4.10 gears...not what I expected.

[Bob Eyres]

The short, smart*ss answer is, It doesn't matter. Because the one with the best e.t. wins.
I don't pay much attention to trap speed because I dont' care how fast you're going in the traps if you're behind me.

With the 4.10 gears I trap 117+ with a stock motor and boltons. That's a whole lot better than my early efforts with stock gears that trapped a best of 110-111mph.

The short gears allow you to keep the engine up in it's most powerful rev range for more of the time during the race. Someone running the quarter in two or three gears spends more time climbing up to max power, as in your example. That's another way to explain the advantage of short gears.

Of course, those with a torque converter overcome that disadvantage in another way. But that's a whole other discussion.

[Hog]

Originally Posted by Bob Eyres

The short, smart*ss answer is, It doesn't matter. Because the one with the best e.t. wins.
I don't pay much attention to trap speed because I dont' care how fast you're going in the traps if you're behind me.

With the 4.10 gears I trap 117+ with a stock motor and boltons. That's a whole lot better than my early efforts with stock gears that trapped a best of 110-111mph.

The short gears allow you to keep the engine up in it's most powerful rev range for more of the time during the race. Someone running the quarter in two or three gears spends more time climbing up to max power, as in your example. That's another way to explain the advantage of short gears.

Of course, those with a torque converter overcome that disadvantage in another way. But that's a whole other discussion.

Tee-hee, reason I asked about mph as it is the indicator of power, moreso than ET.

I've noticed that sometimes in a 1/4 mile drag situation, that with lower rear gears, that while ET can increase, trap mph can decrease, all else equal.
If I am reading correctly, you have been experiencing highr MPH trap speed with your lower gearing? Interesting.

xxxxxxxxxxxxxxxxxxxxxxxxxxx
I just ran some numbers:
7000rpm/3.45 gear/25.5"tire 1:1 4th gear gives 154mph
7000rpm/3.73/25.5"/4th gear gives 142mph
7000rpm/4.10.25.5"/4th gear is 130mph
7000rpm/4.30/25.5/4th gear gives 123mph
7000rpm/4.56/25.5/4th gear is 116mph
7000rpm/4.88/25.5/4th gear is 109mph
7000rpm/5.13/25.5/4th gear is 104mph, **** to 5th and 138mph is attaiable at 700rpm, then shift again into 6th gear and 211mph is attainable at 7000rpm. 5.13's in 6th gear at 70mph would be revving 2325rpm. 7000rpm in 1st gear with 5.13's gives you 39mph.

Looks like the amount of power the engine makes, will affect just what gearing you would need to run, IF the goal is best 1/4 mile ET.

The lower the rear gear (higher number) also helps to reduce driveshaft/trans/clutch/engine loading. Everything after, starting with the ring gear to the tires would experience increased loading.

[USAZR1]

Originally Posted by Hog

Tee-hee, reason I asked about mph as it is the indicator of power, moreso than ET.

I've noticed that sometimes in a 1/4 mile drag situation, that with lower rear gears, that while ET can increase, trap mph can decrease, all else equal.
If I am reading correctly, you have been experiencing highr MPH trap speed with your lower gearing? Interesting.

If all else is equal,both LT5's make the same power or very close to it.
So,their trap speeds should be very close to the same. Only way that would be lower is if the engine is running out of breath at the lights.
As Bob said,only the ET matters in drag racing. MPH is just a by-product though it is a honest indicator of how much horsepower you're putting down.

[rhipsher]

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?

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,,

Clint as rare is it might be I am one of those guys that have gone well past the 120 mark on many occasions. And I can say from my experience that top speed is achieved in 5th with the stock 3.45. When I shifted into 6th gear I fell from 182mph to 168mph in a hurry. At top speed I was pegged at 7200rpm's. 4:10's might make 6th gear useful but I wonder if I would run out of RPM's before reaching top speed with them.
I'm with Pete on this one. If I had $1,500 to burn on performance mods I go with the ones that are actually going to create more HP. Because more HP is just more. And with 3.45 your going to see gains in every way. Launch and top end. Id rather have the overall increase than one or the other.

