3.3 vs 3.69 Final Drive with FI setup

Diabel · 08-13-2014, 05:42 PM

To boosted guys: has anyone here with MT and FI done a final drive change from OEM 3.69 MT to 3.3 AT? How much does that help with e.g. 1/4 mile time? Is that worthy of 0.2-0.4s less for 1/4 mile?

DEpointfive0 · 08-13-2014, 06:02 PM

There are a few who have. If their names pop into my head I'll PM them to chime in...

If you WANT to make the switch, I'm more than happy to swap with you!!!

Diabel · 08-13-2014, 06:16 PM

Quote:

Originally Posted by DEpointfive0

There are a few who have. If their names pop into my head I'll PM them to chime in...

If you WANT to make the switch, I'm more than happy to swap with you!!!

I hope someone done it before and will share with us some results, I know that 1&2 gear traction should be better but would that be a real gain with better time on 1/4? I already have the Racelogic Traction Control, Whiteline bushings, Toyo r888 and looking something more...

Mitco39 · 08-13-2014, 06:24 PM

Quote:

Originally Posted by Diabel

I hope someone done it before and will share with us some results, I know that 1&2 gear traction should be better but would that be a real gain with better time on 1/4? I already have the Racelogic Traction Control, Whiteline bushings, Toyo r888 and looking something more...

Your working against physics. There is only so much traction available at any given time. Changing gear ratios does not change the amount of torque you can apply to the wheels before slipping. If you want to control your slippage you have to control the torque, this can be done through a boost controller that limits boost on throttle position and rpm. The torque can be "curved" to only increase in the upper rpms where it can become usable.

R3drckt09 · 08-13-2014, 06:29 PM

I did, got the diff from an auto 350z so it's a 3.3 vlsd. I guess I don't have a lot of info though since I swapped before I went FI, and I haven't really launched my car yet (still getting used to the new power). It seems like everyone has traction issues in 2nd even from rolls though, and while it spins into 2nd if say I do a 20 roll from 1st and then shift into 2nd, if I'm going like 35 and mash it in second it kinda chirps and then grabs.

1slow370 · 08-13-2014, 06:30 PM

oooorr you can put a 3.33 rear gear in like he is suggesting and reduce the torque delivered to the wheels by 11%. FYI that is why nissan puts a 2.66 rear gear on the m56

most porsches and supercars with "more traction" also happen to be gear 10-20% higher than the factory z. the more torque you have in a light car, the higher you you want the gearing to be control delivered torque.

R3drckt09 · 08-13-2014, 06:40 PM

Yeah look at the ZR1, thing does like 66mph in first gear lol. Probably a big part of why it's 0-60 is so fast

Nixlimited · 08-13-2014, 07:23 PM

Edited...

There are other consequences of the switch that have kept me from doing it thus far. First, SRM will not work well the farther you get away from the factory MT rear end ratio. My guess is 3.53 is not that big of a deal, but 3.3 could be. Also, cruise control will not work properly in at least 6th gear with even the 3.53 (I believe) and definitely not with the 3.3. I can't be without cruise control!

R3drckt09 · 08-13-2014, 07:47 PM

Yep, did lose cruise in 6th gear (which is like the most important one lol)

1slow370 · 08-13-2014, 08:10 PM

Quote:

Originally Posted by Nixlimited

There are other consequences of the switch that have kept me from doing it thus far. First, SRM will not work well the farther you get away from the factory MT rear end ratio. My guess is 3.69 is not that big of a deal, but 3.3 could be. Also, cruise control will not work properly in at least 6th gear with even the 3.69 (I believe) and definitely not with the 3.3. I can't be without cruise control!

Just an FYI the factory MT rear end ratio that is in your car is already 3.69

Cell · 08-13-2014, 09:25 PM

Can a tuner adjust SRM to match a 3.3 gear?

esfourteen · 08-13-2014, 09:54 PM

Quote:

Originally Posted by Cell

Can a tuner adjust SRM to match a 3.3 gear?

You can with ecutek. I'm running the 350z 3.52 final drive and the SRM is close enough to still work well and you don't lose cruise control like the 3.3 does, but 3.3 is your best bet for a twin turbo if you want the most traction, no question.

esfourteen · 08-13-2014, 09:59 PM

Quote:

Originally Posted by 1slow370

oooorr you can put a 3.33 rear gear in like he is suggesting and reduce the torque delivered to the wheels by 11%. FYI that is why nissan puts a 2.66 rear gear on the m56

most porsches and supercars with "more traction" also happen to be gear 10-20% higher than the factory z. the more torque you have in a light car, the higher you you want the gearing to be control delivered torque.

exactly. another example are the twin turbo 1/3 series BMW's that have a 3.0 final drive as well and don't have anywhere near the traction issues we do while running smaller tires and better 1/4 mile times.

phunk · 08-14-2014, 12:06 AM

I did the 3.3 in my 350z and it was worth it. I plan to with my 370.

dang, I didnt know the 370z dropped cruise with the 3.3. Hmm, I will have to ponder why the cruise control cares about the final drive. I figured it would just be a wheel speed based thing, and it would adjust throttle to achieve the target wheel speed. Anyone clear on why we lose cruise? I am drawing a blank at the moment.

