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ZZP 3800 Downpipe

The stock downpipe uses double-walled tubing with an inside diameter of just over two inches. Following the restrictive downpipe section, the stock unit subjects the exhaust gases to the choking effects of the catalytic converter. After the cat, it flattens out into a section dubbed the infamous "U-Bend," which is a section of pipe crushed into a "U" shape by GM in order to fit a rear o2 sensor. This section has less volume than the same length of 2" pipe, and approaches the volume of a 1.75" pipe with the rear o2 sensor in place! Our downpipe eliminates all of the aforementioned problems! Gains of over 15HP have been seen, along with a substantial drop in knock. Most users can drop a pulley size and/or eliminate 5-7 degrees of knock. This part can typically be installed in under an hour.

All downpipes are sold with a high flow catalytic converter. 

Our downpipes are made from high quality stainless steel. Even the flanges are stainless, which isn't something any other company offers. All welds are held to the strictest of quality control standards to ensure a professional finish. Our Weld quality is higher than any other downpipe manufacturer. When shopping around, ask if the downpipe is 100% stainless, ask if they use stainless and for a close up shot of their welds. Compare them to ZZP's, and it will be apparent why ZZP's downpipes are leaps and bounds ahead of the competition. They are guaranteed leak free and feature high quality welds, laser cut flanges and 16 gauge metal. We have test-fitted our bolt-in pipes on both stock and modified cars with perfect fitment. Our pipes even include the slight factory angle offset on the flange.


Interlock flex, sometimes called turbo flex is the best flex money can buy. Typically, the downpipes in our market use a single wall flex. This is durable but has a ribbed inside design that can disrupt airflow. This type of single wall flex is what people are running when you hear them complain about a whistling or ticking noise coming from their exhaust section. To remedy these issues, you can buy a double braided flex which has braided stainless on the inside, as well as outside, of the flex. The problem is that they fail very easy on supercharged cars. Interlock flex is the 3rd solution and while is costs more, it is the best possible option. It withstands the higher temperatures of boosted applications and provides a flat smooth surface for the exhaust gas to run over. 


Most common downpipe gaskets can be found here, exhaust manifold to downpipe inlet gasket, downpipe to factory catback/2.5" catback gasket.


04+ Grand Prix' (Series III cars) will require a style "B" o2 extension for the rear o2 sensor. 

Please use factory torque specs when installing our downpipes.


This downpipe is not compatible with any aftermarket headers, it is designed to fit the stock OEM rear manifold.

*Shipping charges are based on dimensional weight

Compatibility

This will only fit the 3800 v6 engine, does not fit LS4 V8 cars, if you have an LS4 powered car, you would want our "GXP" downpipe instead.

This fits on all the following cars:

  • 1997-08 Pontiac Grand Prix with 3800 Series II engine-Both Supercharged and Non-Supercharged cars
  • 2000-05 Monte Carlo 3800 3.8L Engine Only
  • 2000-05 Impala 3800 3.8L Engine Only
  • 1997-04 Regal 3800 3.8L Engine Only
  • 1998-99 Intrigue 3800 3.8L Engine Only

Our downpipes come with a high flow catalytic converter that is 48 state legal. Our catalytic converters will not pass California or New York state emissions. Please contact customerservice@zzperformance.com if you have any questions.

We are currently offering $100 in store credit to purchase your stock catalytic converter back from you. If you're interested, take a photo of your stock downpipe and email it to Henry@zzperformance.com. We will provide prepaid shipping labels for domestic (U.S.) shipments.

Customer Reviews
4.8 Based on 288 Reviews
5 ★
88% 
252
4 ★
9% 
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3 ★
3% 
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RK
01/17/2022
rich k.
United States United States

Downpipe 2.5

Unit received in good order Welds look good Installation will happen in the spring Warmer weather you understand It will give me time to purchase gaskets. Purchased a new 25 mm rear sway bar It also came in good shape and in a timely fashion (Of course I wouldn't mind if zzp sent me a set of gaskets for my downpipe)

AB
12/29/2021
Abren B.
United States United States

Solid purchase

This cat. Was a great purchase although my installation could have been better from my local shop

MS
12/13/2021
Matthew S.
United States United States

ZZP downpipe

This item fits perfectly and works with a new O2 sensor. High flow cat doesn’t make a difference in sound

DJ
12/03/2021
DeWayne J.
United States United States

3800 Downpipe 2.5

Great product Zzp. This fixed P0420 and gave ol gal a better sounding tone. The added Front powerlog really makes the car feel like an SS. 03 Ss Mc 3.8l

ZZPerformance ZZP 3800 Downpipe Review
KS
11/24/2021
King S.
United States United States

3.5” with 2.5” exit

Great quality piece to replace your old Catalytic Converter and let your 3800 breathe. Loud, Power, and looks is what you get out of this.