twospyders

I previously did the following DUNDON Exhaust modification on my manual 2018 GT3 (which I love ~12k):

-991.2 GT3 Long Tube Street Header Exhaust System, 991GT3-RS-LT-Catted Full System

-GT3 Lifetime Center Muffler, Black (Loud) 991

I am now considering upgrading to a 93mm plenum throttle body and air filter box.

Per DUNDON...

“Help your 991.2 GT3 BREATHE!!!

We found in our exhaust development and testing of the 991.2 GT3 and RS that they are intake limited both through the factory airfilter box and throught the 82mm Throttle body. A bit of history. The Bosch 82mm Throttle body is the largest Bosch makes and was used as far back as the 996 GT3 which made 380hp. The Air filter box used on the 991.2 GT3 and the 991.2 GT3RS originally showed up on the 2013 991 Carrera S which makes 350hp. Your 991.2 GT3 is rated at 500hp, so you can see just from these numbers that the intake side of things is a constriction.

In our testing we found the the stock airbox to be about a 0.2-0.3psi pressure loss and the 82mm throttle body to be about 0.3-0.4psi of pressure loss. Naturally aspirated engines make power from the force of the atmosphere pushing air into the engine, so every 0.1 psi helps! Our combo of 93mm Throttle Body and Dual Cone Airbox reduces the losses to under 0.1psi.

Dual Cone Airbox for 991.2 GT3

Stock Filter Area :1.77 ft2

Reverse Dual Cone Filter Area: 4.96 ft2

280% more than stock.

More filter area means slower air speeds through the filters and less pressure drop across the filter element

93mm Throttle Body has 28.6% more area than the 82mm throttle body.”

It’s my understanding that this upgrade improves the performance in the upper revs. Is this worth the $8k+ cost? Opinions? Has anyone done this?

Johnny Five

Lots of guys running them and I’ve seen only positive reviews. Impressive dyno results per Dundon. I bought street headers, airbox, plenum, throttle body when they first came out. Parts are still in my garage I need to find some time to install soon. Will report back.

Drifting

Good question. My impression has been that of the two options, installing the Dundon headers provides the most bang for the buck because while you’re dropping 40lbs from the car removing the side mufflers, you’re also adding a lot of low end torque (which the car particularly needs), and a modest amount of high end torque (average of about 6-8lbs in higher range, basically .2 RS torque in higher ranges.

Adding a few additional ft lbs more torque in higher ranges with the airbox/plenum sounds nice, but 8K is a lot of money for that.

Would nice to hear from someone who tried both products back to back?
Headers alone, and then headers + airbox/plenum.

bogey1

subscribed. I just did the street headers / black center. I held off on the plenum/air box thinking it may void my CPO warranty with the tune.

Jerrym

Losing 40lbs is quite a bit.. but im like 200lbs post-marriage versus 150lbs pre-marriage. need to hit the gym..

On a side note: I've been looking at the GMG Headers.. Has anyone compared them with the Dundon ones?

AllAboutThatP

Tune is not required with the plenum/air box. I have the full package on mine with no tune.

bogey1

Good to know. From what I understood, to get the full potential of the set-up a tune was required. This thread probably cost me another $8,000 !

Johnny Five

I bought it for the purple line. Green is stock Orange is headers and side delete Purple is the full kit with intake and throttle body. Yes please.

XrussianX

^^^^^^^
That is some sexy hardware

joejenie

I did the whole Dundon deal with full exhaust (loud muffler), plenum and airbox. Been running it for 2-3 months. Love it and would do it again. Changed the car. It is very noticable. YOLO.

WantA997

I had GMG headers on my 997.2 GT3. Was a nice upgrade, but nothing to write home about.

I have Dundon race headers on my 991.1 GT3RS. Fully transformed the car. Hands down the best money I've ever spent.

Power. Noise. What more can you ask for?

FourT6and2

I'd like to know the results of just doing the intake/plenum/throttle body, but with stock exhaust.

Drifting

I second that request

Jamie@dundonmotorsports

We’ll add it to the list and look at this with our intake runner development. Typically you need to couple the suction wave from the exhaust and the resulting large differential pressure between the exhaust side suction and the plenum side manifold pressure to get fresh air charged into the cylinder. When you take one side away the effect of the other is diminished.

That said we do still see sub atmospheric pressure in the plenum with the stock exhaust and stock TB.

goldberg

I am considering buying this Airbox.
I already have full Akrapovic Titanium system (headers, high flow cats, side deletes & muffler box)
Seen as though my current system isnt DUNON could i still expect similar results?
And do Dundon ever do "sales" % off.

Thanks