siscogts

Hi !
2 hours went by searching on rennlist (and elsewhere) about changing my GTS intake tubes( poorly made, with an iron spiral covered with a stupid foam...and ridicolous price) with "old style" tubes from S4-GT.

Are S4/GT tubes interchangeable?
Do S4/GT tubes affect performance?

last question(I bet every GTS owner asked himself this question):
WTF were Porsche engineers thinking when they designed that costly tube-shaped pile of misery ?

thank you for your replies and time.

Francesco

RKD in OKC

Roger has some from Home Depot ducting that work well. They are plastic or ABS.

Vilhuer

Get four Mercedes plastic tubes with part number 117 094 03 82 and two 3" diameter pieces of black silicone hose. Looks like it could come from factory and lasts long time.

siscogts

3" is for inner diameter? Right?
Thank you for your suggestions...

Vilhuer

Or 76mm in Europe. MB tubes have different size ends. One end fits right over factory plastics at fan thing and filter cover same way as stock factory tube. Other end outside diameter it mm or two larger than 3" silicone hose inside diameter. Hose stays on nicely. Only thing needed is to make hole to two tubes for cambelt cover breather.

Gary Knox

The MB tubes are exactly the correct diameter, and fit perfectly. You just need to make a hole in each of the front pair to fit over the outlet from the front cam covers, and to cut a slight triangle out of the end of two, so they can be 'inserted' into the other two to form a continuous tube.

NoVector

I bought the MB tubes from Roger 4 years ago for my GTS and they're holding up great. If you do go that route, you'll need to save/reuse the rubber doughnut end pieces from your GTS tubes though. As good as they are, if someone ever sources an OEM looking tube that doesn't suck, I'm in for a pair--I'd like the engine to look stock.

MainePorsche

Good to know.
Thanks Gary.

ROG100

I sell the aftermarket Mercedes tubes (not HomeDepot 8>)) for $75 the pair. We use a silicone joining tube that is available in red, blue or black.

MainePorsche

That is even better to know.
Thanks Rog.

Rob Edwards

That's a great price, Roger, given that the '87-91 S4 intake tubes went completely ballistic in the fall of 2013 and are now what, $140 each?

Randy V

I just went with the standard tubes after my top end refresh.

No change in noise or performance over the GTS tubes. My understanding is that the insulation on the GTS tubes was intended to reduce intake air noise?

x98boardwell

Randy, what is your black hose running just above your oil fill but below the cross beam and runs from once side to the other disappearing underneath both valve covers?

Rob Edwards

Bryan, that's a factory 'late' GTS breather hose- connects the two front breather elbows to equalize crankcase pressure between the two heads.

Randy V

What Rob said.

The hose is connected to a vent port located on the top of each valve cover.