External Wastegate Hoses

[3340TH]

Hi just have a mate putting his Gts-t back together after being off the road for extreme amount of time.

He's decided to put it back together, asked for my help and im not sure either.

Its been changed from normal setup to a hi-mount turbo with external wastegate...now there is two hoses coming out of the wastegate, thin hole and a thick hole one. And not sure where they should be going. Also the two hoses/pipes coming from the little black cylinder thing at the front is just floating in the engine bay (normally connected to the overhead cam thing (sorry not a grease monkey))

Photos of my engine bay not his.

[axe s]

im pretty sure that the hoses in your 1st pic go to the charcoal filter (the black cylinder thing), and the 3rd pic is the old boost controller, u don't need it connected if u have a new bost controller....

[3340TH]

Yeah, that whole rail going from the charcoal filter is loose and neither pipes are connected into the overhead cam (where they are in pic 1) connected at the filter though.

The top arrow in the first pic is going into the intake pipe not back to the filter like in my skyline. (custom piping)

[Beer Baron]

your first problem is that it's a blow off valve, not a wastegate...

[3340TH]

your first problem is that it's a blow off valve, not a wastegate...

Pics of my car, not his.

He has Super sequential HKS BOV and external wastegate down under the inlet manifold.

Two hoses out of the charcoal filter and the two hoses out of the back of the wastegate, trying to find out where they go.

[Beer Baron]

lol, ok my bad. the top wastegate hose needs a pressure feed from somewhere after the turbos compressor outlet. the other one is a vent. the charcol canister I'm not sure.

[StockyMcStock]

lol, ok my bad. the top wastegate hose needs a pressure feed from somewhere after the turbos compressor outlet. the other one is a vent. the charcol canister I'm not sure.

see this is why people blow engines up by accident

external wastegates have two pressure feeds, one on each side of a diaphragm. boost pressure needs to push the wastegate poppet valve open (against the spring's resistance) and hence the BOTTOM wastegate line needs a pressure feed from the compressor outlet/piping.

[2rismo]

The bottom one needs to be connected to the washer bottle hose so you don't need the washer motors any more. Big weight savings!

[Rush Hour]

this guy knows wat he is talking about, do you (stockymcstock) have pics of diagrams for this? it would make it so much easier for him (not a grese monkey)

[BezerkR32]

are u sure the gate is under the inlet manifold?

might have it mixed up with the nitrous solenoids.

Pics of my car, not his.

He has Super sequential HKS BOV and external wastegate down under the inlet manifold.

Two hoses out of the charcoal filter and the two hoses out of the back of the wastegate, trying to find out where they go.

[3340TH]

see this is why people blow engines up by accident

external wastegates have two pressure feeds, one on each side of a diaphragm. boost pressure needs to push the wastegate poppet valve open (against the spring's resistance) and hence the BOTTOM wastegate line needs a pressure feed from the compressor outlet/piping.

So where does the boost pressure come from, can you point them out in the pics i have displayed or not? Compressor outlet/ piping (on the custom pipes?)

It Looks like it is under the inlet manifold...I'm taking his word for what is there as he would have been told while it was getting fixed. The car was running about 6 months ago, he paid a bloke $4500 to get it fixed. Then a bolt came loose and was floating around the engine, so they pulled it apart 6months ago, and have just forgoten where they pulled the hoses off. I'll try get some pics up of his.

[StockyMcStock]

Look, if he's got an external wastegate then it is not underneath the inlet manifold. it should be underneath or to the rear of the exhaust manifold. You only really need to connect one hose to it, and that is the BOTTOM pressure fitting on the gate, in other words the pressure fitting that is closest to the heat of the exhaust gases. This fitting needs to "see" boost pressure, this can come either from the plenum or from a fitting on the piping somewhere, it doesn't really matter.

Hooking boost pressure up to the top wastegate fitting will cause the car to run unlimited boost and it will destroy things.

Essentially the moral of the story is, if your mate doesn't even know what an external wastegate is, or how it works, he should probably get it put back together by a workshop to be on the safe side.

[shanef]

hahaha yeh if u plumb both top and side port upto manifold pressure, then it'll make unlimited boost (i/ve seen this happen recently ).

[anthonymcgrath]

hey guys

hope you dont mind me reviving an old thread, but I did a search and couldn't find much recent, so rather than start something new figured I'd add to this one...

I'm in the midst of fitting my external wastegate at the moment - I've got it linked up to my downpipe and it all seems to fit neatly... pics below... I'm not running screamer - just back into downpipe... dont fancy being a police magnet really...

there's 2 fittings on the wgate - one on the side (just visible in this pic) and one on the top of the bell housing bit (dont know the terminology sorry)...

so reading the posts above I would hazard a guess that a 6mm vacuum hose coming off my greddy GTR style plenum onto the side fitting would be a good starting point. I'm guessing that would feed pressure to the wgate? However I'm a bit lost as to what the top one does... I found this diagram on Tial's site but it appears to be linking into a boost controller too...

any advice on the ext. wgate stuff would be great thankyou!

ant

uk

ps - this is my engine bay at the moment below... I'm fitting a gt3076 turbo... a few of the guys on here were following it on another thread about fitting a gt3076 turbo to an RB25DET....

[JonnoHR31]

you only use the top fitting when using a boost controller. if your not using one then plump a boost line into the side fitting and leave the top port open

[anthonymcgrath]

hi Jonno thanks for your reply there - so basically If I just wanna run psi that the spring inside the ext wgate gives, then I would run a feed in through the side.

If I want to run more then I will use a boost controller (which I plan to with my G4 link ecu) then I plumb from:

plenum --> boost controller --> top of ext. wgate

did I understand that right?

[TiTAN]

you run the line into the side of the wastegate boost controler or not

you also run the line into the top from your boost control solenoid if you have a boost controler

[anthonymcgrath]

ah okay so:

6mm vac hose off plenum --> side of wgate - got it thankyou

so if I dont run the boost controller will it only make the psi that the wgate spring is rated to (I think mine is only 12psi or something)? I mean theres a hole in the top now if I just run the one hose.

Not 100% sure on how it all works tbh

Edited September 20, 2010 by anthonymcgrath

[JonnoHR31]

yes it'll run whatever the spring pressure is (assuming eveything else is working fine). dont worry about the open hole, it wont leak is its on the opposite side of the diaphram to the boost source

[anthonymcgrath]

cool cheers Jonno - that sounds okay to get it up n running. I can fit the boost controller pipe once it arrives lol!