I spend some time over at the 350Z sites and I'm amazed by the 60 foot times the 350Z 5ATs are pulling compared to our G35 5ATs. The 350Z auto makes about 8whp more than G sedan, the Z weighs 110lbs less, and has a shorter wheel base, but that still doesn't explain the stump ripping stock and mostly stock 60 foots the Z autos can pull. Common 60 foots are 1.9-2.0 for these cars. With the G, mid 2.2s are common with a few getting lucky and grabbing a 2.1. Most of you G drivers have probably noticed the bog in acceleration until about 3000-3500rpms. In my G, the bog is really defined and it's clear there's a Nissan nanny holding the car back initially. The Z owners report absolutely no bog and they're able to launch at 1000-1800rpms and pull 1.9-2.0 foots. If we could pull 2.0 foots, we'd be about .3-.4 quicker.

What's everyone's take? Is it the ECU dialing back the throttle initially? Lots of timing retardation? If we could just unlock whatever it is that Nissan programmed in, we'd have some seriously quick G35 autos running around.

 

Dave, I don't think the Z's have VDC. They have traction control which can be disabled but I read that only the touring comes with VDC. I could be wrong though.

 

I've been wondering the same thing. I figured that it was mainly due to the weight. I also think that our stock rims are considerably heavier than theirs. It would be interesting to see if there is something built into the system that is causing it though.

My best 60' was 2.19 which at this altitude probably isn't too bad, but then again I have a lot of mods.

 

I'm going to data log my G and see what the timing and throttle position numbers look like at WOT from a stop till the top of 1st.

 

The weight is a factor overall, but on the initial 100' of a launch it should account for too much. The stock 350Z 17s with tires weigh 48-51lbs depending on who you ask. I weighed my 17" Sport rim combo and they came to 46lbs. The Track 18s are decently light, but their added rotational inertia negates the gain of the weight reduction. I'm of the belief that there is some sort of control that is holding back the G35. You can really feel it when you launch.

A 2.19 60' is really good. I was able to pull a 2.21 60' on my 17" EL42s without chirping a tire. I think low 2.1s are possible when I get some more power and run in 50 degree weather vs 70 degree weather.

 

What about tires? Are these 350Z guys running slicks or at least higher-perf. tires than us?

 

I'm curious too. I'm running the 19" stock wheels on mine with Bridgestone Potenzas.

 

I think the phenomoneon Dave desribes could almost be compared to a turbo lag one might experience from a single turbo where the boost builds and all hell breaks loose at 4000 or 4500. Omni GLH anyone?

I think the lightweight crank pulley is a direct attack on this delay even the ECU is the cause. Let's not start the pulley debate here - it's only one possible approach to this issue with an ECU upgrade being the most obvious choice for a solution. Does the Z get to the torque peak sooner or have a more generous value at the 3000-3500 range? I've never compared curves.

Also, why wouldn't the shorter wheelbase and drivline make up most of the difference in 60' times? It's a big % of the wheelbase total, the difference between the G and Z --- 10% I guess.

 

In addition to being shorter, the Zs also have a carbon fiber drive shaft. That's a factor to consider.

 

The Z has a 104" wheelbase and the G has a 112" wheelbase or roughly an 8% difference. I don't think that's going to make much difference at all. Same goes for the CF driveshaft. You're talking about a driveshaft that's only 8" shorter and probably only weighs 2-3lbs less than the Gs alumninum shaft. Whatever gains the CF driveshaft gives the Z is showing up in the slight power advantage it has. IMO, the UDP isn't going to help things, but if someone could show me a 60' improvement with theirs, I might change my opinion.

As for the Z parts and G parts, their all the same. It's the same exact engine, top to bottom. I wish we could see power issue on the dyno, but the problem is most auto G35 dynos have to start at 3200-3500rpms or just after this bog occurs therefore the HP/TQ plots follow that of the Z plots. Like SixFive said, it does feel very much like mild turbolag.

 

I think any 2-3 of the following mods helps this lag but up to a point. Maybe only the LS vette motor is going to get you what you want!:

Hi Flow Cats, UR pulley, Plenum or Spacer, and intake mods that actually add power. Max torque isn't low enough I guess for some of us but the thing still pulls strong. Better than Vtec!

 

I've been trying to understand the Yaw Rate/Side G Sensor's function(s) and it�s effect, if any, on straight-line acceleration.

Since 9/25/03 I've been running the Technosquare ECU re-flash and believe it provides part of the solution. The following info is from their website.

"Drive By Wire Adjustment
Throughout our testing we found, the drive by wire system was program to never fully open (throttle flap) when you smash the accelerator pedal. In fact, it actually closes the closer you get to the rev limiter, by as much as 20%. This restricts air into the motor and causes HP and Torque numbers to go down. We have remapped this setup so when you go wide open throttle, the throttle flap fully opens and STAYS open, increasing HP and Torque.

Ignition Timing Map Adjusted
There wasn�t much room for improvement at the bottom end since the ECU retards a lot of timing by using a feed back system in stock trim. So, we have added more timing at the mid range - higher end to take additional advantage of higher-octane gasoline. This aids in improving torque from 3000 rpm and up.

Fuel Map Adjusted
Stock fuel was set to detune the top end horsepower. We discovered that the car runs extremely rich after 5000 rpm. Air to Fuel ratio (A/F) of 10.5 was found right before the stock rev limiter kicks in. Cleary, Nissan was trying to detune the power output at higher rpm to discourage the driver from hitting the rev limiter. For the performance enthusiasts, however, this is unsatisfactory, so we set the A/F to 12.5 all the way to redline to provide adequate power gain while still maintaining a safe margin.

REV limiter modification
We found that with the ECU upgrade, more power can be gained with a higher rev limiter. A 7100 RPM (stock 6600 RPM) rev limit is set to take advantage of top end horsepower, while still providing a safe protection for the motor.

Speed Limiter Removal
The speed limiter is removed. The stock limiter was set at 234Km/h (146 MPH), so for all practical purposes, we could have left it alone. But we decided to remove it, just in case someone feels the need to go beyond that.

Adding to above modifications, a few other adjustments were made to other maps to enhance the feedback function which improves power, torque and drivability. The resulting achievement is a remarkable improvement in driving feel, which is more than what numbers alone can tell you. We are very satisfied with the results and are proud to release our TECHNOS ECU for this tuning-challenged ECU, blowing the lid off what was thought to be an automobile already running pretty near its maximum capability."