Actually I take that back...just got off the phone with Wrey @ BGB. He advised that they dont have a dyno in house and we would have to arrange for dyno time at a different shop at an extra cost (whole day event). Looks like I will be doing the remote pro-tune with him and then going to they dyno I originally went to and get final numbers. I will have to work with the dyno owner to see if there is a way to get an RPM signal-maybe now that I have race headers there will be more room to work under the car and pick up a signal from the coils. Yargk you may get your wish after all!!!

 

 

 

Some excellent work there! It's what I would do if I was remotely auto-mechanically inclined. I also don't like the design and material of the IPD and think it's a bit of a ripoff. A necessary evil if you want a bigger plenum.

That said, I'd do this happily on a 3.8L GT4 but the 3.4L isn't really suffering from the smaller TB I reckon. You can get a few more HP at the very top end with a bigger one but probably at some slight cost lower down due to lower air velocity. It's not a slam dunk upgrade like headers are.

It obviously doesn't hurt, but I don't think there is any measurable improvement to be had from insulating the plastic plenum. Plastic doesn't hold much heat and doesn't conduct it very well either, plus a plenum is not really built as a radiator so not all that much surface area for the air to heat up anyway. Plastic is better than metal but I think even the Alu one doesn't really suffer much from heat transfer.

 

I agree-I plan on monitoring my intake air temps once I get the car back together and see what the difference is vs the ambient (outside) air temp. Prior my IAT's were at least 20 degrees higher than the ambient temps once the car was warmed up for a bit. Sitting in traffic I saw as high as 35 degree differences-I am hoping it will keep them down a bit, or if not-take a bit longer for them to heat up. Does anyone know if the sensor in the middle of the plenum pictured below is the intake air temp sensor (the one with the red tab)?

 

Hi,
very interesting mod.
Is there any way of getting a IPD Y silicon pipe or any other Y pipe fitting the 981 inlets and the 82mm throttle body?

 

 

Hi, I assume a silicon pipe would be easier to install and less likely to leak. Imo there won't be any difference in air volume, speed or temperature.
Since there are hardly any used OEM Y-Pipes on the market here in Germany, pricewise there won't be much difference between new OEM and Silicone.

 

I agree-hopefully there may be a source for the silicone hoses that will sell just the hose.

Here are the pics I was talking about to show the possible differences in length just based on the pics-unfortunately I do not have one to compare and take measurements hand in hand so I may be wrong:



To me the stock seems like the throttle body is out further...may just be my mind playing tricks on me.


Here is another angle.

 

BTW-ran through a few miles with mine (around 100 or so) and all is well-no lights, strange issues, noises, etc. Performance seems as good as it was before if not slightly better (based on butt dyno). Part throttle intake sounds seem to be a bit more noticeable. Overall I am happy with it and cant wait for the protune to see the final numbers!!!

 

You could try giving Tom at TPC a call...they had the Y silicone hoses done for the GT3 plenum/TB upgrade that never happened. Maybe they are willing to sell them alone....

 

To the OP - did you consider simply mounting the entire intake tract from a 991S or even GT3? Should fit when turned around 180 deg. unless the mounting holes at the engine don't line up. Any insight would be helpful.

 

The GT3 wont work with 9A1 on the GT4......TPC was working on a adapter plate so it could be used but haven't seen any updates on this on a long time. The 911 X51 intake might work but that one is design to maximize the heads and cams that come with that package......

 

Thought about this but after speaking with a few shops they confirmed that it more than likely wont work-even if it did bolt up, the ports and sensor holes would be on the underside and would be too much to get them right. I was on the hunt for one to see for myself but the 981 plenum came up first so I gave it a shot.

 

BTW so far so good-no complaints, ran about 1/2 tank of gas through it with no ill effects. Induction sound seems a little more noticeable (could be tied to the freshly cleaned filters also). And there does not seem to be a loss in power-will know for sure if there were any gains once its dyno'd/pro-tuned. The only thing I did notice is that the car "idles down" quicker on a cold start than before. For example, it would take 45-60 seconds to idle down before and now it takes approx 30-45 seconds to idle down since the plenum/throttle body. It could be the ECU still needs to adapt to the new setup, but not sure. Either way, it does not seem to impact anything as far as I can tell.