4.08 Final drive - feedback please

KusoSama · 05-03-2011, 02:22 PM

Quote:

Originally Posted by Kastley85891

^My budget all in was about 1500 bucks so looks a go go, thx for information

Have you finished install on this update?

I'm interested how you're liking it.

I have a thread about going in the opposite direction with the axle ratio.

Kastley85891 · 05-03-2011, 03:49 PM

Not even got parts as yet but thinking on it,,, 2 of my 4 kids at docs this week so just dropped 700 bucks, on hold for a little while, but will get it done.

Red__Zed · 05-03-2011, 04:18 PM

I'm hoping to make this switch soon.

Z eliminator · 05-03-2011, 04:37 PM

The 4.08 's work great with my 7 AT. 1/8 mile in 8.01 seconds, the 1/4 in 12.42 @114.3. Im turning 6000 rpm in 5th.
The diference in rpm is aprox, 700 to 800 rpm more and fuel consuption goes from 37.5 to 31.5 mpg.
2nd gear is the gear of punishment as the car just screams. Now hold the gas and brake at 2200 rpm and launch the car . It becomes a cruise missle. I shift at 7800 to 7900 rpm.
3rd gear is also very powerful and fast.

KusoSama · 05-03-2011, 05:03 PM

Quote:

Originally Posted by Z eliminator

fuel consumption goes from 37.5 to 31.5 mpg.

Is that really in the 30s for you?? :O

murphman · 05-03-2011, 05:07 PM

Quote:

Originally Posted by Z eliminator

The 4.08 's work great with my 7 AT. 1/8 mile in 8.01 seconds, the 1/4 in 12.42 @114.3. Im turning 6000 rpm in 5th.
The diference in rpm is aprox, 700 to 800 rpm more and fuel consuption goes from 37.5 to 31.5 mpg.
2nd gear is the gear of punishment as the car just screams. Now hold the gas and brake at 2200 rpm and launch the car . It becomes a cruise missle. I shift at 7800 to 7900 rpm.
3rd gear is also very powerful and fast.

whaaa 37 mpg?

Zat_Zuma · 05-03-2011, 10:56 PM

I found that the 4.08 gears are too much gear for the manual transmission drivers. The shifts between 1'st and 2'nd are so quick, I bounced off the rev limiter far too many times in first and second gears.

The SRM seemed to be out a few hundred RPM but either it has adapted or I'm use to it now as I barely notice it.

I've changed my rear diff to the 3.9 gearset from the 4.08 and hopefully this will make the 1'st and 2'nd shifting easier, SRM and less rev limiter bounces.

Time will tell.

chuckd05 · 05-03-2011, 11:06 PM

I have the 4.08s and have no complaints.. i took videos of myself at different cruising speeds before and after and i forget the exact difference it was but it was only like 4-500 rpms... at 80 i think I'm at 3500 or so... for some that may be too high but I still get 24+ on highway and 15-17 city... This really all depends on your right foot though, the FD def didn't hurt the gas substantially...

I myself don't have a problem hitting 2nd, its not all that quick IMO, top end wasn't hurt that much at all but the final drive does help you down low more than up top... the car "feels" much faster and its faster but not like night and day you know...

but note the two best times for us 370s have 4.08 FD, one auto (z elim ) 1 6M....

i went 12.94 without the final drive but have yet to go back... swapping to 305s and the GTS's helped with traction from my stock sized nt05s that were worn down when i installed the final drive... the worn tires had a little traction issue in first after final drive...

also note that i do not have SRM so i can not tell you how it effects it... my right foot works just the same as it did before the install tho!

Is it worth the money ? I am sure, its up to the person... If you plan to go FI at any point, obviously don't do it.. but if you want to optimize your car NA'ed than go for it..

jnaut · 05-03-2011, 11:30 PM

Ok , you will lose cruise control with and auto on these gears, top speed not so much as i have gone 167 with limiter removed. i usually charge about 1100$ for the gears installed so this will help you to have an idea on cost. The SRM will be off about 300ish rpm. I have had the SRM shut down from time to time doing high speed runs , typically 120+ speed. I have not installed the gears on an auto yet, but i do know the carrier is different from the auto to manual. So i can to be sure the these gears will bolt to an auto carrier. to be sure you will need to find a manual diff from a 370 or later model 350. I have heard that the diff from the 350s will fit but the pinion flange is different, so that will have to be swapped, no big deal. The gears will make a HUGE difference !!
Also if you need the gears let me know as i can get them at a great price!!

