Nissan 370Z Forum  

VHR + FD Gear Ratio upgrades - 3.9 and 4.08

So, does anyone know where the syncro rev match gets its speed signal to match the engine speed? If it is from the tranny itself then changing the rear end

Go Back   Nissan 370Z Forum > Nissan 370Z Tech Area > Engine & Drivetrain


Like Tree10Likes

Reply
 
LinkBack Thread Tools Display Modes
Old 08-14-2009, 01:37 AM   #1 (permalink)
Base Member
 
Join Date: Jul 2009
Location: Simi Valley
Posts: 38
Drives: 2009 370z white m6
Rep Power: 17
The Arp is on a distinguished road
Default

So, does anyone know where the syncro rev match gets its speed signal to match the engine speed? If it is from the tranny itself then changing the rear end ratio won't affect it right? The reason I ask is, I think changing the ratio on my 6 speed to 4.08 is next on my list since I really only drive my car for fun and the occasional errand. I auto-crossed it last weekend and the car is just a little weak coming out of the slower corners in second and this would be a very stealthy way to fix that. Now I just need to find a shop in the SFV to do the swap and get approval from my "boss".

Last edited by The Arp; 08-14-2009 at 09:52 AM.
The Arp is offline   Reply With Quote
Old 08-14-2009, 01:49 AM   #2 (permalink)
A True Z Fanatic
 
wstar's Avatar
 
Join Date: Mar 2009
Location: Houston, TX
Posts: 4,024
Drives: too slow
Rep Power: 3595
wstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond reputewstar has a reputation beyond repute
Default

Quote:
Originally Posted by The Arp View Post
So, does anyone know where the syncro rev match gets its speed signal to match the engine speed? If it is from the tranny itself then changing the rear end ratio won't affect it right?
SRM is based solely on the engine RPMs and the gear ratios in the 6MT. Your rear diff ratio can't affect it. Changing out gears in the 6MT would though.
__________________
7AT Track Car!
Journal thread / Car setup details
wstar is offline   Reply With Quote
Old 08-14-2009, 07:44 AM   #3 (permalink)
Enthusiast Member
 
Join Date: Apr 2009
Location: Jacksonville, NC
Posts: 453
Drives: 2009 Nissan 370z
Rep Power: 17
Solus will become famous soon enough
Default

Quote:
Originally Posted by Supergoji View Post
My Z32 comes with the 4.08 stock. people sell them very cheap on 300zxclub.com
Does the z32 have that same r200 diff as well?
Solus is offline   Reply With Quote
Old 08-22-2009, 03:49 PM   #4 (permalink)
Base Member
 
Join Date: Aug 2009
Location: St. James, NY
Posts: 237
Drives: 350Z
Rep Power: 16
Z1Performance is on a distinguished road
Default

Quote:
Originally Posted by Supergoji View Post
My Z32 comes with the 4.08 stock. people sell them very cheap on 300zxclub.com
Z32 rears will not fit into the 350Z, 370Z, they are totally different

FWIW, lots of cars (not just Nissan's) use the R200 - however, there are many flavors of R200, and not all swap with one another
Z1Performance is offline   Reply With Quote
Old 08-22-2009, 09:21 PM   #5 (permalink)
Base Member
 
Join Date: Mar 2009
Location: killeen tx
Posts: 202
Drives: black 09 370Z 6spd
Rep Power: 17
black09Z is on a distinguished road
Default

i wish i knew how to do this, or at least where to go to find out what i should get
black09Z is offline   Reply With Quote
Old 08-23-2009, 12:21 PM   #6 (permalink)
Base Member
 
Join Date: Aug 2009
Location: St. James, NY
Posts: 237
Drives: 350Z
Rep Power: 16
Z1Performance is on a distinguished road
Default

the 4.08 is without question the one to get. It's a big enough step up from the factory 3.7 that it will provide a noticeable change in acceleration, but without putting the car into some crazy rpm zone on the highway in 6th

Here is how it shakes out vs the stock 3.692 final drive. Tire used for these calculations is the 275/35/19 found in the sport package, and the factory 7500 red line. This is top speed per gear, based strictly on ratios. Obviously wind drag has a huge effect, but for purposes of this discussion it is not taken into account

Stock 3.692
1st Gear 42.36MPH
2nd Gear 69.15MPH
3rd Gear 98.95MPH
4th Gear 126.44MPH
5th Gear 160.7MPH
6th Gear 202.39MPH


4.08
1st Gear 38.33MPH
2nd Gear 62.57MPH
3rd Gear 89.54MPH
4th Gear 114.41MPH
5th Gear 145.42MPH
6th Gear 183.15MPH

As you can see, acceleration per gear will be ~10% quicker per gear, and top speed is reduced by ~10% per gear
370zrider and kinitox like this.
Z1Performance is offline   Reply With Quote
Old 08-28-2009, 01:25 PM   #7 (permalink)
Base Member
 
Join Date: Jul 2009
Location: Italy
Posts: 22
Drives: BMW 325i
Rep Power: 17
Luigi is on a distinguished road
Default

So has anyone put the 4.08 into a 370Z Manual Trans?
This would be the best bang for the buck mod!

