Well after messing with the Stillen S/C Kit with intake and exhausts, we found that the stock intake with a drop-in K&N filter puts out the best #'s.

I picked up the car from Stillen with the factory intake and exhaust, and drove it home, and had Injen put their exhaust on my car. Well , i noticed that the car wasnt as linear as it was and it seemed a bit more sluggish at the bottom end.
Well a couple days ago, i took my injen exhaust with me down to a dyno shop. We put the injen exhaust on my car, and dyno'd the vehicle. We then took the exhaust off and put the stock one back on and re-dyno'd no more than 30 minutes later. The results.....

The stock exhaust system pushed out an additional 8.1HP to the wheels and the torque curve was much more aggressive with the stock setup. After talking with Stillen, they stated that their S/C system is built to use the stock intake and exhaust and that their exhaust system and intake are as well, but really never tested for on a F/I car.
Now before this starts into a "I knew Aftermarket parts didnt do jack for your" argument, you have to consider that this is a F/I application that the intake and exhausts were not tested on, So they may make HP on a N/A car, but for F/I, it doesnt do jack.

Stillen Stage 2 Supercharger, Stillen Front Bumper, Stillen Carbon Fiber Hood, Injen SES Cat-back Exhaust, Injen Cold Air Intake, 19" Axis Hiro Anthracite, Clear Corners

 

Hmmm. This is very interesting. So did I just waste a grand and make my car loud for a loss in HP? I've got Stillen CAI and exhaust with the stage 2 SC.

I understand Stillen says their SC is good with their stuff, but if they never tested it, I wonder if it's true...

If I'd have more HP/torque and be _way_ quieter, and save myself whatever I can get by selling the exhaust used, that's far preferable. I don't need the sound.

Hrm.

Carlin

 

Dyno test for yourself... I did it twice and both times i came up with better numbers.

THe exhaust definatetly is killing the car. You can feel the change instantly.

Stillen Stage 2 Supercharger, Stillen Front Bumper, Stillen Carbon Fiber Hood, Injen SES Cat-back Exhaust, Injen Cold Air Intake, 19" Axis Hiro Anthracite, Clear Corners

 

you need to tune the car to the exhaust....

then your numbers will be better (the ecu is not dialed to accpet the flow, IMO)

 

Stillen S/C is not tuneable. Its a stand alone system . I already talked to them about it and they stated that their system is made to run with sotck intake and exhausts, and that their piggy back system learns to the car. I think their full of schit, so i tok my exhaust and intake off, got a $1000 back in my pocket and the car runs better.

Stillen Stage 2 Supercharger, Stillen Front Bumper, Stillen Carbon Fiber Hood, Injen SES Cat-back Exhaust, Injen Cold Air Intake, 19" Axis Hiro Anthracite, Clear Corners

 

Jim

Here is your problem (my theory).

A free-flowing exhaust lowers the exhaust manifold backpressure, which results in better gas-scavenging and better charging of the cylinders. This, unfortunately for you as you have a non-adjustable system, lowers boost (probably by about 0.5 psi). This is what is causing you to lose power, not because the exhaust is worse (it is far better especially in an FI setup) but because you lower boost and tus make less power. The HP drop would have been a lot bigger if it weren't for your exhaust (if you could just lower boost and keep your exhaust contant). So yes, in your case, the stock exhaust is better b/c it prevents efficient clearance/charging of the cylinders and has the "nice" side effect of raising boost.

Now, if you can get a pulley to raise the boost justa little bit, then you are in business. But I think the next pulley they offer raises boost from 5 to 7 psi.

Gurgen

 

The Stiilen system is tunable.It took me weeks of nagging to finaly hear them say they will tune it if I put the headers & h/f cats on.I dont think they tune it,that's why it took them so long to find out if they can recalibrate the box.I found out that they take it to a local shop in Santa Ana.They dont want anyone finding out who tunes it or who can tune it because then we'll be seeing more blown motors.And that will give them a bad name.If you haven't noticed,the Stillen SC hasn't blown one motor.Probably because they tune it sooo damn rich.
You can bail the piggy back and choose any form of engine management(APEXi,Technosquare are my two choices) to pull an easy 10-20 hp.Of course,if you put new mods with your SC and you dont tune it you will lose power.Just like a stock motor & mods with no tuning.The only thing you need to do is tune it afterwards,then this discussion will be how you lost low end power but gained high end power due to relieving back-pressure and increasing flow.Ask any professional tuner,not us unthusiasts(we tend to think we know everything).Give me a few weeks and I should have proof.
I might make it to LACR on wed with my new mod I'm excited about

Blk G35c AT Stillen SC Volk LE37's Tein susp.
"throw it in the gutter and go buy another"

 

its not worth it to me to spend 800-1000 on an exhaust, and another 500-600 on re-tuning the ECU or 500+ on a new engine management for a measly 20HP. I could live without and keep my 2k in my pocket and buy myself something else or invest in somethng that wont depreciate, like another house =)

Stillen Stage 2 Supercharger, Stillen Front Bumper, Stillen Carbon Fiber Hood, Injen SES Cat-back Exhaust, Injen Cold Air Intake, 19" Axis Hiro Anthracite, Clear Corners

 

Personally, I'm gonna bite that extra 20hp for the Ooohh sweet, sweet sound .....

Colin


G35c 6MT - Pearl white, front / rear spoiler, 35% tint.
19" Racing Hart GT5, 245/35/19, 275/35/19
Stillen intake, s/charger, cat back exhaust (est. 400hp)

 

im getting a Greddy Rear section exhaust tonight from a friend for free....=) Ill throw this on the car tomorrow and dyno and see what we get.

Stillen Stage 2 Supercharger, Stillen Front Bumper, Stillen Carbon Fiber Hood, Injen SES Cat-back Exhaust, Injen Cold Air Intake, 19" Axis Hiro Anthracite, Clear Corners

 

I will also dyno and post after the install on wednesday, can't wait .... I am also gonna do a comparison dyno, same day, stillen vs stock exhaust ....

Colin


G35c 6MT - Pearl white, front / rear spoiler, 35% tint.
19" Racing Hart GT5, 245/35/19, 275/35/19
Stillen intake, s/charger, cat back exhaust (est. 400hp)

 

Hi, Cersoft,

I'm waiting to get an appointment for a dyno at Stillen, but only after all mods. I have no baseline dyno.

I'm very interested to see what your Stillen vs. Stock exhaust dynos show with your Stillen SC. Philip at Stillen has told me that their exhaust yields less gains on FI versus NA, but still gets about 12-15HP.

Thanks!
Carlin

 

Wes - I guess that's why Stillen is working on a Stage 4 ( off road use only - HA!! ) for those of us with test pipes & headers. I remember seeing a post on my350z.com about a speed shop in Boulder that will make any pulley that U want. Another of our group said that, as Gurgen explained, when he had test pipes on his Stage 3 it was only making 6+# of boost but when he put his cats back on, he got the full 7#. My plans R to wait on the Stage 4 ( & redesigned hood ) then if it doesn't make the 8# Stillen promises, I'll contact that Colorado shop & have them machine me a pulley for at least 8#!!

Gene

 

If anyone is interested, my S/C setup is up for sale in Parts/Accessories for sale.

Stillen Stage 2 Supercharger, Stillen Front Bumper, Stillen Carbon Fiber Hood, Injen SES Cat-back Exhaust, Injen Cold Air Intake, 19" Axis Hiro Anthracite, Clear Corners

 

Hey, Jim,

What didn't you like about having FI?

Carlin