Hey y'all. My recently acquired 997.2 came with a decklid that had a wing and no airducts to the airbox. I wanted to go back to a standard decklid, so jumped on a good deal that I found that was complete with the retractable spoiler.

When I fitted the decklid, I realized I forgot that the 997.2 ducts for the intake are different, with the 997.1 version only having 1 different shaped duct on the left. Has anyone fitted a 997.1 decklid to a 997.2?

I figured I could just purchase 2 ducts and figure out a way to get them on the 997.1 lid. Unfortunately I'm finding that the right side duct is discontinued from Porsche. I'm assuming the sides are not interchangeable?

I could probably find a used right side duct from a breaker. Possibly cut a hole to fit the duct into?

I was also considering running an open Fabspeed intake, but I would think I still want ducts on both sides forcing cool air into the intake.

 

Look up Michael Cypher on Facebook. Think he's in the middle of doing a reproduction dict run if you want them, but if you go to a CAI, it will suck in plenty of air when the car is underway to not worry about the ducts.

I've never run ducts.on the TT rear spoiler on my wife's C2S and it's totally fine (been this way since 2013). Hers has the EVOMS intake and is a 997.1.

 

In addition to modifying the 997.1 decklid, you might also need to change the fan. They seem to have different part numbers. There is no problem running without the scoops, but you are sucking in hot air from the engine compartment, which has an impact on engine performance. It is hard for to find a 997.2 decklid and the 997.1s seem to be readily available. There are several 997.2 decklids with scoops on ebay right now.

 

This is really only a factor when the car is not underway, like on a dyno or in traffic. Once the car is moving at normal speeds there is far more outside air entering the engine bay than the little bit of heat being introduced by the engine. It's why the dyno results from CAI aren't representative of real world performance. Gasongasoff did a very smart test tracking Fuel Trims and MAF readings between his stock airbox and a CAI which showed that significantly higher MAF values were recorded with the CAI than with the stock airbox and the fuel trims were also maintained at 1.0000 which means that more fuel was being mixed with that additional air mass - there's no way that more fuel and more air being mixed together at the same AFR isn't making more power.

Here's the thread if you're interested in the real world analysis rather than a stationary dyno one - https://rennlist.com/forums/997-foru...surements.html

but here's the crux of it...

Cold Air Intake (Fabspeed) vs. Stock (MAF measurements inside)

There seems to be a lot of controversy about the CAI design. On the one hand, flow is supposed to be improved. On the other hand, people say that the design actually draws more hot air in. Is there a net performance benefit? One way to test this would be via a dyno. However, the only dyno results I've seen are manufacturer-conducted, and there has been a question about what conditions were used for each run. The dyno also does not really replicate real world air flow (i.e. when the car is being driven on the road).



To settle this matter myself, I purchased a Fabspeed CAI from an online retailer. I have no affiliation with Fabspeed or that retailer. I then took OBD tracings of MAF vs. RPM and compared them for Stock vs. CAI under similar conditions.



MAF is measured in grams of air per second and already factors in temperature and air density. By comparing MAF readings for the CAI vs. Stock airbox, assuming no change in AFR or engine efficiency at a given RPM (just by changing intake pipes, which there shouldn't be), and assuming no change in MAF accuracy between intakes, the % difference in MAF should = the % difference in HP. I realize this isn't a perfect assumption, but here it is anyway.

One caveat is that the Stock airbox filters were not new and had some visible dirt accumulation.



Vehicle: 997.2S PDK

Existing Mods: sharkwerks bypass, IPD plenum

Measurement: OBDII data (~19 samples/sec) via OBDLink LX, and OBDAutoDoctor software

Data Collected: includes MAF Mass Air Flow (grams/sec air) and RPM

Test: same freeway onramp (done safely, no traffic laws broken)

Repetitions: 4 consecutive runs with STOCK airbox, followed by 3 with Fabspeed CAI, done on same day, similar ambient temps



Results:

+2.5% to +4% in MAF between 4000-7500 RPM in 1st Gear

+5% in MAF between 4500-7000 RPM in 2nd Gear

+19HP (ballpark), assuming the relationships above and stock HP of 385 @ (+5%).

Unable to show a difference < 4000RPM in 1st Gear

 

Cool stuff - many thanks for posting!

 

Thanks for the responses. The knowledge and experience here never ceases to amaze me.

I think I'll pick up a Fabspeed CAI and see how it goes. Good call on looking at the fan, definitely want to make sure that will work.

Also thanks for the link to Cypher, I was not aware of his products. He's creating some awesome stuff!

 

If you are not planning on installing the ducts, you don't need to worry about the fan.

 

Huh? I think he's talking about the corrugated baffled that connect the decklid to the airbox inlets, not too side ducts. The barrels have to do with intake air and the fan has to do with cooling the engine. Can't see how those are related, or maybe I'm misunderstanding the original question.