HPDE guys, what gear ratios are you using?
 

Hi all,

Interested in what rear gears everyone is running for road courses. 4.11/10 seems like you would have to be using 5th gear since 4th would top out in the 140's. what speeds do you typically hit on the road courses? That may help.

The idea i've gotten from reading around is you don't want to go past 4th gear since 5th and 6th are overdrives. Don't know how correct this is so I'd like to discuss.

Also post rwhp, rwtq, etc.

:popcorn:

I don't plan on touching the diff gearing until I open the trans and put in the 1LE gear set. This assumes it doesn't explode on me. Its far better to shift less. I wouldn't go past 3.91 if you decide to do something. Best price and strength too. I've been 135-140ish in 4th gear with stock gearing, don't remember the rpm though.

I'll be putting money in wheels/tires and durability mods first (radiator, oil cooler, etc)

415ish rwhp

If you are running a road course and that is what you are locked into, then I would stick with the 3.90 ish gear.

You shouldn't need to worry about custom gears for HPDE. That will only become an issue if you start competing and are looking to shave the last second or two from your lap times. What road course are you running? On most of them you won't see speeds much above 140 unless you're an advanced driver running a modded car on race tires.

I put 3.7 gears in my manual shift SS. This lets me use 3rd all around the track except for the high speed straight where I shift into 4th. The stock 3.45 gear needed 2nd gear too much, now I don't need to shift down to 2nd.

Well, the 1LE is a "track capable" car and it comes with 3.91's. So, I'd say 3.91 (which is exactly what I have).

The 3.91 1LE ring & pinion kit will be available from Chevrolet Performance in Q2.

Depends on the track you're running on. Are you planning on running every month at an HPDE track event? Planning to travel to various tracks?

I've got the stock gearing for a 2010 1SS and it's plenty good for the track near me. If you're going to change the diff gears to 3.91 take note that Chevy ALSO changed the trans gear ratios in the 1LE package to come up with a combo that would balance the 3.91.

If there's too much torque at lower speeds it becomes difficult to smoothly accelerate out of corners and into/through transitions. If the gearing is too tall (for high speeds) then either 2nd is too high or 3rd is too low. If the gearing is too low (for 1/4 mile type speeds) then you spend too much time shifting between 2nd and 3rd trying to find the right combo for corners, and believe it or not that can actually slow down your lap times.

Ideally you want a smooth and usable 2nd gear for low to medium speed corners and 3rd can handle everything else, unless it's a high speed bank or sweeper. You don't want too much power too quick or the back end will want to kick around on you when you're trying to accelerate out of a corner or out/into a transition between corners.

My recommendation before you start messing with the gears in the differential is to spend the money at a reputable high performance driving school and learn how to wring the most out of what you already have. THEN you'll have a much better idea of what mods you want to make because you now have the skill and experience with your car to know what needs improving, how much, and why.

This is excellent advice.

Doc, I appreciate your post. I constantly use your thread as a reference with all the info you have in there for weight loss. :thanks:

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.

I've got the 3.91 in mine and I like them. My car pulls so much harder out of the corners and all around. I've gotten decent with heel and toeing with 3rd and 4th but 2nd I just couldn't get it smooth. With the gears I avoid 2nd almost all together and use 3, 4, 5. As far as having too much power coming out of corners, that's what's called car control.