ZZP 3800 Downpipe


250 reviews

This variant is currently out of stock

ZZP 3800 Downpipe
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


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
ZZP 3800 Downpipe
ZZP 3800 Downpipe
Customer Reviews
4.9 Based on 250 Reviews
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United States United States
Catted downpipe 2.5”

The piece looked good from the get go. Its a quality piece with welds of excellent workmanship. I would have chosen the catted version even if the non catted version was available as it helps with air quality and doesn’t **** you with obnoxious fumes. This went on my ‘04 MCSS that has 105k miles. It was installed along with the full dynomax super turbo exhaust. Sounds beautiful with an aggressive low rumble. But at idle it is not too loud. I think I would consider using the zzp mid muffler/resonator/glass pack instead of the dynomax piece because the dynomax can be a little too much drone at lower speeds as you accelerate. The downpipe is worlds better than the oem piece with its restricted u-bend. My installer could not get the old o2 sensor out of the stock downpipe so we just installed a new one so be prepared if yours cannot be removed at install time. This downpipe definitely adds power that you can feel and removed the hesitation off idle during acceleration. Next up I want to get the zzp pcm update. Thank you ZZP for supporting an older 3800 platform. Much appreciated. Love this piece!

ZZPerformance ZZP 3800 Downpipe Review
Dan D.
United States United States
amazing quality

very easy install even on my rusty northwest Ohio car. Very high quality welds perfect fit no leak . Got rid of 5 degrees of kr. i couldn't be happier.

ZZPerformance ZZP 3800 Downpipe ReviewZZPerformance ZZP 3800 Downpipe Review
Jean R.
United States United States
Amazing Quality

Overall the installation was pretty straight forward. I went with the 3 inch with 2.5 exit since I have stock catback exhaust. I don't really hear any actual difference in exhaust note but I do feel better throttle response. Overall I would recommend this to anyone with a 3800 car in order to remove the nasty u bend.

ZZPerformance ZZP 3800 Downpipe ReviewZZPerformance ZZP 3800 Downpipe ReviewZZPerformance ZZP 3800 Downpipe Review
Jonathan I.
United States United States
2.5 downpipe

Buying experience was great, shipping was quick and I think was the quickest/easiest exhaust install I've ever done. Definitely satisfied.

Danny W.
United States United States
Zz downpipe order

Had a great experience using this item. Ashley was amazing at handling things. She is the best.