[tico915007]

I started this thread in nasioc got some answer hopefully could get more here....

I feel like an idiot but here it goes.....This is a 2007 STI mods are HKS catback and Cobb Intake. Maybe someone can help, yesturday I was adding some oil to my car was missing half a quart. To make a long story short i was in a hurry and i left the oil cap sitting on my intake manifold for about 24 hours unoticed obviously. While i was driving the car i was amazed to how much it pulled it had its initial jump but instead of staying consistent after 5,000 RPM it kept pulling like a champ. Thinking i was going crazy i took my buddy for a drive and he said my car felt faster and this morning my Girlfriend asked me if i did something else to make my car faster...... I finally notice my oild cap was off check my oil lever and it was fine. My question is does running with your oil cap off release presure in the motor allowing you to inadvertly run more boost or am i going crazy..... On my car before a 2004 gto i know when people were running boost on them the got a breathable type oil cap to releave crankcase presure is this so on our car?

This is what im talking about on an ls1 motor





Finally what i concluded releiving the vacume created on the unserside of the motor the car noticably feels faster not neccesarly more horsepower but something to the effect of a lighter flywheel or crank pully.... my final question is does removing that vacume negatively affect the sealing of the piston rings??

[rs_wrx_sti]

leaving your oil cap off = faster car, hmmmm.....
I doubt it. The PCV and valve cover breather should take care of crankcase pressure. Just for kicks, next time you get a dyno do a pull w/o the cap to see if it makes any difference .

[STUKA]

I don't see how it could! But if I were you. I would put that oil cap back on. If the car is getting more boost, this could mean you are running lean!!!!

[Szumita]

very strange. would it lean it out?

= bad on a 07.

[flatthump]

You got plenty of info in the Nasioc thread.

Why don't you tap into the oil cap and include it as a breather? That's definitely what I'm doing this weekend.

[jph]

Originally Posted by flatthump

You got plenty of info in the Nasioc thread.

Why don't you tap into the oil cap and include it as a breather? That's definitely what I'm doing this weekend.

link to said thread?


J.

[Szumita]

yeah, id like to read it.

[Al from jerz]

Originally Posted by jph

link to said thread?


J.

No Oil cap=More boost?????? HELP - NASIOC

[Szumita]

wow... interesting.

so the effect may be similar to a lightened pulley it seems.

[shockey`]

hm. i just took it off and there is a noticeable amount of air coming out at idle. im going to throw a rc car air filter on it with some tape and go take a drive.


i cant feel a noticable difference with/without.

[importfanatic17]

So we should put holes in the oil cap in order to relieve vacuum? That will then give us the effect of less strain on the engine (i.e. similar to a lightweight flywheel) but with no ill effects?

[flatthump]

^NO. Even though you can't feel it, there are vaccuum pulses that come out of the crank case too. If you just have a hole on there you'll get a lot of dust and **** in your crank case...bad idea.

My suggestion is to tap the oil cap with a barbed fitting and run it (in conjuction with your other breather lines) to a catch can.

It's not similar at all to a lightened flywheel. It will just relieve more positive pressure in the case.

[importfanatic17]

Originally Posted by shockey`

hm. i just took it off and there is a noticeable amount of air coming out at idle. im going to throw a rc car air filter on it with some tape and go take a drive.

Let us know.

[Szumita]

subscribed...

[polyol]

Originally Posted by Szumita

subscribed...

Ditto...would love to see a dyno graph...