4.10 gears...not what I expected.

[USAZR1]

Originally Posted by Hog

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 can't 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).

"The engine will accelerate to red line quicker with lower gearing but the car will not accelerate harder." Someone please explain this statement to me because it just doesn't make any sense.

That's all I thought we were doing here,,benchracing and having fun.

[Paul Workman]

Originally Posted by USAZR1

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?

Minor correction: 120 mph with stock wheels the ZR-1 will be pretty close to 7000 rpm in 3rd gear, but we're talking a modded LT5 at those 1/4 mile speed levels (above 500 hp). A stock LT5 would be more likely at 110 mph at the top of 3rd gear with 3.73s, actually.

Originally Posted by USAZR1

... But,I ask the question once again: How many times a year does your ZR-1 see speeds way over 120mph?...

Uh...more often than you might think! Gears are dandy, but horsepower ends the acceleration vs. top end compromise!

[Bob Eyres]

Originally Posted by Pete

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

This bench racing is fun isn't it? It saves on parts

I still think Pete could cut quicker times with 4.30's, or 4.56's (depending on tire). As he says, the 4.10's got him a 1.59 60ft. time, that's phenomenal, and a big advantage in the Qtr.

A .15 advantage in the first 60ft. is several car lengths in the traps. You don't lose that much, (maybe a fender), during the 3-4 shift.

That tells me that the 4.10's are not too much gear, but not enough. The reason his times got slower is not the third to fourth shift, but because he wasn't peaking out to 7,400-7,500 in the traps. The trick is getting the great launch AND peaking at the right rpm in the traps.

I see the stock gear as a disadvantage at launch. If he cuts 1.74 60 ft time with 550+h.p. and a stock gear, and I cut a 1.76 with 4.10's and a stock motor. How is that using all that horsepower that he's spent so much time and effort building? Just sayin'

More gear, more tire

[Hog]

Originally Posted by USAZR1

"The engine will accelerate to red line quicker with lower gearing but the car will not accelerate harder." Someone please explain this statement to me because it just doesn't make any sense.

That's all I thought we were doing here,,benchracing and having fun.

Explaination:Just because the engine is revving to redline quicker(less time) doesnt necessarily mean that the car is also accelerating quicker. Think of a "block and tackle" a single pulley will be able to lift LESS weight, than 3 pulleys. But the single pulley will lift its weight by winding up less rope than the 3 pulley system. Though the 3 pulley system does move more weight, it also requires many more times the amount of rope to lift any weight. The single pulley being analogous to stock rear gears(3.45), and 3 pulleys being analogous to lower gearing(4.56).


Yes, bench racing is what we are doing here, and it's fun, so long we bring the Scope.

[Bob Eyres]

I don't agree. You don't have to go to a block and pulley analogy to explain it. Just look at 60ft. times.

If a ZR-1 cuts a 1.50 60ft., and another cuts a 1.60, who's accelerating harder?

The ZR-1 with 4.10's will cut a better 60ft. every time. All other things being equal.

[XfireZ51]

I was told by someone who raced SuperStock for many years that a smaller gear absorbs more energy than a taller gear and so wheel spin is easier to control.
You need more rpm to turn the wheel once w a smaller gear.

[Bob Eyres]

The shorter gear actually allows you to apply more rpm, thereby more torque to the wheels at launch. Gears don't literally absorb energy.

It's really about leverage. Short gears give more leverage, but require more rpm to do it. The ZR-1 develops it's power at a higher rpm, therefore requires shorter gears.

[Hog]

Someone mentioned that a 4.10 gear isnt worth it for a 1/4 mile run based on the addition of a shift, and not trapping at peak power.
Then someone mentioned that the 4.10 may not have neen enough gear, perhaps a 4.30 or 4.56 is in order?
I would agree with that. So long as you can hook, your 60ft will decrease which will help 1/4 mile times. This is true because of the extra torque applied at launch, extra Force. This decreases as you move off the line as the engine approaches and passes peak power.

I had a drag vehicle that made peak power at 4800rpm. With 3.08 gears it would trap the 1/4 mile at 5500rpm in 2nd gear. Swapping to 4.10 gears allowed for a trap rpm of 5000rpm in 3rd gear. In this experience 60ft et dropped, 1/4 mile et dropped, but 1/4 mile speed also dropped 3-4mph.

Torque=Rotational force at any moment
Power=(Torque(lb/ft) x rpm)/5252
Acceleration=Change in velocity over time
Work=force which acts on an object which results in a displacement, if you push on a car with a force of 100 pounds, you are expending energy through your muscylar effort, but if the car doesnt move, no work has been accomplished Work=Force x Displacement
Mass=Vehicle weight

We also have to remember that when we shift from 4th(1:1) to 5th(0.75:1), or lets say the driveshaft rpm is 7,500rpm in 4th gear with a 7500 engine rpm in 4th, the same 7,500engine rpm becomes 10,000 driveshaft rpm, in 6th 0.50:1 would be 15,000rpm.

Some of the newer transmissions (TR6060) have less split from 4th to 5th, which helps reduce that nose-over feeling that some experience when shifting to OD.
Engine torque=400lb/ft
Rear Gear 3.45:1
Engine Torque x trans ratio x rear gear=torque applied to ground
400x2.66x3.45 =3671lb/ft
400x1.80x3.45-2484 lb/ft
400x1.30x3.45=1794 lb/ft
400x1.00x3.45=1380 lb/ft
400x0.75x3.45=1035 lb/ft
400x0.49x3.45=676 lb/ft

SO throwing a 4-5 upshift losses 345 lb/ft of applied torque combined with the fact that at this speed aerodynamic forces are increasing, thus adding to negative acceleration.

Fascinating discussion, so many variables. With the extended rpm potential of the LT5 conventionally agressive gearing, isnt so agressive when used with the LT5.

[Schrade]

Originally Posted by Schrade

Just hung up with Psychic Hotline. They said heated discussion on the way yup...



This statement needs quantification, for starters...

And I think a more judicious use of the term "multiply torque" is in order.

[Hog]

Originally Posted by Bob Eyres

I don't agree. You don't have to go to a block and pulley analogy to explain it. Just look at 60ft. times.

If a ZR-1 cuts a 1.50 60ft., and another cuts a 1.60, who's accelerating harder?

The ZR-1 with 4.10's will cut a better 60ft. every time. All other things being equal.

I had to go to a block and tackle as the other gentleman didnt understand.
My point was, that just because your tach reaches 7500rpm quickly, doesnt mean that your speedo is accelerating as quickly.

I agree with your drag scenario a car cuts a 1.50 60ft, and another hits a 1.6 60ft. The 1.5 60ft is accelerating harder.

I also agree, a 4.10 geared ZR-1 will cut better short times(60 ft) than a higher geared ZR-1, all else equal.

Now I ask you this, in your scenario ZR-1 #1 cuts a 1.50 60ft with its 4.10 gear, and ZR-1 #2 cuts a 1.60ft short time with its 3.45 gear.

Which ZR-1 will trap with the higher Speed MPH? All else equal.