SoCalLove

I'll tell you guys as best as I can...and I'm bone stock (and gunna stay that way )

I vented my bov and crv, was pretty fun actually, but when I put in my boost gauge, (hopefully I did the boost test right) I got something like 9-8-9.... . Ok.....

So, I routed the bov and crv back into the intake, I did the test again, (3rd gear WOT, right?) and my boost was 10-8-10. Cool.

But lately, when I turn on my car from a cold start, it sits at 20 in hg. when I first put in my gauge it sat between 14-16 in hg.

But the weird thing is, I had just did the fan mod. When I dont turn on my fans, my vac. will sit at 20 and my idle will sit at 1k.

When I turn the fans on, my vac goes up between 14-16, and my idle goes down to 7-500k?

My car has never stalled. It drives smoothly and pulls hard.

I talked to a local 7 shop and I told them about my vac problem but I didnt mention the fan or idle. They said its normal to start at 20 and then eventually rise to 14-16 in hg. (which is a healthy engine).

Oh and after driving a while and at op. temp. the car will sometimes sit at 16 w/out my fans on.

Any clues, ideas, suggestions, flames...

Jammer5703

sounds fine

ech

Ditto - Higher RPMs and a little more load (alternator) will increase the vacuum. You have described a healthy engine and no vacuum problems.

OptusX4

Well, intake vacuum is dependant upon idle. So, I wouldn't get all happy about the 20in.Hg at 1k. The good measure is to look at vacuum when the car is under NO load (no accy's or anything) at about 750RPM, whereat you said you were getting 14-16. So, I would think 14-16 to be the correct reading.

RXJJang

iTrader: (52)

I agree with these responses as well. My engine idles at around -22, so I don't think you have much to worry about in regards to what you have described.

RX7Elmo

wow 22in/hg??? holy moly. even piston motors wiht CR of 8:1 don't idle that low. Sounds good!

Also, i had no clue that venting the CRV and the BOV would yield less boost? does this mean that they leak or someting?

danny

SoCalLove

Phew! Who is that guy who has the sig. "exageration leads to paranoia". I just wanted to make sure. Again she runs smoothly.

And I thought to myself I just might be putting extra load on the alternator, now with the wiring of the guage, timer, fan mod.

When my car is just idling, nothing on, like radio or fan, it'll pretty much sit at 20 in hg. with my idle at the notch below 1k which i assume is 750 ( i just said 1k since the needles is close to it). Again when I turn the fan on then the rpm needle will just drop slightly, but not to the point of stalling, not even close.

Thanks again guys. Add anything else if you'd like.

nocab72

The benchmark for a healthy non-ported engine is idle 750 - 850 rpm vaccuum 15.

Ported engines will have a slighly higher idle and slighly lower vaccuum readings.

I would say your engine is healthy!

K

SoCalLove

Well, from my previous experience from a turbo car ('95 eclipse gs-t). If you vented the bov w/out it dumping back into the intake, it could create some turbo lag.

So I just thought about that and re-routed the bov & crv back into the intake, and it seemed to do the trick. But while the bov was vented it did seem to hiss a little at idle, so I'm thinking it might not be fully closed. So again I routed'em back, which fixed my boost.

Personally I love the loud swoosh sound (I miss it right now). But my stock bov might be leaking, so eventually I'd like to get an aftermarket bov.

RX7Elmo

okay, well, i think the result of your lower boost is from a leaky bov. Venting a bov doesn't create more turbo lag. You have to realize that the bov open to atomsphere or to the intake makes no diff to the turbo characteristics until you let off the gas pedal and open up the bov/crv

Also, one tick below the 1000rpm mark is 900rpm. If you notice, the ticks up to 500rpm are very close then spread out up to 1000rpm. Sounds like your idle is a bit on the high side if it's really that close to 1000rpm.

duboisr

Going from 20 inch to 16inch is not increasing vac ,it is decreasing,when you up the rpm it takes more air and the vac should decrease to 14 -16 ok but this is decreasing not increasing.it will decrease to 0 then positive pressure starts known as boost.