Author Topic: Boost return pipes  (Read 5788 times)

Offline Alexiskayak_7

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Boost return pipes
« on: September 09, 2008, 04:41:31 pm »
I'm thinking taking off the boost rerturn pipes...
-I would like to know the pross and the kons of  that mod.?
-The distance of spraying PTFE (every how many miles)?
-When i take of the boost return hose, i have to conect the oil vapour tube with a small filter or i leave it like that?  
-I have to close the left chargers port (the cap is going to be a custom made)
-Any power gain?
-Will the fuel consumption increased?
-In a stock G do i hear the whoshhh? (lol)
Thank for your time, Alex!
« Last Edit: September 09, 2008, 04:44:26 pm by Alexiskayak_7 »

Offline hayesey

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Re: Boost return pipes
« Reply #1 on: September 09, 2008, 05:32:02 pm »
[quote pid=4052 author=Alexiskayak_7 date=1220974891]I'm thinking taking off the boost rerturn pipes...
-I would like to know the pross and the kons of  that mod.?
[/quote]

this is all a matter of opinion really, read what people say and make your own mind up.  For me though:

pros:

- ptfe lubricates the charger much better than the scum that comes out of the oil breather (use a catch tank for a while and look at what collects in there)
- the charger is always taking in cold air from atmosphere not heated up air recirculating through the boost return (colder air = denser air = more power)
- the noises, they sound cool!

cons:

- you have to remember to lubricate the charger every so often or you'll kill it, also not put too much ptfe into it
- the noise??? some people don't like it...

Quote

-The distance of spraying PTFE (every how many miles)?

I give it about five short sprays every 1000 miles.  It's not an exact science but that seems to be roughly the right amount.

Quote
-When i take of the boost return hose, i have to conect the oil vapour tube with a small filter or i leave it like that?  

run a pipe from the breather pod (remove the plastic one-way valve) to a catch tank.  If you just leave the pipe open or even with a filter on it you'll get oil vapours and mist all over your engine bay.

Quote
-I have to close the left chargers port (the cap is going to be a custom made)

yes, or run twin inlets.  A few years ago the done thing was using twin inlets where you have an airfilter on each charger inlet.  These days everyone just puts blanking plates over the 2nd inlet.  I got rid of my 2nd inlet with a blanking plate to gain a bit more under bonnet space.

Quote
-Any power gain?

technically there should be a slight increase, yes.  Not massive though!

Quote
-Will the fuel consumption increased?

not noticeably so if at all.

Quote
-In a stock G do i hear the whoshhh? (lol)

yes

Quote
Thank for your time, Alex!

no problem  :D

Bear in mind, these are mainly my opinions, albeit gained with years of messing about with g40s and from advise from people in the know.  I also know there are other people who think this modification is the spawn of the devil and will cause kittens to die.

Offline Alexiskayak_7

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Re: Re: Boost return pipes
« Reply #2 on: September 09, 2008, 10:17:23 pm »
Oh... Thank  you very much... You covered me in every single question...
But, where can i find an oil catch tank? OR do you have any pictures to make a custom?
« Last Edit: September 09, 2008, 10:21:45 pm by Alexiskayak_7 »

Offline G40DAS

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Re: Re: Re: Boost return pipes
« Reply #3 on: September 09, 2008, 11:53:41 pm »
I'm in the "don't take it off" club and my reasoning is unless you are on boost continuously, the manifold will be below atmospheric pressure some of the time, i.e your boost return stub is sucking-in unfiltered air, which will be wearing your bores and valve seats much quicker than normal. (INCORRECT INFORMATION, Dknight, Admin)
I've recommended an aquaintance of mine (with an eaton conversion on his G40) to put a small, conical, motorbike K&N filter where the boost return used to be. Even with the eaton conversion he wasn't on boost all the time.
He still gets his "whoosh" but he's not wearing his engine out.
Just a thought.
Anybody else filtering thier boost return stubs ?
« Last Edit: September 12, 2008, 01:21:45 am by DKnight »

Offline PeteG40

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Re: Re: Re: Re: Boost return pipes
« Reply #4 on: September 10, 2008, 08:21:03 am »
if you feel your boost return stub, as long as the engine is going, even not on boost there is a volume of air coming through that.. it manifold is below atmospheric its because air is going through the boost return stub!!! so when running it wont suck in any unfiltered air.  You might get spiders in there when its stood mind

Offline G-spot

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Re: Re: Re: Re: Re: Boost return pipes
« Reply #5 on: September 10, 2008, 09:00:32 am »
[quote pid=4073 author=peteg40 date=1221031263]if you feel your boost return stub, as long as the engine is going, even not on boost there is a volume of air coming through that.. it manifold is below atmospheric its because air is going through the boost return stub!!! so when running it wont suck in any unfiltered air.  You might get spiders in there when its stood mind[/quote]

I second that, though on principle the obvious thing to think is that the engine will pull in air through the boost return valve, but in fact the G-lader will always shift more air than the engine requires at said RPM so there is never a vacumm effect.

Offline hayesey

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Re: Re: Re: Re: Re: Re: Boost return pipes
« Reply #6 on: September 10, 2008, 09:18:54 am »
Quote
I'm in the "don't take it off" club and my reasoning is unless you are on boost continuously, the manifold will be below atmospheric pressure some of the time, i.e your boost return stub is sucking-in unfiltered air, which will be wearing your bores and valve seats much quicker than normal.

that's just not true, even at idle and low engine loads there is still a large volume of air blowing out of there, air never gets sucked in, the charger would have to somehow stall for that to happen.

Offline Tav

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Re: Re: Re: Re: Re: Re: Re: Boost return pipes
« Reply #7 on: September 10, 2008, 09:46:18 pm »
Yup just pop your hand in front of it and you'll feel the warm boost blowing out at idle.

Offline tjp_lawson

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Re: Re: Re: Re: Re: Re: Re: Re: Boost return pipes
« Reply #8 on: September 11, 2008, 10:27:11 pm »
so does anyone adjust the boost return linkage when they remove the return pipe then

Offline G-spot

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Re: Re: Re: Re: Re: Re: Re: Re: Re: Boost return pipes
« Reply #9 on: September 12, 2008, 08:28:34 am »
I've always set mine to be fully closed when the throttle is fully open, though now that I'm running 51mm throttle body I could probaly get away with it closing slightly earlier, but to be honest I don't really know whats the best recommended set-up.
I always felt that there is no point having the BRV colsed if the throttle is only partially open as it it does is build up back pressure in the boost pipes and put load on your charger, and then your engine resulting in loss of preformance.

Offline Raw

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Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: Boost return pipes
« Reply #10 on: September 12, 2008, 12:38:51 pm »
[quote pid=4073 author=peteg40 date=1221031263]You might get spiders in there when its stood mind[/quote]

I once had a mouse climb in mine!



 LOL *not true* (don't want Dan editing my post!)


[quote pid=4074 author=G-spot date=1221033632]so there is never a vacumm effect[/quote]

There will be a small vacume when off boost as there is on NA cars but it's caused by the restriction of the throttle valve. Above the throttle valve (where the lader is always flowing air) there is no vacume.

Offline G-spot

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Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: Re: Boost return pipes
« Reply #11 on: September 12, 2008, 08:00:32 pm »
[quote pid=4101 author=Raw date=1221219531]

I once had a mouse climb in mine![/quote]

I could tell you a sorry about a rat that disabled our Audi!!


As for the vacumm quote, yes there is a vacumm between the throttle body and the head, but not enough to draw air back through the BRV. :)