best transmission gear ratio for drag racing

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Let's say you already have an idea of how fast you want your car to be and at what RPM the engine peaks out at and you want to know what gear ratio to go with so the engine's RPM maxes out at the top speed you want to go. In other words, with a typical street car that has 400 - 450 HP you'll NEVER be able to get to 164 MPH in a quarter mile, let alone 1 full mile because most cars will float and lose control at that speed without suspension modifications, ground effects, etc, so that gear ratio is completely useless for drag or street racing, although it's a great ratio for running down the highway at a decent RPM for long distances. 3.25 gears x 336 = 1092. The best way to determine what gear ratio you need is to determine how you'll be driving the car. Rear end gears are EXTREMELY important for how a car performs. So the reality is, you might THINK you'll be at 2,700 RPM but with the converter slippage you could really be at something more like 3,200 RPM or more! Keep in mind, and this is VERY important, torque converter slip! A Mustang usually has a pretty short tire diameter of like 25 inches, so we'll use 25" as our baseline. All of this math is for a 1:1 high gear ratio which is what all TH-350, TH-400, C-4, C-6, FMX automatics have for high gear, as well as pretty much all 3 and 4 speed manual transmissions. BTE manufactures all of the critical components to make the powerglide transmission the best choice for drag racing. The gearing is the other half. I agree to receive emails from RacingJunk.com. World's #1 Racing & Performance Classifieds, December 8, 2016 In a 4.10 gear set you will have to rotate the pinion gear 4.1 times to rotate the ring gear once. We offer a variety of gear ratios, input shafts, clutch drums, roller components, and other items to custom fit almost any high performance vehicle. For example; a really low set of gears would be something like 4.56's. When guys want to make their cars "perform" better, (and don't know any better), the only thing they look at and consider is the engine. That means there is a 420 RPM difference between 3.00 gears and 3.50 gears on that car. In other words, the math might say you'll be at say, 2,700 RPM at 60 MPH, but if you have a slippy converter, such as a 3,000 - 3,500 stall, you can easily have 500 or more RPM of slippage which will add to that cruise RPM you calculated. How-To and Tech Tips, News, Slideshow, Tech Tips, Transmission and Clutch If you can't launch and GET to your speed quickly, you won't run a good elapse time. To select the ideal gear ratio, you must take into account vehicle weight, engine camshaft specs, the powerband, optimum engine rpm, intended vehicle use and the axle gear ratio. The math is: RPM x tire diameter, so 6400 x 28" = 179200. PONTIAC POWER RULES ! Occasionally you'll find 3.89's or 3.91's, but just to keep it simple, let's say your choices are either 3.73's or 4.10's. So 70 x let's try a gear set of 3.50's, x 336 = 82320. This is another simple equation. For example, the Richmond transmission has several different first gear sets available: 3.33:1, 3.06:1 and 2.89:1. When picking gears, remember specific ring and pinion sets are engineered for high shock loads (drag racing) while others are built for street use. Now that we know a little more about gear ratios and how they affect your car, let’s look at how to choose a gear ratio tailored to your car. This is especially true when trying to determine what RPM you'll be at when traveling down the freeway at 60 MPH because at that low of an RPM, your 3,000 RPM stall converter is slipping several hundred RPM which will throw you a curve ball when trying to calculate these numbers. Transmission gear ratios are designed to work with a range of rearend gear ratios so that the engine operates within the part of its power band that generates the most power. Divide 179200 by 1092 and you get 164.10 MPH. This nearly equates to skipping from first to third gear with a manual trans. I learned this lesson many years ago when I started drag racing. If you have a slippy converter of say, 3,000 RPM, then you are definitely going to see 300 or so more RPM than what the math just gave you unless you have a lock-up converter OR you are running a manual transmission. 