How to Choose Rear End Gear Ratios

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  • čas pƙidĂĄn 5. 10. 2020
  • Rear end gear ratios can drastically alter how a car applying torque. Learning how to choose rear end gear ratios will get your build on the right track by maximizing all of the other parts. Whether you're building a fast 1967 GTO or a rock crawling XJ; gear ratio matters. We also discuss when to shift gears in a car and how it impacts the overall performance.
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Komentáƙe • 56

  • @LSxHunter
    @LSxHunter  Pƙed 3 lety +1

    Want to see more videos like this? SUBSCRIBE 🔮 bit.ly/2UTdkct 🔮

  • @annasbanana729
    @annasbanana729 Pƙed rokem +3

    Would love to hear more about torque converter stalls

  • @unicornsteaks6769
    @unicornsteaks6769 Pƙed 2 lety +2

    Man, you have a voice for radio.

  • @brentonwickham69
    @brentonwickham69 Pƙed 3 lety +1

    Great video, great information
    Thanks man

  • @robertswain8665
    @robertswain8665 Pƙed rokem +1

    If you wanted to keep your Car/Truck pretty much stock other than gearing and you had an Ford FE 352 and all you wanted to do was wake it up a little (not for track purposes) what gear ratio would you choose for your vehicle as in not to recommend myself or anyone else, but what would/could YOU choose without having to change the torque converter or whatever else to make the difference improve noticeably?
    And Thank You for your time and input.

  • @emanuelrusinga4584
    @emanuelrusinga4584 Pƙed 3 lety +3

    Whats the best gear ratio for turbo ls truck applications? Would 4.10s or 3.42 gears be better? I hear some say 3.42s are better for loading the turbo?

  • @davidvonanderseck8649
    @davidvonanderseck8649 Pƙed 2 lety

    Good info thanks

  • @LaSierraAcresQuailFarm
    @LaSierraAcresQuailFarm Pƙed rokem

    currently running 4:11 gears in my 67 pontiac lemans with a 389.. rpm is pretty high, so im looking at 3:55 gears to drop down the rpm's.. i would like to do more highway driving than going just around town.. will lowering the gear ratio to 3:55s also help with keeping the engine running cooler also? would like a good cuising speed at about 75mph while keeping the rpms as low as possible, but still have some get up and go...

  • @MrSeanthedon369
    @MrSeanthedon369 Pƙed 3 lety

    I have a 393 Windsor with 11 to 1 compression and a 600 lift cam The max RPM is 7000 I have 3.08 gears in it now thinking of putting 3.73 or 4.11 maybe 4.10 what would be the best sitting on 15 inch drag radios

  • @rifleman7313
    @rifleman7313 Pƙed 2 lety +2

    I know that there's probably a computer program for this I just don't know it. But how do you think a combination of 4.88 gears, 30 inch tires, a 4L60 transmission, and a gear vendors over/under drive would work for a 4000Lb 4wd vehicle with a built 800+ H.P. 383 stroker built on a 5.3L LS. According to my rough calculation with the grimmjeeper gear calculator it should hit about 200mph at 6000rpm.

  • @TechTokOffical
    @TechTokOffical Pƙed 3 lety +1

    So I'm swapping my bmw from auto to manual right now. I'm using the same rear diff for both that has a 2.91 gear ratio. Everyone in the forums is says gonna be a problem on the highway and ill be riding a like 4000rpm when crusin 80(that seems normal tho). Am I going to run into issues.

  • @am211
    @am211 Pƙed 3 lety +3

    Love your videos man! I have a 67 Firebird convertible with a 2.56 gear and I have a 350 HO with ram air III #16 6x heads and a ram air IV cam. I am still in the break in period in the rebuild and have not gotten on it at all. What I have noticed is that there is literally no power during the lower RPMs. Mind you, I am just turning out into traffic to get up to speed and have not punched it at all. I am looking to install a posi unit and either a 3.55 or 3.73 gear so I can more off the line power. Based on your video, it seems like the 3.73 is going to be a better choice? I am only driving it around town and not on the highways.

    • @LSxHunter
      @LSxHunter  Pƙed 3 lety +1

      Keep in mind when you change the gears from a 2.56 you usually need to change the carrier and sometimes the differential. I'm a big believer in 3.73s, there's a reason they've been the street/strip standard since the beginning. If it's a car I wanted to drive 3-5 times a week I'd go with something like 3.23s or 3.42s with an OD transmission. The fuel economy is hard to fight sometimes.

    • @robbyrob8349
      @robbyrob8349 Pƙed 3 lety +1

      @@LSxHunter I have a 3:23 gear ratio on my 2017 Escalade and I’m looking to put a 3:73 or 3:90 gears. Do I have to change the carrier?!

