bronson7

Very interesting to see how Porsche responds to warranty in different counties. Why is this?

Macca

I understand your skepticism. I felt the same way. I emailed 4 parties who had received and fitted the headers by PM to ask them their genuine views on the DMS headers. Im well enough known around here so I asked for it straight. One party is personally known to be and much regarded (Australian 991 RS owner). The others were from the middle east, Asia and USA. Two parties had independently dyno'd their cars with the headers before and after and produced traces (and in one case 1/4 mile before and after time slips from teh drags although im not sure how empirical that is) that were equal or in excess of the claims made by Dundon for these headers. I spoke many times to Jamie, asking questions and requesting plots from their dyno. The modern DFI cars have ECUs with torque limiters that are focused around emissions. They are sensitive to many variables. It would seem that removing the cat and working with resonance tuning (with the equal length and considerably longer header tract) its possible to improve exhaust side scavenging and thus cylinder fill efficiency during the combustion cycle. It would appear the factory ECU still leaves a little power on the table in favor of meeting Euro 5/6 standards. I dont know what gains my car has made, perhaps only the 30-35 bhp but it certainly has made some gains as I have a pretty well calibrated bum for this car after almost 3 years, 15,000 miles, 20 track days and three engines.

However, like I said I will try these on the track and see if my lap times improve. Currently on my local track Im fairly consistent - here are my 16 best laps from a half day track session at my local track on 30 March, the last time I was at the track with the car (the car was 100% stock including pads, rotors, tyres and exhaust - with the exception of the DSC suspension module and SRF brake fluid). It is the quickest car in our club of 70 x Porsches (around 35 attended this day including 3-4 x 991 GT3 & 1 x GT4). We hire track privately with open pitlane so very little traffic.

Im pretty good with car set up and have a pretty good "bum" for testing Im told. I think when Im next out at the this track dependent on barometric pressure, humidity and temperature I should hopefully run quicker. The only changes I have made to my car is the DMS (and some RT RE10 pads). Of course tyre condition is paramount too and the laps below were run on fresh MPSC2. But I have alot of traces from this track in the GT3 in stock trim so should beable to know better once Im out there again. Unfortunately I do not live in teh same country as the car and tracks so I tend to do concentrated track work over a 2-4 week period 2-3 x a year usually in the warmer months...

Macca

P.S. I run maybe only 40-50 laps that day. You can see 16 of them within 0.5s variance. Also I run 35 of those laps that day within 1s variance. This includes 2-3x back markers and some other traffic...ambient temperature was 24C or 75F. My telemetrics can tell me barometric pressure on the day and I also take track temp and wind speed as a 30kmph wind down the front straight will reduce vMax by 2-3 kmph in the 991 GT3 I have found...

qbix

Great! That would do the trick. Real world results

I think that is even a better angle than comparing stock vs DMS. One Gt3 is not equal to another GT3 car.
As an example my friend is racing with me same car but no roll cage, has carbon ceramic brakes and to my eye he weights 10-12kg less than me. That gives 60kg less total weight including 20kg less unsprung weight. Our cars pull out of corners exactly the same way...

Again thanks for the review and looking forward to check your track results!

kaboobie

Hi Macca,

I hope you don't mind me asking some questions. Is the above statement resemble drone noise between 2000-2500rpm ? Does it happen in normal driving mode when no button is pressed ?

Also how do you like your DSC ? Is there a big difference ? I'm also thinking of getting one.

Thanks

Jamie@dundonmotorsports

Macca's commenting with the valves open, drone/resonance is killed by using the long path of the muffler with the valves closed...

Jamie@dundonmotorsports

Thanks for the review Mark! We're happy that you're happy!

Jamie@dundonmotorsports

Here's the pure power equivalent. 1/4 mile drag time slips, same car same driver

Left is Dundon Race, Right is center muffler bypass... The ET's are a bit of driver skill, the trap speeds tell the tale...

TRAKCAR

I visited Dundon in Seattle and drove Jamie's GT3.
It's a great setup, sounds great, gets you HP and you lose 40lbs.

I haven't gotten a ride in an RS yet, but I'm stalking Bill who has it on his RS here in South Florida..

cmanquat

Yes, very strange but not funny here in France...

CAlexio

Are your warranties also shorter in Europe?

cmanquat

Under PORSCHE Approved warranty, nothing can not be changed to replace oem, including brakes, exhaust, suspension, ...

Different in the US ?

Macca

Yes. As Jamie is saying. Only in loud mode at 2500 does that happen.

As the sound is the same both mode from 3800 and as in both modes this exhaust makes the same power - I really see no need to use loud mode really unless going for fast back road weekend drive. Even on the track I am never below 3800 as you can see on the telemetry X data.

Macca

Local law over riding warranty rules. Why should fitting non standard pads affect the warranty when your GT4 manual transmission dies for example? That makes no sense. Manufacturers in our part of the world cannot contract out of the local "fair trading" and "consumer protection" laws regardless what they write in their policies.

CAlexio

Well put, although I was also referring to the length in years/mileage of the warranty.. I thought in Europe it was shorter than the 4yr/50,000 miles we have in US? I know for Bmw it is much shorter