4.10 gears...not what I expected.

[XfireZ51]

I'm using 3.73s BUT I also have taller 19" wheels which effectively makes my gearing ~ a 3.50. Lgaff and myself had nearly identical setup a few years ago w the exception of gearing. He had a 4.10 in his 92 red, I had 3.45s w 92 aqua. Bot were top end mods and had the same headers, Watsons. Lee was usually faster by about .3-.4 but our trap speeds were within 100ths of a mph. He would beat me to the 1/8th w a higher mph but by the end, I would be gaining on him. Pretty sure that after the 1/4, I would have overtaken him. Just some anecdotal evidence.

[5ABI VT]

Originally Posted by XfireZ51

I'm using 3.73s BUT I also have taller 19" wheels which effectively makes my gearing ~ a 3.50. Lgaff and myself had nearly identical setup a few years ago w the exception of gearing. He had a 4.10 in his 92 red, I had 3.45s w 92 aqua. Bot were top end mods and had the same headers, Watsons. Lee was usually faster by about .3-.4 but our trap speeds were within 100ths of a mph. He would beat me to the 1/8th w a higher mph but by the end, I would be gaining on him. Pretty sure that after the 1/4, I would have overtaken him. Just some anecdotal evidence.

Which in my eyes shows the only advantage is having a shorter first gear. If you can take advantage of the increased torque at the tire in first it will get you ahead and then it's an even race until the shorter geared car hits 5th which is pretty much an overdrive then the stick geared car should catch and usually the race is well over before needing to go to 6th.

I ran a similar race when my 93 lt1 was bolt ons with 4.10s. When I started in 2nd gear from a 15 mph roll when the stock geared car was in 1st.. Were were pretty much neck and neck until I hit 5th. I would pull slightly and then lose it on the shift and repeated in every gear. If I launched hard in 1st I kept that advantage (about a car and a half) until I hit 5th where he would catch and pull slightly ahead before he hit 5th.

Personally I hated the gears back then. It was fun at first until I realized for all that extra push, I was moving at a slower speed in each gear. I started to miss that nice long uninterrupted pull.

[USAZR1]

Originally Posted by Hog

All else equal, the 3.45 geared car will win from a roll. Unless you are rolling on in 5th gear.

No,it won't. From 60-120mph,all else being equal,a mildly modified ZR-1 w/4.10's will dust one w/3.45's. The car with lower gearing will pull harder to redline every time

[5ABI VT]

Originally Posted by USAZR1

No,it won't. From 60-120mph,all else being equal,a mildly modified ZR-1 w/4.10's will dust one w/3.45's. The car with lower gearing will pull harder to redline every time

I don't believe that's the case . It pulls harder to redline but you're shifting faster and the speed at which gear tops out at is much less. What I'm trying to say is assuming the stock geared car is in 2nd and the 4.10 car is in 3rd.. How is the 4.10 car accelerating harder ?

Final drive in 2nd gear with stock gears is : 1.8x3.45 =6.21
Final drive in 3rd gear with 410 gears is : 1.29x4.10 = 5.28

Speed for stock gear car is 60 mph and 4900 rpms. If you ask me that's right in the sweet spot

Speed for the 4.10 car at 60 mph is 5800 rpms in 2nd and if using second it has a more favorable final drive for the split second it takes to hit the limiter and then will lose that momentum in the shift to 3rd where the final drive favors the stock geared car again. At 74 mph in 3rd (assuming shift at 7200) the 4.10 car will be at a lower final drive than the stock geared car until the stock geared car needs to shift at 90 mph at which point the advantage goes back to the 4.10 car.

Confusing but it's back and forth depending on who's in the sweet spot if were talking roll on races . The only advantage in final drive a 4.10 car has is 1st gear because that is the lowest gear that is possible to use. If a 4.10 car has slicks and dumps at 7200 and hooks and launches a full 2 car lengths ahead.. It will maintain that because after first gear and shifting into second the final drive advantage goes back to the stock rear car that is still in 1st. And so it goes back and forth .. Get it ? THAT is why gears show a e.t difference but no difference in mph.


So my conclusion is .. 4.10 gears are great for a 1 gear advantage only. Off the line if you can hook. That's it.


