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We tried a bunch of things out, and liked this as a stopping point until we get some more feedback from Cobb. We'll be doing this all again for the intake mods.
I had a few questions via phone and PM. The cost of the tune will be the cost of the Cobb AP and the cost of our Dundon Pro Tune. With the Pro Tune as we do more with it you will get free updates. Also when we make our final recommendations and changes for intake side modifications you will receive the updated tune for that as well. What we can't include are custom changes for modifications we haven't built tunes around at our facility.
To that end, here's the goods!
30 lbft wtq and 44whp gains at 7400rpm, GT4 Dundon Race Headers an Dundon Pro Tune
55 lbft wtq and 52 whp gains at 5000 rpm, GT4 Dundon Race Headers and Dundon Pro Tune
51 lbft wtq and 35whp gains at 3500 RPM, GT4 Dundon Race Headers and Dundon Pro Tune
377.1 whp at 6400rpm and 374 whp at 7400rpm, GT4 Dundon Race Headers and Dundon Pro Tune
30 lbft wtq and 36whp at 6400 rpm, GT4 Dundon Race Headers and Dundon Pro Tune
Peak Torque +24lbft from 288 lbft to 312 lbft at the wheels at 5700 rpm
Peak HP +36whp from 341 whp to 377 whp at 6400 rpm
Max Torque +55lbft from 241 lbft to 296 lbft at 5000 rpm
Max HP +52whp from 228 whp to 280whp at 5000rpm
We confirmed today that Rev 3 was the right choice (went back and retested a few other variants). Parts will be here end of this week and we will be able to get some pricing together from there.
We'll be track testing the Dundon Stage 2 GT4 at the Ridge this Friday (will be 90 degrees so good chance to do some torture testing and log the results!)
Pardon my stupidity, I am new to Porsche modding, but is this purely with the Dundon Race Headers and Tune with remainder being the standard PSE? This means that it keeps the valves for loud and quiet and mode using the button in the car?
Thank you, it's lots of fun to take cars and wring more performance out of them!!
Originally Posted by Charliekay
Pardon my stupidity, I am new to Porsche modding, but is this purely with the Dundon Race Headers and Tune with remainder being the standard PSE? This means that it keeps the valves for loud and quiet and mode using the button in the car?
No stupid questions at all! Short answer is yes! Take the stock headers out, install the race headers that bolt directly to the PSE. You keep the button and the quiet when you want it and the loud button when you want to make some friends!
Our catted system (not finished with development quite yet) will have a few options. A full kit that replaces the PSE, will still have valves as we believe strongly in the dual use of these fine machines, and a version that slip fits onto a trimmed version of the PSE.
Let us know if you have more questions and feel free to write direct to us via email!
Thank you, it's lots of fun to take cars and wring more performance out of them!!
No stupid questions at all! Short answer is yes! Take the stock headers out, install the race headers that bolt directly to the PSE. You keep the button and the quiet when you want it and the loud button when you want to make some friends!
Our catted system (not finished with development quite yet) will have a few options. A full kit that replaces the PSE, will still have valves as we believe strongly in the dual use of these fine machines, and a version that slip fits onto a trimmed version of the PSE.
Let us know if you have more questions and feel free to write direct to us via email!
Thanks Jamie.
How much louder than stock are your race headers? Much drone if any?
Your catted system with valves, would that operate using the button in the car or a separate remote?
How much louder than stock are your race headers? Much drone if any?
Your catted system with valves, would that operate using the button in the car or a separate remote?
Around town no drone as the PSE does a good job killing it. Race headers when putted around are quite tame. When you get on it there's a deeper more substantial presence to the car. Goes up through the rpms to a great wail as a Porsche should sound.
The valves would be operated by the factory button. Same as we did for our 991GT3/RS systems!
Around town no drone as the PSE does a good job killing it. Race headers when putted around are quite tame. When you get on it there's a deeper more substantial presence to the car. Goes up through the rpms to a great wail as a Porsche should sound.
The valves would be operated by the factory button. Same as we did for our 991GT3/RS systems!
Wow so much headroom for an NA car. Can't wait to get these. Quick question are the numbers provided with the valves closed or open and does it make a difference. Currently running straight pipes on my car and curious to see the how much worse it is then with the stock pse.
I disabled the valves so they're open all the time, and didn't take note of when the valves open when the PSE button is on, but I've read that it's map controlled in the 3-4K range.
