A Tuner told me Stock throttle body works better then 82mm? WTF? True?

Im not trying to beat a dead horse here. Ive read plenty on the IPD Plenum and GT3 82mm Throttle body . BUTT!!! I was talking to Softronic the other night and told the guy that I wanted to get a tune to go along with my IPD plenum and 82mm TB. He flat out told me to remove it because the few HP you do gain over 5500rpm, you lose even more at the bottom end.. Then he went on to explain it all and it all seemed to sound correct??? He told me if I was going to do anything that I should get the IPD plenum for the stock 74mm TB because the 82mm is way too big for that car as it slows down air velocity. So for shits and giggles i decided to put it back stock (no biggie cause its only an hour long mod). So now its back to stock with a K&N filter and thats it. Heres the kicker... After 150km of driving I really don't feel any difference.. -is the Plenum + 82mm TB a waste of money? or - is it a waste of money if thats the only mod you have? or -would it kick *** if I had the exhaust done and then get a tune. (which makes more sense to me) For the record, I bought the car with the intake upgrades already done.. Any thoughts?

He's not the only one, Fabspeed 's tuner told me something similar. A lot of topics on here have touched on the subject. Personally I am also on the side of the IPD plenum being a pointless and possibly counter-productive modification. Certainly unless specifically tuned for, it's more likely to cost you performance than gain any.

If the 3.4L DFI engine: For the 981 I would say that there is little to be had in terms of power since the 981 has dual intake and can take maximum use of the existing throttle body. Which is also why porsche had to limit the TP opening on the 981 , otherwise they would all make 340-ish HP regardless of boxster och cayman version. The 981 benefits greatly from a tune since it has all the conditions in place to get good gains (i.e it’s limited electronically from factory). Excluding GTS version which is the only ”unlocked” version. The 987.2 makes significant performance with the TB. Because it has a single intake, just like the 991 3.4DFI. And they are mechanically the same engine with the only difference being 74mm vs 82mm TB (which is why it says 991 on the plenum), The 987.2 make 330-ish hp (CR) while the base 991 makes 350. Only difference between them being the plenum/TB. Many, myself included, have proved this and dyno sheets exist. Just google, I would kinda agree it’s a dead house. The 987.2 can make little use of a tune since it has already full TB opening is CS, Boxster Black Ed or CR. I have made posts about this in the past too, with data logging to prove it. I might do some logging on my BS to see if it is fully opening or not since it is supposed to have ”only” 310HP. Then a tune might be worth it. If the 2.7L DFI engine: I would agree that adding a plenum or TB is unecessary regardless of 987/ 981 generation. A tune to make sure the TB plate is fully opening might be worth it (Boxsters and Caymans have slightly different power output, which is related to sw restriction). Regardless, you are not going to ”feel” the slight increase in HP/TQ that all these mods do. You are going to have to measure it either by timer (0-60 1/4 mile etc), datalog or dyno. My advice is to ask yourself why you want to do these mods in the first place. To get power? Get a different car. To improve sound? Then buy headers . To tinker? Then go for all! Best of luck. :cheers:

Yep pretty much my conclusion as well. I would save the 1300 bucks or so from buying that 'upgrade'.

This is an old story. Most everyone seems to think that every car needs more air so bigger intake bigger exhaust . All that maybe fine for more top end HP but typically at the expense of low and mid range HP. Top end HP might indeed help raise your top end speed (172mph), something you will never see on the track. What you need is mid range grunt and that won't happen with a bigger Plenum. Listen to your tuner, he/she knows what they are talking about. Good luck and have fun!

I have an IPD Competition Plenum, GT3 TB, Long Tube Street headers , race cats and Carnewal GT exhaust . While the installation is recent, the effect has been significant and immediate. Let me say this. I had the same conversation with a guy from Softronic and the outcome of that conversation was that Softronic is a company I will not do business with. The guy told me to expect a CEL and my PDK going in to Limp Mode. None of which has happened. This was not the conversation I expected. What I expected was someone who would suggest how their product might enhance the modifications I had chosen to make to my car. Instead, the guy essentially intimated that I was an idiot. The arrogance was off putting at the very least. What I have have is a car that feels quicker and no longer has that "lag" at 2300 rpm commonly found on Cayman R's. I made these changes to improve the power and exhaust note. I am eminently satisfied with the results and I do perceive a difference. As I said in another post, my PDK car with Sport Chrono , feels like it is in "Sport Mode' when I'm running in "normal" mode with "Sport Mode" now feeling more aggressive. I may be an idiot, but I'm a satisfied idiot.