The most common mistake I see people do is compare the SAME gear roll ons from a rear gear swap vs stock. That's not really fair to do because the speeds and ranges of the gears has now changed somewhat . In many cases the stock gear car should be in a lower gear where the final drive may be in it's favor for a brief period and pass it back and forth.

[XfireZ51]

Lee was at top of 4th while I was topping out in 3rd at the end of the 1/4. I was gaining on him in the last 300'. He typically would have a higher 1/8th trap by about 1-2mph. But by the end of the 1/4, our Mph was nearly identical. The next shift would have reversed positions. We're talking about somewhere around 118mph. And frankly, Lee is a better driver than I am.

[USAZR1]

Originally Posted by 5ABI VT

I don't believe that's the case . It pulls harder to redline but you're shifting faster and the speed at which gear tops out at is much less. What I'm trying to say is assuming the stock geared car is in 2nd and the 4.10 car is in 3rd.. How is the 4.10 car accelerating harder ?

Final drive in 2nd gear with stock gears is : 1.8x3.45 =6.21
Final drive in 3rd gear with 410 gears is : 1.29x4.10 = 5.28

Speed for stock gear car is 60 mph and 4900 rpms. If you ask me that's right in the sweet spot

Speed for the 4.10 car at 60 mph is 5800 rpms in 2nd and if using second it has a more favorable final drive for the split second it takes to hit the limiter and then will lose that momentum in the shift to 3rd where the final drive favors the stock geared car again. At 74 mph in 3rd (assuming shift at 7200) the 4.10 car will be at a lower final drive than the stock geared car until the stock geared car needs to shift at 90 mph at which point the advantage goes back to the 4.10 car.

Confusing but it's back and forth depending on who's in the sweet spot if were talking roll on races . The only advantage in final drive a 4.10 car has is 1st gear because that is the lowest gear that is possible to use. If a 4.10 car has slicks and dumps at 7200 and hooks and launches a full 2 car lengths ahead.. It will maintain that because after first gear and shifting into second the final drive advantage goes back to the stock rear car that is still in 1st. And so it goes back and forth .. Get it ? THAT is why gears show a e.t difference but no difference in mph.


So my conclusion is .. 4.10 gears are great for a 1 gear advantage only. Off the line if you can hook. That's it.


The most common mistake I see people do is compare the SAME gear roll ons from a rear gear swap vs stock. That's not really fair to do because the speeds and ranges of the gears has now changed somewhat . In many cases the stock gear car should be in a lower gear where the final drive may be in it's favor for a brief period and pass it back and forth.

Michael,I said "all else being equal",did I not? How is one car being in 3rd gear and one in 4th, equal? Try a roll-on with both cars in the same gear,especially in 3rd gear or higher as that will take tire spin out of the equation,and get back to me.

Reading your last paragraph made me chuckle. How is all else equal not being fair?

You don't believe it to be the case? I have done 3rd,4th,and 5th gear roll-ons against other ZR-1's and did find it to be the case.

18% increase in torque doesn't lie,does it?

[USAZR1]

Originally Posted by XfireZ51

Lee was at top of 4th while I was topping out in 3rd at the end of the 1/4. I was gaining on him in the last 300'. He typically would have a higher 1/8th trap by about 1-2mph. But by the end of the 1/4, our Mph was nearly identical. The next shift would have reversed positions. We're talking about somewhere around 118mph. And frankly, Lee is a better driver than I am.

Sure,you were starting to reel him in. His LT5 was probably starting to run out of breath in 4th gear with those 4.10's. Whereas,at 120mph,your car with the 3.73's was still hitting its stride.
But,you didn't catch him,did you?