  • @rogerhankins6905
    @rogerhankins6905 Pƙed rokem

    I have a 71 clone convertible with a 455 and right now it's got 256 they got to go also changing the transmission to a 4 speed I'm. old school and don't know a lot about some of this but it's a retirement project and I want to do everything myself any help I can get would be appreciated

  • @GARZA313
    @GARZA313 Pƙed 2 lety

    1993 chevy silverado on 6.0L with a th350 what gear ratio do you recommend ????

  • @billmiller5075
    @billmiller5075 Pƙed 3 lety +1

    Great info

    • @LSxHunter
      @LSxHunter  Pƙed 3 lety

      Anything you'd be interested in seeing?

  • @phoenix21studios
    @phoenix21studios Pƙed měsĂ­cem

    if you drive a lot on the interstate, pick 373s or 390s. everything else 410s for the street.

    • @doomman700
      @doomman700 Pƙed měsĂ­cem

      I use 3.90 in 1/8th mile car. They are terrible at highway speeds.

  • @hopebrowning6300
    @hopebrowning6300 Pƙed 3 měsĂ­ci

    Not always true..big blocks love higher gears .had a 73 Oldsmobile omega with a mild built Pontiac 455 , peak tq 515 around.2,500 rmp, max rmp 5,000.came with 263? Or 266 can't remember but change to 373 slowed us on mph and time.342 did also not as bad as the 3.73 , 308 mph drop few mph but time all most same as stock .we didn't have 273 to test

  • @marblemaker117
    @marblemaker117 Pƙed 11 dny

    Wait, you guys are talking about racing, launching. No, no race here. I’ve got a ‘69 Chevelle, stock 2bbl 307 and I’m assuming 3.08 gear. At 70-80 mph I’m screaming down the highway and need it to do better. I’m thinking 2.73. Not looking to race anyone, just need the rpm’s to come down. Will it be enough? Can’t afford a 700r4 right now. 😱

  • @jeffgonzalez513
    @jeffgonzalez513 Pƙed 3 lety +2

    I’m currently looking for some help on what would a 3.9 do compared to a 4.1 or 4.3. It’s a LSD for a Miata not sure if it’ll help but right now I’m cruising at 80 mph @4000rpm not sure what ratio I’m running but would love some help!

    • @RMAGEDN740
      @RMAGEDN740 Pƙed 3 lety +3

      Final drive is heavily dependent on each individual gear. If you're cruising 80mph at 4000rpm, your transmission gearing is short (higher numbers), as well as your final drive (higher). If you have a lower final drive ratio (lower numbers), you would essentially be stretching the individual gears longer (lower). This would lower your cars rpm at 80mph, however, if you're on a stock miata, it's gears are short due to it's lack of power/torque. So if you go with a lower final drive, you're going to make the car more sluggish. Powerband is very important to setting up gears. Pontiacs work better with lower final drive ratios because of the mid range torque. 3.73 keeps in the strong part of the power curve longer. Capeesh?!

  • @shawneewarclub
    @shawneewarclub Pƙed 2 lety +1

    Good discussion but

    My 4.10 cars all went 2-3 tenths faster in the quarter than the exact same car with 3.73s
    Granted 99% of the guys out there aren’t looking for max et but I’ve been street racing Pontiacs since the early 80s so all I care about is results
    400 with worked 16s or 62s, worked stock intake, worked q-jet, raiv cam 1.6 rockers, recurved distributor,10.5-1 forged pistons, balanced rotating Assy, 4 tube headers with turbo mufflers, Vega converter with long snout in a built turbo 350, 10 bolt with 4.10s 11.30s- 11.50s from spring till fall on 80s street tires with a 150 shot in my back pocket those cars were almost unbeatable on the street in the 80s and 90s
    It took race cars to beat the car I hauled my kids to school with
    I’ve street raced since 77 until the 90s if you had a 11.50 car you weren’t afraid to race anyone!
    The truth is a 11.50 car was super dominant on any street most guys who thought they had fast cars would get bus gapped by a 11.50 car
    Give me 4.10s for the win😎

  • @gregschultz2029
    @gregschultz2029 Pƙed 3 lety

    Fun ,Thank You ,I like numbers !!!

    • @LSxHunter
      @LSxHunter  Pƙed 3 lety

      Anything you'd be interested in seeing?

  • @titosvip0125
    @titosvip0125 Pƙed 3 lety

    I'm just getting into gears . I drive a 2010 jaguar xfr 5.0 Supercharged.....what gear ratio would u recommend??? I'm making about 461 torque..... thanks

    • @LSxHunter
      @LSxHunter  Pƙed 3 lety

      I think those use a ZF 6HP? I know the 5th gens really like 3.91 gears with a similar gear setup and I think it's only 420ftlbs. You might run into hooking issues in 1st gear but if you can get it to hook the 60' would be gnarly. I'd imagine those XFRs have a lot more in them than their factory rear/tires allow.

