A&Q about 350Z
Q:
I was thinking today...
If I put some power on my Z...say FI or something, and got it about 400 RWHP. What do you guys think about spreading out the ratio's a little bit in 1st and 2nd to take advantage a larger power band? Maybe I am way off base, but it is my understanding that gear tuning is very critical to maximizing use of potential power. Will it only affect top speed, or would changing the close ratio gears in the stock tranny to something a little larger affect acceleration as well?
Just a thought. The Z33 has a really close ratio on it's gears, which is great for quick shifting and road racing, but I am wondering if those who seriously increase their hp are getting the most out of their power input without upgrading/changing their tranny?
If I am way off base, I hope some of you gear heads will put me in my place. I asked this question cause i want to learn...
Previously owned: 2005 Z Enthusiast, Super Black, 6 spd.
Currently lease: 2006 Pathfinder S, Silver, Auto
"She is (and always will be) my little deuce coupe, you don't know what I got!"
A:
What you'd have to do is build your engine first. That way you can dyno it and custom tailor the gear ratios for the powerband of your setup.
For example, the earlier 350Z had its peak torque of 274ft/lbs at 4,800RPM and the peak power of 287ft/lbs at 6,200 RPM. Go out and try this:
From a stop, drive in first gear to 6,200 and then shift right there. You'll notice that 2nd gear will start almost exactly at 4,800RPMs. So during racing, once you've cleared first gear, all your shifts will keep your engines power between its peak torque and peak horsepower. As you get into the higher gears, the spacing gets somewhat closer together to keep the power loss through the drivetrain at a minimum and keep acceleration relatively smooth.
So yes, if you do major modifications to your engine you will likely alter its peak power band somewhat. If its a dramatic change, you can definitely get your gear ratios customized to better utilize its power and also to increase its top speed. However, most of the time, applying forced induction may change the powerband slightly, but it doesn't usually dramatically change the shiftpoints too much.
So to answer your question properly, you'd have to actually build your engine first, dyno it, and then you'll know if you should bother with different gear ratios or not.
----------
1985 300ZX n/a