4.10 gears...not what I expected.

[Hog]

Stock gearing 3.45

385 lb/ft engine torque/2.66:1 1st gear ratio/3.45:1 rear gear'

385x 2.66x3.45=3533 lb/ft torque at the rear at the halfshafts

4.10 gearing
385 lb/ft torque/2.66:1 1st gear/4.10 ratio

385x2.66x4.10=4198 lb/ft @ the rear halfshafts.

4198/lb/ft3533lb/ft=18.84% increase in torque

We are measuring the actual torque or twist that is seen at the rear wheels, not calculating the torque of the engine.

There would be a measureable difference if before and after 1/4 mile runs were done.

I went from a 3.08 gear to a 4.10 gear and was unimpressed in gains in acceleration during WOT SOTP testing.

[PhillipsLT5]

SOPT = butt dyno

[zrwhat]

I recall when I went to 4:10's in my 91 ZR-1, I shaved .3 tenths off my quarter mile times and the fact that 6th gear could be used more often without downshifting was priceless, before that 6th gear was pretty much worthless unless you were going 70mph on a flat road.

I felt it was a worthwhile change and cheap $ to get there a little faster, I guess I'm one of the few that did notice a big difference with the gear change.

Gibby

[Pete]

Originally Posted by LGAFF

http://www.carcraft.com/techarticles...s/viewall.html






Geared Up For Speed
Hot Rod did a test of gear ratios and converter sizes (smaller equals higher stall speed) versus engine rpm and quarter-mile times for their June '95 issue. We helped with the testing, so we don't feel too bad about ripping them off and reprinting the numbers here. The car used was a small-block Nova with 26-inch-tall tires. We tried four gear ratios with two TCI converters, and here's what we found:

Same Car....
3.50 gear 13.40@102.59
4.11 gear 13.18@102.81

Read more: http://www.carcraft.com/techarticles...#ixzz32C7fPvaZ

A bit difference with our manual 6 speed Z's.

I agree money would've been spend better in other mods.

My Z has run 11.04, 11.09, 11.06 with 3.45 gears I install 4.10's thinking I will get a 10 sec pass well that did not work as I thought I got a killer 60ft time and thought h@ll yeah this is it picked up my timeslip 11.10's well anybody wanna guess why, ok i'll tell you had an extra shift.

4.10's are lame and loose big end that's what our cars were made for,top end.
With 3.45 gears I top out 4th at 155-160mph with 4.10's 135mph
and if anyone has shifted into 5th would also know she falls flat on her face in 5th.

4.10's will get you better 60ft times over the 3.45's but with the extra shift takes it right back.

Reinstalled 3.45 back in her and happy again.
Pete

[Bob Eyres]

So Pete, how much better did your 60ft. times get with the 4.10's?

The combination of a better 60ft. time, combined with the advantage of being able to stay in a, (higher), more powerful RPM range throughout the run should add up to a better e.t.
It doesn't seem possible that the brief power shift from 3rd to 4th costs you THAT much.

Is it a possibility that with your high power output, (550+?), and the 4.10 gears, you may need more tire to see the full advantage of this gear ratio?

Your times are phenomenal. But its just hard for me to believe that the best 1/4 mi. e.t. for a high power, high rpm ZR-1 is with a three speed with no torque converter.

[PhillipsLT5]

Originally Posted by Pete

A bit difference with our manual 6 speed Z's.

I agree money would've been spend better in other mods.

My Z has run 11.04, 11.09, 11.06 with 3.45 gears I install 4.10's thinking I will get a 10 sec pass well that did not work as I thought I got a killer 60ft time and thought h@ll yeah this is it picked up my timeslip 11.10's well anybody wanna guess why, ok i'll tell you had an extra shift.

4.10's are lame and loose big end that's what our cars were made for,top end.
With 3.45 gears I top out 4th at 155-160mph with 4.10's 135mph
and if anyone has shifted into 5th would also know she falls flat on her face in 5th.

4.10's will get you better 60ft times over the 3.45's but with the extra shift takes it right back.

Reinstalled 3.45 back in her and happy again.
Pete

Shifting into 6th from 5th @ 7200RPM with 4.10's & 422RWHP car really noses over, fighting wind resistance

[USAZR1]

Originally Posted by Pete

A bit difference with our manual 6 speed Z's.

I agree money would've been spend better in other mods.

My Z has run 11.04, 11.09, 11.06 with 3.45 gears I install 4.10's thinking I will get a 10 sec pass well that did not work as I thought I got a killer 60ft time and thought h@ll yeah this is it picked up my timeslip 11.10's well anybody wanna guess why, ok i'll tell you had an extra shift.

4.10's are lame and loose big end that's what our cars were made for,top end.
With 3.45 gears I top out 4th at 155-160mph with 4.10's 135mph
and if anyone has shifted into 5th would also know she falls flat on her face in 5th.

4.10's will get you better 60ft times over the 3.45's but with the extra shift takes it right back.

Reinstalled 3.45 back in her and happy again.
Pete

If your car is trapping at 129mph and 4.10's are good for 135mph in 4th gear,why are you having to shift into 5th?

[USAZR1]

It really noses over from 5th to 6th,with 3.45's also. I really liked the 155mph 4th gear w/3.45's but I find the 4.10's are a much more useful ratio,overall.
Our car will see a bunch more 0-120mph blasts than it ever will to 150+. If top end blasts are your thing,3.45's or even 3.07's are the way to go.

[Pete]

Here's what i think.
That auto car for example, lets say peak power is at 5500 rpm with the 3.50 gears it would finish the 1/4 at 4700 rpm with the 4.11 it would finish at 5500 this is the reason for the much better ET's.

My Z peak power 6900rpm with 3.45 i finish in 3rd gear at about 7400 rpm
With 4.10's i finish in 4th at 6800 below my power peak so either i god with 4.33's or 4.50's
My Z looses about 15hp from peak (6900) to 7400rpm so not much loss.

Also i did not mean going into 6th i meant going into 5th i know you don't feel it much but trust me car does not pull as hard in 5th if you shift her at 7k rpm it drops way below peak power down to 5200 rpm what you have to do is run her to 74-7500rpm just to get her closer to peak power going into 5th.

I went from 1.74 60ft to 1.59 you would think 1.5 at 60 foot would get me 2-3 tenths i can't shift that fast so i loose it at the extra shift even if i got 11.00 it still did nothing for me.

Pete

[USAZR1]

Originally Posted by Pete

Here's what i think.
That auto car for example, lets say peak power is at 5500 rpm with the 3.50 gears it would finish the 1/4 at 4700 rpm with the 4.11 it would finish at 5500 this is the reason for the much better ET's.
My Z peak power 6900rpm with 3.45 i finish in 3rd gear at about 7400 rpm
With 4.10's i finish in 4th at 6800 below my power peak so either i god with 4.33's or 4.50's
My Z looses about 15hp from peak (6900) to 7400rpm so not much loss.
I went from 1.74 60ft to 1.59 you would think 1.5 at 60 foot would get me 2-3 tenths i can't shift that fast so i loose it at the extra shift even if i got 11.00 it still did nothing for me.
Pete

So,you're going through the lights in 3rd gear,not 4th? If your stock displacement LT5 makes peak at 6,900,I agree a 4.30 cog might work better than a 4.10 for your combo. A 4.56 would probably be too much gear.