6 Speed Getrag Into A Gtt

[Marco-R34GTT]

Ok...

I wonder what the sixth gear ratio from the 350Z is in comparison to the fifth gear from the GTT...

If it is no taller then it kinda compromises my goal of a 'cruise' gear... I mean even a gain of a coouple of hundred rpm would suffice...

Where can I find some stats on the gear ratios from both the 350Z and the GTT??

[heller44]

350z.. 0.794

gtt.. 0.752

[GTS20X]

The cheapest & easiest way to drop the rpm a small amount would be to fit taller rear tyres.

[Marco-R34GTT]

  heller44 said:

350z.. 0.794

gtt.. 0.752

HHmmmmmm, what sort of a difference would that yield??? 150/200rpm???

[PT]

But the 6spd is going to be a close ratio box so you can run a lower final drive (ie 3.69) in the diff and still have good acceleration, yet 6th gear will be at much lower RPM on the highway even if 6th is near/same ratio as 5th in a 5spd. 9as opposed to 5spd with 4.11)

[Angus Smart]

If thats all you want to do is lower the revs while country driving a diff is surely going to be a cheeper option.

as for those who say the 34 getrag is weak? i'd like to know where you saw that!

[Marco-R34GTT]

  PT said:

But the 6spd is going to be a close ratio box so you can run a lower final drive (ie 3.69) in the diff and still have good acceleration, yet 6th gear will be at much lower RPM on the highway even if 6th is near/same ratio as 5th in a 5spd. 9as opposed to 5spd with 4.11)

Is the Zed's final drive 3.69 is it???

So what RPM difference would I acquire with 6th gear and the Zed box compared to 5th in my GTT box?

Edited January 21, 2008 by Marco-R34GTT

[heller44]

  Marco-R34GTT said:

HHmmmmmm, what sort of a difference would that yield??? 150/200rpm???

Wrong way matey. Zed box will make it rev higher at 110.

Looking at it, even dropping in 3.9:1 diff gears will be the only way to do it nicely (hopefully the speedo can be corrected with the speedo sender cog or something else) but even then its only about ~150rpm difference.. If you were looking for an increase in fuel economy i'd be looking somewhere else.

As an aside, I don't really mind the 4.375:1's in my car at highway speeds.

aussie zed specs.. http://www.nissan.com.au/z/specifications.asp

Edited January 21, 2008 by heller44

[Marco-R34GTT]

Even without the box swap, would the Zed's diff fit on the GTT with some modification???

[casuarina26]

Changing the Diff ratio would be the easiest. Prior to owning my R34 GT I had 2 commodores a black manual & a white auto (4 speed), both had the same diff ratio (3.08:1), the black manual at 110 kph sat on 2500 rpm where as the white auto at 110 kph sat at 2000 rpm, I did some research and found that the auto top gear was 0.70:1 & the manual 5th gear is 0.81:1. Now the Skyline 5th gear is in between the commodore at 0.759:1 with a 4.111 diff ratio.

So looking at it if you can get 3.08 diff ratio it should give you say 110kph @ 2250rpm or there abouts

Hope this can help,

Phillip

[R31Nismoid]

Dont forget also the R34GTR Diff's are a very different to accommodate the 6 speed's closer gearing.

So with a factory GT-t ratio diff, its going to be a bit silly with 4.11's

[Marco-R34GTT]

Yeah, thats got me thinking...

Obviously with the Zed's six speed box, and the GTT final drive, of course the revs would be higher..

However, if I manage to use the Zed's box with the equivalent ratio diff....

What I'd like to find out, if anyone here drives a 350Z, is what RPM they do at 120kph... Then I'd know whether the drivetrain would be suitable or not..

[casuarina26]

Check out this on eBay

http://cgi.ebay.com.au/3-45-ratio-diff-gea...0QQcmdZViewItem

Edited January 25, 2008 by casuarina26

[Marco-R34GTT]

That diff witht he 350Z box would be perfect...

[dead32]

convert it to a girlie box *auto*. it'll give you a nice overdrive and you could have it shift kitted so that when you wana give it some stick it'll do the job.

or wait auto's are heavier on the juice :S

[Marco-R34GTT]

I mean no malice when I say this...

But I'd rather torch my car than convert it to auto, I had an Auto N/A VL crumbledore and I will never drive another auto again....

[rockabilly]

just to help guys. the 32/33 5th gear is .83.

whereas the 34gtr 6th is .79

but the 32/33 rear diff is 4.11.1

the 34gtr rear diff is 3.45.1

hence the lower revs on the 34.

i am led to believe the reason nissan used the getrag box was to decrease the gaps between gears, hence quicker acceration as you are in the boost range more.. bernie

[Duncan]

350z doesn't really rev that low at 100, I'll check next time Kel lets me drive it, but it feels like 6th in the z = 5th in the stagea, so its no better. I think the z box is shorter in 1-4, i never use 5th and 6th like i said the same as 5th in other cars.

anway....diff is the simplest way to lower the overall revs.

[Marco-R34GTT]

Yeah I realise that, I'm just hoping not to entirely kill the acceleration either... Shorter ratios allow for sharper acceleration whilst the taller final drive will allow me some scope to 'cruise' in top gear...

If that makes sense, sry, I'm posting after a very big aussie daayy..

[Marco-R34GTT]

Ok Folks, I asked Yo-Yo, who owns both an R34 GTT and a 350Z to take both for a spin and see what RPM's both cars achieved @ 110kph.

Here are the results for anyone who is interested...

  Quote

Hi mate,

Got around to seeing the rpms for ya:

GT- T: 2,900RPM @ 110km/h (5th gear)

350 Z: 3,000RPM @ 110km/h (5th gear)

2,400RPM @ 110km/h (6th gear)

Good luck with the eventual conversion

hope that helps;

PJ