1) The install and dyno took only about 2 hours to complete.

2) The Stillen G35 Coupe exhaust is, in fact, their dual catback exhaust for the 350Z with two 7" extension pipes to make up the difference in length.

3) The "drone" has quieted down since heating up yesterday and cooling down overnight. But the "drone" is across the entire rpm range, not just at ~2500rpm (3500rpm was a mistake on my part). However, it is only when the engine is under load. E.G. Accelerating, climbing a hill, fighting head winds from a hurricane, etc... At idle or cruisin' on the flats or downhill, the engine gets very quiet.

4) The sound is that of a Suzuki cafe racer on steroids.

5) Kit included everything except for 2 gaskets (the high heat resistant ones that go between the cats and the catback). Since this is a new car the old gaskets were like new so they were reused.

6) Construction is high grade. There were only 3 items that caused 2 problems.

6a) The right side pipe's flange was rotated to a slightly different angle compared to the flange of the right side cat. While it was only about 1mm - 2mm difference, it did require the use of a "persuader" since neither the cat nor the exhaust could be twisted to get the cat's bolt to line up with the exhaust pipe's bolt hole.

6b) The 7" extensions required 4 "C" clamps and the right side exhaust pipe, which goes "over" the rear sway bar, requires 1 "C" clamp. Strongly recommend getting 5 "Flat" clamps to use in place of the "C" clamps as they will do a better job of "closing" the seams and strengthening the assembly. More on this later.

6c) The left side exhaust tip is tilted slightly down compared to the right side tip. This is noticable only from a ground level viewpoint. The mufflers are parallel with the bumper and the ground yet the left tip is angled down by about 1 degree as compared to the right tip. More on this later.

The 2 problems are 1) the downward pointing tip and 2) a rattle that developed after the "cool down" period. Both problems were solved with about 15 minutes of work.

The "rattle" was where the left pipe crossed over the frame brace. After "heating up" and "cooling down", the pipe sagged too close to the brace and started tapping the brace whenever I hit a sharp bump or when the car was twisted such as when I'd accelerate up a tight right hand on-ramp. This sagging was due to the loose assembly point where the front half of the exhaust was coupled to the back half of the exhaust by the 7" extensions. Between the two pipes there are 4 points of possible failure. The expansion and contraction of the pipes caused the pipes to sag right at the extensions bringing the left pipe too close to the frame brace. This problem was solved by 1) moving the left rear exhaust hook up one notch in the "rubber" hanger and 2) loosening the "C" clamps, levering the pipes up with a 3' screwdriver, putting the "C" clamps as close to the end of the pipe joint as possible and then re-tighten the "C" clamps. This is where "flat" clamps would improve the situation as they would provide a better joining of the pipes.

This fix moved the pipes about 1/4" higher above the frame brace (but also about 1/8" closer to the rear sway bar) and pointed the left tip up to where it is in the same plane as the right tip.

So, the suggestion is that when installing this exhaust, use a lever or a wedge to hold the pipes up from the frame brace before tightening the "C" clamps.


<font color=red>Image of 7" extensions, joints, "C" clamps and rear hanger:</font color=red>



1 - Open seam, due to the use of a "C" clamp and incorrect positioning of said clamp, shows a failure point. This was missed during the review of the installation.

2- Left side exhaust pipe too close to the frame brace. This too was missed.

3 - Left side hanger which was eventually moved up one notch.


<font color=red>Image of difference in angle of the tips.</font color=red>



4 - Gap between bumper and left side tip.

5 - Gap between bumper and right side tip.


<font color=red>Image showing the point of the flange misalignment.</font color=red>



6 - Point where the exhaust pipe had to be "persuaded" to slip over the cat's bolt.


<font color=red>Image of the 7" extension pipes.</font color=red>



7 - The 7" extensions. (Actually they're longer than 7" in length in order to overlap the pipes. The 7" length is used here based on the assumption that it is the 7" difference in wheelbase between the "Z" and the "G".)

Screamin' Daemon - L5AT

 

Excellent attention to detail suprhulk! If I were manager of the R&D dept. at Stillen I would compensate you for your time spent on resolving quality management issues. If I were to buy Stillen, I would definitely wait until Beta testing on the public is over.
Having supplied my 99 Acura TL to Comptech USA, here in Northern Cali, I can attest to good R&D. My car was fitted with an exhaust that had to be refitted and retipped due to complaints from consumers that the exhausts vibrated and that the tips were not true Stainless Steel.....all of which I should mention that Comptech handled with excellent customer service. Comptech listens to feedback from it's consumers, hopefully Stillen will do the same. I'm thinking about driving down to their HQ for the 350Z/G35 Cpe/Sdn inivitation. Thanks again for a thorough follow-up.....excellent work. *hats off*

"Use the Forced Induction Luke!"
-Jedi
Ordered 4/03: 2003 G35C, 6MT, Blk/Blk. Loaded ETA ~ 7/03

 

Well, four days of driving with the Stillen exhaust and I can say:

1) Definite performance increase. "Seat Of the Pants" can detect this increase. When the RPMs get up to ~2500, the "G" really kicks you in the b*tt. It's enough of a kick that it really takes me by surprise when it happens. It's how I imagine driving a "Turbo" would feel when the impellers spin up (I'm assuming that the spin up of the turbo impellers is <font color=red>very</font color=red> fast, i.e. instantaneous), when pushing the "fire" button on a NOS equipped vehicle or when kicking in the "after burner" on an F/A18. Since I've never driven either type of car (or an F/A18 [img]/w3timages/icons/crazy.gif[/img]), I'm only guessing. For those of you into "drag" racing I'd highly recommend getting a "High Stall" T/C that lets you rev up to ~2500+rpm before launch.

2. It is <font color=red>not</font color=red> a drone. It is a <font color=red>very</font color=red> loud exhaust that makes itself known whenever then engine is under <font color=red>any</font color=red> load. With the windows rolled up it is quite intrusive. With the windows rolled down it is actually pleasing. Fortunately for me, I don't listen to music (to busy thinking to listen). But for those of you who do listen to music, you'll have to <font color=red>crank it up</font color=red>. Technically, I'm ambivalent about my decision to go with the Stillen exhaust. On the one hand, the stock sound was pleasing but too quiet. I couldn't tell what gear I was in without looking at the Tach or the Gear indicator. On the other hand the Stillen does improve performance and it gives me an audible RPM indicator. But, the loudness and the slightly "<font color=red>ricey</font color=red>" (read 900cc Suzuki/Yamaha cafe bikes) sound of the Stillen exhaust is going to take some time to become accustomed to it.

Screamin' Daemon - L5AT

 

is it like a 300zx with dual Trust exhaust? sounds just like a civic with 2.50 inch piping Y split to 2 cans.

BS G35C 6spd navi/aero/prem

 

Hi,
I am in full agreement about sound and power increase. I would like to find out if I can use different resonators to silence it back to stock. ( maybe sacrifice a couple of horsepower) I would be happy with 12 of a possible 14, or what ever it is. It is just too lound now.
Any ideas about resonator changes?
Alan:-)