I currently have the 2003 AT w/Stillen High Box, Z-tube, Grounding Kit and Stillen Exhuast, but I don't feel any low end power, it is almost slow getting up over 3000RPM and then...WHOOSH! every thing kicks in and I'm gone. I really noticed it today, my friend just got a Chrysler Crossfire and we raced and off the line, he had me! But in the end, of coarse, I blew him out but it bothered me that my take off time is slow. Any suggestions on how to pick up the power off the line?

03 Sedan, White on Black. Clear Corners, Blinker Mirrors, Stillen: High-Flow Air box, Grounding Kit, Exhaust, Eibach Pro Kit, 18'' XS Style 420.

 

Torque Converter! My next mod is going to be to have the stall speed in my Torque converter raised. This will get you off the line much, much faster. So much as to swipe about .5 seconds off your 1/4 mile time. all this for about $800-900 installed.

Luv My G

 

I overheard some guys at atco say they thought the stillen z tube combo lost HP. I have injen and cant speak to those claims but with inejn there is still some lag - its not a twin turbo thats for sure. My mods seem to strenghten low end a bit more than top - at least the pulley. The plenum is good all over the graph I believe.

2003.5 DP 5AT Sedan (E-thing but Nav)
14.2 @ 97.18
Injen CAI
10 Wire Hyper-Ground
Crawford Plenum (V4)
UR Crank Pulley
Polk ex-3500 Tweeter Upgrade/Shock Sensor/H-Liner Under Hood

 

I noticed the same thing, while driving the loaner g35 sedan, and compared it to the my coupe. the sedan seems to have more get up and go in the low end!! What's up with that.....!the car is mod with pulley, JWT, y-pipe magna flow exhuast.
i don't understand.

 

Im going to get creamed for this but someone should test whether short intakes are even better at all than stock ones. I've heard too much speculation to the effect that they are not and one guy put the injen together as a short tube and said the car was weaker by far. I've never driven a car with a short A/M intake so I have no opinion on what is really happening.

2003.5 DP 5AT Sedan (E-thing but Nav)
14.2 @ 97.18
Injen CAI
10 Wire Hyper-Ground
Crawford Plenum (V4)
UR Crank Pulley
Polk ex-3500 Tweeter Upgrade/Shock Sensor/H-Liner Under Hood

 

Jasijay: That's your turbo kicking in!!! [img]/w3timages/icons/laugh.gif[/img]

Every once in a while mine does the same. Sometimes, I think it's the different gas my wife puts in the car.

03.5 G35S 5AT - Desert Platinum/Graphite/350Z Tube/Clear corners/HG kit/30% Tint

 

Tsafano does have a point on the torque converter, releasing some of those limitations will make those tires grip better and accelerate at a quicker rate. Another point to take in mind is how much lighter the crossfire is over the G35, by several hundred pounds. Driver skill also takes effect, not sure if you did a drop clutch start and such. In the end, the torque finally came in on the G and you were able to take him by having more power period. But keep those other things in mind, especially the torque converter.

G35sedan03
03.5 briliant silver, 6MT, premium pkg, 19" Kaizer wheels, Skyline badges, HID upgrade, Racing pedals, clear lenses, 35% tint (Coming Soon- Grounding Kit, CAI & Exhaust, Coilovers)

 

And the ECU reset will make this interesting - try it and then go for a spin while noting the lag time...

2003.5 DP 5AT Sedan (E-thing but Nav)
14.2 @ 97.18
Injen CAI
10 Wire Hyper-Ground
Crawford Plenum (V4)
UR Crank Pulley
Polk ex-3500 Tweeter Upgrade/Shock Sensor/H-Liner Under Hood

 

I'll test this as I'm buying a Nismo CAI next week and selling my JWT P/C. I'll take HP and track times with calibrated G Tech Comp, control for conditions and posted corrected findings.

I'm beginning to think the longer CAIs should make quite a difference. The other day I tried to measure the temp at my JWT by opening the hood real quick and putting my thermometer right next to it and it really shot up pretty good, quickly clilmb into the mid 100s. I haven't done this at speed, so this could be meaningless, but the temp down by my lower grill (with asphalt heat beating down on it) was only about 110.

Even 10 degrees will make a few percentage difference in your relative HP to rated. Even 2% is worth 5 HP.

2004.5 Coupe/5AT/Ivory/Everything but chin spoiler/Z Tube-Popcharger/Crawford V5 Plenum on the way

 

keep us posted catatafish

G35s6mt/TSecu/350Z Springs&Struts/JWTpopcharger+Z-tube/StillenDualExhaust /6WireGroundKit/KinetixHighFlow

 

My experience with intake and plenum on my 5AT sedan was very poor. Actual dyno showed a 7HP and a whopping 12 lb torque loss with the K/N typhoon short ram and Crawford plenum. I could actually feel the loss. After I took them both off and went back to stock the car would launch much better and the partial throttle shift points were much lower RPM as well indicating better lowend pull. All I have now is K/N panel filter in stock intake, Stillen true dual exhaust, and full set of UR pulleys. The car pulls strong all the way from idle up to redline now.

Some people think that the resonator in the intake is just to quiet things down, but it actually does much more. It absorbs the standing waves that accumulate in the tube from the negative pressure differential between throttle body and MAF. Intakes are tuned throughout RPM range for specific velocity just like exhausts. When that is altered, most ECU's dont like it and clamp down on fuel and timing to be "safe". NA mods should be looked at as a basline for maximizing gains when FI is added. Thats my next step with a Vortech at a safe 5-6 PSI, and should get 330-350 at the wheels for around $7K installed.

 

Guys, thanx for all the good advice. I will try the ECU reset and take some notes. Also, where would I get a torque converter from? What about an ECU upgrade? will that help the Torque and low end HP??

03 Sedan, White on Black. Clear Corners, Blinker Mirrors, Stillen: High-Flow Air box, Grounding Kit, Exhaust, Eibach Pro Kit, 18'' XS Style 420.

 

The torque converter is my next mod, but if you don't wanna do that, replace your pulleys with after market ones. All pulleys give you really is the low end torque.

 

My understanding is that the less restriction you have results in somewhat of a reduction in low end torque but is made up for in the high end improvement. I heard that this is particularly the case with exhaust systems because you are producing less back pressure. Can anyone confirm?

2003.5 5AT
Premium Package
Tire/Wheel Package
K&N Filter, Z-Tube, EGK

 

jasijay,

IMO your listed mods look great to me. Most likely you need one additional mod to bring it all together.

The 2003 AT Sedan's ECM program was seriously detuned for "luxury". The a drive-by-wire system has a limiter that prevents the throttle body's butterfly from being opened too fast. Also the stock ECM's fuel and timing maps need help as does the TCM's program.

DaveO

2003 G35 AT Sedan / DP / Willow / Premium / Sport
350Z T-Stat & Air Duct / Stillen CAI / Crawford Plenum
GrdGear 7-Wire Kit / TS ECM / E-Fans
Street Edge TC / B&M Cooler / Stillen Exhaust