Boost return mod.

[Gugge]

Hi.

ive just bought a g40, it sounds so nice. but im missing the blow off sound.(i had a saxo turbo before)

have heard of a return boost mod but cant find any guide or information about this mod? isnt it the same as fitting a blow off?

Gugge

[hayesey]

hi, welcome to the forum.

It just means removing the pipework between the boost return valve and the charger.  You need to block off the 2nd inlet on the charger, fit an oil catch tank (as you'll have to remove the breather pipe too) and then lube the charger every so often with ptfe spray (look in the mechandise section of this site, you can buy the right stuff there).

[Gugge]

aha..

ive had been thinking a small theory through my head.

sry about my english im from denmark.

i was wondering if i did mount a blow off on the pipe between the valve cover and the inlet. i have a picture here http://www.bilgalleri.dk/html/alb_vis.asp?AlbumID=37512

the pipe marked with red i would mont a bov and remove the pipe that goes belove the inlet manifold.
then put a plate af metal between the g-lader and return pipe with a 15-20mm hole in it so the air could still travel but with high rpm and gear shift the blow off would take care of the air.. same as the boost return mod just still with flowing air?

[hayesey]

well the whole point of the boost return mod is so the warm air isn't flowing back into the charger and it's only sucking in new colder air from outside. 

[hardchargin40]

well the whole point of the boost return mod is so the warm air isn't flowing back into the charger and it's only sucking in new colder air from outside. 

...and prevent recirculating hot oil vapour back through your inlet system if you haven't got the strongest engine in the world, that'll be lowering your octane therefore power.

BOV's have been done before welded onto the back of the TB etc, i think they effected the ecu readings and also i remember a BOV being done the same as gugge as described, it worked but more of a 'can be done' exercise but kinda pointless and defeating the point of doing the Boost Return deletion.

[Gugge]

okay. that way.. so it just vents out in the free air?

what about the valve cover. shouldnt it be blocked where the pipe goes through?

[hayesey]

BOVs aren't designed to work with superchargers anyway, they can't constantly flow air, they are made to relieve pressure quickly between a turbo compressor and throttle plate when you lift off.  It's been done before as Paul said, they can't flow the air properly, meaning you get a slight pressurisation of the inlet even at idle which will be what affects ecu readings (to the map sensor anyway).  Just remove the boost return pipes, blank off the charger inlet and fit an oil catch tank to the oil breather pipe, it's the best way.  You get a nice whoosh noise from the boost return valve anyway if it's a noise you are after.

The pipe through the valve cover doesn't need blocking off, it's just a pass through.

[tdh-syorks]

Hi Gugge, i just read your thread and i think this will help you a lot.

http://homepage.ntlworld.com/nick.lewis0/Boost_return_mod.mht

[Gugge]

tdh-syorks.

the link sadly doesnt work..

[NeilG40]

That link's always been a bit funny with certain browsers, it works fine in internet explorer.

[hayesey]

it's a format that firefox can't read, you need to install this to view it in firefox:

https://addons.mozilla.org/en-US/firefox/addon/8051