VHR + FD Gear Ratio upgrades - 3.9 and 4.08

Mike · 10-22-2009, 09:00 AM

Quote:

Originally Posted by Denny McLain

Kinda down to the wire on delivery as my flight to a meeting in San Francisco leaves later today. Hopefully Fed Ex will catch me before I leave. My wife is coming with me but returns before I do. Just something about spending money on parts and tearing apart a new car she just doesn't get. Everyone does that to their six month old car right?

Of course! Mine came straight home from the dealer and up on jack stands!

soaka1 · 10-23-2009, 03:52 PM

i had the 4:10 set up with spray and drags and i ran 12.6 at 118 for my very best time. nut now the car is in shop and ill have much longer gears for the twin turbo set up =]

cant wait !

mpp9 · 11-07-2009, 04:28 AM

I read on a 350z forum that an upgraded lsd is required to be able to handle the power from 4.08 gearing and bolt ons. 1st and 2nd gear just spin even with the viscous let alone the open diff that I have in mine right now. If that's even remotely true it'll affect us more having more power stock and making more power from bolton's than 350 hrs. Z eliminator said he had trouble getting traction from the 1 to 2 shift dragging but his is an automatic which is going to be harder to deal with than a manual I'd guess. Anyone think it's a waste to buy the gearing without going with a better lsd? Quaife, Kaaz, nismo, etc.

Z1Performance · 11-07-2009, 05:52 PM

Quote:

Originally Posted by mpp9

I read on a 350z forum that an upgraded lsd is required to be able to handle the power from 4.08 gearing and bolt ons. 1st and 2nd gear just spin even with the viscous let alone the open diff that I have in mine right now. If that's even remotely true it'll affect us more having more power stock and making more power from bolton's than 350 hrs. Z eliminator said he had trouble getting traction from the 1 to 2 shift dragging but his is an automatic which is going to be harder to deal with than a manual I'd guess. Anyone think it's a waste to buy the gearing without going with a better lsd? Quaife, Kaaz, nismo, etc.

Any aftermarket diff will improve traction, but the bulk of any spinning issue is in the tire/launch technique, and alignment. The aftermarket diffs really shine in the turns

That being said, an aftermarket lsd is a very, very worthwhile upgrade on any Z, especially if it's a base, but even vs the stock viscous (which is no bueno as it is). It all comes down to budget ultimately

racerxj17 · 11-07-2009, 07:40 PM

can someone provide a solid list of what install kit and gears are needed with part numbers? lots of people want to do this. IIRC the speedo is not affected correct?

mpp9 · 11-07-2009, 08:20 PM

Quote:

Originally Posted by Z1Performance

Any aftermarket diff will improve traction, but the bulk of any spinning issue is in the tire/launch technique, and alignment. The aftermarket diffs really shine in the turns

That being said, an aftermarket lsd is a very, very worthwhile upgrade on any Z, especially if it's a base, but even vs the stock viscous (which is no bueno as it is). It all comes down to budget ultimately

So ur saying the car handle the power in a straight line given good tires and driver? Im just worried 1st gear will be useless until i upgrade to a better lsd which is over a grand without install.

SOLISIMO · 11-07-2009, 09:19 PM

Im still wondering If I can do this on my G37

marcussoori · 11-17-2009, 10:17 PM

Someone, PLEASE update with part numbers and prices necessary.

Z1, please let us know when you will be updating your site and offering the complete kits for this install for the 370Z.

Finally, it would be great if someone could take pics of the install process...Denny, could you do this and post when you get yours installed? That would be awesome! And, it would reduce confusion by our respective mechanics and lower our install charges and hassles...

Thanks in advance...

SOLISIMO · 11-19-2009, 03:19 PM

bump........

Zsteve · 11-19-2009, 06:12 PM

so do we have to have an LSD to go to different FD gears or can us non LSD guys still do the gears?

mpp9 · 11-19-2009, 07:09 PM

Im doing hfcs intake and tune and see what kind of traction i have and go from there.

Z1Performance · 11-20-2009, 04:22 PM

The installation is not a DIY at all - you need a shop experienced with ring and pinions to handle it. It's not an install where pics will really help anyway - it's a direct swap for stock, and all the labor involved is in setting the spacing up/shims

For those interested, we have them available for purchase on our site:

http://www.z1auto.com/prodmore.asp?m...ne&prodid=4392

Z1Performance · 11-20-2009, 04:30 PM

Quote:

Originally Posted by Zsteve

so do we have to have an LSD to go to different FD gears or can us non LSD guys still do the gears?

nope, not necessary at all - as long as you have a manual transmission car, these will go right in!

Zsteve · 11-20-2009, 06:26 PM

I gots the 7AT so what would I need to change FD gears to 4.08?

