We just did an install with the stock rear muffler this winter.... For sort of a 360 degree sound skip to 11:10 in the second video. The headers are great.. We installed them by themselves and it was okay, but did throw a check engine light. Ultimately we bundled it with the Dundon airbox (kept the stock manifold and throttle body), and the dundon pro tune. It's really really good. They gave me a pretty steep discount on the tune for buying all three pieces together. For my money, you're really missing out if you don't pair it with the tune. With a little over 1000 miles on the setup we've experienced OEM levels of reliability and drivability. I also really enjoy having the stock center muffler. Our recent "autocross week" trip included about 700 miles of street driving in the GT3, and sometimes it was nice to relax with the valves closed.

 

I'm running the full Dundon setup with street headers and loud muffler on (2) 997.1 GT3s. One RS and one non RS. Thousands of miles between the two, never had a CEL or any other issue.

 

Next week is the install so I'm looking forward to it! I think paired with OEM rear box is perfect for my application.

 

Can we somehow get 2 members to do a highway pull or something? So we can see real life differences b/w the Dundon mods (intakes, tune, exhaust, headers) and a stock car.

I feel like the Dundon claim of 50+ hp with bolt ons is the Sasquatch of rennlist. Some say it’s true, some say it’s absolute bs. I’m skeptical to get that much power just from bolt ons and a tune. But would love to be proven wrong.

I’ll sponsor the event with pizza

 

I would really love to know how this works on a 996 gt3! We don't have all the ecu-controlled resonance flaps and exhaust valves that help maximize torque and power and different rpm levels. Hell, we don't even have varicoam plus! Wonder what it would be like pairing this power package on my 996 which is now running the SW 3.9 stuff (including cams). Hmmmmm.

 

I promise you wouldn't want to line up a stock 7.2 GT3 next to mine. The changes are transformitive. I don't have the dundon intake manifold, but I do have an RS ring and pinion. A stock GT3 feels like a dog compared to this setup. I have before dyno numbers, and I'll re dyno soon, if the place isn't out of business. Bxster lives near by, we could do some rolls, if it could be done without being a menace to society or unsafe.

 

F50nut can chime in here to confirm, but we did this a few weekends ago. His .1 RS full exhaust vs my .2 RS w the full D4 kit. Think we did a roll in 2nd and a roll in 3rd. IMO the difference seemed way more significant than when I’ve rolled a .1 in the past before the D4 kit. Seemed/looked like more than 50 horse to me.

 

Trust me, I want the claims to be true. I know its a lot of coin, but in the future I had always had in mind of doing a 4.0 build with AutoMetrics, but obviously the thought of permanently modifying the motor gives me a little pause. If I can achieve some great gains from the Dundon kit, then that would be a good middle ground for me. Get some substantial gains, but not at the sacrifice of opening up the motor. The 997.2 just needs a little bit more power and then I would be totally satisfied.

If you guys could do a little video, that would be awesome. I know a lot of people would appreciate it

 

Indeed. I’m in same situation.

Meanwhile, what was the result?

 

Not sure if there's a stock 3.8 near me to do this with, but I do have a video next to a 991.1 3RS which should suffice being that it's 4.0L and PDK lol. Its from a few weeks ago on my instagram handle @997gawd. Keep in mind - he jumps me AND there's a nasty pothole you can see/hear me avoid (I let off quickly for a sec). My buddy in the 991 was shocked when we slowed down.

 

Just watched the vid, surprising result. Would like to see it against a stock 3.8 or a built 4.1. Also just realized your 360CS is gated!

 

I was not exaggerating - and remember that's PDK! Having logged a good amount of seat time in a stock 997.2 4.0L I'm pretty confident in saying they'd be neck n neck - may even have it by a smidge up top. The 4.0 will always have more grunt down low and mid range - no replacement for displacement, but the car costs twice as much.

Yes the gated CS is magical lol. Not an EAG or Dr S conversion either. 18months of hunting down every required factory 360/430 part. Only thing I didn't realize (after buying a second hand OE clutch pedal for an arm and a leg) is that the finish on the CS gas and brake pedal is different than the standard cars so I've got a matching billet clutch pedal in the works.

 

I have Dundon v1 street heads and loud muffler on my 997.1 GT3 - 2k miles without triggering CEL. I guess YMMV?

 

It's starting to sound like the V1 headers had more success at no CEL. Mine are V2 and got a CEL nearly immediately.

 

I reached out to Dundon Tuesday and they said no CEL would be triggered. Who knows, maybe the issue is solved now. I will find out next week but based on their reputation I’m doubtful they would lie.