hey Guys

I have been having major issues with backpressure and my Stillen exhaust.

Well, today I finally swapped out the rear muffler on the stillen exhaust for a Magnaflow dual in/out muffler with a X-perforated core (part #14468), as you can see from the pictures below. The body is 18" long vs. Stillen's 14", but it is quite a bit narrower in it's oval cross section, 5"x8" vs. Stillens 6.25x10.x.





I would have preferred a non-X-pipe muffler, but alas it doesn't seem to exist in the needed dual in/out 2.5" configuration.

Maybe more importantly, look at how POOR the Stillen muffler is made, i neve
r really imagined how bad it is until now. Look at the picture below, the view INTO the muffler inlets, the so-called 'true dual'. What BS!!!!




There is a hard stop, followed by a single pipe going through the muffler!!!???!!!

Here is the finished product...






Mike of Mike's Muffler in El Monte (I think) (at Garvey and the 10fwy) did a very nice job. The muffler still maintains the angled fit, i.e. angled up a few degrees as you are moving aft. In other words, it doesn't have that 'hanging can' muffler look common on the 4-banger compacts. It's pretty nice and neat. A piece of sheet metal toward the back of the original muffler 'housing' needed to be bent up to make room for the additional 2" that the muffler now needs to fit; it also extends the other 2" inches (to account for the 4" by which it is longer) in forward direction. Hence, it fits without too much trouble.

Subjective impressions:

1. MORE POWER...absolutely and unmistakably. At least 20whp.
2. The boost curve now does NOT decline at all as the car revs into the upper rpm range, confirming that there was a backpressure issue with it before.
3. Overall the car runs higher boost at the same setting. Need to investigate this further.
4. the car IS significantly louder, with significantly (IMO at least) more drone up to about 2200 rpm. It's like being back in N/A wide open stillen cofiguration.
5. The whistling sound comign from the muffler is GONE. When this was present, it was very difficult to impossible to hear and discen the engine knock as it was drowned by the exhaust sound. Now, the exhaust note, albeit louder, is of a very different frequency from engine knock, a great thing for me. Already today, i confirmed that I WAS INDEED knocking on the top end as my timign is way too aggressive there (20 degrees) at 9-9.5 psi boost.

Hope this was informative.

 

Gurgen...Looks good .
I have the Stillen on my coupe and they use 2 mufflers . Do you or any one else know what mufflers are used on the Stillen coupe exhaust ?

 

No idea, sorry

 

They told you it was a true-dual and sold you that??? I'd be up in arms.

 

That's Stillen for you. I wouldn't be surprised if the salesman didn't know that it wasn't. One arm doesn't know what the other one is doing.

 

Congrats Gurgen! Glad you got it done

Can’t wait for next dyno day to see (and here) how much better this set up is! If no dyno, we have Ted’s upcoming Super VQ drag meet!!!!

 

Gurgen,
I'd love to take her out for a spin.


Booger,
The Stillen 'Sedan' exhaust is quite different from the 'Coupe' version. In your case (the coupe model) you do indeed have a true dual outlet. I would leave as is.

 

Awwww yeah!

20+whp?
Me, Anthony and Elian are gonna get back in your ride.
This time, we're all eating milkshakes and putting on a combined 100+ lbs to re-enact the last meet's runs.

Let's see some TIRE CHIRPAGE! YEAH!!!

 

Naw Thats STEALIN' They think People are Stupid.......

 

Yeah Mikes Does Good Work Had them do the Custom Apex Exhaust on My CL Type-S. Now You Gotta Scratch off that Stillen Logo on your Exhaust tips.......

 

Booger,

The Stillen G35 Coupe - 350Z Exhaust has an X-pipe, dual resonators and dual mufflers. Their Sedan Exhaust has the X-pipe, dual resonators and a single muffler.

 

hehe

 

Met up with Gurgen yesterday at TechnoSquare and got a first hand preview of his latest exhaust mod and a demo ride in his "beast".

First off, to me his exhaust is louder and has a deeper more agressive sound even with the noise reducing turbos. Adding this Magnaflow muffler to a N/A Sedan's Stillen Exhaust would probably be very loud.

As for my ride in the "beast", dyno-butt wise the car is fast... very fast. (Recently I witnessed his car make a dyno run and, if memory serves me right, he was making around 70ft-lbs more torque than the highest we observed during our turbo-shootout.) With his new valve body mods, the AT shifts are very firm and fast, spinning the tires from first to second more often than not.

 

3. Overall the car runs higher boost at the same setting. Need to investigate this further.

It sounds as if your previous backpressure may have been significant enough to affect the performance of the turbo's wastegate, not to mention the overall flow of the hot side of the turbine.

Resetting/Recalibrating your boost controller (not sure if you're using a mechanical or electronic controller) should take care of it.

Careful with that hi-end knock.. that's the stuff piston meltdowns are made of!

 

Yep, that must have been the case. I am not running at 9.3 psi across the board, WITHOUT a full psi drop between 4000 and 6800 rpm.

What's puzzling though, is that these are supposed to be 7.3 psi (half bar) springs. they must have given me the wrong ones?

Gurgen