IPD Plenum

[paulstevens]

Hi All,

I am looking at installing the IPD Plenum as a replacement for the existing plastic plenum on my C2 (http://www.ipdplenums.com). I have trawled t'internet for info, and it does seem that the installation offers significant rear wheel horsepower gains (20-30bhp). I am also looking at installing the K&N cold air intake cone filter. I have emailed IPD about the mods and they think the IPD plenum and the K&N will work very well together. Unfortunately IPD will not sell to the public, only through dealers (Design911 @ £595).

Anyone had experience with these mods?

Cheers all.

Paul

 

[okellyt]

K & N induction system is very good []

IPD plenum - interesting, 20-30whp is a serious improvement, depending whether its peak or across the range, I'd like to see a before and after dyno using the same correction algorithm and %'s as well as the same dyno.

Basically a combination of upgrades (eg induction and remap or exhaust and remap) is normally required to get anything like 20-30whp on a normally aspirated engine. SO the plenum is either a bit of a miracle must have item for tuners or its a bit enthusiastic in its claims - no idea which. But a clue might be that when I spent time with Parr looking at how to improve my cars performance, there was no mention of plenum changes, they sold them, and these guys build/ modify racing Porches... However there can be a surprise - when we fitted the K&N to mine for example.


K&N

Noise = very good, really rorty and gurgly so adds some real character
HP gains = very good
Driveability = Mid to top end benefits, kicks hard from 4k revs so a little bit like a turbo, not a lt below 3k, 3-4k pulls, hard kick at 4k+ revs

Porscheshop sell a modified one its is even better (I think Parr do them as well).

Hope this helps


Hope this helps

 

[paulstevens]

Thanks for the reply. Good to hear that the K&N is a good choice.
Re: the IPD plenum, I have done some more research and have seen dyno charts demonstrating decent gains >20whp (all results are from the USA) all C2 charts made the same power as a C2S after the plenum install, but it does seem to be in the midrange with a reasonable gain up the top of the rev range.
I might talk to a local dyno shop nearby in Southampton to do a before and after, although I have heard that due to the way Porsche cars breathe, a dyno only offers the difference between before and after, but not an accurate power output.
Cheers
Paul

 

[okellyt]

Yep

dyno figures can be a bit of a shock, as you don't get the airflow while the car is stationary and the flat 6 is an air hungry engine

You never quite know whats going to work but I am surprised the plenum on tis won makes such a difference, in combinations with other items I get it as you then improving airflow in several areas.

So yes you get before and after comparisons if you go tot eh same dyno but you also get different values with different dyno's so you kind of have to stick with one and see the relative difference.

Let me know how you get on

 

[berty987]

I think you will only get 20rw Hp with both the plenum and a bigger throttle body. IPD dont normally indicate or publish a HP figure for fitting the plenum on its own , instead they quote an increased response and better power statement. If you are simply looking for bolt on performance , why not buy a Gt3 throttle body and plenum , it will be much cheaper and give almost identical gains. The main gain is from the increased size of the throttle body 82mm vs 75mm stock. Id be surprised if the 997 needed any better airflow through the filter so the k and N is likely to be more of a placebo effect than real gain. The throttle body upgrade will give gains both mid range right through to full revs , the Kand N is marginal at the top end only.