No Gearbox Chatter?

semtex · 06-25-2009, 06:48 AM

Hmm . . . it's a little hard to compare the two vehicles, but I'll try.

The shifter was a lot smoother on the S2K, and it had to have had a much lighter flywheel. Noise-wise, hard to say as that entire car was noisy (which might be why the Z never bothered me). But I say that it's hard to compare because the S2K was so low on torque, and it had a 9000 rpm where you didn't even really get any decent power until 6000 rpm! So it's easy for the transmission to be smoother on the S2K when it didn't have to handle as much torque. Plus that flywheel had to be light in order to spool up to 6k rpm in a half-decent amount of time, and I think the lightness of the flywheel also aided the smooth 'feel' of the transmission. You know how in the Z if you downshift without rev-matching it feels really jerky? Well in the S2K you could downshift like that and the transmission would hardly jerk. It'd 'absorb' the mismatched revs much easier. That's all down to the weight of the flywheel. The reason it jerks so hard in the Z is because it has a heavy flywheel, which means more rotational inertia. So the S2K's tranny was smoother, but it's easy to be smooth when you're low on torque and have a lightweight flywheel. Swapping the Z's stock flywheel for a lightweight one would help, but noise will go up.

6SPD_FTW · 06-28-2009, 08:14 AM

As far as low-end torque is concerned, I came from a 2007 Altima 3.5SE 6MT. Now, as far as low-end torque from a V6...AMAZING!! The VQ35DE was absolutely fantastic in low-rpms! Had a VERY smooth/flat torque curve!! I loved it! I could EASILY shift gears without EVER getting over 1500rpms and still had plenty enough power to accelerate and keep up with traffic. It is a fantastic drivetrain.

THEN, I hopped into the Z and thought "what crap from a 3.7L V6". BUT, after I've broken it in fully, this engine has damn decent low-end torque! I can still shift through the gears @ 1500rpm and have plenty of power to accelerate! I think the amazing top-end kind of overshadows the low-end on the VQ37HR. It's just the peaky powerband on this engine that makes you think that the VQ37HR has no low-end, but it really does!! LOL.

Either way, I have the clunk in the transmission and I hear it ALL the time on the 1-2, 2-3, and sometimes the 3-4 shift! But I like it! Sounds aggressive, I think! Although....I also have the notorious 6th gear grind. The 6th gear syncro is just GONE! Even shifting from 5-6, I get crunching when shifting normally. So, I developed that little problem @ around 5000 mi, and now have 7000. It will be going back to the dealer, but if I shift slowly into 6th, it is fine. So, I've just been living with it til now. Add another to the BAD 6th gear synchro thread! LOL.

Late,
Trav

06-25-2009, 06:48 AM	#1 (permalink)
semtex A True Z Fanatic Join Date: Jan 2009 Location: Behind enemy lines Age: 54 Posts: 5,995 Drives: People to drink Rep Power: 33	Hmm . . . it's a little hard to compare the two vehicles, but I'll try. The shifter was a lot smoother on the S2K, and it had to have had a much lighter flywheel. Noise-wise, hard to say as that entire car was noisy (which might be why the Z never bothered me). But I say that it's hard to compare because the S2K was so low on torque, and it had a 9000 rpm where you didn't even really get any decent power until 6000 rpm! So it's easy for the transmission to be smoother on the S2K when it didn't have to handle as much torque. Plus that flywheel had to be light in order to spool up to 6k rpm in a half-decent amount of time, and I think the lightness of the flywheel also aided the smooth 'feel' of the transmission. You know how in the Z if you downshift without rev-matching it feels really jerky? Well in the S2K you could downshift like that and the transmission would hardly jerk. It'd 'absorb' the mismatched revs much easier. That's all down to the weight of the flywheel. The reason it jerks so hard in the Z is because it has a heavy flywheel, which means more rotational inertia. So the S2K's tranny was smoother, but it's easy to be smooth when you're low on torque and have a lightweight flywheel. Swapping the Z's stock flywheel for a lightweight one would help, but noise will go up. __________________ "There are no small accidents on this circuit." -- Ayrton Senna 316.8whp & 248 ft/lbs (Dyno Dynamics) \| 319whp & 256 ft/lbs (DynoJet) (04/23/10) Stillen G3 CAI, CBE, Pulley / F.I. LTH / GTSpec Ladder Brace / Setrab Oil Cooler / UpRev-tuned by Forged Perf.

06-28-2009, 08:14 AM	#2 (permalink)
6SPD_FTW Base Member Join Date: May 2009 Location: Bristol, VA Posts: 59 Drives: 09 370Z Bl 6MT Rep Power: 16	As far as low-end torque is concerned, I came from a 2007 Altima 3.5SE 6MT. Now, as far as low-end torque from a V6...AMAZING!! The VQ35DE was absolutely fantastic in low-rpms! Had a VERY smooth/flat torque curve!! I loved it! I could EASILY shift gears without EVER getting over 1500rpms and still had plenty enough power to accelerate and keep up with traffic. It is a fantastic drivetrain. THEN, I hopped into the Z and thought "what crap from a 3.7L V6". BUT, after I've broken it in fully, this engine has damn decent low-end torque! I can still shift through the gears @ 1500rpm and have plenty of power to accelerate! I think the amazing top-end kind of overshadows the low-end on the VQ37HR. It's just the peaky powerband on this engine that makes you think that the VQ37HR has no low-end, but it really does!! LOL. Either way, I have the clunk in the transmission and I hear it ALL the time on the 1-2, 2-3, and sometimes the 3-4 shift! But I like it! Sounds aggressive, I think! Although....I also have the notorious 6th gear grind. The 6th gear syncro is just GONE! Even shifting from 5-6, I get crunching when shifting normally. So, I developed that little problem @ around 5000 mi, and now have 7000. It will be going back to the dealer, but if I shift slowly into 6th, it is fine. So, I've just been living with it til now. Add another to the BAD 6th gear synchro thread! LOL. Late, Trav