Why are you talking about fuel trims "hunting for stoich" here?

Unless you have a really crappy, dirty or totally undersized air filter, your system has no vacuum when the vehicle's under boost correct? Having some sort of restriction between the blower inlet and air filter is the only way you're going to have any vacuum there.

 

? not following you.......if you are using the RX dual valve system while not under boost the vacuum from the intake manifold provides evacuation. As soon as the intake manifold becomes pressurized from boost, the primary check valve closes and the secondary valve opens using vacuum from the inlet side of the head unit. If you are connecting to the air filter then you are correct as the filter will not allow enough suction to do anything. If you install it correctly you are tapping into a spot just before the inlet turbine on the head unit and the venturi effect will give you between 8-12" of vacuum when measured there (see a few of the others on here that have run vac guages and measured).

Since you have a SD tune you have no MAF related fuel trim issues like those with the clean & dirty sides mixed together do.

You description said you are running both the clean and dirty side together if you described it accurately.

 

Perfect understanding. My hats off to you for understanding.

 

Here are some pictures of the unassembled separating system for big boost turbo or front mount SC's:

Shows the inner components:


Assembled but not in the canister...the bottom is facing up:


From the top. It comes with -8 or -10 AN fittings and inline flow control checkvalves:


It is large and not for the avg street build.

4" wide x 7.5" high with triple baffleing and good to 1200 hp turbo or front mount SC.

 

Why didnt I get one of these... Only kinding man I will be putting the D/cans on the car this weekend. Robert

 

I guess if you want to run all that oil vapor through the blower, IC, engine at full load go right a head. Catch cans don't do THAT good of a job at oil seperation, especially under high flow. I'd like to see crankcase pressure numbers under load to see if it can actually pull vac on the engine though. Better run a big line.

Factory turbo cars have done this type of thing for years without the catch can in between. For emissions they need to keep a closed system, but end up with oil all over the intake track, not just in the intake manifold.

 

I think what he means is if you add the oil cap valve cover breather and you are still running your MAF, your STFTs are going to change because of the unmetered air.

I remember when I first got my breather from ECS I hooked up HPtuners and saw a change but it wasn't a lot. That was a long time ago though...

 

I have had the discussion with several customers about the use of a breather and tuning. (the unmetered air)

Basically yes it is unmetered air, where as the factory set up pulls it's air from after the MAF-before the TB so it is not. However, the amount of air is so minimal being pulled threw a PCV/check valve.
It is also a constant value, so it is very easily tunable. Definitely not something to be in the least bit concerned about IMO.

 

Trims are always bouncing around. They could change with an SD tune as well as MAF tuning. Changes in vacuum more than 1.5" will move you to a different cell at idle. I know you're aware the trims are based on feedback coming from the 02's and while we try to zero them out, they will never stay zero'd out.

For the record, I completed my changes to my existing valve covers, adding -8AN ports to the valve covers and baffles and have driven the car quite a bit. Now mostly only water comes out when I crack the drain open.
I still have new valve covers in the works. I'll be picking them up next week and off to powder coat.

Bat Car dude, since you're deeper into this than anyone in the thread and have spoken about contaminating the oil by not pulling fresh air through the crankcase and the damage caused by it, I'm wondering where you gathered your evidence from. Oil analysis by chance? I would love to see all of the evidence you've gathered from your studies. I think it would be helpful. So far I've made the decision to stay with my current configuration, but that may change depending on what you bring to the table.
Next issue is: how much flow do we really need? In other words, what size ports is necessary in order to satisfy a purpose-built F/I motor? I'm aware the demand will vary based on ring gaps, displacement and cylinder pressure, but how about a range here?
Say an "average" 346 with .027" ring gap on the top ring, running 17psi boost and making 800RWHP.
Then change to a 434 with a .028" ring gap making 20psi boost and making 1100RWHP.

 

The RX system and a few others DO catch all the noticeable oil via the separation cans and your correct, you want NO oil entering either a turbo or a SC as the residue/varnish left can throw off the balance and that is critical to the bearing life. I think your confusing so many of the marginally functioning cans on the market that do let 20-30-40% or more of the oil through. It's all in the design and function. Again, we have thousands of these out in use over the years and doing the job trapping all or nearly all noticeable oil. Factory turbo & SC cars are horrible for the oil ingestion, just talk to a Mercedes tech on the L-4 Kompressor engines. Thats the reason for this thread and discussion as so many don't understand the solutions.

Yes, years of oil analysis with the drag motors (Pennzoil was sponsoring one of the cars for a season and did analysis with every oil drain) and we have done them for years as well. The PPM levels of the abarsive carbon particles, unburnt fuel, and acid levels were the ones we look at the closest and then iron, brass, etc. for wear indicators.

On builds like your talking we have had success with -6, but if ring seal is not excellent then we go -8 or -10 like the unit above. But for most builds the -6 (3/8"ID) has been fine to 900-1000 rwhp. Problem we see FAR to often are pinched ringlands & pistons damaged by detonation that are allowing far to much blow-by for any system do deal with. These make good power and seem to run well but a leak-down test (not a compression test) will pinpoint the problem cylinder(s).

Of course the tuners that do the damage never seem to acknowledge they went lean or added a little more timing than the combo could stand, and how many see knock sensors desensitized or turned off because the tuner was fight spark knock?

 

So did you retain these analyses? Care to share them with us? We would need to see one with a breather can and one with your setup on it, but to be fair, it shouldn't be a drag car. Those cars don't run long enough to burn off contaminants. It should be a street car that gets a reasonable amount of run time before being shut off.
Heck, if you don't have the data retained, I may just sample my oil and send it off and post it up. Then we'll all know what to expect on this side of the fence.

 

Great suggestion....lets get an unbiased example. There are sevral good companies doing this for reasonable $ and results are pretty quick. I would really like to see it from the same car where it is the same amount of serivce on the oil, same driving (as close as possible) that is running kjust breathers or a breathered can and then switch to the proper evac system to show. :thumbsup:

 

Is there a way to use the front passenger side valve cover port for the fresh air source in conjuction with the breather? I don't like the looks of the breather on oil fill cap.

 

Yes....you would just need to use a long enough hose to remotely locate the breather alone not bonded to a oil fill cap. Just dont do both.

 

Like this?

 

That works!!

 

So in non-boost, the intake manifold & blower inlet will pull vacuum on the outer two fittings?

And in boost the one-way valve in the outer fitting to the intake manifold simply closes and continues to pull vacuum on the other outer fitting from the blower inlet?

 

How do I make sure to order the breather w/check valve not bonded to the cap?

Also how long are the hoses in the F-body kit? I plan to mount that down below as well.

 

Correct but just from the primary valve. It closes when it detects boost and the secondary valve then opens using the SC inlet suction. is yours a front mount SC or a top mount?

PM me and I'll give you special instructions.

 

good info.