Pfadt headers installed.

[smokum]

Thanks GMTool. I wanted people to be able to hear what it sounds like.

[Deezee]

Sounds great! What all mods are on it? Any videos driving under load? Thanks for sharing!

[smokum]

Only mods on engine are l99 conversion and headers. Still has stock exhaust and airbox. Im installing adm race intake this week. Then getting it retuned. Ill get a couple vids driving and try to post them. Sounds pretty good from inside the car. Quiet driving normal but it really snarls when you get in it.

[smokum]

Oh, forgot the cam is a brian tooley stage 3 blower grind for future mods.

[62nalide]

Wow stock L99 exhaust with the big a $$ resonator? Sounds good too me! Maybe I don't need a catback after all!!!!

[Deezee]

Originally Posted by 62nalide

Wow stock L99 exhaust with the big a $$ resonator? Sounds good too me! Maybe I don't need a catback after all!!!!

Yea I had mine up on a lift doing some mods the other day and got a good look at the exhaust (LS3/NPP) and I have to say that after the cats, it seems to look pretty free flowing. Im interesed to see how it sounds when I install my tri ys this week. Im not sure an x pipe would even be worth it untill I go FI...

[MrGs SS]

I have these headers, had no fitment issues at all on my 2013. They sound great with my Corsa cat back, no drone at cruising speed. I will post a sound clip when I figure out how..lol

[SSeniorMoment]

Nice sounding exhaust video/audio. Went for a drive yesterday and drove the same area that I drove Friday with the stock exhaust manifolds. Not only are there noticeable gains in HP, but I'm also seeing better fuel mileage, I'll learn how much at my next fill up. To my surprise, in town I chirped 3rd gear short shifting ~37mph.

Looking forward to the CAI install. With the exhaust now free flowing, I'm wondering if a scoop is necessary on the CAI, thoughts?

[PfadtRacing]

Originally Posted by GMTool

Sounds great. Here is the video.

Man that sounds good! Thanks for taking the time to post the video!

[PfadtRacing]

Originally Posted by SSeniorMoment

Received the headers yesterday afternoon and installed them today. Pfadt did their R&D homework, nothing rubs and there aren't any hang down issues.





Once we figured out the firing order, it was a breeze;



Steering shaft not bolted yet;



I don't have dyno numbers, but acceleration gains were very noticeable comparing yesterday and today. This is a good upgrade, exhaust sound is different from the inside, even those standing close to me stated the exhaust sounded different at idle.

For me, this is a better upgrade than an exhaust only because there is a definite performance gain, factory exhaust cat back seems to flow well and there's a definite growl when working the engine.





After the big smile test drive;

Nice install! Is there a separate thread I can link to in the future? Lots of good pics here.

[texjsleigh]

On Sept 28, 2013 I installed these headers after ordering directly from Pfadt. What a great modification! I ordered with high flow cats.

Key take aways:
1. The sound is incredible and real seat of the pants noticeable in horsepower. 2. The throttle response is much better. With less resistance, the shifting is improved as the rpm doesn't die off as fast as well.
3. Workmanship with GTAW welding is superb.

Installation comments:
1. 20" lift clearance was plenty of room to install and a shorty flexible ratchet is highly recommended
2. Passenger side exhaust tip at rear stuck out 10mm further than driver side. I am not sure whether the long tube, cat, or factory piping created this situation. I removed cat and put in vise and used hack saw to cut off 10mm. The issue was the driver high flow cat and factory exhaust were matted up while passenger side had a gap. No issue now.
3. One spark plug rested on tube on driver side (used knife to cut corner of spark plug rubber shroud. No issue now.

Here is my feedback so far after 3500 miles.
1. I just had LMR in Houston perform a dyno tune to clear the check engine light from the O2 sensors downstream of the cats. The air to fuel ratio was high 13.5 and now at 12.5. I will have to comment on another thread, but WOW the car has come alive especially at low rpms (2-3K). With STD dyno graph (SAE J607) with a temperature of 43 F, 29.9 Hg pressure, and 59% humidity, the final pull was 432 HP and 432 ft-lbs at the rear wheel. Don't wait to get a tune like I did.
2. I have a drone at 2000-2250 rpm.
3. So much more fun to drive.
4. Improved gas mileage (average 1.0 MPG increase)

[Deezee]

Congrats on the install. I have about 4k on mine now and they are still just as amazing! Enjoy

[bwk1971]

Love these headers!

[SSeniorMoment]

Good to read another positive post on the Tri-Ys, I also have about 4k miles on mine, plus dyno numbers that confirm the butt dyno feeling. This pic shows the Tri-Y design along with weight savings compared to factory;



Driver's side clearance;



Passenger side;



Cars in the park dyno run, 10/12/13 @4600ft;



Only other bolt on is a CAI;



Now for the numbers and a few side notes;



The first pull showed a lot of torque down low and maintained 400ft/lbs to nearly 5000rpms.

I inadvertently paddled up from fourth gear on the third and final pull. I was surprised at how fast the speedometer hit ~150mph causing the engine computers to shut down.

371 whp seems decent w/o a tune and at altitude, still no check engine light. Good HP given that a T bucket with a very nice sounding SBC 350 was in the high 200s, a new Shelby GT 500 Mustang (rated 662hp/crank) pulled in the 570-580hp range.

I hope to have a VVT cam install before Baytown next May