stock bov pipe unblocked = faster car??

[Mr GTS4]

i only noticed this the other day.. i have a apexi bov in the standard position and the pipe that comes up beside to recirculate the air back into the system. i put a coke lid in there when i put the bov on, now the other day it come out ( i didn't know ) and the car went alot faster than normal on 10psi. the last dyno i had so on a 40 degree day with the coke lid in there and the A/F ratio's went down into the 9's at high rpm.

is it possible that the car is sucking air in through that pipe and leaning out the mixture? the car isn't pinging so it's all good.

the car just feels a Shite load quicker. this morning i turned the boost upto 13 and holy crap... i think i forgot what boost felt like lol

[Sydneykid]

Hi Mr GTS4, that pipe plumbs into the inlet after the AFM, so the engine is getting un metered air. Air that the ECU doesn't know about, so it isn't adding fuel for. It is unfiltered (dirty) air as well, so not all is good. If the A/F ratio is 9 t o1 then its time you did some correction, an SAFC or ECU upgrade would give good results by the sound of it.

Hope that helps:cheers:

[GunMetalR33]

AFR's of 9 to 1 are pretty rich right??

So if their is air coming in through the BOV recycle pipe after the AFM it should lean out the AFR's (as SydneyKid said). Sounds like there is not much air coming from the BOV pipe at all if your AFR's are 9 to 1.

Doesn't seem to make sence to me...

[Mr GTS4]

i noticed this after the dyno.. so the a/f ratio's would be alittle leaner than that now.

[cul202]

If you block (as you said, with the coke lid) the return pipe & vent the bov to atmosphere the ECU has already registed the vented air as passing the AFM so yes, the mixtures will richen up.

If unblocked it they would be a little leaner due to some entering air bypassing the AFM. Oh, & dirtier due to it also bypassing the filter shouldn't be the other way around!?

I tried the blocked pipe/vented std bov and found that the car went noticably differently, which means that my car is out of tune

Std bov is way loud when vented & the stalling at idle became rather irritating.

.

[Mr GTS4]

what about sticking a little air filter thing over the pipe, the smaller ones you see people using ontop of there engine???

cul202 - i don't get any weird idle problems either... must be a freak thing