It opens after 4K even if the PSE button is off.
You would want to pin the valves closed for tracks that have noise limits that the GT4 exceeds after 4K.
The valves are only useful to me if I wanted to quiet the car when it starts, otherwise coming off the gas aor shifting up lowers the noise.
With the valves disabled I've confirmed the one minute period of extra loudness at start is due to the ignition maps described in the Technik, and not due to the valves being open briefly as some have described.
My comments are for the NA ECU, I've read that ROW countries such as Australia have a different map that leaves the valves open under 3K.
Wow so much headroom for an NA car. Can't wait to get these. Quick question are the numbers provided with the valves closed or open and does it make a difference. Currently running straight pipes on my car and curious to see the how much worse it is then with the stock pse.
These runs are all with sport on and valves opening all the way. We have done a few runs with sport off and valves closed and it is a low end difference mainly below 4000. Some of the difference is from the change in the maps but there is a difference from the flaps being closed mostly around 2500rpm. I will see if I can find a graph to compare and post.
Originally Posted by d00d
I disabled the valves so they're open all the time, and didn't take note of when the valves open when the PSE button is on, but I've read that it's map controlled in the 3-4K range.
It opens after 4K even if the PSE button is off.
You would want to pin the valves closed for tracks that have noise limits that the GT4 exceeds after 4K.
The valves are only useful to me if I wanted to quiet the car when it starts, otherwise coming off the gas aor shifting up lowers the noise.
With the valves disabled I've confirmed the one minute period of extra loudness at start is due to the ignition maps described in the Technik, and not due to the valves being open briefly as some have described.
My comments are for the NA ECU, I've read that ROW countries such as Australia have a different map that leaves the valves open under 3K.
Cold startup changes everything. Intake Cams are at full advance and at high valve lift to hear the cats up fast. We have the ability to change all this just have not done so yet.
Row ecus do seem to be slightly different.
Also to note. The V3 headers have a different exhaust note than the rest of the others that we have tested. They are slightly quieter as well and sound better. Smoother note and a lot less rasp.
With the valves disabled I've confirmed the one minute period of extra loudness at start is due to the ignition maps described in the Technik, and not due to the valves being open briefly as some have described.
My comments are for the NA ECU, I've read that ROW countries such as Australia have a different map that leaves the valves open under 3K.
The reason for the valves open at startup is because they need vacuum from the engine to close....you don't have enough vacuum at startup hence the valves stay open. This also goes in hand that at WOT you have zero vacuum so harder to keep them closed and anyway you would want them open for max power. The ECU may control the valves after startup and across the rev range but I don't have info on that.....
Before I disconnected the solenoid, I know my NA ECU and vacuum caused the valves to quickly close within seconds at startup so that there was no perceptible loudness.
The rich mixture, ignition advance and higher lift occur for a longer period of about a minute with cold start, so I assume some can hear this difference, but incorrectly attribute it to the exhaust valves.
The reason for the valves open at startup is because they need vacuum from the engine to close....you don't have enough vacuum at startup hence the valves stay open. This also goes in hand that at WOT you have zero vacuum so harder to keep them closed and anyway you would want them open for max power. The ECU may control the valves after startup and across the rev range but I don't have info on that.....
Originally Posted by d00d
Before I disconnected the solenoid, I know my NA ECU and vacuum caused the valves to quickly close within seconds at startup so that there was no perceptible loudness.
The rich mixture, ignition advance and higher lift occur for a longer period of about a minute with cold start, so I assume some can hear this difference, but incorrectly attribute it to the exhaust valves.
__________________
2016 white/black GT4; https://rennlist.com/forums/gt4/9321...e-journal.html
2008 white/amaretto S8
997 and newer engines have a mechanical vacuum pump and no longer use manifold vacuum to "supply" vacuum to the solenoid valves for vacuum control. I have not physically checked the ecu programming in the gt4 to see if they are actually open the whole cold start process. The 991 gt3 is this way.
High valve lift full cam overlap helps heat the cats up faster for cold start emissions. Yes it is a lot louder but that is just a byproduct of having more fuel/air being burned.
If we get a chance we do want to mess with cold start up maps to quiet it down a bit. No cats on the car means no point for fast cat warm up maps
07-26-2016, 10:53 PM
GT4 Race Headers with Tune Update
