AZ350Z

iTrader: (5)

Last night I had the new Stillen exhaust installed. We Dyno'd before and after and came up a little short on the advertised HP but much better on the torque #'s. The sound alone is worth the $1100. Dyno charts to follow, confirmation available at dynocomp.com.

droideka

Dyno after 200 miles or so and then get back to us.

lEtMeZ1

Sounds very promising , but like droidekaus said , drive around a little more and dyno again please!

AZ350Z

iTrader: (5)

Should the gains go down? If so, why?

droideka

Because the ECU doesn't negate gains in a few minutes or miles.

Going by intake examples, dynos done immediately after an intake install show gains. Dynos done after several hundred miles show zero gains or even losses. SKiDaZZLe had a baseline and Injen dyno done one month apart and the Injen showed ZERO gain. Infact, it read as the EXACT same HP/TRQ as the baseline. He put 300+ on the Injen before the dyno.

Don't know if this will hold true for exhausts as well.

stx

The ECU rumor is not true! The ECU just adjusts to come up with its air/fuel ratio so if you have more air it will add more fuel to equal the same ratio. Example if you have an air/fuel ratio of 12 and you have 120 parts air the computer will adjust the fuel to 10 parts fuel to equal twelve. If all of the sudden the air increases to 240 parts the ECU will try to adjust the fuel to 20 parts to equal 12. Plus how can a cat back exhaust be affected by the ECU? The ECU can only sense to the cats which only senses the amount of oxygen, not the flow of exhaust.

Ben Davis

I would be curious to hear your logic for how
1: the ECU recognizes mods and or adapts to them
2: how it negates mods (timing, fuel....)
3: proof that it has negated mods (dyno, track times....)

Ben

Chebosto

iTrader: (43)

anything prior to the last o2 sensor on the car, the ecu has control over. somewhat. i.e. fuel curve .

the exhaust, being free flowing more so than the stock setup, will yeild gains, but again, more exhaust flow, less back pressure will affect prior to the catback, and the ecu might still alter its curve.

dynoing after 300-500 miles is a good idea for the sake of testing and data analysis...

the more data points you have, the better one can evaluate a system.

droideka

What part of my post did you miss that refers to dyno results? Do you need a picture?

Ben Davis

Easy tiger, simple question, but yes I would be interested to see the dyno's myself.

Ben

droideka

Read this entire thread. Results inside...

Ben Davis

Good thread, thanx for the info, i guess the question becomes:
(basedo nthe ECU theory stated in that post)
If the ECU sees more air (leaning out) why does it retard timing instead of just adding more fuel?!?!? (seems obvious to me)

Ben

dougrace zs

iTrader: (2)

Ok, I can attest to the fact that it does take the ECU a while to adjust to exhaust mods cause I have done them ......
The last time we took the car apart to do the second set of headers for production we obviously killed all the maps that were in the computer for the headers that we had on the car already.Car ran like ***. It took almost 500 miles for the car to start running the way it did before we took it apart with the exact same headers. So it does take a while for the ECU to remap for any exhaust mod .
Don't know about intake mod's but the stock airbox is ramming air
anyway.

Ben Davis

As with any car the ECU basis its descisions on either a open or closed loop system and some recent history, so breathing mods may change the car to running a little lean untill the ECU realizes it, but the issue at hand is not that the ECU takes time to adjust, (i think we all agree it is not instantaneous) but that it supposedly adjusts in a manner than NEGATES the mod in question! That is just weird!

Food for thought: in a recent SCC the WRX lost a solid 12 hp and 10 lbft throughout a major portion of the rev band with only a reset ECU.
Ben

droideka

I think the answer to that question is... lawyers. I'd bet that a tuned ECU could easily yield 20 WHP like Hondata's getting for the RSX-S guys.

Ben Davis

If that theory holds true the DEFINITLEY 20 hp easy.... good lord i hate lawyers..... So being new to THIS car anyways take it easy on me, no ECU upgrade or piggyback at all?!?! Anyone try an FPR/Pump yet?!?!

Ben

TOM Z CENTRAL

I had my Stillen Xhaust installed about a month ago,3000 miles on the OD.It sounded better from the start.A week later,it sounded even better & seemed to be have more torque.I had to drive the Z back to my house in Arkansas from Arizona last week.[I flew back last fri.to AZ to pick up my motorhome,jeep & RoadKing ]Anyway.when the OD got to around 5000 miles,the Xhaust seemed deeper & the power has increased.Since my Z is a 5AT,I opted to only install a K&N drop in because, I can't stand a drowning intake/exhaust.But,I agree with you.The sound of the Stillen is well worth the $.I think the X true dual is the best bang for the buck.It will a fine day when someone opens up the ECU.Then the X of the Z will roar.Tom

rodH

iTrader: (2)

that is why I can't wait for an ECU to comeout (preferably Nismo), then I will get more excited.

btw, if I don't have a problem with the stock sound of the exhaust, I shouldn't get this one?? in other words-I am NOT getting performance mods for "sound" it is icing on the cake if it sounds better, but NOT why I want performance mods.

webcarconnection

That is one case, I'm seen more than 6 cases that the Injen gave 6+ whp long after install.