Red__Zed · 05-03-2011, 11:34 PM

^ pm price?

jnaut · 05-03-2011, 11:38 PM

Quote:

Originally Posted by Red__Zed

^ pm price?

ok i will tomorrow

FL 4Motion · 05-04-2011, 12:52 AM

Quote:

Originally Posted by jnaut

Ok , you will lose cruise control with and auto on these gears, top speed not so much as i have gone 167 with limiter removed. i usually charge about 1100$ for the gears installed so this will help you to have an idea on cost. The SRM will be off about 300ish rpm. I have had the SRM shut down from time to time doing high speed runs , typically 120+ speed. I have not installed the gears on an auto yet, but i do know the carrier is different from the auto to manual. So i can to be sure the these gears will bolt to an auto carrier. to be sure you will need to find a manual diff from a 370 or later model 350. I have heard that the diff from the 350s will fit but the pinion flange is different, so that will have to be swapped, no big deal. The gears will make a HUGE difference !!
Also if you need the gears let me know as i can get them at a great price!!

Jnaut, I have a quick ? regarding the 4:08s.

Our car will be seeing it's share of HPDE track days. Obviously the gears are a big improvement for drag racing, what would be the pros and cons for track use? I've gotten conflicting opinions on the gears for track use. Thanks.

Mr&Mrs · 05-04-2011, 12:44 PM

Quote:

Originally Posted by Z eliminator

The 4.08 's work great with my 7 AT. 1/8 mile in 8.01 seconds, the 1/4 in 12.42 @114.3. Im turning 6000 rpm in 5th.
The diference in rpm is aprox, 700 to 800 rpm more and fuel consuption goes from 37.5 to 31.5 mpg.
2nd gear is the gear of punishment as the car just screams. Now hold the gas and brake at 2200 rpm and launch the car . It becomes a cruise missle. I shift at 7800 to 7900 rpm.
3rd gear is also very powerful and fast.

I think he meant 27/21. Z since you seem to be the only 7AT to chime in on this I would benefit asking you some more direct questions.

How has your SRM been effected?
What is your RPM's at 80 considering this is my average speed in the interstate.

Thanks!

Quote:

Originally Posted by jnaut

Ok , you will lose cruise control with and auto on these gears, top speed not so much as i have gone 167 with limiter removed. i usually charge about 1100$ for the gears installed so this will help you to have an idea on cost. The SRM will be off about 300ish rpm. I have had the SRM shut down from time to time doing high speed runs , typically 120+ speed. I have not installed the gears on an auto yet, but i do know the carrier is different from the auto to manual. So i can to be sure the these gears will bolt to an auto carrier. to be sure you will need to find a manual diff from a 370 or later model 350. I have heard that the diff from the 350s will fit but the pinion flange is different, so that will have to be swapped, no big deal. The gears will make a HUGE difference !!
Also if you need the gears let me know as i can get them at a great price!!

J would you be willing to source all the parts I need to get this done on my 7AT?

Thanks everyone has been given rep that has helped me!

Z eliminator · 05-04-2011, 06:31 PM

My gas milage is in Canadian gals. Converted to US gal it would be 31.25 and it droped to 26.25 mpg.

Z

Kastley85891 · 05-04-2011, 06:49 PM

Jnaut - full install kit price PM please...

05-03-2011, 03:49 PM	#17 (permalink)
Kastley85891 A True Z Fanatic Join Date: Nov 2009 Location: ATX 370 - Sold Posts: 1,149 Drives: 2003 Wagon Rep Power: 18	Not even got parts as yet but thinking on it,,, 2 of my 4 kids at docs this week so just dropped 700 bucks, on hold for a little while, but will get it done. __________________ Boosted V8 hunter 2850 lbs and 375WHP

05-03-2011, 04:37 PM	#19 (permalink)
Z eliminator A True Z Fanatic Join Date: Jul 2009 Location: Ontario Canada Posts: 1,659 Drives: 370 Z 7AT Sports Rep Power: 19	The 4.08 's work great with my 7 AT. 1/8 mile in 8.01 seconds, the 1/4 in 12.42 @114.3. Im turning 6000 rpm in 5th. The diference in rpm is aprox, 700 to 800 rpm more and fuel consuption goes from 37.5 to 31.5 mpg. 2nd gear is the gear of punishment as the car just screams. Now hold the gas and brake at 2200 rpm and launch the car . It becomes a cruise missle. I shift at 7800 to 7900 rpm. 3rd gear is also very powerful and fast. Smashley likes this. __________________ 12.343 @114.14 . 4.5 stroker motor is now being built. Dec 1 2015.

