BOV vent to atmosphere fix

[Grant]

I figured out a way on the rally car to vent to atmosphere and have the car still run nicely. I am using a stock Legacy turbo BOV (thanks Jason G) on my Colt and the problem was that under idle the valve was open and thus sucking a small amount of air into the engine. Not only was it unfiltered, but it was causing a lean condition due to more air than the MAF was detecting coming in. My first fix was just to get a Crankcase Breather filter and that way it was at least filtered air, but this idea still caused the lean condition and the filter extremely hindered outward flow. Then I had an idea. I went to my local Ace Hardware and in the plumbing section found a 1/2" Check Valve. This unit only allows flow in one direction. Installed it and now the valve works perfectly. The idle is right and it allows the extra air to discharge during shifts allowing faster acceleration. I am planning to get a air/fuel gauge before our next event in May as I know since all the air going out has been measured I will run rich temporarily but it currently doesn't seem to affect it at all. We also bought another valve for my codrivers Talon and we'll know how the fuel mix is tomorrow as he has the AF gauge. Anyhow, nice little fix for only $6.99.

[ciper]

Such an easy fix and nobody thought of it!

What is the "flapper" material made out of? Are you worried that it may come apart and enter the engine?

[Grant]

The one I bought is plastic. I ran about two feet of heater hose between it and the bypass valve so some of the heat would diminish and keep it from melting. Hadn't thought about it falling apart though. I did run into a new issue with it however. When cruising at highway speed it starts to basically leak air out almost constantly as you push in the gas and let it out. It gets pretty annoying and once again, I know it is making it run rich. I think the solution we are going to try is to incorporate a T that will allow the air being released to either go back into the intake right before the turbo OR be vented to atmosphere through the check valve. That way I can leave it on recirc when driving around town and on transits, and then put it on vent to atmo. when driving on stage. Also going to try to make it so the codriver can change it from in the car. I'll post results when we do it.

[mTk]

Heh, i did this a few weeks ago. Talked about it on IRC. I liked it, but if i was not driving fast ie just getting into boost, then shifting, the rich condition was causing some stumbling on further acceleration.

I got the idea from my friend who uses it on his audi.

MK

[mTk]

and, mine was brass and was 4.99

MK

[Grant]

Eeeyyyeee had to buy some hoses and fittings too though. Arrr