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Dundon catted system v2 is in process. We're waiting for some parts to arrive here in the next week. While we're waiting getting some work done at the shop.
Steel workbenches under constructions at Dundon Motorsports Headquarters!
The tuning on the 997.2RS took longer than we expected due to travel delays and some technical issues with overwriting the ECU after previous tunes by other tuners, so we'll have to wait until next month or so for the 991 Stage 2 tune and testing of the catted system.
We expect to have the next version of the Dundon 991 Catted system with optimized based on what we learned last time in the next few weeks.
Lots going on right now with the catted GT3 setup, the GT4 getting home and opening the shop!
The catted setup makes power, about 30whp over stock, but I am not happy with the overall curve compared to the RH setup so I want to do some revisions and dyno again to compare before I build a final system. This way you get the best, not just the first thing produced.
Once the new shop is setup, things will go much faster
few pics of the catted 991 system in progress, still hoping to hit the dyno friday.
Ah, so you've adopted the Supersprint design utilizing the space vacated by side mufflers. Smart move. Have you tried stepped diameter tubing as a means to deal with the mid-range issue? Also, what are you getting for weight saving over stock system.
Ah, so you've adopted the Supersprint design utilizing the space vacated by side mufflers. Smart move. Have you tried stepped diameter tubing as a means to deal with the mid-range issue? Also, what are you getting for weight saving over stock system.
I wouldnt say I have "adopted" that design, I tested a version that used the side muffler space, but it does not look like the supersprint setup at all. If you are asking if I have tried stepped headers then you really dont know my products
The Race header setup using the stock steel center muffler weighs about 1/2 of stock or a 43lb savings roughly, with a TI center its 11lbs lighter, so a 54lbs savings. I think thats correct, would have to confirm with Matt's thread.
The catted setup will weigh atleast 8-10lbs more just because of the cats. the problem is just trying to get everything to fit without altering the design of the headers too much, and killing power with the location of the cats. May have to do 2 more tests
If you are asking if I have tried stepped headers then you really dont know my products
Is that a yes?
Regarding Supersprint design, perhaps adopted is the wrong word but not unreasonable when you compare the respective solutions. I don't know any other exhaust manufacturer other than you and Supersprint utilizing the space created by removal of the side mufflers.
Short answer, yes the headers have a stepped design, this is something Charles has used in his designs since the beginning!
We didn't copy SS, the only way for you to fit more length (like a cat) and keep the tuned length of the headers is to use all of the available space. That space happens to be up into the side muffler area. We are working to fit the cat in there and leave it straight with similar header length, this will help on the midrange power loss and the bit of drone from the v1 setup.
What do you believe about the noise levels on the catted version?
I need to comply with euro rules on track...
The catted version should be similar to stock, or a car with side muffler deletes, as the car bypasses the side mufflers at higher load like on the track.
The cats will kill a few dB from our Race header kit and the rest is factory...
Yup! I replied as well... Thanks for sending it. Too bad it isn't the 300V Motul, just Xcess 8100.
Originally Posted by Alan C.
I've been using Motul 5w40 X-Cess with good results in my last 3 cars.
Originally Posted by GT3 KSA
Did you get my email with letter attached to it?
Originally Posted by GT3 KSA
Yeah they are thumbs down here. I was told if i get a letter from Porsche Germany approving the aftermarket product then it is fine just like the letter i got from Motul ... I guess i should contact Akra and start working on this
Originally Posted by 911_RS
You got a letter from Motul that the dealer can put it during their oil change?? I need that! Btw, did they approve you to use 300v 5-40?
Originally Posted by GT3 KSA
@Alan C - you got the letter as well right? I used Motul on my 911 50 anniversary and been using it on my daily driver BMW 435i Gran Coupe ever since i bought them. Once i traded the 50 for the GT3 it only made sense to continue using it.
Motul 300v is on the Porsche approved list of motor oils (which includes Mobile 1, the OEM fill here in the U.S.).
Regarding Supersprint design, perhaps adopted is the wrong word but not unreasonable when you compare the respective solutions. I don't know any other exhaust manufacturer other than you and Supersprint utilizing the space created by removal of the side mufflers.
Yeah the side area is the only way to get enough space to keep the cats and decent primary length.
Most, but not all, of my (our) headers are stepped. Most just once, some have 2 steps and some I build have none. Really depends on the testing done and involved and such.
Biggest issue is not cutting corners to save cost as most of the time that cuts performance.
The catted version should be similar to stock, or a car with side muffler deletes, as the car bypasses the side mufflers at higher load like on the track.
The cats will kill a few dB from our Race header kit and the rest is factory...
Have you done a test without cats?
How much louder will it be? I've had side muffler deletes and even now (it may be broken) I can't tell a difference between exhaust button on or off except at idle.
In my experience the OEM Ti won't survive as it is and even less chance with side muffler delete, so I'd find a strong quiet center muffler.
I don't know enough about how it all works, so maybe I should come by for an education about no cat OEM tune options..
How much louder will it be? I've had side muffler deletes and even now (it may be broken) I can't tell a difference between exhaust button on or off except at idle.
In my experience the OEM Ti won't survive as it is and even less chance with side muffler delete, so I'd find a strong quiet center muffler.
I don't know enough about how it all works, so maybe I should come by for an education about no cat OEM tune options..
We haven't done a dB test with the Race setup, have a dB tester just need to have it and my car at the track at the same time!
We're working on a solution for the OEM Ti muffler, Charles has some sheet Ti that we can reinforce the back of the muffler if necessary. So far 911_RS has pushed his RS the most and no issues thus far.
the 997.2 RS with a Ti muffler it did have some issues after 2 full days on the track. We swapped it out with a Steel and are repairing it now...
04-06-2016, 08:45 PM