05-03-2011, 10:56 PM	#22 (permalink)
Zat_Zuma A True Z Fanatic Join Date: Nov 2008 Location: Edmonton, Alberta ...eh Posts: 1,171 Drives: 2017 Touring auto Rep Power: 19	I found that the 4.08 gears are too much gear for the manual transmission drivers. The shifts between 1'st and 2'nd are so quick, I bounced off the rev limiter far too many times in first and second gears. The SRM seemed to be out a few hundred RPM but either it has adapted or I'm use to it now as I barely notice it. I've changed my rear diff to the 3.9 gearset from the 4.08 and hopefully this will make the 1'st and 2'nd shifting easier, SRM and less rev limiter bounces. Time will tell. __________________ [B]2009 & 2017 370Z Touring Sport Autos SOLD

05-03-2011, 11:06 PM	#23 (permalink)
chuckd05 A True Z Fanatic Join Date: Oct 2009 Location: NY Posts: 2,391 Drives: No longer a Z Rep Power: 20	I have the 4.08s and have no complaints.. i took videos of myself at different cruising speeds before and after and i forget the exact difference it was but it was only like 4-500 rpms... at 80 i think I'm at 3500 or so... for some that may be too high but I still get 24+ on highway and 15-17 city... This really all depends on your right foot though, the FD def didn't hurt the gas substantially... I myself don't have a problem hitting 2nd, its not all that quick IMO, top end wasn't hurt that much at all but the final drive does help you down low more than up top... the car "feels" much faster and its faster but not like night and day you know... but note the two best times for us 370s have 4.08 FD, one auto (z elim ) 1 6M.... i went 12.94 without the final drive but have yet to go back... swapping to 305s and the GTS's helped with traction from my stock sized nt05s that were worn down when i installed the final drive... the worn tires had a little traction issue in first after final drive... also note that i do not have SRM so i can not tell you how it effects it... my right foot works just the same as it did before the install tho! Is it worth the money ? I am sure, its up to the person... If you plan to go FI at any point, obviously don't do it.. but if you want to optimize your car NA'ed than go for it.. __________________ 09 370Z 6M PW - FBO Best 1/4 mile = 12.926 @ 109 SOLD -- 08 BMW 135i - FBO 12.1@120mph SOLD -- white 09 e92 335 Coupe Mtech - 11.9 @ 119 :-)

05-03-2011, 11:30 PM	#24 (permalink)
jnaut A True Z Fanatic Join Date: Dec 2009 Location: wpb, fl Posts: 1,146 Drives: 09 370z Rep Power: 18	Ok , you will lose cruise control with and auto on these gears, top speed not so much as i have gone 167 with limiter removed. i usually charge about 1100$ for the gears installed so this will help you to have an idea on cost. The SRM will be off about 300ish rpm. I have had the SRM shut down from time to time doing high speed runs , typically 120+ speed. I have not installed the gears on an auto yet, but i do know the carrier is different from the auto to manual. So i can to be sure the these gears will bolt to an auto carrier. to be sure you will need to find a manual diff from a 370 or later model 350. I have heard that the diff from the 350s will fit but the pinion flange is different, so that will have to be swapped, no big deal. The gears will make a HUGE difference !! Also if you need the gears let me know as i can get them at a great price!! __________________ Best 1/4 mile 12.24 Best mph 114.5_______

05-03-2011, 04:18 PM	#18 (permalink)
Red__Zed A True Z Fanatic Join Date: Jul 2010 Location: window seat Posts: 28,940 Drives: Mostly on two wheels Rep Power: 120	I'm hoping to make this switch soon.

05-03-2011, 11:34 PM	#25 (permalink)
Red__Zed A True Z Fanatic Join Date: Jul 2010 Location: window seat Posts: 28,940 Drives: Mostly on two wheels Rep Power: 120	^ pm price?

05-04-2011, 06:31 PM	#29 (permalink)
Z eliminator A True Z Fanatic Join Date: Jul 2009 Location: Ontario Canada Posts: 1,659 Drives: 370 Z 7AT Sports Rep Power: 19	My gas milage is in Canadian gals. Converted to US gal it would be 31.25 and it droped to 26.25 mpg. Z __________________ 12.343 @114.14 . 4.5 stroker motor is now being built. Dec 1 2015.

05-04-2011, 06:49 PM	#30 (permalink)
Kastley85891 A True Z Fanatic Join Date: Nov 2009 Location: ATX 370 - Sold Posts: 1,149 Drives: 2003 Wagon Rep Power: 18	Jnaut - full install kit price PM please... __________________ Boosted V8 hunter 2850 lbs and 375WHP

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