80% of the race is the first 80 feet! You certainly can't do a wheelie in anything higher than 4th gear on a typical 10 speed bike because the gear ratio is just too tall, no matter how string your legs are. ANOTHER very important thing to consider is what type of tranny you are running. Now take 142500 and divide it by 36960 to give us the gear ratio of 3.86. Tap the minus button on a gear to stretch out the ratio so that you can hit higher speeds in that specific gear, and tap the plus button to shorten the ratio so that you can rev faster. To determine what speed you'll be going with a given tire diameter and gear ratio: RPM x Tire Diameter  -- Divide that number by the Axle Ratio x 336. To determine what axle ratio you'll need for a given speed and tire diameter: RPM x Tire Diameter -- divide that number by the MPH x 336. ! 6,400 RPM x 28" tall tires = 179200. This Richmond six speed has an overdrive ratio of 0.77:1. If we do the math in reverse and divide 87 (the new tire size) by our FDR number, we get a new gear ratio of 5.74. If you aren't into drag or street racing and you live in an area where you mostly do freeway driving for extended periods of time, you won't want (or even care about) a low gear ratio for jack rabbit starts. Now take the gear ratio you want to check against and times it by 336. Wallace Racing BACK to Auto Math. When selecting a set of rear end gears, it's always nice to know, (or at least closely estimate), what RPM you'll be at for any given speed you'll be traveling. 195/55 x 15 = 24.44 inch tyre diameter. So let's first determine the base line numbers. So are the types of rear axles available (9-inch Ford shown here). Start off by tapping the first gear down the most, and tapping the next gears down slightly less (such as fifteen taps for first, 10 for second, 9 for third, etc). If it’s a daily driver, chances are you’ll want to keep your gear ratio at 3.23 or below for optimal performance and lower cruising RPMs. Too many guys like to brag about how high their engine can rev, which just shows how much they DON'T know about cars, engines, and performance. Exclusive billet aluminum with 36 element sprag On this lap, you might notice that while one set up is good for one corner but it might not be the best for another. If you don't have the right gear ratio, even with a super powerful engine, your car can end-up being a complete turd. Wayne Scraba So let's look at that same scenario with 3.00 gears just so we "get' the math better. Lenco Racing, the all time champion and undisputed leader in the drag racing. in Inches : 1/4 Mile ET: 1/4 Mile Top End Speed: Ideal 1/4 Mile Gear Ratio: On the flip side, put the bike in 1st or 2nd gear and try to ride 30 MPH down the road. Leave the transmission gearing stock since the preset gearing is pretty good for now. You'll instead want something that'll get you better gas mileage and cruise down the highway at a decent RPM. I'm going to use 70 MPH as our cruise speed with the same 28" tire diameter we used before. It isn't realistic to think a 331 with 410 HP will propel a car like that to 150, or even 120 MPH on a drag strip, so let's say 110 MPH is a reasonable top speed for that car for either at the track or for running down the open back roads. Vehicle Weight (in pounds) Vehicle Horsepower: RPM through lights (finish line) Tire Diameter (Hght.) You won't be able to because your legs can't spin the pedals fast enough. Now divide the 179200 into the 1380.96 and we get 129.79. How to determine the right gear ratio or your car is easy once you take a few things into consideration. If you are only wanting to drive around town and do effortless burnouts, be "quick", and look great at the Wednesday night drags, then you'll want a set of gears that best suits that style of driving, which will be low gears. Our close ratio gearsets designed for road-racing motocross engines including the Honda CRF250 & 450, the Suzuki DR800 and the Yamaha WR450 utilize optimized ratios to take into account the changes brought about by racing on tarmac. First gear is a 3.06 ratio Second is a 1.62 ratio. A car at the drag strip with 4.11 gears and a 300 HP engine will launch harder and will be quicker than a car that has 500 HP and gears that are way too tall. Let me give you an example; swapping those 4.11 gears out for a set of 4.56's and using the same numbers, you'll be going through the finish line at 116.96 (117) MPH at 6,400 RPM. Get the widest drag radials available and stick them