Jamie@dundonmotorsports

Thank you, was getting to it, just a lot going on!

ISPYA718

It was a fun watch. Interesting how much power gains these exhausts are getting. Long live the free market system. The competition and choice out there benefits the consumer

Ted@dundonmotorsports

Happy New Year gang!

We are excited to bring the latest update to our 718 GT4 project to you after a long, involuntary break from track driving. Our time frame was adjusted for us by a combination of things:

First off, our local track, the Ridge Motorsports park has been shut down for the last two months to receive the top coat of asphalt. Second, Washington state was hit with another round of lockdowns, which has made it tough to get out on the track. We hope you all are staying safe out there, and hope you enjoy the content! This was already linked above, but here it is again for good measure

Episode 4

We’ve had a few developments since our last update; we’ve finalized the specs and begun production of our Street Header system for the 718 GT4. Click to watch the video for more information on those. Spoiler alert: we were quite eager to try out the extra 30 horsepower on the race track! Take a look at the video of our best lap of the day here:

718 Fast Lap
Besides the sizable power increase, we were eager to hear how the system sounded on the track. The car definitely sounds better, but we know there’s room for improvement. The factory muffler splits the flow and ends up with a bit of rasp.

At Dundon, we’re not known for “good enough”, so Charles put on his mad scientist hat and fabbed up some pieces to try a different muffler. Our standard GT3 muffler fits the space nicely, but it doesn’t play well with the factory rear diffuser. That said, we tried it anyway! The noise improvement was awesome! With a tip to tail system the 718 has a proper GT Porsche sound. However, the factory diffuser produces great downforce, and driving the car without it was… interesting. We will be developing a muffler to work with the stock aerodynamics to achieve a more desirable sound and keep the downforce our friends in Weissach worked so hard to find.

Here's the crew swapping the muffler at lunch to get that downforce back!





In our last video, we were dialing in the Motion Control Suspension, and determined we needed to adjust the spring rate to give the car more grip on the track and make it more compliant on the street. The slightly softer springs combined with a slightly more aggressive alignment definitely got us closer to the mark. A few turns on the shocks and the car is planted, predictable and fun!

We’re of two minds on the resurfacing of the track. On one hand, the new surface is awesome, smooth and fast. On the other, we’ve been working hard to collect objective data to quantify the effects of our parts. The re-pave definitely muddies the waters, but we will forge ahead and do our best to be transparent. One good thing is that we had our 991.2 GT3RS or “Lab Rat” at the track, and we can use that data to serve as a “control vehicle,” as that car has not changed since the re-pave.

Check out a flying lap from our fully outfitted 991.2 GT3RS using the new Garmin Catalyst system:

GT3RS Fast Lap

The best lap we achieved with the 718 previously was a 1:49.0 on the old pavement. The best lap for the GT3RS on the same circuit, with the same pro driver with the same setup was a 1:44.9. We saw significant improvements with the 718 GT4 after getting it dialed in. The best lap on the new configuration was 1:45.39, while the GT3RS ran a new best of 1:42.3. The lap times are significantly faster, but the main take-away for us is that the delta between the two cars is shrinking (used to be 4 seconds apart, now only 3 seconds split the two). We have a sneaking suspicion that the car will go even faster with a few more suspension tweaks.

We forge ahead with our development on this project, with continued fine-tuning of the suspension, the development of an Inconel megaphone rear section and a Dundon Lifetime muffler, and the addition of a track-ready aero package to continue making the 991 GT3 RS owners nervous!


Sneak peek of the forthcoming Inconel megaphone rear section "Crack Pretzel":

CAlexio

I'm really surprised that the GT4 small diffuser actually makes a tangible stability/downforce difference and isn't just a marketing pretty piece. Is it because your car is lowered so it actually can work?... or do you think it has some effect on all the cars?

mjw930

Contrary to most manufacturers, every piece of aero placed on a Porsche GT group product is functional. This particular piece was developed as a result of the GT group being assigned the Speedster and Spyder projects. Both were the first open top cars for the modern GT group and they had to figure out a way to prevent lift without using a rear wing. Rear wings are much less effective in an open top street car since there is no consistent smooth flow of air over the top and across the rear boot and would seriously detract from the look both of these cars are trying to achieve. It was adapted to the GT4 production for build consistency but helps the 718 GT4 produce 20% more overall downforce then the 981 GT4 @ 124 mph (200 kmph).

BTW, there’s more going on underneath the car than just the diffuser.

https://newsroom.porsche.com/en/pres...rodynamik.html

.

lovetoturn

Removing the diffuser for basic driving will not likely affect much, but at full tilt on the track, absolutely. Subtle changes to the alignment, sway bars, tire size, and of course the aero package will definitely affect the way the car handles. When you raise the rear wing from like 5 degrees to 7 degrees, Porsche says you need to remove those small plastic pieces in the front to keep the car in balance. Those two little plastic pieces pale in comparison to the size of the rear diffuser tunnel. I bet the car is a real handful to drive at the track, at the limit, without that rear diffuser in place.

Ted@dundonmotorsports

It was definitely a handful. Much more confidence inspiring with the diffuser installed. That said, the car did sound way better with the other muffler :P

lovetoturn

Yes a complete and thorough mixing of the cylinder banks so it sounds like a wonderful Porsche flat-six.

WGBCGT4

what was the speed difference between the 2 cars headed into T1?

speed difference with the (4) after exhaust into T1, 2-3mph?

Tay101

Lookin good.

Where can we get those canards?

lhouck12

What point are you using to jack the rear up with? Assuming its on the engine block? If so did you use regular side jack point to access the rear to remove the panels and diffuser first then lower onto jack stands then place jack under the engine? Just curious on the process to get panels off. Quick jack I have blocks some of the panels making them difficult to remove.

Knutsm01

Is there going to be a version of the crack pretzel that goes with the OEM OAP’s? Or will this only work with the Dundon street header set up?

Ted@dundonmotorsports

@Tay101 Those are our own canards that are in development. Initial feelings were positive, but we will have the CFD analysis done in a week or two to determine if the shape and placement are ideal for the 718 platform. Stay tuned!

Ted@dundonmotorsports

PM'd.

user1029

Any improvements that can be made on the intake side of things for the 718 GT4? Bigger runners or plenum?