WHP Vs Diff ratio
 

I currently have about 450whp using an "air to air" supercharger setup and a 4.08 diff gear ratio with a Cusco LSD (manual transmission) that I've had since I was normally aspirated. I have good sticky tires but find it very hard to not spin the wheels as the boost rises in 1st, 2nd and even 3rd gear. It's good at the track when you're already moving and the tyres properly heat up but for normal driving on the road it's a bit crazy I think. Would it be better/more realistic to put the stock diff ratio gears back or something in between? Does anyone have some sort of recommendation of what WHP Vs what Diff gear ratio?
Thanks. :driving:

Learn to control your right foot ?? Use the "feather-touch" or go after-market TC

4.08 is great for the track !!!

I don't think many would recommend 4.08 gears with a boosted setup ... most stay with the stock gearing

Really not a huge difference between the 2 (4.08,3.69).
about 4mph in 1st,7 in 2nd & 10 in 3rd...
Unsure if you have a track set-up or drag set-up...but more meat contacting the surface w/minimal camber will help,,,also spring ratio will make a difference.

Now; A set of 3.357 A/T Diff gearing will make a pretty good change.
8,13 & 19mph faster in 1,2,3rd.

I would stick with the stock gear ratio with a power adder on these cars not unless you spend the coin for nice suspension set up and sticky tires to support it. Most people will see traction issues with the 4.08 ring and pinion though. The 4.08 ring and pinion I think is ideal for people how want to keep their 370Z naturally aspirated or go to the track a lot. At 450 whp that must be amazing!! If you are running the stock VQ engine making 450 whp you are at the border line. I wouldn't run more than 400-450 whp on the stock VQ engine or you could be running on barrowed time good luck.

I think you should listen BGTV8...as he said my words, your right foot is not an on off button. Ease or squeeze into the throttle. I don't think at your power level making another change in gear ratios is going to make big difference. I would as other suggested start building your suspension. This includes coilovers and spring rates. What tire compound are you running and you may want consider a square setup.

I have a hard time with second gear turns as well. They are difficult because the torque comes on so strong. I will generally see how much time I gain or loose by taking the turn in 3rd gear vs down shifting to 2nd.

Simply not true! That is not a lot of power for the VQ engine and there are a number of us that run way more torque than he has whp with no issues.

Yeah VQ's are very powerful motors in the stock from. Some people DD 600+whp TT kits with no issues. Really it's more about torque then HP if your worried about breaking something.

As for the 4.08 gears they deffintely are not helping your traction issues but like others said swapping back won't make too much of a difference. Get wider tires and be easy on the throttle depending on your situation. When your boosted first gear will always spin if you floor it

:iagree:
Don't stomp the loud pedal. Think that you have an egg under your right foot and ease down on the pedal. Learn what the car is telling you. If you feel wheel spin, hold or ease off a hair. If you feel a lot of wheel spin. Don't completely lift. Just back off a little more. :driving: If you completely lift off in a turn. That's the fastest way of looking at who's behind you, eyeball to eyeball. :eek:

Thank you all for the excellent answers and advice as I've been thinking about this a lot lately. :tiphat:
I think I'll take BGTV8's advice and practice "feathering" the throttle more. I guess I'm a bit slack and too used to using it as an "on/off" button.

I do have I think a pretty good suspension setup now with every part upgraded (except for front camber arms). Earlier this year I had MCA Red (custom valving) coilovers fitted (true coilover in rear now) which replaced my BC-BR coilovers when the car was lowered and have had it raised again to optimise the suspension travel and adjustements.

I'm using Yokohama AD08R tyres but the standard 370Z sizes. It was not possible to get wider tyres to suit the Z in Australia due to our small market here without paying stupid prices. They're just not normally available here as they are in the US.

:tup:
Good for you. At least you are listening. :tup: Unlike some of these ricers who think they know more then someone with years of experience in a racecar. (BGTV8)

Driving a NA Z has me at odds. I ease on the throttle like I am in a turbo car. 3 of my last Z's were turbo cars. It is hard for me to be more aggressive with the throttle.

:iagree: I totally get this even in when I drive other boosted vehicles and I have two others lol!