BrianDT3wZ

iTrader: (5)

Also...since I Really Don't Know.. Even If U Have To Shift Into 4th Gear, Won't That Effect The Trap Speed And Not The Time ? I Remember Reading During A Search That 1/4 Mile Times Have Been Reduced After The Swap..

Voboy

iTrader: (58)

When you track the car, just let your automatic tranny do the work for you (dont use tiptronic), and keep the pedal to the metal when your at 4th gear?

Suvlaki

The FD swap reduces ur 1/4 time by 0.5 sec. If you don't believe me, run a search on some N/A autos that have had the swap. You will see that they have all reduced their 1/4 by half a second. It really does make a huge difference.

N/A manuals have to swap their 3.5s with 3.917s though. However, the 3.917s are rather expensive, as the 3.5s can just be swapped with a stock stick shift final drive.

I see you have a supercharger. An N/A 3.5fd auto Z would keep up with you through 1st, 2nd, and sometimes some of 3rd (depends on the drivers.) However, during 3rd, the sheer horsepower of the supercharger will show as it will destroy the N/A Z (as it rightly should, by all means.)

If you are planning on staying N/A (as I am,) you should really look into swapping out ur FD with a 3.5. It is hands down the best mod you can do for any N/A car, and especially for the Z (as our N/A mods usually have little to no effect.) I am planning on swapping out my FD very soon but since my Z has only 6000 miles on it, I want to wait at least another 4000 before I start messing with my tranny.

EDIT: run a search on final drives. There are a few threads on this board that will explain everything you need to know about what it is and how it works.

EDIT: Also, you may want to think about a torque converter upgrade if you're serious about getting the most performance out of your Z. Only problem with the torque converter is that your daily driving goes to ****. Every shift snaps your head back. But of course, if you don't worry about that sort of thing, you can lower your 1/4 by 0.7-0.8 sec just by torque converter / FD swap. (The main reason I chose an Auto vs. a Manual.)

marques1

iTrader: (5)

thanks for all the suggestions fellows they are very much appreciated very good info.

ZLadie2000

iTrader: (12)

Did traction issues become worse?

BrianDT3wZ

iTrader: (5)

Yes... More so in this cold weather we are having up here. You have to re-learn your throttle control off the line and you will have to adjust your shift point or you might bounce off of the rev limiter. On a cold day I have had some spin into 3rd gear. When I say tire spin, it's not like you will be there roasting the tires, you will have plenty of forward momentum, you will rev faster, hence shift earlier or you will hit the fuel cut off. All I can say is, it was a great mod, probably the best for acceleration on the A/T N/A.. Now I am looking into tires and suspension.

ZLadie2000

iTrader: (12)

Hmm...what type of tires you looking into? I need new tires too...my rear Pirelli F-Zero's (285/35/18) are pretty bald and I cant get much traction off the line NOW...I know it will get worse with the new 3.5 fd Im installing Thurs at Forged.

Top end, like on a highway roll is better, right? I cant wait for this mod!

BrianDT3wZ

iTrader: (5)

Eagle F1 GS-D3.....And yes better acceleration in each gear, but not as profound as the lower gears.

Sean_350z

I think you mean a valvebody upgrade. A TQ converter won't change the firmness of the shift. Simply moves the flash or stall point higher.

Aggro_Al

4th gear in the 5AT is the 1:1 gear, it isn't meant to be a torque multiplying gear. If you wan't more torque, downshift. In the Nissan 5AT, you don't need 6 gears like the 6MT. The 6MT has 6 fixed gears. The 5AT uses a performance torque converter. The 1st, 2nd and 3rd gears can adjust torque (gearing) when there is a difference between the impeller and turbine. Adding another gear would just overlap one of the other gears and it isn't necessary. The first three gear aren't fixed until it couples or locks. 3rd, 4th and 5th gear have the ability to mechanically lock the gear with a mechanical clutch. 3rd is a partial lock up and 4th and 5th are full lock up gears. When the torque converter is locked, it uses a mechanical clutch and operates like the 6MT. There is no fluid connection when the TC is locked. Part of the reason 4th doesn't feel like it pulls as much as the first three gears is because the TC is locked. You no longer get the torque multiplying effect of the TC because the stator can no longer return the fluid to be re-accelerated in a locked or coupled TC.

If you just want to go faster use the same mods that everybody else uses. Some of the better mods for the 5AT are a high-stall torque converter, valvebody upgrade, ECU reflash and a turbocharger. Turbochargers work better on a car with a torque converter because you can minimize or eliminate lag and you can also pre-load the turbos with a torque converter.

modzs

why would you buy an automatic Z?

Aggro_Al

Does it matter why he bought one? It doesn't have anything to do with what he's asking about.

Since, you're a noobie, I just want to give you a fair heads up about starting MT/AT wars here. Be prepared to get flamed. Do a search and you'll see why.

Bottled Water

so in a stock N/A MT Z w a 3.9 what 1/4 times am i looking at??

jcpeyton

iTrader: (1)

Subscribing.

titankiller

4th gear has always been a problem for me. While n/a on the dyno, 4th gear would pull my timing down to around 17 degrees and third gear would show 28 to 30. Dyno showed with basic bolt ons 218rwhp in 4th and 244rwhp in 3rd. Even the EManageU would not keep the timing in 4th gear up. The huge gear jump from 3rd to 4th has the ecu overcompensating by pulling timing to reduce pinging during gear shift. The best solution as stated in previous replies is the gear swapp and the valve body upgrade. The 3.5 is the first choice but the 3.7 would best best if you are using large aftermarket wheels and tires which in most cases would have a larger diameters than stock. If you go 3.9 you would need to run at least a 27.5" diameter tire to have some reasonable highway driving rpm.

I did see a strange mod a few months ago which is an billett adapter plate which mates a GM turbo 350/400 tranny to the vq35. This tranny with just a few upgrades can be made to handle up to 1500hp while being a daily driver. Have not seen or heard of anyone doing this mod but I think it's worth a little researching.

Sean_350z

the th350/400s are 3spd automatics though and you'll lose overdrive. Fine for drag racing but not ideal for daily use. IMO, the stock 5spd is nice w/ the closer ratios. If you were going to do a swap though something like a GM 700r4 that has a larger aftermarket support base might work well.

Dyno'ing in anything under a 1:1 ratio in the trans is always going to result in a higher value. Swapping the ring and pinion to a deeper gearset will drop the numbers too.

ZLadie2000

iTrader: (12)

Why didn't Nissan put the 3.5fd in the auto's to begin with??

takissd

iTrader: (13)

hey guys, do you know where i can buy a pumpkin with a 3.7 or one with the 3.9 FD , and the cost? I have an AT non turbo/sc
Also , i know there will be a reduction of high end speed, what would it be with a 3.7 and what with a 3.9FD ?
thanks

Minda

iTrader: (5)

I believe 3.5FD on 5AT would have adverse effects on MPG, which are not great anyway. 3.7 or 3.9 FD would kill your MPG on 5AT.

350Zum

How much work is involved in replacing the FD?