[mgg]

I have read most of these post and it is a fascinating discussion. The one thing that no one has brought up is how does the single mass fly wheel affect al of this. I have a 90 ZR-1 with Marc's 510 hp package. I also installed 4:10s a few years ago. With the single mass flywheel getting to the torque curve and Hp sweet spot much more quickly I am curious how this would impact the discussion. Personally I really like the 4:10s. I only drag race once or twice a year. I don't own drag radials so trying to hook the car is just about pointless from a dead stop but it does pretty well from even a first gear roll. I am curious what the opinion is on how a single mass fly wheel would impact this discussion. I can tell that I am thrilled with the result of Marcs 510 package the gears etc. The car now has some "edge " to it and makes it really fun to drive. I know it will take some drag radials to take advantage of the launch but I 1/4 racing was not the biggest priority in purchasing one of these cars.

[rhipsher]

Originally Posted by mgg

I have read most of these post and it is a fascinating discussion. The one thing that no one has brought up is how does the single mass fly wheel affect al of this. I have a 90 ZR-1 with Marc's 510 hp package. I also installed 4:10s a few years ago. With the single mass flywheel getting to the torque curve and Hp sweet spot much more quickly I am curious how this would impact the discussion. Personally I really like the 4:10s. I only drag race once or twice a year. I don't own drag radials so trying to hook the car is just about pointless from a dead stop but it does pretty well from even a first gear roll. I am curious what the opinion is on how a single mass fly wheel would impact this discussion. I can tell that I am thrilled with the result of Marcs 510 package the gears etc. The car now has some "edge " to it and makes it really fun to drive. I know it will take some drag radials to take advantage of the launch but I 1/4 racing was not the biggest priority in purchasing one of these cars.

I did. Look at post number 5.

[USAZR1]

Originally Posted by rhipsher

Clint as rare is it might be I am one of those guys that have gone well past the 120 mark on many occasions. And I can say from my experience that top speed is achieved in 5th with the stock 3.45. When I shifted into 6th gear I fell from 182mph to 168mph in a hurry. At top speed I was pegged at 7200rpm's. 4:10's might make 6th gear useful but I wonder if I would run out of RPM's before reaching top speed with them.
I'm with Pete on this one. If I had $1,500 to burn on performance mods I go with the ones that are actually going to create more HP. Because more HP is just more. And with 3.45 your going to see gains in every way. Launch and top end. Id rather have the overall increase than one or the other.

It's ok to disagree,Rick. Like I said earlier,different strokes for different folks.
I've been over 175mph too many times to count in my 90 ZR-1 while it still had 3.45's,,way over. Been over 200mph more than a few times too,on some of my turbo/nitrous prostreet bikes.
This is my 3rd ZR-1 so I've been around the block a few times,so to speak.

Our 94 came with 4.10's when I bought it,a free mod.

BTW,good to see you posting again. Welcome back.

[Bearly Flying]

The Point being, if you want driveability, and NOT pure quarter mile performance, is the swap to 4;10's worth it?

I can already light up the tires at will with the 345's , if I drop to 4:10's it will only get worse?

I don't run 1/4 mile at all, just street driving.

[KILLSHOTS]

Originally Posted by Bearly Flying

The Point being, if you want driveability, and NOT pure quarter mile performance, is the swap to 4;10's worth it?

I can already light up the tires at will with the 345's , if I drop to 4:10's it will only get worse?

I don't run 1/4 mile at all, just street driving.

If you want driveability, then yes, it is a great swap. I don't think I would do it again, given the same scenario of spending $1500 to have a mechanic complete the job. But if I was doing the work myself and only spending the $500 or so in parts, then yes, I would go for it. It changed the character of the car but surprisingly, it wasn't a lot more tail-happy. For what it sounds like you're looking to accomplish, it's a great swap.

[XfireZ51]

I went from 3.45s to 3.73s due to the 19" Z06 wheels I have. It effectively bumped my rear from a 3.30 to ~ 3.55. The car felt more responsive to throttle changes. It became more fun to drive.