I won't argue the point that 3.45's aren't an excellent cog for top-end blasts over 120mph. But,I ask the question once again: How many times a year does your ZR-1 see speeds way over 120mph? Probably,not that often. How often do you find yourself driving down the expressway in 5th gear,instead of 6th? When my car still had the 3.45's,I caught myself doing it quite often. To be perfectly honest,I wouldn't mind if our 94 had 3.45 cogs because the Texas speed limits are 75mph or even higher.
But,I still prefer a little more acceleration over a little more top end. Different strokes for different folks,,

[Paul Workman]

Originally Posted by USAZR1

No,it won't. From 60-120mph,all else being equal,a mildly modified ZR-1 w/4.10's will dust one w/3.45's. The car with lower gearing will pull harder to redline every time

Well, 18% torque increase for any rpm is correct, but it is a bit simplistic: The torque curve is not flat across the rpm range, and speed at the top of every gear is going to be 18% less for any give rpm. The combination of rising and falling torque curves over rpm and the fact of some loss in speed/time for each shift apparently tends to mitigate a substantial amount of the advantage of the 4.10s for the ZR-1 in the 1/4 mile - or so it seems from observation.

And, to Dom's point, Those that ran the 1/2 mile drags in Monee last year, the 3.45 geared cars really featured the LT5's strong suit - faring much better at 140+ mph in 4th than that reported by the 4.10 guys - having to shift to 5th and experiencing the cars acceleration "dive" when they did so.

What is starting to emerge, sans any formal analysis here so far, is the 4.10s may not be big enough for either the 1/4 or even the 1/2 mile contest to make a clear, indisputable advantage over the stock 3.45 "cog", but only in part due to the extra shift. In both cases ending in 4th in the "quarter" or 5th in the 1/2, the LT5 is not at peak power. So, less than peak power in the trap PLUS the extra shift eats up most of the torque advantage of the 4.10 in either contest: just NOT quite enough gear. Something like a 4.3:1 gear might fix that, me thinks.

I like 5ABI VT's description of the "back and forth" advantage when comparing the two (3.45 vs. the4.10) in the quarter mile contest (and perhaps the 1/2 mile too). Not so clearly cut and dried as comparing gear ratios alone would suggest.

Interesting discussion.

[USAZR1]

Originally Posted by Paul Workman

Well, 18% torque increase for any rpm is correct, but it is a bit simplistic: The torque curve is not flat across the rpm range, and speed at the top of every gear is going to be 18% less for any give rpm. The combination of rising and falling torque curves over rpm and the fact of some loss in speed/time for each shift apparently tends to mitigate a substantial amount of the advantage of the 4.10s for the ZR-1 in the 1/4 mile - or so it seems from observation.

And, to Dom's point, Those that ran the 1/2 mile drags in Monee last year, the 3.45 geared cars really featured the LT5's strong suit - faring much better at 140+ mph in 4th than that reported by the 4.10 guys - having to shift to 5th and experiencing the cars acceleration "dive" when they did so.

What is starting to emerge, sans any formal analysis here so far, is the 4.10s may not be big enough for either the 1/4 or even the 1/2 mile contest to make a clear, indisputable advantage over the stock 3.45 "cog", but only in part due to the extra shift. In both cases ending in 4th in the "quarter" or 5th in the 1/2, the LT5 is not at peak power. So, less than peak power in the trap PLUS the extra shift eats up most of the torque advantage of the 4.10 in either contest: just NOT quite enough gear. Something like a 4.3:1 gear might fix that, me thinks.

I like 5ABI VT's description of the "back and forth" advantage when comparing the two (3.45 vs. the4.10) in the quarter mile contest (and perhaps the 1/2 mile too). Not so clearly cut and dried as comparing gear ratios alone would suggest.

Interesting discussion.

I agree that is overly simplistic,Paul. Nothing is ever cut & dried. Just having fun with Michael. He's a good poster and has interesting opinions.

I also agree that 4.10's would not be my first choice for 1/2 mile drags or especially full mile runs. With those new racing venues,4.10's aren't as big a deal as they used to be when I owned my first two ZR-1's over ten years ago.

[Hog]

Originally Posted by USAZR1

No,it won't. From 60-120mph,all else being equal,a mildly modified ZR-1 w/4.10's will dust one w/3.45's. The car with lower gearing will pull harder to redline every time

Modified or not, the facts are the same. The engine will accelerate to red line quicker with lower gearing but will the car will not accelerate harder. F=MA

You dont want lower gearing for roll racing(dead stop drag racing is different), nor do you want to roll race a manual trans against an auto trans, all else equal.

You cant directly compare 2 cars, you have to test the same car, then make changes and retest. All else is benchracing(which can also be enjoyable).