Can somebody tell me what would the new topspeed is for a 5at g35 coupe if they were to put in this:

http://www.performancenissanparts.co...oducts_id=1962

My guess would be with the same gear ratios as a 6mt but only have 5 gears, a 5at would probably have the same topspeed as a 6mt in its 5th gear. Im not sure if that is true or not.. Just a guess... Would somebody that knows more about this explain what the new topspeed would be? I know it'll definitely be lower and if the topspeed is the same topspeed as a 6mt in its 5th gear.. What is the maximum speed that can be reached on 5th gear for a 6mt????

 

That's not quite true. if you look at the ratios, 5th gear on the AT is < 1.000 where at 5th gear on the 6MT is 1.000.

5th gear on the AT is very close to 6th on the MT.

So your top speed won't be lowered much, if any, since our top speed of 156 mph is limited by the ecu, and that occurs at way lower than the redline (I forget what rpm, maybe someone in here knows).

 

yea i understand that... but i think if i get the 6mt final drive, my 5th gear for AT will be closer to 5th gear on the 6mt, which will be 1.000.. so my top speed will be similiar to that of the top speed of the 5th gear in 6mt.....

 

The 6m/t final drive is 3.538:1
the 5a/t final drive is 3.357:1

If you put the 6m/t rear gear in the automatic rear, you'll prolly lower you top speed slightly since you don't have the 6 gear.

In any case the ECU prevent the automatic from exceeding about 145-150.
The ECU allows the 6 m/t to top out at 150-155.

The higher numerical final drive is a good mod altho not many have done it that I know of prolly due to warranty issues.
It would allow quicker acceleration due to higher multiples of the gears tho.

 

I know the top speed would be lower, but does anybody have any idea just how low the new top speed would be??

 

I have mine going in maybe this weekend, weather permitting. I will post back and let you know my opinion. Won't have any information on top speed for you as it's January and I am in NY and that would be f-ing crazy! From what I have seen, if you get the TS ECU done and remove the top speed limiter, it shouldn't be an issue. I certainly didn't worry about it.

 

3.357/3.538=0.9488411 ~~ 5.4% more rpm at same speed as auto diff gear.
Acceleration would improve by 0.1 seconds in quarter mile.........not real cost effective.
As mpg will decrease by nearly that amount [at least 2.5-3%] at highway cruise from higher rpm.

 

what is the top speed of a 6mt in its 5th gear?? Can anybody answer me that???

 

I have done this. I have the 3.538 diff in my car. the acceleration is definitely better. Also, i DID do the calculation of the top speed possible (can't remember if this was at the stock 6600rpm redline or the raised 7100 rpm redline). Either way, for the same redline, the stock 5AT and 6MT have identical top gear FINAL gearing for 201 mph, while MY gearing (to the best of my recollection) was 192mph. Not 100% sure. Will doublecheck later..

 

Our cars would be drag limited anyways to be well short of the 190+ mph mark. So the theoretical top speed shouldn't be a factor in deciding to switch from the AT final drive to the MTs final drive. Increased gas consumption and cost effectiveness should.

 

Thanks Gurgen, Now that you mention it, I do remember you talking about gearing and theoretical top speed some time ago.



I agree , DKLau33, to most of us, the increase consumption and cost effectiveness is most important, but to some, higher performance is the ultimate goal and to them most important.
I went thru a period like that and it was much fun.

 

Sure, the numbers say that one should only see a decrease in quarter mile times of 1/10 sec. but what about the stock numbers from the two? By what I've observed, it looks like the difference is closer to .3-.4 sec...

Not that I care... I put on a set of drag slicks (16x10" from a mustang) the last time at the track and was running consistent 13.8's (fuse pulled, drove around waterbox) from the high 13.9/low 14.0's I was running on 17" street tires... cost-effective this mod is not...

 

Sorry to bust your chaps son...but what does PROLLY mean? Is it like a trolly?

 

WEll I know how much you enjoy that, so I just do it to bust your 'chaps' , pops.
...
It's either that, or I'm just a lazy SOB who's always lookin' for shortcuts. One of my many faults

You think?..........PROLLY??????? haha.