I just had a set of 4:10 GM Gears put in my 99 M6. I know they give you killer bottom end but do they kill your top end? My car seems slower on top end now.

 

with those gears u def will lose a lot of top end

 

How fast are you trying to go? With a stock rev limiter 4th gear is still good until about 117 mph instead of 134 or so. The final drive ratio in 5th with 4.10's is 3.03. Not to bad if you ask me, but perhaps the cam makes up for the percieved high sped loss. The car still pulls hard in 5th, but rarely ever goes there as I don't need a nasty ticket. For 99% of the driving most people do with these cars 4.10's are an improvement.

 

What do you mean by top end??

Are you referring to the higher rpms (this would be encountered in every gear) making the engine feel as if it was 'over-revving'.

Or

Are you referring to high speed use?

Your terminal speed in gear should have reduced but at the benefit of reaching speeds quicker.

 

I asked this a wile ago......https://ls1tech.com/forums/gears-axles/461252-4-10-vs-3-42-a.html

here they say you will get better topend.

 

Obviously you will not go as fast with the 4.10 gears as you would with the 3.42's at the same rpm. You will get to your redline rpm quicker with the 4.10's. You will get through your gears quicker with the 4.10's. If your tires give you decent traction your 4.10's should be much quicker in the 1/4 mile or 1/8th mile. You may very well have a higher actual top end in 6th with the 4.10. Theoretically though, your top end will be less with the 4.10.

Not considering the gears of your transmission at all, just spinning the driveshaft yoke at the rear end, with the 3.42 gear you must spin the yoke 3.42 times to make the tire turn one full revolution. On the other hand, with the 4.10 gears you will have to spin the yoke 4.10 times to turn the tire one full revolution. It just means you will have to turn about 20% more rpms with the 4.10 to go the same speed you went with the 3.42's in any given gear. But you'll get there a lot quicker.

 

What I mean by top end is...my buddies I use to pull on the highway(3rd gear punch at 70) with the stock gears I cant pull hard now. I use to pull 1-2 cars on him, my buddy did get the jump but I couldnt fetch him it seemed or if I was it was really slow, and all he has is a stock A4 SS.

 

that shouldn't be..you should pull harder in every gear, but you'll just be limited to 223 at 6krpms... so theoretically..if your car was capable of doing that..with 4.10s..it would get there sooner than with 3.42s.

 

So 60-120 should be faster with 4.10. i would like to se a race with 2 stock cars but one of them with 4.10 or 3.73, in higher speeds and lower speeds.

 

I lost 15 mph when i installed my 3.73s in my auto

 

SHOULD...its all up to the drive..your gonna have to shift faster..and mroe to take full advantage....but all things being equal..the person with the 4.10s should accelerate faster.

 

I dont understand why so many people are quick to say go 4.10s and never look back. They never point out that while your car might be snappier and quicker, the side effect is you loose higher mph top speed in 5th gear. And what about the challenge to launch your car on street tires?

3.73s are working out great so far in my car, 3.42s are not that bad given the fact you arent stock and are pushing at least 350rwhp.

Goin from 3.42s to 3.73s is not alot and thats what I wanted, now the car just feels lighter . And its more fun to drive while not killing my top speed or making it too sensitive on the throttle.

 

your limited to 151 at 6k in 5th gear... why is that so bad?

 

I think this is just about matching revs to speed better. With 3.42 STOCK gears 70mph in 3rd would be a sweet spot @ ~4100rpm, so just shy of PEAK torque. Yu should have a lot of punch and still be able to hold 3rd all the way upto 100-103mph before shofting into 4th. But with 4.10 gears 70mph = 4900rpm so it'a past PEAK torque (about 4400rpm) and is also very near to the red line. This means two things:

1. You can only go uptp 86mph (red line) so the 'range' of speed is much reduced. This means you will have to put an extra shift in, this all takes time and cost ground.

2. Due to the gearing it may feel like the engine is 'over-revving'. As soon as you hit the loud pedal you need to shift, it isn't making the best use of the torque/hp available. This is like, if you have ever been in a big diesel truck or lorry, 1st gear is often very short, so you think hay it will accelarate really well. But it doesn't it just tends to make a lot of noise and reaches the limiter really quickly. The low gear only exists to get the rig moving when fully laden.

4.10 gears could be veiwed similar, at the 1/4 mile they will really help fire the car out of the hole (grip dependant), but from a high speed roll they may lose they're affectivness.

You may find your car responds better in 4th @ 70mph, either that or run from a speed that better suits your gearing. 55-60mph in 3rd will be a good spot or 75-80mph in 4th.

The thing to remember is 4.10 gears give you better in gear accelaration, but at the cost of terminal speed in gear. This means that in most cases you have to shift more times to reach the same speed. So good fast and smooth shifting is far more important. As when you change gear you are NOT actually accelarating, so you need to minimise this period of non-accelaration in order to take advantage of the shorter gearing.

If you don't feel you can shift as fast as you would like (or is required) then your car with YOU as the driver may well actually be faster with 3.73 or 3.42 gears.

Take my Auto Z28 for example it has 2.73 rear gears, so 'in-gear' accelaration won't be as strong, but it will run to higher speeds in each gear. 70mph happens to be a good spot for it has it will kickdown to 2nd and be at ~4050rpm, it will then run all the way upto over 100mph before shifting into the 3rd and this gear will take me to the 158mph limiter. So very little time is lost in shifting.

 

The "lower gears kill top end pulling power" is all a myth.

Going from 3.42s to 4.10s will lower your absolute top speed, but it doesn't reduce your pulling power from a roll...it does the exact opposite. You're starting in the wrong gear, or you're slow on the shifts. Or if you're on a stock tire...you're getting some spin and you don't realize it.

 

I ran a friend of mine from a 60 punch. We both have cams, and put down similar numbers. He is an A4 with 3.42 gears and a 3600 stall. I have 4.10's and a 6 speed. If you plug the number into a gear calculator you can see who has the mechanical advantage at different speeds. I had a mechanical advantage through my 3rd, and fourth gears. I had to shift to 5th at 117. He then has a mechanical advantage from 117 to 134 because he is still in his 1:1 ratio. At 134 he would shift to OD, and I would have a mechanical advantage until 150+ where I would begin to run out of gear. Ultimately, I pulle 3/4 to 1 car through 3rd and 4th, and he maintained after I had to shift to 5th.

 

Its not bad.........but is 350hp stock enuff? NO....its not bad. More is just better sumtimes.!!

now is 170mph so bad?

 

your toppspeed is 150 with 4.10 but would you reach it before 3.42 or 3.73....nah you have to go in 5th way before and 5th dosen´t pull as 4th does.

I think 3.73 would give you the best of both highspeed and low speed.

 

I have been well over 150 with 4.10 gear it limits the what mph you car COULD reach if you red line 6th gear but we can't do that anyway, and you car can pull threw 6th easier with a 4.10 so no it does not lower you cars real speed just what you COULD DO IF YOU RED LINE 6th

 

6th gear w/ 4.10 might get you over 150mph but you wont pull over 4700rpm or so and the car will probably be struggling with that small *** gear.
anyhow a top speed burst would prolly be done in 5th.

Consider this.

3.42 = in the area of 170mph -180mph depending how muchpower you got.
3.73 = 170 or a lil more
4.10 = 150 or so