Irn Bru Posted November 24, 2016 Share Posted November 24, 2016 I'm not the most techy guy and have trouble getting to grips with diff tech talk. Can a member who does know the techy stuff explain (in layman terms) what the different diffs and ratios mean and do and whats best for fast road use and if you do change the diff / ratio, does it go hand in hand with upgraded suspension ? Looking at this as a mod for next year if there is an real difference in the feel and power delivery of the car in doing this. Or if this has been covered before can you point me to the link as I cant find what I looking for exactly. Quote Link to comment Share on other sites More sharing options...
StevoD Posted November 24, 2016 Share Posted November 24, 2016 1 Quote Link to comment Share on other sites More sharing options...
brillomaster Posted November 24, 2016 Share Posted November 24, 2016 well i'll start you off... most diffs list the final drive, ie what the speed differential between input shaft and output to the wheels. switching ratios for a larger number (say going from a 3.3 to a 3.6) will give greater acceleration, at the expense of higher cruising rpm, poorer economy and ultimate top speed, if your car is gearing limited rather than power limited. 1 Quote Link to comment Share on other sites More sharing options...
brillomaster Posted November 24, 2016 Share Posted November 24, 2016 darn it Stevo's post has made mine look like a pre-schoolers now Quote Link to comment Share on other sites More sharing options...
Irn Bru Posted November 24, 2016 Author Share Posted November 24, 2016 well i'll start you off... most diffs list the final drive, ie what the speed differential between input shaft and output to the wheels. switching ratios for a larger number (say going from a 3.3 to a 3.6) will give greater acceleration, at the expense of higher cruising rpm, poorer economy and ultimate top speed, if your car is gearing limited rather than power limited. Do people do this as a mod to the zed ?. I've seen posts regarding the quaife diff and watched a few yt vids, is the quaife really as good an upgrade as the vids make out, as in for real road driving experience or is more for track / racing you would do it ? Quote Link to comment Share on other sites More sharing options...
StevoD Posted November 24, 2016 Share Posted November 24, 2016 darn it Stevo's post has made mine look like a pre-schoolers now i cant really take credit for it Quote Link to comment Share on other sites More sharing options...
StevoD Posted November 24, 2016 Share Posted November 24, 2016 (edited) well i'll start you off... most diffs list the final drive, ie what the speed differential between input shaft and output to the wheels. switching ratios for a larger number (say going from a 3.3 to a 3.6) will give greater acceleration, at the expense of higher cruising rpm, poorer economy and ultimate top speed, if your car is gearing limited rather than power limited. Do people do this as a mod to the zed ?. I've seen posts regarding the quaife diff and watched a few yt vids, is the quaife really as good an upgrade as the vids make out, as in for real road driving experience or is more for track / racing you would do it ? yea for driving hard a Diff is an amazing upgrade. i'm running a 2 way Kaaz in mine and its fine for normal use and amazing for when i want the rears locked up for drifting. Although not to say a 2 way or any aftermarket diff just locks the wheels and makes you slide. also the Final Drive as Brillo says can make a massive difference to how the car drives and pull. ut there are side effects to moving either way up the scale. Edited November 24, 2016 by StevoD Quote Link to comment Share on other sites More sharing options...
Irn Bru Posted November 24, 2016 Author Share Posted November 24, 2016 darn it Stevo's post has made mine look like a pre-schoolers now i cant really take credit for it I've watched that a few times a still struggle with the maths . So... If I wanted faster 0-60 for Crail drag strip days, I would increase ratio to 3.9 or bigger then ?? Quote Link to comment Share on other sites More sharing options...
StevoD Posted November 24, 2016 Share Posted November 24, 2016 darn it Stevo's post has made mine look like a pre-schoolers now i cant really take credit for it I've watched that a few times a still struggle with the maths . So... If I wanted faster 0-60 for Crail drag strip days, I would increase ratio to 3.9 or bigger then ?? most common one is the 4.08 Final Drive which going by youtube (i know its not totally reliable) but take a stock 350z 0-60 of around 5.7 to 5.1ish alot of money when you put it that way but on track it will allow out of corner acceleration to be increased and for drifting it will allow for the use of the torque a bit more, But all at a price of high rpm at motorway speed and a lower top speed. 1 Quote Link to comment Share on other sites More sharing options...
Paddy78 Posted November 24, 2016 Share Posted November 24, 2016 I guess the question is - why do you want to upgrade? What application are you going to use it for and why is your current diff not good enough? Drifting, 0-60 drag racing or track days maybe improved by an upgraded diff, but maybe not by the same one. 1 Quote Link to comment Share on other sites More sharing options...
docwra Posted November 24, 2016 Share Posted November 24, 2016 Drifting, 0-60 drag racing or track days maybe improved by an upgraded diff, but maybe not by the same one. Actually, a decent 1.5 or 2 way would improve the car for all three as it happens. 2 Quote Link to comment Share on other sites More sharing options...