  • @MIKELOTEMPIO
    @MIKELOTEMPIO Pƙed rokem

    Hey man. I have a 78 Camaro 350 small block with a th350 and I just put 4.11 in the car. Im debating on dropping down to 3.73 or even Lower. Before the gear switch I had 2.73 and could cruise to 140 mph no problem. The car now can’t even hit 90, the engine is just screaming. Any tips or certain combination I need to get this car running right!?

    • @LSxHunter
      @LSxHunter  Pƙed rokem

      4.11s will definitely hurt the top end but it’ll make it way snappier to get there. Personally I’m a big fan of 3.42

    • @kellynestegard5208
      @kellynestegard5208 Pƙed 6 měsĂ­ci

      Consider swapping in 200-4r trans. The only change needed is moving the crossmember. If you have a lot of power, the 200-4r will need to built up, they can be made to handle 800 hp if you have the $$$. The overdrive (.67:1) will make your 4.11s like your old 2.73s.

  • @rickeyhahn-wi9ju
    @rickeyhahn-wi9ju Pƙed rokem

    You never talk about us 4 speed transmission users

  • @Celticman197
    @Celticman197 Pƙed 7 měsĂ­ci

    Yeah, but what happens after the 1/4 mile.

  • @biggyles9550
    @biggyles9550 Pƙed 2 lety +1

    Mercury grand marquis 2.73 to 3.73 how will it do on highway

    • @woodburn2597
      @woodburn2597 Pƙed 2 lety

      3.73 is the way to go

    • @BladesRKing
      @BladesRKing Pƙed 2 lety

      You will run higher engine RPM at highway speed which = less MPG. Around town you will see a lot more pep.

  • @joshbrekke6374
    @joshbrekke6374 Pƙed 3 lety +1

    There is a very intelligent solution available now.
    Winters Street Rod Performance V8 Quick Change rear end.

    • @LSxHunter
      @LSxHunter  Pƙed 3 lety +2

      I've heard of them but never played with their products. Seems like a good idea.

    • @joshbrekke6374
      @joshbrekke6374 Pƙed 3 lety +1

      You should put one in and do a review for us. I dare ya!

    • @LSxHunter
      @LSxHunter  Pƙed 3 lety +2

      😂 if only I had the money! I've got 12-bolts everywhere at this point

    • @cheekydemon6131
      @cheekydemon6131 Pƙed rokem

      I am here 2 years late, but I have a question anyway - how does this quick change work?

    • @LSxHunter
      @LSxHunter  Pƙed rokem +2

      Better late that never. They’ve got a housing that allows you to remove the back plate - slide the gears out the rear without removing the axles and just pop the new gears in. It’s like a 10 minute process.

  • @harryjohnson2
    @harryjohnson2 Pƙed 2 lety

    In actual real world testing, I went from 2:73 to a 3:73 gear and dropped .3 tenths on average in the quarter and maybe 1 MPH. 13.7 to 13.4 with no other changes. IDK who in there right mind would think you can drop a second and pick up 5 MPH from a gear change

    • @scottedwards8220
      @scottedwards8220 Pƙed 2 lety

      I'm new to this, but what was traction like between the launch on 2.73 vs 3.73? Did you spin more on the 3.73?

    • @harryjohnson2
      @harryjohnson2 Pƙed 2 lety

      @@scottedwards8220 you will definitely spin alot more with 3:73 if your dont have a good tire or chassis set up. If you have traction, you will notice much more bottom end power through 1st gear

    • @LSxHunter
      @LSxHunter  Pƙed 2 lety

      It’s important to note this is with PERFECT traction. Slicks on a strip with sticky sauce. I’ve personally seen just under second gains going from 2.73 to 3.42s BUT that cars intake hated the 2.73s.
      There’s a lot of pieces to the combination that can drastically alter the results

    • @harryjohnson2
      @harryjohnson2 Pƙed 2 lety

      @@LSxHunter Ive seen somebody knock off 4 seconds with nitrous. but the bottle pressure had to be perfect 🙄

  • @clayclifton2255
    @clayclifton2255 Pƙed 3 lety

    Everyone’s different I would’ve thought being here you get better gas mileage and plus when you get out I have 150 160 mile an hour

  • @jordanpeele5306
    @jordanpeele5306 Pƙed 3 lety +2

    this makes no sense. much like biden as president

  • @djrosa773
    @djrosa773 Pƙed rokem

    Can you contact me so I can ask you a few questions about my 67? Chevelle rear? End Guerrero with my new 454th street driver. I just had installed in my car thank you so much d j