510 Differential question.

[lovememydatsun]

Hey guys I'm currently trying to buy a r160 lsd with 4:11 gear ratio? My question is this what kinda gas mileage will I get on my 510 with an l20b with a weber 32/36 but otherwise practically stock. I forgot to mention as of right now my differential is stock

[bertvorgon]

That is kinda hard to say, so many variables, even your tires are gears too, how tall might they be!

That being said, I have 4:62 rear gears with a 23" tall tire, Weber 32/36, jetted to give a 12.5 - 13 A/F and on steady state cruising, I get about 23 MPG with a mixed driving of maybe 22+ MPG.

Extrapolating if I leaned it out a tad, I could MAYBE squeek 25.

At freeway cruise you will be turning just around 4,000 RPM...if you have a 5th gear!

[okayfine]

Impossible to say. Everything's a variable, including how you're going to drive the car. 4.11 vs. 3.9 isn't a huge change, gearing-wise, so it's not going to dramatically affect your mpg unless you hoon on it all the more.

My SR510 with 4.375 rear gear got ~27 on the highway. It got ~30 on the highway with 3.9 gears. That's a rough generalization, but about as close to apples-to-apples comparison as I can give you.

[defdes]

Good luck finding one of those too, in CLSD at least. You'll likely end up putting the LSD from a 3.9 in a 4.11 open carrier.

[lovememydatsun]

Thanks guys for the replies, the reason I'm just trying to switch is because in a couple months I'm planning on installing a vg33 and I'm thinking that maybe this is the best route.

[Byron510]

My suggestion if looking for a diff is to buy an R180. It's bigger size will benefit you. Also if pulled from an 1980-83 4x4 pick up (front diff), you'll have 4.375 gears, 84-86 have 4.11. The stub shafts from your existing R160 can be utilized if you remove the dust shileds or find stub axles from an 240Z diff. In either case, the side R160 needs to donate the side gear buttons to have the threaded inserts installed in the R180 diff to bolt the stub shafts into.

Or go R180 from a Subi, buy the stub shafts from Futofab and away you go.

Just a couple thoughts anyways, that R160 will be under some stress with the torque of the VG33, even if you take it easy.

Byron

[okayfine]

VG33 you're going to want a 3.7 or taller (smaller numerically). The VG will have torque to pull the higher gearing, and it'll keep the revs down at cruise. 3.7s are the way to go for KA on up for a street 510; had a CLSD in my KA510 and it was great.

[JordanTr]

I went from a 3.9 cLSD to a 3.7 vLSD (because road trips) and now I'm going back to a 3.9 with a 1.5way cLSD. This provided as a matter of perspective. I miss that last bit of torque I had before. This is a fully dressed 2dr with a stock KA-DE.

To have comparable gearing to a "normal" car, a 3.7 would get my vote.

[lovememydatsun]

Thanks guys for the replies I appreciate it.