RyanM

iTrader: (1)

From reading forums and tech specs, sounds like the EIDS is the "technological" approach to fixing the stall issue due to MAF instability during VTA. What about the root cause of the problem? If the air flow near the intake is the issue, the way I see it there are three choices.

#1. Use 3" Aircraft Grade tubing to vent the BOV exhale to another location. I'm not sure what the temperature of the air venting is though or what the impact would be to the BOV performance, this is something I'd really like to find out from someone if I could. (possibly out the hood louver or towards the ground on the other side of the engine bay)


#2. Using a Ram air duct in the bumper molding and 3" tubing to direct air directly to the intake, (in my case an HKS RS). I can re-apply the filter at the Ram duct or figure out an alternative filter mounting method, Not the prettiest approach but definitely an option. I'd could also add a duct from my RMR hood scoop to force more to the intake.

#3. Utilize a 6in tube and reroute air flow from the fender well /front end to the HKS RS. Install a blocker of some type between the bov and the HKS RS to prevent the turbulence from reaching the intake.

Check out http://www.discoveryparts.com/cgi-bi...roduct=ducting to see what I'm talking about for parts

Am I way off base here or misunderstanding the problem? I have a shiny new SSQV XM-002 kit that I'd love to install but I don't want to stall my car every time I VTA. I know I should just recirc but I want the exhale.

Would the methods I outlined work as the solution to the root cause of the problem?

My ulitmate goal here is a rev happy engine. When I step on the gas, I want as instantaneous throttle response as possible. The counter side to this, is I also want the engine to return to idle just as fast. The EIDS will not allow that to happen.

I'll never get that F1 Air Valve sound, but thats a good of example of what I'm looking for. (2stroke sport bike rev sound would be nice as well)

marksae

iTrader: (12)

Are you thinking about routing the air from the BOV back into the air filter, before the MAF? If so, that's still not going to work because the metered air being dumped is going to get metered again, thus leading to a rich condition inside the engine.

If you really want to VTA, you need to get the blow-thru MAF and place it between the BOV and throttle body or just get a standalone and use a MAP sensor configuration.

LEVIII

iTrader: (11)

Im not sure you understand why the stalling occurs. Actually I am not sure either but I have assumedthis..... that the stock valve opens and releases air back into the intake before the turbo but after the MAF. When you VTA and the BOV opens, the car thinks there is more air in the intake piping then there actually is because the only air it reads going in goes past the MAF, since the car thinks theres more air it dumps more fuel, causing stalling from too much fuel and causing crappy MPG. I think.

RyanM

iTrader: (1)

I'm looking at trying to keep the air that is being vented from the BOV away from the Intake. I might be misunderstanding the problem, that is correct. I was under the impression that the VTA dumping too much air that close to the intake was the issue. But if its if there is a momentary back surge on the inside of the intake system that causes that variation then none of my solutions will address that issue. (but why does the BOV, which is supposed to be a one way valve (essentially) allow that surge back into the intake system? Also, if the BOV is causing the variation on the inside of the intake system, why do recirc BOVs not cause the same momentary air variation?

BTW, the HKS XM-002 kit is kick ***. I highly recommend purchasing this one over the standard kit. You get a highly polished HKS IC pipe with the BOV mount ready to go. No welding or cutting involved, straight bolt on action.

http://www.hksusa.com/products/?id=793&rsku=

Like I said, I might be confused here but looking for the light.

4ce fed

iTrader: (11)

It has nothing to do with variation, or the air being vented too close to the intake. The air that the BOV vents has already been "counted" by the MAS when it entered the air filter. If the air is shot back into the intake track after the meter (since it has already been counted), there is no problem, because the ECU will add the correct amount of fuel for that air.

If you shoot that air into space, the ECU still thinks that air is in the system, so it adds fuel for it. Oops, it's not there. The ECU added too much fuel, and you are running rich. LEVIII had it correct.

ghostrider

iTrader: (13)

Yep, simple as that. Going VTA causes you to lose air that's already been calculated into the a/f mix. Once the throttle plate opens back up you then have less air due to VTA and it runs rich.

I'm gonna be setting my Lancer to VTA once I get rid of the MAS altogether. I'm gonna use the pressure sensor for the e-manage and run a MAP sensor.

EidolaDream

I havent added a bov to my evo yet, however I do have one on my msp (mazda speed protege) It works great I just had to tune it... I guess my question is can you not tune the bov to work with evo's? Again I have never tried. I would asume you could tighten it that would reduce the the amount of air that can be vented.

RyanM

iTrader: (1)

So basically, I'm going to have to get the EIDS to compensate for the issue since the SAFC Decel requires a hot wire air flow sensor.

Is there a way to wire that type of sensor in for the SAFC?

Thanks for the information though, greatly appreciate it. I didn't have a clear understanding.

orion981

iTrader: (2)

What I don't understand is why we can't just relocate the MAF next to the intake manifold and after the BOV. By doing this, when you VTA, you would be venting air that they MAF HASN'T counted yet, so there wouldn't be a problem, right?

The only potential issue I could see with this would be if the ECU calculates some delay time between the time it meters the air and the time it gets to the intake manifold (since that metered air still has to be spooled and intercooled). This is a significant amount of time to a computer (I'm guessing somewhere around .3 - .5 seconds). If so, then running this solution might have the oppostive effect, making you run too lean (because there is more air going into the intake manifold at that time then the computer is expecting.) Anyone know about this?

tokeone

iTrader: (4)

best fix is the eids and to recirc (you can buy a flange for the hks. its $12)

4ce fed

iTrader: (11)

The stock MAS can't handle the pressure. And I believe the air going into the MAS in it's stock form needs a specific flow pattern to work correctly, hence problems people have when they upgrade the intake. Putting it directly before the IM would drastically change the flow pattern.

However, there are solutions like you describe. I believe UR makes a meter that will work in the upper IC pipe. For DSMs, there is a MAF translator that allows you to run a GM MAF just like you describe. The translator takes the Hot Wire signal from the GM MAF and translates it into a Karmann signal so the ECU can understand it. You can vent all you want to.

areet

iTrader: (1)

HKS EIDS if you're not using any piggybacks or standalones. The EIDS works fine VTA, I run a TurboXS RFL without any worries of stalling.

orion981

iTrader: (2)

Yeah, I didn't think about the fact that the air is pressurized at that point. Makes sense. Thanks for the tip on the UR meter. I'll definitely have to check that out. It would be nice to have my cake and eat it too.

Wow, just checked out that meter -- it's freakin expensive! $650??? I'd rather save that money and put it towards an AEM standalone. Solves the VTA problem and gets you more performance.

RyanM

iTrader: (1)

I run the SAFC and an EIDS. Works great, actually, works really great. If any of you have installed the SSQV kit with the IC pipe, there is a c-ring/snap ring you have to use to mount the BOV. I didn't have the snap ring pliers to finish the job. (my other car is now my Evo support vehicle) I could actually start my car without the BOV. This would have been impossible without the EIDS.

In other words, this simulated massive and total VTA and the EIDS was able to compensate. I didn't go anywhere, but I was just surprised it ran.

Assassin

iTrader: (4)

Ok from what I've heard, the stalling issue with the VTA is caused by the hole left in the intake by removing the recirculation tube. Is the BOV before or after the MAP? I was told that recirculation doesn't really matter. Because with a dual vent BOV, at high boost, it vents to atmosphere anyway.