924Board.org

bass gt · Posted: Sat Feb 04, 2006 11:04 am Post subject: Wastegate Operation

Guy's,

A quick question please. My wastegate has a pressure line running from the top of the housing to the charge tube. Is this a line FROM the W/G or TO the W/G???
ie, if the former, am i right in assuming that if this line is closed/blocked, the W/G cannot vent and will over boost? or do i have it arse about face??

Cheers,

Steve

Paul · Posted: Sat Feb 04, 2006 11:13 am Post subject:

The pipe on the top of the wastegate is a vent.

The pipe from the charge tube should be connected to the fitting on the side of the WG.

If the vent is blocked, the wastegate will allow more boost than it should.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

bass gt · Posted: Sat Feb 04, 2006 12:02 pm Post subject:

Strange,
I have a copper pipe which comes from the top of the W/G up behind the engine, along the head and connects into the the charge tube.????
I have the feeling something is amiss here. Anyone got any pics??

Steve

Smoothie · Posted: Sat Feb 04, 2006 12:25 pm Post subject:

No pics, but Paul's right. The top-center is a vent. If there's a connection from there to the charge tube, then that's bassackwards. Pumping air in that way would only keep the wastegate closed. The charge tube to WG connection should go into the WG at its' side, lower down, below the bell-shaped spring&diaphragm housing.
_________________
"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

Smoothie · Posted: Sat Feb 04, 2006 1:19 pm Post subject:

wastegate drawing -
http://pg.photos.yahoo.com/ph/smoothies931pics/detail?.dir=7a86&.dnm=da96re2.jpg&.src=ph
_________________
"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

Paul · Posted: Sat Feb 04, 2006 1:35 pm Post subject:

The vent pipe in its stock location terminates with a J pipe bolted to the rear of the head.

Maybe your car has a boost controller attached to your vent line before it gets to the charge tube?
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

sequential · Joined: 18 Nov 2005 Posts: 500 Location: BANNED

u63af · Posted: Sat Feb 04, 2006 8:58 pm Post subject:

I have the type with the control line going to the bottom of the waste gate. When i put in a boost controller (the sort with the ball bearing and spring) the car overboosts even if i have the spring on its loosest setting. Is this a normal problem with the 924 turbo or do i have something wrong with mine?

sequential · Joined: 18 Nov 2005 Posts: 500 Location: BANNED

bass gt · Posted: Sun Feb 05, 2006 4:07 am Post subject:

Cheers Guy's!!

Yep, there is a manual valve in the vent line, which then connects to the charge tube. Obviously, with this valve shut, the W/G cannot vent, hence overboost. I've since found the valve is faulty, and is pretty much blocking the line to the charge tube.
I'm going to look into the various type of EBC's, and make a decision for or against. If they really are as good as the blurb says, they must be worth it? Or is it all smoke and mirrors, and another electro wizzy gimik for our ricer friends?? wooosh wwwwooooooooshhhh
Regards,

Steve

Smoothie · Posted: Sun Feb 05, 2006 5:14 am Post subject:

Actually there are at least 2 ways of installing a simple control valve and I think at least half of us that are using one have it in the control line, with the top WG port being left open as a vent. This is the quickest-easiest way of hooking it up. It works, but is probably functionally a second best to the next arrangement -

Control line from charge tube to bottom-side of WG is left alone and the valve is placed in-line from the vent port with the flow direction going away from the WG (if the valve being used is directional), but the other end of this vent line downstream of the valve is left open to atmosphere - it's not connected back to the charge tube (doing so would render the WG inoperable since you'd be pumping charge air into the top and bottom of the WG at the same time).

As far as the electro wizzy gimik thing - I think it is for the most part. I'd go with a simple $5 needle valve like numbbers is using. Try it, you'll probably like it. If not, it was only $5...remove and put it to use on a fish tank, or drip irrigation for your plants and replace with an EBC.
_________________
"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

sequential · Joined: 18 Nov 2005 Posts: 500 Location: BANNED

bass gt · Posted: Sun Feb 05, 2006 9:49 pm Post subject:

Wayne,

I'm looking into the DTA P8Pro at the moment. Seems to do a few things that the lower end units don't. Whats your take on this unit?

Steve

sequential · Joined: 18 Nov 2005 Posts: 500 Location: BANNED

bass gt · Posted: Thu Feb 09, 2006 7:05 am Post subject:

Wayne,

I think it may be the S60 i go for, and add the RaceLogic TC system later. It has much more adjustability than the DTA. However, the S60 does exactly what i want. As for the maps, thanks, i will drop you a line closer to the time.

Steve