At a recent DE my instructors friend who was also an instructor had a 987.2 with Softronic . Had the IPD 82mm combination but due to the heat sink of the aluminum IPD Plenum he kept having TB failures. Went back to stock with no loss in performance. He still had the stock header but was very quick around the course. The suspension was not stock and he was using racing tires . The stock heads of the 3.4 can only handle so much Air. I have Softronic on my 981S and couldn’t be happier. Noticeable improvement throughout the powerband.

I also read at another thread in another forum that at least in the 981 models adding the throttle body plenum gives the engine a lot more air but then the ECU does not know what to do with the extra air and throws an error. The tunes basically deal with the error by ignoring it or else a CEL light would be running all the time. Apparently though if you go and get your emissions tested they can potentially pick up that error and then one would not be able to pass their emissions tests!

I have heard the same thing. BUT. I am pretty sure Porsche used the 82mm body on the 991 3.4. The 981S used the smaller body. Despite being the same motor, the intake plenum on the 991 3.4 is different than the cayman . The exhaust has different routing, etc. These differences result in most 991 3.4 tunes generating a tiny bit more power than the 981s counterparts. (10 hp difference). Torque could be lower in the midrange. Don't know. Given the cost and effort to make these changes, I don't see how it is worth bothering with.

The 911 is a different car with a different layout. ALL 991 from the 3.4 up to the 3.8 GT3 all used the 82mm throttle and specific plenum and ALL 981 from 2.7 to 3.8 GT4 used the 74mm throttle and specific plenum which is not directly interchangeable with the 991 version due to plumbing differences. It seems like a simplification on Porsche's end more than anything else. Because they certainly did not need that 82mm thottle to make 350hp with the 3.4. Even the GT4 seems barely restricted by the smaller throttle in the end. I will say that if the 991 plenum was a simple drop in I would consider it. I think it's better than the IPD version, it's just that you need one of those bloody things if you want the bigger throttle body.

The point is that you would get the exact same performance you have now with all the same mods minus the plenum/TB. All of us that didn't do the plenum have the exact same experience that you described above. This particular mod has been around for years through multiple models and no one has ever produced any dyno results that demonstrate there is anything worthwhile to be gained from it. It's the headers and tune you are feeling and the dyno can easily demonstrate this

I may just leave it stock as I feel zero difference with the 82mm off. Tune and exhaust it is then

yes well another day in the books and I can tell you that I don't need a dyno to tell me that the 82mm TB and comp plenum makes zero improvement to the car.. If anything the car has gotten better on the bottom end with the stock setup, which makes sense because there should be a little bit more air velocity.. My friend has a Z06 with a 7L and his TB is only 90mm... Makes it seem even more pointless to put a 82mm on a 3.4 flat 6... I can see the engine being held back because of 4 cats but not a 74mm TB. And remember, I bought the car with the 82mm on it, so I had no idea what it felt like without it. and just too add. This is the only porsche I've ever driven so I didn't even have another one to compare it too. Even still I do not feel any difference with the 82mm taken off, except maybe a bit more bottom end and I can only feel that going up a hill at cruising speeds. Im sold on the fact that its a waste of money but to each their own

If anybody needs all the parts to put there car back to stock plenum and TB I have the parts. I bought them thinking I might use a company called maxbore to bore out the stock TB 3-4 mm. But have never taken the time to do it.

I have not had any "tune" performed on my car. It's still running off the factory ECU calibrations. Neither do I have a problem being perceived as an idiot for my choices. I'm happy with my car and how it performs. I guess with Fabspeed as a Planet-9 sponsor selling IPD Plenums and GT3 throttle bodies, the site administration is not prepared to take a position and force this sponsor to put an end to the IPD Plenum "scam" so many are convinced is being perpetuated. Perhaps Fabspeed would like to join the conversation and explain why they still sell this product if the consensus seems to be that it is essentially fraudulent.

I feel as though if you go back to the stock plenum and Tb that you will notice very little difference, if any... There is plenty of room in the stock intake to move the air needed for this engine. No doubt your gains are more significant with the other mods you have but not 1500 to 2gs worth though.. But hey, its your car and your money so go for gold