997 T plenum - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Newsguy · 05-14-2020, 04:44 AM

A question for anyone who has installed the 997 plenum: how did you compensate for the large difference in diameter from the plenum outlet to the manifold? There' a 9mm step there and only a short distance to make it. I've ordered some step-down silicone hose but think it's going to be too long to work.

NewArt · 05-14-2020, 06:49 AM

Watch this video on my YouTube channel to see the simple solution at 3:15.
https://www.youtube.com/watch?v=QHAoJDKqxZE :dance:

Newsguy · 05-14-2020, 07:24 AM

Do you worry they'll fail being stretched that far?
I would love to have seen you fit the plenum in there with them attached! I'll bet it was fun.

NewArt · 05-14-2020, 07:58 AM

Quote:

Originally Posted by Newsguy

Do you worry they'll fail being stretched that far?
I would love to have seen you fit the plenum in there with them attached! I'll bet it was fun.

Not really a big problem. I ordered a set of silicone reducers but in the end I never used them since the factory ones fit nicely.

The original sleeves stretch easily if they're warm. They are quite strong.

78F350 · 05-14-2020, 08:09 AM

My 2000 was already modified when I bought it, but it has the silicone reducers.
Here's pics from when I was cleaning out the oil from a bad AOS:

hotdawwgman · 05-14-2020, 11:01 AM

Currently using the OEM ones as well. They fit. Should be good for a long time!

flmont · 05-14-2020, 04:26 PM

Is this Mod worth doing on a 2.7,.I would keep my air box,.MAF sensor Etc..and just change plenum and TB.?? or do you need to change the air tube and box aswell..??

Newsguy · 05-14-2020, 05:47 PM

If you search the other threads, I think you'll find the 987 airbox is critical to helping breathing.

78F350 · 05-18-2020, 07:48 PM

One more thought while the topic is up: The hose that goes from the AOS to the throttle body did not fit well with the 997 Plenum on my car. I took it off and used a heat-gun to soften it and flex it to a better fit. Is there a better hose to use or did anyone fabricate a good one?

NewArt · 05-19-2020, 05:47 AM

Quote:

Originally Posted by 78F350

One more thought while the topic is up: The hose that goes from the AOS to the throttle body did not fit well with the 997 Plenum on my car. I took it off and used a heat-gun to soften it and flex it to a better fit. Is there a better hose to use or did anyone fabricate a good one?

I did the same as you although if the hose is old, it might crack. I'm sure someone has made their own tube?

edc · 05-19-2020, 06:11 AM

Quote:

Originally Posted by flmont

Is this Mod worth doing on a 2.7,.I would keep my air box,.MAF sensor Etc..and just change plenum and TB.?? or do you need to change the air tube and box aswell..??

You can change the plenum and throttle body but will need to make up a run from the MAF to throttle body.

maytag · 05-19-2020, 10:40 AM

Quote:

Originally Posted by NewArt

I did the same as you although if the hose is old, it might crack. I'm sure someone has made their own tube?

I made my own from a clear wire- reinforced hose, with about a foot extra, looped down below the tb, so if it gets accumulation I can see it. Works REALLY, really well.
The non reinforced hose didn't work.... when it was warm it would collapse under vacuum.

Sent from my SM-G970U using Tapatalk

NewArt · 05-19-2020, 12:36 PM

Quote:

Originally Posted by maytag

I made my own from a clear wire- reinforced hose, with about a foot extra, looped down below the tb, so if it gets accumulation I can see it. Works REALLY, really well.
The non reinforced hose didn't work.... when it was warm it would collapse under vacuum.

Sent from my SM-G970U using Tapatalk

Yeah, didn't you make a post about that? Maybe a thread about catch-cans or something? Or was that someone else?