Originally Posted by Hydrazine

The sound of the Stillen Muffler was driving me nuts so I cut it off and put on a pair of Magnaflow 2.5" stainless straight through 14"x8" oval offset mufflers. (Part # 14211) These Magnaflows are typically used on the Mustang Cobras so flow restriction is not an issue. The sound is clearly quieter, milder and smoother. There is also much less back pressure than the Stillen muffler had.

WOT, 4th gear @ redline, the Stillen muffler produced 2.8 psid just upstream of the muffler inlet.

WOT, 4th gear @ redline, the Magnaflow mufflers produced 0.19 psid upstream of the muffler inlet. A big improvement.

Less noise and less back pressure with the Magnaflows... Who would have though less noise and better performance could go together?

BTW, the Stillen tips are really nice. I cut them off and welded them onto the Magnaflows. The Stillen muffler went into the trash.

For specific muffler details see:
MAGNAFLOW 14211

I did a lot of research on the muffler and found a really good price. $75 each.

Tony

Originally Posted by Xman

Tony,

This is a great find! I think if I go for the Cats I'll seriously consider it. For now the new Stillen Catback hasn't gotten on my nerves yet.

Originally Posted by Xman

The new Stillen sound is great. But if I load the car up with the fam and luggage I predict nervous breakdown after a long vacation drive (lol). What's most impressive to me is your pressure data.

Originally Posted by GeoFX

Been lurking here for a few months and decided to join in...

Here's a pic of my recently completed 2.25" custom true-dual exhaust on my Infiniti FX35 (same engine as the G35). Specs are:

2- 6" round MagnaFlow mufflers
2 - 4" round MagnaFlow mufflers (used as resonators)
MagnaFlow Tru-X crossover
Crush-bent aluminized steel tubing

Sound is an improvement over stock. However, I needed to put in the resonators due to some head-splitting droning at 1800-2000K rpms. Without the resonators I felt improvement in performance but that went away after the resonators were put in... I really want to get rid of the resonators but don't want the droning to come back...any advice?

Thinking now about upgrading to mandrel-bent tubing, especially in the front.





Any advice would be appreciated.

Originally Posted by Hydrazine

Wow! Looks like you did a really good job there. Almost looks like a Injen exhaust system.

What sort of performance differences did you note when you put in/take out the resonators? Is the difference obvious? Dynos?

If you can confirm the performance difference, try moving the resonators away from the x pipe and closer to the mufflers.

You can also try using much larger oval mufflers.

Tony

Originally Posted by ryanwiggum

how much did you spend?

Originally Posted by GeoFX

Thanks. The performance differences were based on Gtech 0-60 times between my AWD FX (before and after exhaust) and a stock RWD FX35. There was roughly a .60 sec difference in the times that was narrowed to around .21 after mods. Once I put the resonators on, the gap grew larger again (back to around .50 secs). I think I lost at least .30 secs overall with the resonators if not more.

No dynos to confirm though. I do realize this isn't the most accurate way of judging performace but it does give me a ballpark performace measurement.

I was thinking of moving the X-pipe closer to the engine and replacing the front section (before the X) with mandrel-bent tubing. Think that will help?

Here's a shot of the current X position - I want to move it at least another 8-12" forward.

If I switched to 14" long 5" x 8" ovals, would I still need the resonators? How much quieter are they vs. 6" rounds (14" long)?



About $500.

Thanks!