I did a fair amount of searching before I did had Hill's Garage in Baltimore do this install and it was hard to find this sort of information. I have an 05 350Z that I track 2-4 times per year. The car is NA with a lot of bolt ons plus Wolf C2 cams and makes about 260 whp. I had the UpRev reflash and dyno tune. My major complaint with the car was it tended to "lay down" when I shifted into 3rd gear. The reflash got some of this out of the car but it was still significant. So, I decided to go with the 3.7 gear as I thought the 3.9 and 4.08 would be a little much since I still drive it on the street on weekends mostly. I decided to go for the Nismo LSD and the SPL solid diff bushings at the same time while he had the rear apart. The install was great and Frank Hill really took his time making sure all the clearances were just right as usual. Excellent job by Hill's! Not too many shops with tackle gear installs if it is not their daily routine but Frank is a Master at any Nissan mechanical needs.

First, the RPM difference everyone wonders about. Before the swap I turned 2600 rpm at 65 mph by my tach (the tach and reading from the ODB2 port are slightly different with the ODB port being about 200 rpm lover than the tach). After the swap, at 65 mph my tach read about 2850 rpm or so. At 70 mph I am close to 3000 rpm. Not terrible in my opinion. At least one post on here thought the 3.7 swap made their car scream at highway speeds. My experience is not so much but a notable difference. My oil temp on a 80 degree semi humid Maryland day was 227 running at highway speed (65 + or - 5 mph). That's a little toasty although Mobile says it is in range for the type oil I use; a semi track formula 0-40 weight. I plan an oil cooler in the near future because the last time at the track with 3.3 gears my oil temp topped out at 256 which is definitely toasty. Optimum is around 200-220.

Now how does it drive? Much better with the 3.7. The biggest difference is noted in 3rd gear in the twisties. The car just responds much better now to my gas inputs. It still lays down a bit from 2nd to 3rd but not nearly as bad as before. Going up hills is easier as well. The extra 200 rpm just puts the car that much closer to that 3500 rpm sweet spot when the power and torque really come on with those C2 cams. I can't wait to try it on the track next time as I have not really driven it near its potential on the street (it is not a good idea). However, it has improved how the car responds in corners after you get back on the power coming out of the corner. That's where the Nismo LSD come in. It is set up as a 1.5 way LSD with 40% preload. I noticed several times when I got back on the power mid corner the car wanted to under steer briefly but with a slight correction, the car set up and powered through and out of the corner easily. In fact I think more easily than before. I believe I can get on the power EARLIER than before and with the LSD still maintain traction when exiting a corner. At first it was a little un-nerving but now I expect it and it is no big deal. It almost feels like the car wants to go straight (or straighter) when you first get back on the power so it needs just that little tic of more steering input to keep in on course.

So overall I am very happy with the new set up. Yes, it clunks and pops like Nismo LSDs will do but nothing bad. I've heard it pop a few times going around corners and when I engage the transmission, I always hear a clunk when the tranny goes in gear. Going around corners it will drag that inside tire like a full locker will do and it may "buck" a little like a locker will do but if you shift into a higher gear, that pretty much goes away.

 

Nice write up.

 

Can you please give us a break down on cost for parts & labor including the bushings.

thanks

 

Or you can look in every other FD thread. Great write up op.

 

There is one other thing. I remember reading somewhere that when you do this FD gear change, your cruise control will not work. The definitive answer is not in yet but here is what happened. Coming home from the shop I tried it set at 65 mph. It set for about 30 seconds then all of a sudden disengaged and the "set" light started flashing. I cycled the control on/off and still the set light flashed. Later that day, I took it out for a drive and tried the cruise again at 60 mph. This time NO issues at all and it stayed engaged for a good 5-10 minutes. AS I said, definitive answer is not in but right now, it's 50/50.

 

IN terms of cost- Nismo LSD $1100, 3.7 ring and pinion plus install kit and SPL solid bushings $915 including shipping, labor figure 8 hours at whatever you local shop's rate is. So grand total a little under $3k.

 

Ouch, mine only cost $200 for the driveline shop to shim the new diff and gears in.

 

I guess the LSD and gears were free.

 

how was hill's service/work/price in your opinion? about to take my Z up for some work maybe

 

Hill's service is top notch. You will not find a tech more fanatical about getting it exactly right the first time than Frank Hill. He is incredible. I've never seen anyone like him. He takes his time, he won't sell you something you don't need and if he can't do something, he will tell you. His work is impeccable. How many techs do you know who will measure the drill bit that comes in a kit before they use it on your car. Most simply use it and drive on. He told me he had actually found a kit with a wrong size drill bit in it. He is that meticulous! The price is very fair. I don't think he is the cheapest or the most expensive but for the service and the knowledge, I have never seen any one close. I do think he is on the low side compared to most. He is also an honest guy and you don't meet too many of those these days. Very good people.

 

My OS was roughtly $1600 with bearings,seals and ring gear bolts, gears i actually did get for free, then labor was only $200 and i also installed solid mounts while it was out.

 

Sold me, lol.