Originally Posted by Bomino
Doc, I appreciate your post. I constantly use your thread as a reference with all the info you have in there for weight loss.
i know you have gone down to 19's on your wheels. since that has an effect on your gearing, your 3.45 gearing may feel similar to a camaro on 20's with 3,91's, no? there are calculators to figure out precisely what the equivalents are...
so with your 19's, weight loss, and stock diff, you like the gearing setup for track? you ever considering swapping the gears out?
Well thank you.
I haven't calculated the difference but it's probably not much; maybe like a 3.55 or thereabouts. A 3.91 gearing with 20" wheels would probably pull more like my setup but depending on the track you're on, you'd spend more time shifting between 2nd and 3rd than I do and I'd definitely get you on top end. Plus the weight difference gives me an advantage on quickness of response and cornering agility.
I like the trans and diff gear ratios Chevy chose for the 1LE and I'm assuming they'll be the same (or very close to it) for the Z/28. The extra pull you have with the 3.91 makes 3rd gear usable in most corners except either very slow or long fast ones where you can get into 4th for a bit. On a big Nascar track like the one near me I can get into 5th before going into the bank on turn 1. But that's a hybrid infield road course that uses part of the Nascar track. A true road course is road course only and you're most likely not going to see taking a giant sweeper in 5th gear.
The gearing combo I have right now works pretty good for me. If I had taller gears in the diff I'd have to shift out of 2nd too quick so I'd be either hitting the rev limiter in the middle of a corner, or shifting in the middle which isn't a great idea. If I went into it in 3rd I'd be pretty low in the power band going through the corner and losing exit speed coming out.
The cam I chose gives up some horsepower on the top end in exchange for more torque earlier and more in the mid-range so at 3,500 rpm 3rd gear really starts to come alive. If I come out of a corner in 2nd at 4,500-5,000 then shift into 3rd it drops to around 3,500+ rpm and the car pulls like it's on a turbo. It's a real blast.
Right now I want better tires. There's a lot I can improve including my driving skills before I would need to start changing gear ratios.