Cell · 08-14-2014, 12:20 AM

Quote:

Originally Posted by esfourteen

You can with ecutek. I'm running the 350z 3.52 final drive and the SRM is close enough to still work well and you don't lose cruise control like the 3.3 does, but 3.3 is your best bet for a twin turbo if you want the most traction, no question.

Anyone know if uprev can do it?

08-13-2014, 05:42 PM	#1 (permalink)
Diabel Base Member Join Date: Sep 2012 Location: Bensenville IL Posts: 103 Drives: 370z Rep Power: 13	3.3 vs 3.69 Final Drive with FI setup To boosted guys: has anyone here with MT and FI done a final drive change from OEM 3.69 MT to 3.3 AT? How much does that help with e.g. 1/4 mile time? Is that worthy of 0.2-0.4s less for 1/4 mile?

08-13-2014, 06:02 PM	#2 (permalink)
DEpointfive0 Premium Member Bitches Join Date: Jan 2012 Location: SoCal Posts: 14,824 Drives: a lot Rep Power: 17151	There are a few who have. If their names pop into my head I'll PM them to chime in... If you WANT to make the switch, I'm more than happy to swap with you!!! __________________ Do YOU want to know what/where I got my username from? ( Click to show/hide ) NSFW due to language:

08-13-2014, 06:30 PM	#6 (permalink)
1slow370 A True Z Fanatic Join Date: Aug 2009 Location: In the D Posts: 3,732 Drives: v8 74 260z ;) Rep Power: 7251	oooorr you can put a 3.33 rear gear in like he is suggesting and reduce the torque delivered to the wheels by 11%. FYI that is why nissan puts a 2.66 rear gear on the m56 most porsches and supercars with "more traction" also happen to be gear 10-20% higher than the factory z. the more torque you have in a light car, the higher you you want the gearing to be control delivered torque. __________________ ANSWER PRICE LIST Answers - - - - - - - - - - - - - - - - $0.75 Answers (requiring thought) - - - - $1.25 Answers (correct) - - - - - - - - - - $12.50 Last edited by 1slow370; 08-13-2014 at 06:34 PM.

08-13-2014, 07:23 PM	#8 (permalink)
Nixlimited A True Z Fanatic Join Date: Aug 2009 Location: San Diego Posts: 1,235 Drives: 15 GT-R / 11 Prius Rep Power: 26	Edited... There are other consequences of the switch that have kept me from doing it thus far. First, SRM will not work well the farther you get away from the factory MT rear end ratio. My guess is 3.53 is not that big of a deal, but 3.3 could be. Also, cruise control will not work properly in at least 6th gear with even the 3.53 (I believe) and definitely not with the 3.3. I can't be without cruise control! __________________ Car Sold! Pleasure being a part of the Z community. New ride: 2015 GT-R - 647 WHP / 641 WTQ (e85) & 543 WHP / 519 WTQ (91) Last edited by Nixlimited; 08-14-2014 at 10:37 AM.

08-14-2014, 12:06 AM	#14 (permalink)
phunk A True Z Fanatic Join Date: Mar 2009 Location: Chicago Posts: 3,668 Drives: 370 Rep Power: 974723	I did the 3.3 in my 350z and it was worth it. I plan to with my 370. dang, I didnt know the 370z dropped cruise with the 3.3. Hmm, I will have to ponder why the cruise control cares about the final drive. I figured it would just be a wheel speed based thing, and it would adjust throttle to achieve the target wheel speed. Anyone clear on why we lose cruise? I am drawing a blank at the moment. __________________ Charles @ CJ Motorsports : Website \| Facebook \| Instagram \| YouTube Home of the 9 second, stock longblock, stock drivetrain 6MT 370z. 9.91 @ 142mph

08-13-2014, 06:29 PM	#5 (permalink)
R3drckt09 Base Member Join Date: Jul 2013 Location: Texas Posts: 145 Drives: 09 Nissan 370Z Base Rep Power: 12	I did, got the diff from an auto 350z so it's a 3.3 vlsd. I guess I don't have a lot of info though since I swapped before I went FI, and I haven't really launched my car yet (still getting used to the new power). It seems like everyone has traction issues in 2nd even from rolls though, and while it spins into 2nd if say I do a 20 roll from 1st and then shift into 2nd, if I'm going like 35 and mash it in second it kinda chirps and then grabs.

08-13-2014, 06:40 PM	#7 (permalink)
R3drckt09 Base Member Join Date: Jul 2013 Location: Texas Posts: 145 Drives: 09 Nissan 370Z Base Rep Power: 12	Yeah look at the ZR1, thing does like 66mph in first gear lol. Probably a big part of why it's 0-60 is so fast

08-13-2014, 07:47 PM	#9 (permalink)
R3drckt09 Base Member Join Date: Jul 2013 Location: Texas Posts: 145 Drives: 09 Nissan 370Z Base Rep Power: 12	Yep, did lose cruise in 6th gear (which is like the most important one lol)

08-13-2014, 09:25 PM	#11 (permalink)
Cell A True Z Fanatic Join Date: Jan 2010 Location: Chicago Posts: 1,449 Drives: A Garbage Truck Rep Power: 21	Can a tuner adjust SRM to match a 3.3 gear?

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