Imagine a stock Zed with 4.08, HFC and ECU tune.
13-15% acceleration all around in every gear.
Luigi is offline   Reply With Quote
Old 09-07-2009, 10:45 PM   #8 (permalink)
A True Z Fanatic
 
NewYorkJon34's Avatar
 
Join Date: Jun 2009
Location: Naples, Florida
Posts: 3,041
Drives: 09 Fairlady Z
Rep Power: 1066
NewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond repute
Default

where can I buy these gears from + whats the price?
NewYorkJon34 is offline   Reply With Quote
Old 09-08-2009, 11:22 AM   #9 (permalink)
Base Member
 
Join Date: Aug 2009
Location: St. James, NY
Posts: 237
Drives: 350Z
Rep Power: 16
Z1Performance is on a distinguished road
Default

we offer them, and have tons of 350Z/G35 customers with them over the years

Z-1 Performance Automotive Services Inc. - 4.08 Final Drive for 350Z/G35
Z1Performance is offline   Reply With Quote
Old 09-08-2009, 12:34 PM   #10 (permalink)
A True Z Fanatic
 
NewYorkJon34's Avatar
 
Join Date: Jun 2009
Location: Naples, Florida
Posts: 3,041
Drives: 09 Fairlady Z
Rep Power: 1066
NewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond repute
Default

Wouldn't the 3.9 gear set be better for DD? plus I drive on the highways alot
NewYorkJon34 is offline   Reply With Quote
Old 09-08-2009, 06:37 PM   #11 (permalink)
Base Member
 
Join Date: Aug 2009
Location: St. James, NY
Posts: 237
Drives: 350Z
Rep Power: 16
Z1Performance is on a distinguished road
Default

there is a 4% difference between 3.9 and 4.08 - and a $200 price difference, and the nature of waiting for a special order - IMHO, not worth it, but it's a decision you need to make for yourself. Your money but the factory gears being what they are, it isn't worth the price of admission (to me) to swap in ones that are a measly 5% shorter....especially on a car that wants to rev like the VQ. Heck in my car, I run 3.9's now, built NA VQ35, redline at 8400, and I'm swapping them for 4.3's because the 3.9 just is not enough anymore

the 4.08 is perfect for the VQ35HR (2007-2008 350Z), and even more so for the torquier VQ37HR

Last edited by Z1Performance; 09-08-2009 at 06:43 PM.
Z1Performance is offline   Reply With Quote
Old 09-12-2009, 08:54 PM   #12 (permalink)
Base Member
 
Join Date: Aug 2009
Location: Cerritos, CA
Posts: 39
Drives: 08.5 mazdaspeed 3
Rep Power: 16
steven88 is on a distinguished road
Default

For those of you familiar with this modification, does it effect the overall speedometer/odometer numbers? Or what about Gas mileage numbers?

And also, I know changing the overall diameter of the rear tires will effect final drive gear ratio as well....stock overall diameter for 275/35/19 is 26.5...what overall diameter tire will be required to achieve the same numbers as 4.08 final drive gear ratio? Just curious thats all...I know some might be interested in changing the tire size instead of dropping the rear differential and opening the gear assembly
steven88 is offline   Reply With Quote
Old 09-13-2009, 09:08 PM   #13 (permalink)
Base Member
 
Join Date: Aug 2009
Location: St. James, NY
Posts: 237
Drives: 350Z
Rep Power: 16
Z1Performance is on a distinguished road
Default

Quote:
Originally Posted by steven88 View Post
For those of you familiar with this modification, does it effect the overall speedometer/odometer numbers? Or what about Gas mileage numbers?

And also, I know changing the overall diameter of the rear tires will effect final drive gear ratio as well....stock overall diameter for 275/35/19 is 26.5...what overall diameter tire will be required to achieve the same numbers as 4.08 final drive gear ratio? Just curious thats all...I know some might be interested in changing the tire size instead of dropping the rear differential and opening the gear assembly
speed is taken from the ABS sensor so zero issue with the speedometer

I currently have the 3.9 final drive in my 350Z. Stock final drive on the Z33 was 3.54 for manual trans. cars. So, about an 11% difference. My car gets exactly the same mileage with the gears as it did before them - ~320 miles before it needs to be filled. I've driven as far as 14 hours at a clip with them

you could not put a tire on the car that would equate to these gears. Tire changes amount to very small net changes in the final drive.
Z1Performance is offline   Reply With Quote
Old 09-12-2009, 09:04 PM   #14 (permalink)
A True Z Fanatic
 
NewYorkJon34's Avatar
 
Join Date: Jun 2009
Location: Naples, Florida
Posts: 3,041
Drives: 09 Fairlady Z
Rep Power: 1066
NewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond reputeNewYorkJon34 has a reputation beyond repute
Default

Would the 4.08 gears be good if my car is a daily driver?
NewYorkJon34 is offline   Reply With Quote
Old 09-13-2009, 09:09 PM   #15 (permalink)
Base Member
 
Join Date: Aug 2009
Location: St. James, NY
Posts: 237
Drives: 350Z
Rep Power: 16
Z1Performance is on a distinguished road
Default

Quote:
Originally Posted by NewYorkJon34 View Post
Would the 4.08 gears be good if my car is a daily driver?


there are hundreds of 350Z's using these in normal everyday use
Z1Performance is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Problem after some Audio Upgrades 209Z Audio & Video 1 06-13-2009 01:16 PM
6th Gear Syncros going after 5K. Scribe Engine & Drivetrain 50 05-22-2009 02:54 PM
first to second gear.. DJcuetip Nissan 370Z General Discussions 3 02-06-2009 10:42 PM
Top Gear? 370z2 Nissan 370Z General Discussions 1 02-03-2009 11:43 PM
Close ratio gears? tvfreakazoid Engine & Drivetrain 24 01-30-2009 03:44 PM


All times are GMT -5. The time now is 01:06 AM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.6.0 PL2