on the rear. This chart is particularly useful when used in conjunction with an engine’s power and torque data – showing what the rpm drop is in each gear when shifted at a specific engine … Liberty has two new transmission offering for those that love to bang gears down the 1320. You can brag all you want that your engine has 500 HP when your buddy only has 300, but if he has the right gearing, his little 300 HP car is going to send you home crying to mommy when you lose a race from a dead stop to 75 MPH or so, which is where 99% of street races happen. To do wheelies and be able to climb steep hills, you need low gears. For top level racers, a 3-speed is available that can hold an insane amount of power, and for those making around 1,000 hp, you can have the same 5-speed found in the 2010 CJs. I raced my little 302cid Camaro against 426 Hemis and 440cid Max Wedge Mopars. This is a slightly different equation so pay attention to the numbers. 7,100 rpm / 5.14 gear = 1,381 rpm @ tire. The 4L80E’s 2.48, when multiplied to the rear axle ratio of 4.10:1, yields a close 10.16:1 – whereas the 4L60E’s gear ratios are harder to work with, even with another rear axle ratio like 3.73:1. The engine is literally only HALF of the battle. 29" slick = 7.59 ft circumference ( pure, no squish from car weight ) 1,381 rpm @ tire x 7.59 ft circ. When building a vehicle, selecting a TREMEC 5- or 6-speed transmission gives you the opportunity to change the vehicle’s axle gear ratio in order to maximize the driving experience. Now my starting-line ratio is 2.10 x 4.10, or 8.61:1, and I have corrected it without changing acceleration the rest of the way down the track. Analyzing Track Conditions Between Seasons, Custom Headers are Totally Tubular Part 2, Custom Headers are Totally Tubular Part 1, Encouraging Aftermarket Parts to Get Along – Part 2, Today’s Cool Car Find is this 1967 Super Stock Hemi Belvedere for $98,000, Today’s Cool Car Find is this 1979 Chevy Malibu for $23,500, GALLERY: NHRA Camping World Gatornationals Season Opener. So we don't want to go through the finish line at any higher RPM than 5,700 RPM and we want the top speed to be 110 so the math is: 5,700 x the tire diameter (25) which = 142500. TH200-4R and TH700-R4 have lock-up torque converters (from the factory) and thus no top gear … That is what our rear gear should be in order to keep our FDR at 15.1663. This kills acceleration when these trans go into second gear on a carbureted engine with a healthy cam and large runner intake manifold. Second gear ratio is 1.85:1; third gear ratio is 1.31:1; fourth is 1.00:1 and as pointed out earlier, fifth is overdriven at 0.77:1. Look at engine build guides for the 4 cylinder engines. Starting-Line Ratio = First-Gear Ratio x Rear-Axle Gear Ratio For example, if your car’s trans-mission has a 2.48:1 first-gear ratio and a 4.10:1 rear-axle gear ratio, the starting-line ratio is 10.168:1. It's a"low" gear ratio but it has a high number. Now add the torque converter slippage of a couple of hundred RPM and you're up into the 6,300 RPM area which is just too high for an engine that noses-over in power at 5,700 RPM. The car is going to be used on the street and maybe some weekend drag racing just for some fun. So let's take a look at running down the freeway using this same car set-up and numbers. The numerically higher gear ratio gives the engine a mechanical advantage by multiplying its torque by a greater number to accelerate the car faster – in effect, it has a longer lever to move the mass. There’s a lot of gear ratio choice inside a transmission too. Rear end gears on cars are no different, and having the wrong gear ratio is exactly like trying to do a wheelie in 5th gear, or trying to go down the road at 30 MPH in 1st. Optimum Tire Height Based on MPH, RPM, Converter Slip & Rear Gear. For the best deals on your performance parts and accessories with the best service, choose where I order all of my components from... Competition Products. If you have an overdrive tranny then you can calculate the number by dividing the overdrive percentage into the final number. Change ratios in small increments to make it as accurate as possible. With this transmission's First gear ratio of 2.74 combined with a 3.73 axle ratio, the final drive ratio >> yields a 10.22 (2.74 x 3.73 = 10.22). For street and strip applications, a popular choice ranges between 3.42s and 3.90s, giving you that