does anyone know what the diameter of the piping is? i wanna get some mufflers but i don't know the piping diameter. thanks.

2.25 basically. should also remove the resonators!

i think he's asking the OEM diameter.
~2in.

oh yea..i knew that. but 2.25 is recommended if u staying NA and stock ypipe according to jbrady.

cool. thanks for the info.

Quick Question.


Is my magnaflow 2.25 "Tru X-pipe" Doing more harm than good? Should I have a Y-pipe built?

ur xpipe is working fine, but jbrady (exhaust guru) said that the stock y pipe works extremely well and useless to replace it unless theres like a hole in it or something. not quoting him exactly on that but its on par with what he said...ill pm him and ask him to chime in.

The stock system is built with different tubing sizes. The primary pipes off the catalysts before the Y pipe are 50mm = 1.97". The center pipe after the Y is 60mm = 2.36". This splits with another Y into dual pipes under 2" in diameter. These pipes go into dual mufflers. Out of these two mufflers the pipe is under 2" and each feeds final mufflers.

So, it depends on which mufflers you are wanting to replace and also why? Looks? Sound? There is not much power to be gained without a full exhaust re-engineering and even then the gain potential without other changes is not great.

You can also simply remove the last mufflers. The center mufflers are plenty to quiet the car to reasonable levels. Simply pull off the last mufflers (easy to do) and see for yourself. If that is acceptable you can have a muffler shop bend up some 2" or 2.25" pipe to replace the mufflers and bring the exhaust exits to the final mufflers. This option is cheaper than buying mufflers, weighs less and performs as good as possible for replacing this section. You can add the stock tips or aftermarket tips for looks.

I am NOT a fan of the Magnaflow "true X pipe" for our cars.



The problem is that it is a 2.5" part that uses different sized ends for smaller pipe fitments. This leaves too large of a crossover area and does not function the way a properly sized part would for low end and mid RPM torque and power.

The GS400 and GS430 with 300hp have the SAME size Y pipe as the LS400s. The 1990-1994 LS400 is rated at 250hp but IMO actually only makes 230hp. I currently recommend the STOCK Y pipe on the GS cars with 70hp more. There is no good reason to upgrade the stock Y pipe on the LS400s until you are making more than 300hp (gaining more than 70hp). OR, if you go with S&S headers and those will require modifying the stock Y or building a new one. Even then I recommend 2.00" pipe.

one i move to new mexico, and get my car shipped there. i will need to start doing some exhaust mod on my LS.

Hey J Brady. What is your opinion on a "True Dual" setup. If the banks were not connected at all?