3.5 Final Drive: Feedback please :)

KusoSama · 05-03-2011, 01:00 PM

So my buddy has a 350z which utilizes the 3.5 Final Drive and since he considerably needs more low end torque/acceleration he'd benefit more from our higher Final Drive. (ProAm Drifter)

Will this extremely small difference in Final Drive does anyone feel it'll dramatically affect my SRM experience?

Since I'm looking to go FI anyways I figure I could do this swap now to help my buddy and myself for the future.

Any other benefits from a Final Drive swap such like this where it's lowered instead of increased?

**EDIT**
What increases/decreases will I see for below?
MPG
Top MPH
Horsepower
Torque

Red__Zed · 05-03-2011, 01:07 PM

Even with FI, I wouldn't want to go with a 3.5. I believe most people experience intermittent issues with SRM when changing the final drive as well.

KusoSama · 05-03-2011, 01:43 PM

I'm actually curious how SRM would at all be affected by this since the way I understand it is that SRM will sense a gear change and then measure the RPM delta between transmission:engine and then correct by applying throttle electronically to match.

Wouldn't this mean that this electronic system should be independent of any mechanical updates?

Or is there an SRM hard coded input for calculation of throttle input to transmission RPM?

Red__Zed · 05-03-2011, 01:45 PM

Quote:

Originally Posted by KusoSama

I'm actually curious how SRM would at all be affected by this since the way I understand it is that SRM will sense a gear change and then measure the RPM delta between transmission:engine and then correct by applying throttle electronically to match.

Wouldn't this mean that this electronic system should be independent of any mechanical updates?

Or is there an SRM hard coded input for calculation of throttle input to transmission RPM?

I'm posting from my phone, so no detailed response right now, but check out the 4.08 thread.

KusoSama · 05-03-2011, 01:51 PM

Quote:

Originally Posted by Red__Zed

I'm posting from my phone, so no detailed response right now, but check out the 4.08 thread.

HEHE! I'll read the rest of it to see what they've experienced but that's actually part of the reason I spawned this alternative thread to track my experience with a swap from 3.69 to 3.54.

Thankfully my exhaust system mods have already netted gains in low end response so I possibly will feel closer to stock on low end.

I'll be happy to post all of my experiences though if any of you are interested.

esfourteen · 05-03-2011, 11:05 PM

3.5 to 3.69 or vice versa would not be very noticeable for either of you. for you decreasing to 3.5 would give you slightly better gas mileage, maybe 1mpg, your car would accelerate slightly slower. your top speed would technically increase, but you wouldnt be able to find out since you are drag limited. Even 4.08 gears can do over 167mph, how fast do you really need to be able to go? Also, changing final drive does not affect horsepower or torque at all.

Tell your friend to purchase 4.08's for his 350, you should leave your 3.6 alone.

Quote:

Originally Posted by KusoSama

So my buddy has a 350z which utilizes the 3.5 Final Drive and since he considerably needs more low end torque/acceleration he'd benefit more from our higher Final Drive. (ProAm Drifter)

Will this extremely small difference in Final Drive does anyone feel it'll dramatically affect my SRM experience?

Since I'm looking to go FI anyways I figure I could do this swap now to help my buddy and myself for the future.

Any other benefits from a Final Drive swap such like this where it's lowered instead of increased?

**EDIT**
What increases/decreases will I see for below?
MPG
Top MPH
Horsepower
Torque

Red__Zed · 05-03-2011, 11:45 PM

Quote:

Originally Posted by KusoSama

HEHE! I'll read the rest of it to see what they've experienced but that's actually part of the reason I spawned this alternative thread to track my experience with a swap from 3.69 to 3.54.

Thankfully my exhaust system mods have already netted gains in low end response so I possibly will feel closer to stock on low end.

I'll be happy to post all of my experiences though if any of you are interested.

You are more than welcome to do whatever you like to your car, but there is honestly no reason to move to a lower gear ratio. A lot of FI guys do it because they think they need traction, but that is absolutely misguided. The Z needs shorter gear from the factory, not taller ones.

KusoSama · 06-06-2011, 12:12 PM

I'd like to say that swapping did have a noticeable difference for both parties involved.

I'm much happier that my car is slightly less urgent in the low end gear changing and my buddy is much happier that his 350z gets into his power band much earlier for drifting.

Yes there isn't an uber difference between the two but small changes can become major improvements in either direction.

My question now is would the seal for a 370z pinion fit without modification with a 350z pinion?

05-03-2011, 01:00 PM	#1 (permalink)
KusoSama Base Member Join Date: Jul 2010 Location: UP Posts: 127 Drives: 2010 370Z Sport MB Rep Power: 15	3.5 Final Drive: Feedback please :) So my buddy has a 350z which utilizes the 3.5 Final Drive and since he considerably needs more low end torque/acceleration he'd benefit more from our higher Final Drive. (ProAm Drifter) Will this extremely small difference in Final Drive does anyone feel it'll dramatically affect my SRM experience? Since I'm looking to go FI anyways I figure I could do this swap now to help my buddy and myself for the future. Any other benefits from a Final Drive swap such like this where it's lowered instead of increased? EDIT What increases/decreases will I see for below? MPG Top MPH Horsepower Torque Last edited by KusoSama; 05-03-2011 at 05:09 PM. Reason: Added some structure

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05-03-2011, 01:07 PM	#2 (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	Even with FI, I wouldn't want to go with a 3.5. I believe most people experience intermittent issues with SRM when changing the final drive as well.

05-03-2011, 01:43 PM	#3 (permalink)
KusoSama Base Member Join Date: Jul 2010 Location: UP Posts: 127 Drives: 2010 370Z Sport MB Rep Power: 15	I'm actually curious how SRM would at all be affected by this since the way I understand it is that SRM will sense a gear change and then measure the RPM delta between transmission:engine and then correct by applying throttle electronically to match. Wouldn't this mean that this electronic system should be independent of any mechanical updates? Or is there an SRM hard coded input for calculation of throttle input to transmission RPM?

06-06-2011, 12:12 PM	#8 (permalink)
KusoSama Base Member Join Date: Jul 2010 Location: UP Posts: 127 Drives: 2010 370Z Sport MB Rep Power: 15	I'd like to say that swapping did have a noticeable difference for both parties involved. I'm much happier that my car is slightly less urgent in the low end gear changing and my buddy is much happier that his 350z gets into his power band much earlier for drifting. Yes there isn't an uber difference between the two but small changes can become major improvements in either direction. My question now is would the seal for a 370z pinion fit without modification with a 350z pinion?