350EVO 3.9 Final Drive Installed on my 5AT: Impressions
02-01-2008, 10:44 PM
#1
350EVO 3.9 Final Drive Installed on my 5AT: Impressions
About a couple of weeks ago I purchased a pumpkin with a 350EVO 3.9FD & oem VLSD installed (actually it was a used setup that had around 5000 miles on it + the final drive gear was installed in the pumpkin by 350EVO). Yesterday I got around to installing this on to my car. Here are my impressions:
1)Performance:
All I have to say is WOW. F*cking WOW. The reason why I went with the 3.9 instead of the 3.5 or the 3.7 is because I wanted performance you can feel and this is exactly what I received. Going from a 3.3VLSD to a 3.9VLSD made quite a noticeable difference in the feel and response of my 5AT (actually more than I expected). The response of the car has improved dramatically and it has made an improvement throughout the rev range. I fly through 1st, 2nd, and 3rd. With the 3.3VLSD it felt like it was taking too long to get to the meaty part of the powerband, especially after my osiris reflash with the 7200 rpm limit. The 3.9FD took care of this. WOT in 1st & 2nd gives me a lot of wheelspin
. Rolling on the throttle in 2nd will break the tires loose (and will get the rear light). The car accelerates harder in every gear. There is one onramp where I go WOT (with the 3.3FD) from 1st-3rd and I am able to hit 90 before merging on the highway. Now on the same road I am hitting 95-97 (@7200 rpm in 3rd) before merging on the highway. I am going to the track next friday to see if I can quantify the improvement 
.
This is by far the best mod I have done to this car. I'll probably go with the 4.08's after I go with a more aggressive set of cams. IMO this will be the perfect mod for any 5AT VQHR motor.
2)Streetability:
I know some of you had some reservations about with a 3.9FD in the 5AT but believe me this setup is VERY STREETABLE. It never feels like I am always revving out the car. It feels like a more responsive 5AT G35. This mod makes city driving much more enjoyable and I can get around cars on the highway a lot easier without downshifting. With the 3.3FD the car was dull at low revs and I would have to either downshift or add a lot more gas to speed up or to get around cars. Now I can increase my speed at low revs with a small tap of the gas. This alone will help improve my mpg (less load) in the city as well as save some wear & tear on my car.
As expected my cruise control does not work (the light just blinks when the button is pressed) but I wont be missing it since my right foot does a better job. So far my mpg has gone down only because I can not keep my foot off the gas
. I'm expecting my highway mpg to go down slightly but I'm also expecting an improvement in my city mpg. I didn't buy this car to save gas. When the converter locks the rpms are higher than before (80 is @ 3300-3400 rpm) however its not really bothersome and I'll take the tradeoff for the performance. I also have a slight whine when crusing at a steady speed. I did some research on this subject and I found out that this is because the pumpkin was setup with a little more offset (looser backlash) with the shims. This was intentionally set up this way by 350EVO since it allows for cooler operation of the diff. In a nutshell, the looser (more offset) the gear has, the cooler it runs, but adds to the chance of a rearend whine and the tighter (less offset), the hotter it runs, but lessens the chance of gear whine. The whine is only present when I give it steady throttle and it disappears when I let off or when I go WOT.
Sorry for the long post but I wanted to give a detailed review for anyone thinking about this for their 5AT.
1)Performance:
All I have to say is WOW. F*cking WOW. The reason why I went with the 3.9 instead of the 3.5 or the 3.7 is because I wanted performance you can feel and this is exactly what I received. Going from a 3.3VLSD to a 3.9VLSD made quite a noticeable difference in the feel and response of my 5AT (actually more than I expected). The response of the car has improved dramatically and it has made an improvement throughout the rev range. I fly through 1st, 2nd, and 3rd. With the 3.3VLSD it felt like it was taking too long to get to the meaty part of the powerband, especially after my osiris reflash with the 7200 rpm limit. The 3.9FD took care of this. WOT in 1st & 2nd gives me a lot of wheelspin
. Rolling on the throttle in 2nd will break the tires loose (and will get the rear light). The car accelerates harder in every gear. There is one onramp where I go WOT (with the 3.3FD) from 1st-3rd and I am able to hit 90 before merging on the highway. Now on the same road I am hitting 95-97 (@7200 rpm in 3rd) before merging on the highway. I am going to the track next friday to see if I can quantify the improvement .This is by far the best mod I have done to this car. I'll probably go with the 4.08's after I go with a more aggressive set of cams. IMO this will be the perfect mod for any 5AT VQHR motor.
2)Streetability:
I know some of you had some reservations about with a 3.9FD in the 5AT but believe me this setup is VERY STREETABLE. It never feels like I am always revving out the car. It feels like a more responsive 5AT G35. This mod makes city driving much more enjoyable and I can get around cars on the highway a lot easier without downshifting. With the 3.3FD the car was dull at low revs and I would have to either downshift or add a lot more gas to speed up or to get around cars. Now I can increase my speed at low revs with a small tap of the gas. This alone will help improve my mpg (less load) in the city as well as save some wear & tear on my car.
