Exhaust valve vacuum lines

[titanle]

Quick question guys,

I did the zip tie exhaust valve bypass mod today and I wanted to know whether its imperative that I disconnect and plug the vacuum lines. Right now they are still connected to the exhaust valve.

[titanle]

Heres a link showing cold start and idle with the exhaust valve bypass mod done. It sounds deeper and throatier at idle. There are also some nice backfires/crackles when revving above 3K rpm.

[peter2772000]

This is one of the 1st mods I'm doing when I get back down to the Cape. And, I will definitely be disconnecting/plugging the line and the vacuum port on the exhaust valve to prevent debris from getting in there.

I'm curious to see if I get any drone at lower highway speeds though...

[titanle]

Originally Posted by peter2772000

This is one of the 1st mods I'm doing when I get back down to the Cape. And, I will definitely be disconnecting/plugging the line and the vacuum port on the exhaust valve to prevent debris from getting in there.

I'm curious to see if I get any drone at lower highway speeds though...

I haven't noticed much drone so far.

[omgboost]

What does the vacuum line do, if I just unplugged it without ziptieing the flap open?

[titanle]

Originally Posted by omgboost

What does the vacuum line do, if I just unplugged it without ziptieing the flap open?

from what I've gathered, the vacuum lines keep the flap closed until enough pressure builds up (WOT) allowing the flap to open.

In my X6 removing just the lines does nothing. The flap mechanism itself needs to be zip tied or wired in the open position, otherwise once you let go it springs back to closed position.

[omgboost]

Originally Posted by titanle

from what I've gathered, the vacuum lines keep the flap closed until enough pressure builds up (WOT) allowing the flap to open.

In my X6 removing just the lines does nothing. The flap mechanism itself needs to be zip tied or wired in the open position, otherwise once you let go it springs back to closed position.

That's the same way it works on my X5. I had ziptied mine without disconnecting the vacuum lines. I'm thinking maybe the lines help keep it open after a certain RPM in ours because the mechanism stays closed by default.

[titanle]

Originally Posted by omgboost

That's the same way it works on my X5. I had ziptied mine without disconnecting the vacuum lines. I'm thinking maybe the lines help keep it open after a certain RPM in ours because the mechanism stays closed by default.

I think thats correct. Its a neat little mod, I got that little extra oomph in the exhaust note that i was looking for without it being overbearing.

[peter2772000]

Still no noticeable drone? If you're going to get it, it's typically at the lower end of cruising speeds, 45-55 mph.

[titanle]

Maybe I lucked out, but i haven't really noticed any drone with this mod.

[denaliman]

Originally Posted by omgboost

What does the vacuum line do, if I just unplugged it without ziptieing the flap open?

If you just unplug it without capping the line you will get a error message I believe.

[m5james]

The vacuum line runs from the engine bay all the way to the trunk, tees into a sensor and then vacuum lines run to the valves. Leave any of those unplugged and you'll notice an instant decrease in power. I kept having reduced power warnings (found out it's a different issue), but had assumed my exhaust lines we're capped properly. For anyone who wants to test it, unplug a vacuum line from one of the vacuum canisters in the engine bay, drive away and it'll feel like you don't even have twin turbos.

[titanle]

I just left the vacuum lines plugged into the valves and zip tied the exhaust flaps themselves in the open position. No error codes, no loss of performance, great new exhaust note.

[peter2772000]

Forgot to post back. Did this last year and no drone whatsoever. Gnarly exhaust note on a cold start.
Well, as gnarly a note as one can expect on a straight 6 LOL.

[drantoniorodriguezq]

Hi, how are you? I think I have this problem. I installed a new exhaust, but it doesn't have the valves and it gives me error codes. From what I understand, I have to remove the valves from my original Kavak, connect the vacuum lines and leave them. With the valves hanging with the door open, so that it doesn't give me the error codes.

Thanks