Z1Performance · 11-20-2009, 07:05 PM

I have not looked into auto's at all, so I am afraid I can't answer that. On 350z's, you had to change the differential to one for a manual car in addition to the ring and pinion change. I don't know if it's the same on the 370Z or not though

10-23-2009, 03:52 PM	#92 (permalink)
soaka1 Base Member Join Date: Jan 2009 Location: florida Posts: 54 Drives: 370z 6sp gry. Rep Power: 16	i had the 4:10 set up with spray and drags and i ran 12.6 at 118 for my very best time. nut now the car is in shop and ill have much longer gears for the twin turbo set up =] cant wait ! __________________ 12.22 pass at 117 mph spinnin like hell

11-07-2009, 07:40 PM	#95 (permalink)
racerxj17 Track Member Join Date: Apr 2009 Location: Socal Posts: 555 Drives: 09 370z Rep Power: 17	can someone provide a solid list of what install kit and gears are needed with part numbers? lots of people want to do this. IIRC the speedo is not affected correct? __________________ 2009 PW Sport/Touring/Nav M6 Stillen Gen 3 Intake/CBE/Berk HFC/BC BR Coil over/Phillips 6500k/Hotchkis Sways/Stillen oil cooler/B&M SS

11-17-2009, 10:17 PM	#98 (permalink)
marcussoori Enthusiast Member Join Date: Mar 2009 Location: USA Posts: 468 Drives: 09 370Z Red AT Sport Rep Power: 16	Someone, PLEASE update with part numbers and prices necessary. Z1, please let us know when you will be updating your site and offering the complete kits for this install for the 370Z. Finally, it would be great if someone could take pics of the install process...Denny, could you do this and post when you get yours installed? That would be awesome! And, it would reduce confusion by our respective mechanics and lower our install charges and hassles... Thanks in advance... __________________ Stillen CBE & G3 LTIs, Motordyne M370, Berk HFCs, H&R 15/20mm spacers, CiNcity headlights, yellow OEM strut brace, Password: JDM CF engine bay parts, EVO-R CF front bumper parts, CF "Z" badge, VIS CF hood, Fujimura CF "diffuser", Show-N-Go plate frame, Katzkin red interior, interior CF, Pioneer BT-90 full system, Viper SmartStart

11-19-2009, 03:19 PM	#99 (permalink)
SOLISIMO Track Member Join Date: Apr 2009 Location: Florida Posts: 510 Drives: TOP SECRET G37S Rep Power: 17	bump........ __________________ AUTOKITS-X CF GRILLE l INJEN CAI l STILLEN SWAYS l MXP EXHAUST l LE CF MIRRORS l SSR'S l HANKOOK'S l TS COILOVERS l TS BUMPER l TS DIFFUSER l TS SIDE SKIRTS l SEIBON CF TS HOOD l TS AEROCATCH l 3K HID FOGS l KICS R40'S l ILLUMINATED SILLS l GROUNDING KIT l VLEDS l

11-19-2009, 06:12 PM	#100 (permalink)
Zsteve A True Z Fanatic Join Date: Sep 2009 Location: TX Posts: 3,298 Drives: the 2 balled club Rep Power: 22	so do we have to have an LSD to go to different FD gears or can us non LSD guys still do the gears? __________________ 2010 LS3 C6 Silver coupe corvette

11-07-2009, 04:28 AM	#93 (permalink)
mpp9 Base Member Join Date: Apr 2009 Location: Pittsburgh Posts: 103 Drives: 2012 sti Rep Power: 16	I read on a 350z forum that an upgraded lsd is required to be able to handle the power from 4.08 gearing and bolt ons. 1st and 2nd gear just spin even with the viscous let alone the open diff that I have in mine right now. If that's even remotely true it'll affect us more having more power stock and making more power from bolton's than 350 hrs. Z eliminator said he had trouble getting traction from the 1 to 2 shift dragging but his is an automatic which is going to be harder to deal with than a manual I'd guess. Anyone think it's a waste to buy the gearing without going with a better lsd? Quaife, Kaaz, nismo, etc.

11-07-2009, 09:19 PM	#97 (permalink)
SOLISIMO Track Member Join Date: Apr 2009 Location: Florida Posts: 510 Drives: TOP SECRET G37S Rep Power: 17	Im still wondering If I can do this on my G37

11-19-2009, 07:09 PM	#101 (permalink)
mpp9 Base Member Join Date: Apr 2009 Location: Pittsburgh Posts: 103 Drives: 2012 sti Rep Power: 16	Im doing hfcs intake and tune and see what kind of traction i have and go from there.

11-20-2009, 04:22 PM	#102 (permalink)
Z1Performance Base Member Join Date: Aug 2009 Location: St. James, NY Posts: 237 Drives: 350Z Rep Power: 16	The installation is not a DIY at all - you need a shop experienced with ring and pinions to handle it. It's not an install where pics will really help anyway - it's a direct swap for stock, and all the labor involved is in setting the spacing up/shims For those interested, we have them available for purchase on our site: http://www.z1auto.com/prodmore.asp?m...ne&prodid=4392 Last edited by Z1Performance; 11-20-2009 at 04:30 PM.

11-20-2009, 06:26 PM	#104 (permalink)
Zsteve A True Z Fanatic Join Date: Sep 2009 Location: TX Posts: 3,298 Drives: the 2 balled club Rep Power: 22	I gots the 7AT so what would I need to change FD gears to 4.08? __________________ 2010 LS3 C6 Silver coupe corvette

11-20-2009, 07:05 PM	#105 (permalink)
Z1Performance Base Member Join Date: Aug 2009 Location: St. James, NY Posts: 237 Drives: 350Z Rep Power: 16	I have not looked into auto's at all, so I am afraid I can't answer that. On 350z's, you had to change the differential to one for a manual car in addition to the ring and pinion change. I don't know if it's the same on the 370Z or not though

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