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Tomei Expreme Downpipe Big Mouth ( Part Number:TOM 433001)

Tomei Expreme Downpipe Big Mouth

Part #: TOM 433001
MSRP: This Item is no longer available.



Brand: Tomei
Includes Catalytic Converter: No
Installation Hardware Included: Yes
Mouth Design: Bellmouth
Piping Coating: No
Piping Flex Joint: Yes
Piping ID: 3.00in
Piping Material: 304 Stainless Steel
Piping Taper: No

Mfgr. Warranty: No Warranty
Condition: New Product
Return Policy:

RallySport Guarantee - 30 Days

Items that are covered under the RallySport Guarantee offer a 30 day no questions asked return policy.

RallySport Guarantee items may be returned within 30 days of the original invoice date and must include all the original parts and contents for a refund.

The RallySport Guarantee does not apply to products that have been modified, damaged, misused or abused. All returns require an RMA (Return Merchandise Authorization) Number, and freight charges are strictly non-refundable. For more information regarding our freight refund policy, please refer to our return policy page found HERE.
RallySport Guarantee


After testing a variety of shapes and pipe diameters at the Tomei R&D Lab, they found the optimum tuning point for the best performance balance. This design will extract the full capabilities from the EVO X 4B11 engine. The design also retains the original layout to help with the ease of installation and compatibility with other exhaust parts.


Verified Purchase

Perfect Quality/ Easy Install
travisrgs 2 years ago
I recently decided to do a full turbo back exhaust on my Evo. My first impressions on this downpipe was how high quality the pipe looked and felt, as well as the high quality welds used throughout. It also came with every gasket needed, as well as a much easier install with the flex joint and two piece design. If deciding between this and the AMS downpipe, I would highly recommend the Tomei downpipe for identical high quality, performance, and a lower price point.

LogJammin 3 years ago
Just buy it. You won't regret it!

Great product
mkivjosh49698 3 years ago
Love the sound of my car, and the car definitely feels quicker since installed. It was a PITA to get on but that's just the 4b11 for you. Great product. Would buy again.
Verified Purchase

love it !
AaronA65 4 years ago
i now have the full tomei system and all i gotta say is that i love the sound, does make a HUGE difference with just a straight pipe
Verified Purchase

Amazing Exhaust System
Waters910 4 years ago
So I have the full exhaust system from down pipe to catback and it sounds amazing and is a beautiful looking exhaust. The figment on the evo x is great. No issues with clearance on my h&r lowering springs. Very aggressive tone. Cabin noise is low when cruising. Cold start 40 below is loud for about 4-5 min. 50 and above loud for about a min. Idle is quiet but the low tone can be heard for about 50ft. Nice! Super lightweight and easy to install. My artisan raceback was heavy and ugly after use. I installed this exhaust in fall of 2013. Still clean and luckily haven't scrapped the muffler. Great buy. Hope this helps.

  • Q: Requirements.  july.relatores 4 months ago


    I'm about to buy the Tomei Expreme Ti Titanium Catback Exhaust for my 2012 evo x mr and was wondering if I need the Tomei Expreme Downpipe Big Mouth to get the full experience of the exhaust itself. Also, if I do buy both, which I plan to regardless, would my check engine light come on? (my evo x mr stock btw)

    • A: To gain the most power out of your exhaust we do recommend going with a downpipe. Your check engine light will be on, to get rid of that we recommend your car tuned for a downpipe.

      Luis L. 4 months ago
  • Q: Going full turboback  Djtevox 1 year ago


    So I recently installed the hks hi-power cat back on my 2014 evo gsr and was think about going full turbo back. Would the tomei downpipe and Cobb catted test pipe be a good fit with the hks catback?

    • A: You should have no problem installing those 3 components together as they should all be OEM replacements.

      Connor M. 1 year ago
  • Q: material question  Sriracha303 2 years ago


    is this titanium like the rest of the expreme pieces?

    • A: No, it is made from 304 Stainless Steel.

      Josh P. 2 years ago
  • Q:   steven.arteaga70648 3 years ago


    Will this throw on the check engine light ?

    • A: This product will require a tune and without a proper tune may throw a check engine light.

      Nick S. 3 years ago
  • Q: 2015 Mitsubishi EVO X GSR Fitment  ericlyh 3 years ago


    Doe it fit with 2015 Mitsubishi EVO X GSR? Will it bolts up to the factory catalytic converter?

    • A: We have not had the opportunity to test on the 2015 models but it is likely since nothing has changed between years. This is designed to bolt up to factory length exhaust systems.

      Nick S. 3 years ago