I know the LM I can be a bit much for some.
So SLP must have had a lot of guys wanting them to tame it down.

I just got a LM II muffler for testing, & was surprised to find that it is
restricted inside. A 2.25" pipe is a little 'loose' when sticking it in the muffler, so I'm guessing the inside diameter is at what the inside diameter of a 2.5" pipe is, or approx: 2.37".

So that's why they made the new LM, a 'modular' design, so you can switch out the LM II muffler when you what to make some power at the track. Or is it a 'marketing' move, to package the system in a smaller box ?

SLP Quote on the LM II muffler:
A bit milder without sacrificing that legendary SLP quality & power.
A little quiter than the original LM I.

Ok exhaust flow gurus... Will this perforated 2.5" pipe inside a 14" long, 4" diameter bullet muffler case, cause a HP loss ?? Or does SLP know their ****.

Has anyone tested both LM I & LM II at the track to see if there's a power loss ??

I have a 3" system on a 12.9x @ 107.xx car. I'll be testing this in the rear as a 'tailpipe', in my system. So it will be easy to make a few runs with it in place. Then a few more runs with it removed.

 

IMO, there would to many variables to test if a LM1 or LM2 would slow you down. Variables such as 60 ft, shifting, traction, etc.