Newbie diff upgrade question - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Audioslave1 · 07-10-2018, 01:50 PM

Im coming from the subaru world, selling my 04 STi after ive built it and had fun with it. I dont know if this is the right place to ask but i thought id ask here. The new project is gonna be a s13 with a LS1 thats full bolt on with 150 nitrous shot, so roughly 500-550whp. I have every single nut and bolt on my build list besides my diff setup. Im totally ditching the r200, im not a fan of it. And I really dont wanna make some frankenstein diff from 300zx and q45 bits, i want a simple somewhat drop in option thats overbuilt, correct me if im wrong but that q45 300zx diff setup wont last launch after launch at the strip on big slicks, and breaking parts left and right and tracking down this 300zx part and that q45 part just seems like itd be annoying. The option im looking at as of now is getting the mazworx ford 8.8 IRS diff kit, its not a huge dramatic change and fabrication to the subframe like a solid axle conversion would be but its still a hearty cobra diff. The only downside to the 8.8 IRS is axles are super confusing to me, I would upgrade the diff to a aftermarket 31 spline posi and it looks like 31 spline axles are a custom type order from driveshaft shop, or at least I cannot find 31 spline 8.8 IRS off shelf upgraded axles anywhere. Rear ends arent my specialty, im more of a fabrication and engine guy so this is all confusing to me, is there any diff thats really tough thats relatively easy to fit in the subframe that doesnt make dramatic geometric differences to the rear suspension and all that?

07-10-2018, 01:50 PM	#1
Audioslave1 Join Date: Jul 2018 Location: OH Age: 27 Posts: 1 Trader Rating: (0) Feedback Score: 0 reviews	Newbie diff upgrade question Im coming from the subaru world, selling my 04 STi after ive built it and had fun with it. I dont know if this is the right place to ask but i thought id ask here. The new project is gonna be a s13 with a LS1 thats full bolt on with 150 nitrous shot, so roughly 500-550whp. I have every single nut and bolt on my build list besides my diff setup. Im totally ditching the r200, im not a fan of it. And I really dont wanna make some frankenstein diff from 300zx and q45 bits, i want a simple somewhat drop in option thats overbuilt, correct me if im wrong but that q45 300zx diff setup wont last launch after launch at the strip on big slicks, and breaking parts left and right and tracking down this 300zx part and that q45 part just seems like itd be annoying. The option im looking at as of now is getting the mazworx ford 8.8 IRS diff kit, its not a huge dramatic change and fabrication to the subframe like a solid axle conversion would be but its still a hearty cobra diff. The only downside to the 8.8 IRS is axles are super confusing to me, I would upgrade the diff to a aftermarket 31 spline posi and it looks like 31 spline axles are a custom type order from driveshaft shop, or at least I cannot find 31 spline 8.8 IRS off shelf upgraded axles anywhere. Rear ends arent my specialty, im more of a fabrication and engine guy so this is all confusing to me, is there any diff thats really tough thats relatively easy to fit in the subframe that doesnt make dramatic geometric differences to the rear suspension and all that?