Rear Gears

[Troponin]

So I understand that swaping out gears can increase your 60ft and improve 1/4 mile times (unless you're making a bad change), but for those of us who daily drive their cars and aren't in need of a wicked 60ft, I am wondering what effects it has on passing and roll racing.

Are the benefits of switching out gears pretty much linear, or do the benefits decline greatly the faster you're going, excluding top speed arguments?

I was toying with the idea of going from 2.62 to 3.09, which helps the HCs greatly in the 1/4 mile, but I rarely drag race at the track.

 

[apex svt]

2.62 that's a crazy tall gear. What car is this going in?

 

[KLLR SNK]

Automatic or manual?

 

[sleek98]

Looks like he's got a charger hellcat so it's the a8.

It will shift more often but with the 8 gears your not going to notice a huge difference when cruising on the highway. Maybe 250-300 Rpms.

Even with a 3.09 your not going to get into your 1:1 gear until you past 125 so it's not going to hurt any.

Your first is going to be even more useless.

 

[nxhappy]

Your hellcat will haul ASS with 309s....do it ! At highway speed you will be revving higher RMPs, in my opinion would be better for launching and also for roll racing. You will lose top speed but you don’t need to go 200 mph LOL. If you can hook your quarter mile will improve for sure. Get the gears and then buy some drag radials so you can hook. Make sure the shop knows what they are doing on the gear install. The lash and adjustment has to be dead on, or you will get gear whine.

 

[sleek98]

Dodge sells them As a center section so it's an easy bolt in. I'm trying to talk my buddy into doing it on his car.

 

[zak88lx]

When I first got my 5.0 Mustang (in sig), it had the factory installed 2.73:1 gears. It was a blast on the highway, and I loved the top end for passing, and the fuel economy was also great.

I eventually upgraded to 3.55:1 which made a drastic difference on the low end acceleration, but the car now hits a wall pretty quickly at higher speeds.

I sometimes wish I still had the old gears.

 

[4a7191a]

Old school here.. lol
I run a 456 in my Mach
Never fear the gear

 

[VenomGTX]

2.62 that's a crazy tall gear. What car is this going in?

It sounds worse than it is. The 8-speed auto in those cars has very short gearing (1st is 4.71!). It's actually shorter overall than a manual which has a 3.70 rear end.

 

[black4vcobra]

Yes more gear would be good, I got a ride in a manual Charger Hellcat and down low it was a little weaker than I expected, however, it felt like acceleration was barely tapering off by 95 so that's the trade off.

4.10s in my Cobra and other than a tad too high of rpms on the highway, I wouldn't have it any other way

 

[Torch10th]

Lower numerical gearing applies greater torque multiplication. This effect is throughout the rpm band and regardless speed. Increasing torque will always increase acceleration. The downside is you lower your maximum possible speed.

You can do the math for all of the gears, but if you take your 1:1 gear you can kind of see how it'll effect your car at speed.

Stock you have your engine making 650 ft lbs of torque multiplied only by the final drive ratio of 2.63 which gives you effective torque of 1709.5 ft lbs. Going to a 3.09 gear set, increases your effective torque to 2008.5 ft lbs. A difference of almost 300 ft lbs of torque in your 1:1 drive gear.

Which gear do you think is going to accelerate the car quicker? Overall speed is reduced however. the 1:1 gear in a Hellcat with stock gearing will move the car to around 184 mph based on a 28" tall tire, the factory gear and a 5800rpm redline. Moving to the 3.09 will bring your 1:1 gear top speed down to 156 based on those same factors.

 

[Silverstrike]

Yes more gear would be good, I got a ride in a manual Charger Hellcat and down low it was a little weaker than I expected, however, it felt like acceleration was barely tapering off by 95 so that's the trade off.

4.10s in my Cobra and other than a tad too high of rpms on the highway, I wouldn't have it any other way

It has to be a manual Challenger HC as all Charger HC's are Auto.

I did a 4.10 gear change with the Marauder and other than turning just a tad under 2500 RPM at 70 MPH highway speed it was nice and not real noticible day to day operation in that car.

Now my new 2005 Corvette has the optional 3.15 gear in the 4L60E Auto and it has very similar performance to the land yacht Marauder with 5.0L stroker engine, Trilogy S/C on 11# of boost with the 4.10's. With winter about in Ohio I'll have to wait to see if it can duplicate the 22-25 MPG Highway, I got in the Marauder with the above mods. I think it can top that as it is 1200 lbs lighter and vastly superior in the drag cof.

 

[black4vcobra]

It has to be a manual Challenger HC as all Charger HC's are Auto.

I did a 4.10 gear change with the Marauder and other than turning just a tad under 2500 RPM at 70 MPH highway speed it was nice and not real noticible day to day operation in that car.

Now my new 2005 Corvette has the optional 3.15 gear in the 4L60E Auto and it has very similar performance to the land yacht Marauder with 5.0L stroker engine, Trilogy S/C on 11# of boost with the 4.10's. With winter about in Ohio I'll have to wait to see if it can duplicate the 22-25 MPG Highway, I got in the Marauder with the above mods. I think it can top that as it is 1200 lbs lighter and vastly superior in the drag cof.

Yes, it was definitely a Challenger, brain fart there as the thread was talking about Chargers.

Impressive to make a land yacht like a Maruader run hard, it does take a lot of work though with it's 1000 lbs extra mass over Mustangs of the same year. I bet your Vette can get 28 mpg on the highway and with an intake, exhaust and tune it'll add 40+ hp.