Intake and Idle performance issues.

[Carboy_GT]

Hey all, I'm currently considering swapping the stock air box for a rerouted aftermarket solution. The reasoning is I'm missing the small cold air intake tube (Circled in blue) and on eBay, the cost is $75-ish for a new one. On top of that my current airbox isn't in the best condition either so I'd also be replacing that as well ($150+ from what I've seen). My S is also suffering from a high/surging idle at about 1200rpm-1000rpm up and down intermittently, blipping the throttle can bring it down to 900-1000rpm then it'll randomly go back up to 1200. (Sometimes whenever I come off the throttle, revs drop too low and the engine dies too) so maybe a new intake to help by not contributing to it, I don't know.

944S intake adjustment.jpg (219.63 KiB) Viewed 3960 times

Pros:
-Save a little money (LOL can we ever?)
-Easier to maintain the engine without a big airbox.
-Possible power bump? (Probably nothing noticeable)

Cons:
-Maybe less performance (Depending on if I can get it to a cool spot)

Pics aren't mine but are what I'm thinking about doing.

[Zirconocene]

Have you smoke tested things? It sounds like you have a leak somewhere.

I'm not trying to discourage you with what you want to do but this is something where a little bit of creative patching might solve some problems with the parts you have and get your engine working right.

Good luck

[Bergerac]

Check your idle control valve is good.

Or just buy the Megasquirt pnp and delete everything before the throttle body.

PXL_20230717_083348459.jpg (1.68 MiB) Viewed 3908 times

[SE_944ER]

Hey!

I'm not sure whether the issue that I face is similar and not sure about the ICV as well. The problem is occasionally the car revs up b itself and after a few moments, it gets back to normal driving. Not sure what could be the reason. It happens at idle as well as while driving.
Any suggestion on where to start looking? Mine is a '87 16V.

[Carboy_GT]

Hey!

I'm not sure whether the issue that I face is similar and not sure about the ICV as well. The problem is occasionally the car revs up b itself and after a few moments, it gets back to normal driving. Not sure what could be the reason. It happens at idle as well as while driving.
Any suggestion on where to start looking? Mine is a '87 16V.

After I did a smoke test, my AOS seals were leaking, I had a hunch it was that since I had oil in the black intake pipe. Currently in the process of disassembling my intake to replace all the O-rings associated with it.

[sourcreamfries]

Tbh I tried the aftermarket intake route on my old porsche and ended up going back to stock. Might not be worth the hassle unless you really need to.