BOV: does it really make the car run rich??

So yes, we all know in general....

BUT.... I had this question in the back of my head...... You know when you let off the gas (0% throttle position) on the '02+ WRXs...... the injectors do turn off if you're anywhere above idle engine speed...correct??? SO IF they are turned off.....then why would the MAF override them and tell the ECU to turn them back on?

I can see it where someone runs through the gears and only lets off the gas halfway would it run rich....... or am I wrong??

 

Its expecting the rush of air from the BOV so its giving it fuel for that, fuel without enough air = rich

 

according to my egt gauge the injectors do turn off at coasting speed and when in gear and foot is off the throttle, but the egt gauge slowly goes down, from 1300-0 in about 20-25 seconds. So I'm assuming that the remaining fuel in the cylinders combined with the excess fuel dumped into the cylinders with out the air from the bpv recirc. for that one millisecond beofore you're back on the gas makes your car run rich.

BTW:if you don't want that greedy bov I'll take it

 

Yes, the injectors shut off when coasting, but there is a delay from when you let off the gas to when the injectors shut off.

And yes, the car goes momentarily rich for a split second between shifts -- EVEN WITH THE STOCK BOV. I watch my car do it all the time.

 

Now then with all said, there's not that much harm like what MANY thinks??
How rich have you guys seen the AFR's go?? As rich as a street tune of 10:1??

BTW: I needed a BOV that can hold some 20-24psi of boost from the little EVO3 16G.

 

APS twin vent I love the sound of that little guy!

 

I'll have to doublecheck as I don't remember what the afrs are off the top of my head. I'm thinking it was something in the 10s, but I can't really remember.

There are many misconceptions out there (thanks Nasioc), fyi. I quit listening a long time ago and decided to figure out stuff on my own.

 

so you think its ok to run a BOV that is atmos. venting?? I'd really like to know because the ricer inside me wants one...

 

if we can figure out how RICH it gets and determine if it's GOOD or BAD then we can ALL LET OUT THE R!CER IN OUTSELVES!!

but really I would perfer the HKS if I am shooting for higher boost. The PUSH types doesn't release the boost as good as the HKS. I can HEAR compressor surge when I had my Perrin. We put on a HKS replica and no more surge.

 

I'm fairly certain that the car will run a bit richer between shifts with an atmospheric BOV (as opposed to a stock recirc. one).

The main problem with certain aftermarket bovs is that they sometimes induce vacuum leaks (either from poor fitment or improper installation) -- which make the car run like **** at idle.

It may be hard to gauge what a "bad" afr would be since most widebands won't read any richer than either 9:1 or 10:1. I say that if you can keep vacuum leaks away and the inner ricer in you really wants one (or for the rare case that you actually NEED one for high boost applications), then go ahead and get one.

Besides, fireballs are pretty cool anyways.

 

would boost spikes at 18 psi count as high psi???:yumyum:

 

agreed :biggrin:

 

changing spark plugs is not, though.

 

Yeah Fuji, I went through the same research when I bought my 16g....needed something to hold 20+ with no issues. I went with the APS twin vent. It's very quiet under low boost/part throttle (I have my spring cranked all the way down tight). You will hear the recir. which is cool...but only you can, other cars cannot.

When at WOT shifting do you hear the BIG psshhhh.

fireballs, occassional..depending on my throttle position, and how quickly I let off the gas to shift.

 

Two WRX's parked next to each other in my garage. Two sets of plugs = 1 hour flat from opening the hood to closing the hood.

okay, back to topic

 

lmao no.

 

Is it fair to state that this is also the case with the legacy?

 

Is an EVO3 16G going to be efficient at those kinds of pressure ratios? Thats alot of boost to ask out of that size of a turbo for 2.2L.

 

i have noticed my AFRs quickly dropping to the 10s when i vent to atmo.

 

not answering the question, just adding infomration.

This is the FP model

The TD05H E316g6 is better suited for spool-up and transient response than the larger 18g and has slightly less flow than the 18g. It is therefore matched to a TD05H turbine rather than anything larger. The E316g6 is flow rated at 550cfm and looses it's best efficiency when operated above 20psi but can easily be operated as high as 25psi! It is fitted with a 7cm turbine housing to complement the fast response of the MHI E316g6 compressor.

 

I never said it takes long, just a pita. the quickest I've done mine is in 30 min, but I didn't have the stock air box and that made things go a bit quicker.

So is the aps twin vent like the GFB one where its 50/50 atmos/recirc??

 

post a link to where you got your scuba..

 

yeah 30 minutes is flying...:biggrin:

I'm no bov expert, but it think the answer is no. With the APS only when the pressure reaches a specificed threshold will it vent to atmosphere. (adjustable)

bill, i got mine from rally sport direct for 255 shipped. TMIC of course

 

This EVO3 16G I have is with the 8cm turbine housing. This should allow better efficiency in the higher boost levels. This one is from SlowBoy Racing.

but humm.... I may settle for the HKS...... afraid of compressor surge with push type BOVs.... is someone going to find out what the AFR's are when off the gas with a BOV?

 

Considered Tial?