Paddy78 Posted November 24, 2016 Share Posted November 24, 2016 Drifting, 0-60 drag racing or track days maybe improved by an upgraded diff, but maybe not by the same one. Actually, a decent 1.5 or 2 way would improve the car for all three as it happens. Well I'm sold! What options are there? I've heard of Quaife and Kaaz... any others the OP should be looking at? Quote Link to comment Share on other sites More sharing options...
The Chubby Ninja Posted November 24, 2016 Share Posted November 24, 2016 Brian I'd recommend the kaaz 2 way over the quaife diff you can also change how much lock it has from 90% to 70% I think it is. Ask gary (evilscorp) for more info as he's done it. Clark motorsport can get you a kaaz no problem. Putting a diff in a z really transforms it as the standard diff is pretty pish tbh. As for a shorter final drive, again great mod for the z, really brings the acceleration alive and to be honest as we have 6 gears, the revs really aren't that high at motorway speeds. I think with the 4.2 final drive the car will still do like 180 so it really isn't a problem. Defo on my to do list. If you do end up getting a diff I have a spare diff lying that you could get it put into then just swap that diff with the one on your car the now to save it being off the road for anytime. Upto you tho man 2 Quote Link to comment Share on other sites More sharing options...
Kev T Posted November 24, 2016 Share Posted November 24, 2016 I have the Kazz 1.5 with 60% lock and apart from it being a bit clunky on really tight turns i find it brilliant, best handling mod imho. I would recommend uprating the bushes at the same time if you decide to go ahead. 2 Quote Link to comment Share on other sites More sharing options...
docwra Posted November 24, 2016 Share Posted November 24, 2016 Not used a Kaaz on a Z33 but they are generally a lot more agricultural than the Nismo GT Pro, the Nismo also has more adjustability as well as being convertible from 2 way to 1.5 way. A Quaife is even more user friendly but doesnt work in the same way as a plate diff, I prefer the latter but its a matter of taste I guess 1 Quote Link to comment Share on other sites More sharing options...
Irn Bru Posted November 24, 2016 Author Share Posted November 24, 2016 Thanks lads, just the info I'm looking for. End game is to achieve much better acceleration, happy to lose top end a bit as it's not like your able to drive at 155 top end on our roads anyway. Drag strip is more my thing than track days, but was looking into learning to drift in the new year so looking for a diff that gives me these two options. @ Chubby Ninja, Steve that's very good of you mate, will get in touch nearer the time if I go ahead with this mod. I guess the next question is ..... how much to buy these options ? 1 Quote Link to comment Share on other sites More sharing options...
Richf Posted November 24, 2016 Share Posted November 24, 2016 Many people think the final drive is included as part of the diff and must be changed but whilst they are bolted together you can replace either independently (Not suggesting any confusion here but its worth pointing out) I doubt you will see a great deal of difference in times on the drag strip if changing your gearing , a decent diff will make a significant difference to your 60ft and ET though 1 Quote Link to comment Share on other sites More sharing options...
The Chubby Ninja Posted November 24, 2016 Share Posted November 24, 2016 Thanks lads, just the info I'm looking for. End game is to achieve much better acceleration, happy to lose top end a bit as it's not like your able to drive at 155 top end on our roads anyway. Drag strip is more my thing than track days, but was looking into learning to drift in the new year so looking for a diff that gives me these two options. @ Chubby Ninja, Steve that's very good of you mate, will get in touch nearer the time if I go ahead with this mod. I guess the next question is ..... how much to buy these options ? Apparently standard gearing will do over 200? So with the final drive changed itl be about 180 max or so I've read. Still more than enough. No worries just let me know man as it's just sitting in the garage as a spare incase mine blows lol. Don't quote me but I think the kaaz is around 800 and I think the final drive is 3-400. Should be about 40-100 for fitting if you just hand them the diff. Il help you swap them over once it's done if you want to save you some cash. Doesn't take that long 1 Quote Link to comment Share on other sites More sharing options...
StevoD Posted November 24, 2016 Share Posted November 24, 2016 Thanks lads, just the info I'm looking for. End game is to achieve much better acceleration, happy to lose top end a bit as it's not like your able to drive at 155 top end on our roads anyway. Drag strip is more my thing than track days, but was looking into learning to drift in the new year so looking for a diff that gives me these two options. @ Chubby Ninja, Steve that's very good of you mate, will get in touch nearer the time if I go ahead with this mod. I guess the next question is ..... how much to buy these options ? Apparently standard gearing will do over 200? So with the final drive changed itl be about 180 max or so I've read. Still more than enough. No worries just let me know man as it's just sitting in the garage as a spare incase mine blows lol. Don't quote me but I think the kaaz is around 800 and I think the final drive is 3-400. Should be about 40-100 for fitting if you just hand them the diff. Il help you swap them over once it's done if you want to save you some cash. Doesn't take that long i think there was a Final Drive 4.08 on either RHDjapan or Z1 which was around £250 Quote Link to comment Share on other sites More sharing options...
The Chubby Ninja Posted November 24, 2016 Share Posted November 24, 2016 Cool man il check that out Quote Link to comment Share on other sites More sharing options...
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