Anyone installed a IDP plenum for a 99 cable throttle car? I have a modified exhaust without cats, and was hoping to gain a little torque below 4000 rpm. Is this plenum the answer?

 

No. Whatever claims IDP (or anyone else selling plenums or "cold air" intakes) makes on HP gain or torque gain is bogus. Don't drink the koolaid.

 

🤷‍♂️

 

You know that Jake Raby has mentioned positive benefits of the IPD plenum on increased bore engine builds.

 

Not on a 99 cable throttle car. Trust me, I asked him.

 

With my experience on multiple other Porsches, if you don't install a free-flowing exhaust with the increased volume plenum, it will not increase HP or torque. No point trying to force more air in if it is bottle-necked trying to get out. Hoping to hear from someone who has done both on a '99

 

For what it's worth, I wanted to do this with my FSI build and Jake said it is a waste on cable throttle Carreras.

 

I don't understand why the effects would be different on a cable throttle car. The concept is laminar flow. Improve laminar flow and you get improved volume (provided the exhaust doesn't block it up). The only way I can see it being different in a cable car is if some later piece of the intake system confounds any improvement in flow through the plenum.

 

I don't believe there is a bigger throttle body available for cable throttle cars. The GT3 throttle is e-gas and cannot be used. Without increasing the throttle body bore size I doubt the plenum does anything.

 

S-car-go made the largest throttle body for cable cars. Not near the size of a gt3.

 

Unless you need to move a lot more air the larger TB will act just like you giving it more throttle and let in the air quicker due to the larger exposed area at the same throttle position, giving you the feeling that it is more peppy than it was before.

 

With the 99 throttle cable cars (only the C2) we’ve learned that the gains are negligible, since we cannot tune the early DME to allow for the benefits to make a difference. We keep stock throttle bodies on these engines as well, and still make huge power gains over stock, without any of the issues that we’ve experienced with going larger on these cars, and spending the big money to do that.

What makes sense on a ‘99 C2 is our individual runner throttle bodies, but I only offer those on R Series engines above 4.0L

 

What makes the 99 DME so hard to tune compared to the others? Usually after this much time most computers seemed to be cracked. Not like it seems to make much of a difference but genuinely curious as to what makes the DME more difficult than the later ones.

 

99' C2 needs a chip soldered in, you cant just upload a MAP. As far as increasing any sort of power... The iPD plenum didn't really to anything exciting. The Underdrive pulley probably made the biggest difference for me. Also the RSS motor mounts made the car feel way more connected, I'd do those...

 

Any thoughts on installing 200 cell cats, crossovers or x type? Any power gain?