As expected my cruise control does not work (the light just blinks when the button is pressed) but I wont be missing it since my right foot does a better job. So far my mpg has gone down only because I can not keep my foot off the gas
. I'm expecting my highway mpg to go down slightly but I'm also expecting an improvement in my city mpg. I didn't buy this car to save gas. When the converter locks the rpms are higher than before (80 is @ 3300-3400 rpm) however its not really bothersome and I'll take the tradeoff for the performance. I also have a slight whine when crusing at a steady speed. I did some research on this subject and I found out that this is because the pumpkin was setup with a little more offset (looser backlash) with the shims. This was intentionally set up this way by 350EVO since it allows for cooler operation of the diff. In a nutshell, the looser (more offset) the gear has, the cooler it runs, but adds to the chance of a rearend whine and the tighter (less offset), the hotter it runs, but lessens the chance of gear whine. The whine is only present when I give it steady throttle and it disappears when I let off or when I go WOT.Sorry for the long post but I wanted to give a detailed review for anyone thinking about this for their 5AT.
02-01-2008, 10:50 PM
#3
Originally Posted by fairladyinit
pshhhhh my car doesn't even have cruise control. Glad you enjoy the 3.5 drive, now I'm seriously considering it myself.
. Believe me it is worth it.
Last edited by Frostydc4; 02-01-2008 at 10:54 PM.
02-01-2008, 10:58 PM
#4
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Originally Posted by Frostydc4
I dont have the 3.5 FD I have the 3.9FD on my 5AT . Believe me it is worth it.
. Believe me it is worth it.
02-02-2008, 10:04 AM
#6
Originally Posted by jgregory124
need to start saving, about how much will this cost me?
Last edited by Frostydc4; 02-02-2008 at 02:30 PM.
02-02-2008, 10:13 AM
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damn ive been reading alot into this mod... I go to the track alot, i mean alot, and i want something to beat the damn srt-4's.I run 8.8-9.0 in the 1/8th, they r bout 8.4-8.8.....
I was thinking of going with the 4.08 gears. arent they a nissan frontier stock item and go for only 500 bucks brand new... Why wouldnt you go with this route? it is cheaper and a little more performance accleration wise isnt it?
I was thinking of going with the 4.08 gears. arent they a nissan frontier stock item and go for only 500 bucks brand new... Why wouldnt you go with this route? it is cheaper and a little more performance accleration wise isnt it?
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02-02-2008, 10:16 AM
#8
Originally Posted by 03zcarfl
damn ive been reading alot into this mod... I go to the track alot, i mean alot, and i want something to beat the damn srt-4's.I run 8.8-9.0 in the 1/8th, they r bout 8.4-8.8.....
I was thinking of going with the 4.08 gears. arent they a nissan frontier stock item and go for only 500 bucks brand new... Why wouldnt you go with this route? it is cheaper and a little more performance accleration wise isnt it?
I was thinking of going with the 4.08 gears. arent they a nissan frontier stock item and go for only 500 bucks brand new... Why wouldnt you go with this route? it is cheaper and a little more performance accleration wise isnt it?
Your 1/8 time & trap would definitely improve and it will help to get the heavy G coupe moving a little easier. I bought the pumpkin with the 3.9FD already installed so I had no incentive to go with the 4.08's. However, that may change after I get a more aggressive set of cams.
02-02-2008, 10:18 AM
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4.08 is what I want to go with also. Im just worried about traction with street tires. I already have 285's on the rear and I can totally break them loose in first and second with just the stock gear. Im sure with the 4.08 it will be SPINNNN city!!
02-02-2008, 10:22 AM
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yeah i had 295/30/19 and was spinning all through 1st and 2nd at WOT, now im running stock 18's 245/45 in rear. spun like crazy last time at track but it was 45 outside, too cold for great traction anyways....im going tomorrow and it going to be 65-70 out so maybe ill get way better traction....and get into the mid 8's..
btw, you said you would take to track? have you been already... what were you running and trapping... ive only run the 1/8th and my best is 8.801 and best trap is 82.4 mph... best 60' is 2.001.. i want a sub 2 so bad
btw, you said you would take to track? have you been already... what were you running and trapping... ive only run the 1/8th and my best is 8.801 and best trap is 82.4 mph... best 60' is 2.001.. i want a sub 2 so bad
02-02-2008, 10:26 AM
#11
Originally Posted by 03zcarfl
btw, you said you would take to track? have you been already... what were you running and trapping... ive only run the 1/8th and my best is 8.801 and best trap is 82.4 mph... best 60' is 2.001.. i want a sub 2 so bad
At the track I'm running at now my best time has been a 14.2@100 b/c of elevation & DA. At sea level I usually run 13.7-13.8 @ 102-103.
02-02-2008, 01:16 PM
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do you need to reflash it with osyris or techno square after install? how hard is it to install it? do you think you might burn out your differential if applying to much force to it?
02-02-2008, 01:47 PM
#18
Originally Posted by Dave B
It's too bad no one has come up with a fix that allows you still use the cruise control. There has to be a way to do it.
Originally Posted by spider310
do you need to reflash it with osyris or techno square after install? how hard is it to install it? do you think you might burn out your differential if applying to much force to it?
thinking of going with the 4.08 myself.
02-02-2008, 06:20 PM
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I just got mine in my 6mt HR...but ive only driven it 4 miles back from the shop...have to work 7 days in a row and its not the car I drive to work
Looking forward to my first day off though!
Looking forward to my first day off though!