I looked into Cargraphic and chose Dundon instead based on their use of 321SS as opposed to 304SS and the build quality. I couldn't figure out which 304 Cargraphic is using. There are around 30 variations of 304.

 

why?

 

Jimmy, the air filters are really easy to swap. You have to go through the trunk and remove the vertical carpet pieces adjacent to the oil, & coolant fillers and once the carpet trim is removed, they are sitting right there, and easily accessible. Entire process probably takes around 15 minutes, and the hardest part is removing the carpet trim. Mark

 

Now that the car is adapted how does the upper rpm band feel.

 

You are correct. I was referring to the maximum peak at 7300 RPM. It appears there are 2 peaks in the HP curve (7300 RPM & 6500 RPM), and the one at the lower RPM has slightly higher peak, but for some reason Porsche never makes a mention of it in any of their literatures and they just refer to the HP at 7300 RPM. I suspect the car does produce close to 400 HP stock, but Porsche did not want to advertise this, not to upset the 911 owners, of having a Cayman than produces as much HP as 911 S.

Since Porsche did not advertise this peak, I was merely trying to focus on the one they did advertise claiming its peak is at 385 HP just to compare apples and apples and estimate the mechanical losses. So at that peak where Porsche claims 385 HP, the corresponding wheel HP is between 331 to 334 WHP. At that particular peak the headers upgrade resulted in a net +30 WHP, but my car gained +40 WHP in mid range which is more intriguing to me than the gains at higher RPM as you feel this readily while driving at normal pace & lower speeds. My biggest complaint about the GT4 compared to my GT3 and some of my other cars, the car feels anemic until RPM is above 5500 RPM, and that is finally fixed with these headers. During street driving, I tend to keep the RPM between 3K to 4K, and unfortunately if I needed more power I must down shift one or 2 gears to get to the power band, and that is no longer the case. I used to drive in 3rd gear mainly on the streets and occasionally 4th where now I am driving in 4th gear part of the time & 5th the rest of the time which to me is the biggest advantage of this upgrade and one that I can experience all the time. i can understand why people who drive the car with three headers immediately notice and rave about the power. It is truely usable power. Mark

 

It feels much more linear, smoother and more natural where before the power comes in as surges, so it felt artificial. This is how the car should have come from factory. i honestly feel the car would produce more power now on the Dyno when it is retested again. It would really surprise me if it did not. Even if there was no change in the ultimate maximum figures, it really would not matter much to me because my butt dyno is telling me a different story. Extremely happy with the results. The car is finally alive. Mark

 

I was able to get my car out for a short run today. I agree the mid range is a nice bump over the stock headers. Where I would drop to second I now leave it in third. Looking forward to driving AMPs and Mid-Ohio in the spring

 

As promised here is the link to some of the pictures & Videos. I am still loading more videos, but here is what I got so far.... Mark

https://www.icloud.com/sharedalbum/#B0Y5ON9t3tizAm

 

^^ What was the difference in whp between stock and Dundon system? It's hard t to tell from the video.

 

From memory I think It was 31 WHP at 7300 rpm & 40 to 45 WHP at various spots on the curve and especially in the midrange. But as I stated earlier the PCM was not adapted & car felt like it was detonating during the dyno runs and I believed we are going to see higher gains when I bring it back for retest in few days. I will post the videos of the new runs after the tests. Please note I opted against the tune and elected to remain stock. Mark

 

would love to hear it in person one of these days

 

It's worth the wait.

 

I'll be picking her up in an hour, will drive a bit as we have 50 degree weather today and post some impressions later today.

 

deleted...new thread started

 

Very quick impressions, didn't get on her too hard, roads still mostly wet. All in all, I'm very happy thus far, previous comments are spot on. No more dips in power, very linear delivery, sound is perfect for me, easy to module w/ the throttle with stock level cabin noise at cruising. No drone. PASM rides quite a bit more compliant as well with the DSC now, as well.

Will try and get her out for longer drives in next few days, weather permitting.