooler, there is relatively little compressed air trapped between the turbo and the TB when you let off the gas. Third and most important is the good old subaru dash pot. Its the little thing on the side of the TB that stops the throttle plate from simply slamming shut when you take your foot off the gas. a well adjusted dash pot can easily accomodate the relatively small amount of air a stock EA82T produces.

Now - all of that said, once any of those parameters have changed, the usefulness of a ByPass valve increases dramatically.

1- add more boost? - more highly compressed air. Might be more than the stock set up can handle

2- add an intercooler? depending on the IC you add, you are easily doubling, tripling or more, the amount of air stuck between the turbo and TB between shifts. A Bypass valve becomes your turbo's best friend at that point

3- Raise boost and install an IC? - Better get yourself a bypass valve or your turbo will just hate you. Lag will increase, life will decrease.

And finally, yes, there are way to vent to the atmosphere without pissing your ECU off.

They are called non-maf-based standalone engine management solutions (megasquirt et al)


Did I miss anything?

#7 calebz

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Posted 08 April 2005 - 09:22 AM

The only Atom. Blowoff valve that doesnt affect drivability is the HKS SSQV which is what I purchased for my EA-82-T project thats allmost done :)


Oh? how does that work? if its venting to the atmosphere, the ECU doesn't give 2 ************s about what brand it is..

I also have a WRX intercooler which will be its new home, mmm I cant wait to spool up the new TD04-13G :)



Already there;)

#8 Do It Sidewayz

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Posted 08 April 2005 - 09:52 AM

guys. there is abolsutely NO reason why a Atomospheric BOV won't work with a MAF car.

It's all in the set-up of the BOV!!!!

the reason the HKS SSQV works well for MAF cars is because it is closed at idle. and it's adjustable for this, and it's actually 2 staged. It's also around 300 bucks....

I installed the HKS SSQV on a friends Legacy turbo, which works with a MAF sensor...the car runs perfectly fine in all conditions.

Piston type BOV's will work. you just need to spend some time setting up the spring pressure with shims so it's *just* closed at idle.


As far as running rich for that second when you lift off...in a way it's a good thing. The computer believe you have that air, so it injects extra fuel. So when the BOV vents, you get a little extra fuel which has the advantage of cooling....which is good for the pistons, however not so great for mileage.

Now...there is a great misconseption that a re-circ BOV/BPV helps the turbo spool quicker after shifts....in actual fact it does nothing towards spooling the turbo.

#9 Do It Sidewayz

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Posted 08 April 2005 - 09:56 AM

another thing....the stock dashpot....HAHAHAHA!!!!

i think i've seen ONE that actually still works, and i've prolyl seen 15 or so of these motors.

The actuall purpose the dashpot is so when you close the throttle at cruise or anything, the throttle won't slam shut and you eat the dash board. It's so it makes the car alot smoother.

Many turbo cars come stock with a Bov/bpv, AND a dashpot. The mazda 323 GTX is one of them. The dashpot does absolutely nothing except keep you from eating the dash when you let off the throttle.

don't rely on the dashpot for anything

#10 calebz

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Posted 08 April 2005 - 10:00 AM


Now...there is a great misconseption that a re-circ BOV/BPV helps the turbo spool quicker after shifts....in actual fact it does nothing towards spooling the turbo.



Not true at all. Having a BOV/BPV in a non stock (talking EA82T here) application definitely helps spooling between shifts simply because of the fact that the car is not having to deal with the instant slow down of the compressor that is associated with the compressed air not having anywhere to go but back. Compressor stall is a bad thing.

In retrospect, "spooling quicker" may not be the best terminology. "not spooling down as quickly, thus having to use less kinetic energy to respool" is probably more accurate.

Re: the HKS.. I had forgotten that it stays closed. I'm still not real keen on the richness between shifts. I'm more interested in richness on boost than off.

RE: dash pot.. Interesting. I have seen maybe one or 2 that didn't work correctly.. ehh.. different experiences.

#11 Do It Sidewayz

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Posted 08 April 2005 - 10:11 AM

i was more talking that people believe that a re-circ BOV/BPV will help "spool the turbo" better than an atmospheric BOV. The belief that the air "dumped" into the intake pipe helps spool the turbo. However if it was me i'd rather have a nice fresh cool air, rather than warmer compressed air.

The richness when you lift off is a good thing in my mind as it will help cool the piston tops. The pistons are prone to cracking (too much heat) and any little bit helps. And you get cool flames out the exhaust if you are running catless :D

#12 All_talk

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Posted 08 April 2005 - 10:41 AM

And you get cool flames out the exhaust if you are running catless :D


Now that's the best reason I've heard yet, and way more intimidating than some woosh/pissssst BOV air leak.

Gary

#13 Steveman09

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Posted 08 April 2005 - 10:50 PM

Man Calebz, you need to calm down, were all good people here who love suubies and fixing them up.

I'm happy to see you also did the TD04 Forced EA82!


I'm excited to fire mine up since I have ALLOT of TIME on it, the list is huge.

I also had the whole thing balanced to help out on longevity.

I also have done lots of other things to improve the EA82's restrictive Heads :)

When its running I will post all the pics from the build as well as a video of the dyno runs when I get done with the break-in.

I've rebuilt the entire motor from the ground up with OEM Subaru Internal Parts so it should hold together well.

#14 XSNRG

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Posted 08 April 2005 - 10:53 PM

1- A BOV, by definition vents to the atmosphere. Venting to the atmosphere on a MAF based car can cause a number of niggling little problems. None seiously major, but all resulting in a loss of performance and economy

2- A BOV/BPV's purpose is to release pressure between the TB and the turbo between shifts and such. That is so the compressed air doesn't go slamming back into the turbine, potentially causing damage over time. A stock EA82T has a couple of things going in its favor. First is a relatively low stock boost. Second is, without an intercooler, there is relatively little compressed air trapped between the turbo and the TB when you let off the gas. Third and most important is the good old subaru dash pot. Its the little thing on the side of the TB that stops the throttle plate from simply slamming shut when you take your foot off the gas. a well adjusted dash pot can easily accomodate the relatively small amount of air a stock EA82T produces.

Now - all of that said, once any of those parameters have changed, the usefulness of a ByPass valve increases dramatically.

1- add more boost? - more highly compressed air. Might be more than the stock set up can handle

2- add an intercooler? depending on the IC you add, you are easily doubling, tripling or more, the amount of air stuck between the turbo and TB between shifts. A Bypass valve becomes your turbo's best friend at that point

3- Raise boost and install an IC? - Better get yourself a bypass valve or your turbo will just hate you. Lag will increase, life will decrease.

And finally, yes, there are way to vent to the atmosphere without pissing your ECU off.

They are called non-maf-based standalone engine management solutions (megasquirt et al)


Did I miss anything?



That helps, trying to learn all I can.
The only thing that doesn't make sense to me is the part about the intercooler making the BPV more important. I'm probably missing something but I would think the air would compress quicker in a smaller area.
Thanks for the explaination.




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