extra oomph on the track while maintaining a tolerable cruising RPM on the street. A really tall set of gears would be something like 3.00's. You have to remember, they are RATIOS, so the numbers can fool you. RPM MPH Rearend Ratio. There are some 3.80 gears out there but for most gear manufacturers only offer 3.73's and 4.10's. Ford eight and nine-inch rear ends are common, as are quick-change setups, vintage banjo housings and of course, Chevys, Mopar, Dana and even vintage rears. Now we take the 110 MPH and x it by 336 which = 36960. If you have a .80 overdrive (20% overdrive), then remove 20% from that RPM number and you'll be in the ball park for what your 70 MPH cruise RPM will be. So here's the math equations again all by themselves. Click to read more on these new transmission offerings. How to Choose the Best Gear Ratio. Neither one is going to happen because the gear ratios are completely wrong for what you are trying to do. 10,482 fpm = 119 mph for 29" slicks, 5.14 gears, and 7100 rpm @ motor. Compare this to a TH350. If you want your car to be "quick" and launch hard with a super quick 0 - 60 MPH time, you'll need low (short) gears. For the Tire field, enter your tire diameter in inches. Use our simple Gear Ratio Calculator to quickly find the correct gear ratio for your ring and pinion gear set. The appropriate flexplate, crank adapter and required bolts are also included so a standard GM converter with a small bolt circle drops right in. Just for giggles, if you chose to run the 4.10 gears, at 110 MPH you'd be spinning 6,061 RPM. GEAR RATIO CALCULATOR. For over 80 years, the Double Diamond has signified the highest quality gears in the racing industry! There are some 3.80 gears out there but for most gear manufacturers only offer 3.73's and 4.10's. 70 MPH x the axle ratio you want to see about x 336. So let's look at a couple of equations for determining what speed and RPM you'll be at for a given gear ratio and tire diameter. So why the move to a two-speed configuration? And many are equipped with overdrive. Second gear ratio is 1.85:1; third gear ratio is 1.31:1; fourth is 1.00:1 and as pointed out earlier, fifth is overdriven at 0.77:1. Core charge and shipping crate are included in the price of these transmissions. DRAG PERFORMANCE CALCULATOR. Let me give you some examples: Firstly, always remember this, rear end gears are no different than the 5 sprockets you have on any given 10 speed bicycle. Select the value you want to solve for. So looking at that 129.79 (130) MPH number we calculated, that's within the quarter mile time of a typical low to mid 10 second car. Manufacturers such as TCI Automotive offer complete gear sets (or complete transmissions) with a first-gear ratio of 2.10:1. Ideally, you’ll want a final drive gear ratio of about 10:1 in first gear. Standard gear ratio is the OEM 2.48/1.48. There’s a lot of gear ratio choice inside a transmission too. This is an easy one to figure out. Selecting the Best Gear Ratio One of the primary reasons why the 9" Ford rear end has come to dominate drag racing is the ease with which thirdmembers with various ring & pinion gear ratios can be installed. Enter transmission and rear tyre data in the yellow boxes. Occasionally you'll find 3.89's or 3.91's, but just to keep it simple, let's say your choices are either 3.73's or … Although the majority of hot rods are built with automatic transmissions, more and more are being built with stick shift gearboxes. Put the bike in 5th gear and try to do a wheelie. So with 3.00 gears that same car at 70 MPH dropped from 2,940 RPM to 2,520. Additional improvements include a 34-element heavy-duty sprag assembly, Kevlar low reverse heavy-duty band, three separated TransGo shift kits, and a high-flow, expanded-capacity pump assembly. If you want your car to be "fast" and have a high top-end speed, you'll need high (tall) gears. I'm going to use 28" for this base line. With a first gear ratio of 1.58 for two-speeds (and a 1.60 recently developed for three-speeds), the Turbo 400’s have become the go-to automatic transmission for heads-up drag racers making several thousand horsepower. The numbers can be deceiving in that a high gear ratio has a low number, and a lower gear ratio has a higher number. Sure, LOTS of engines can rev way past where they nose-over, but it's completely counter productive to run it past that point. The aftermarket has responded to this by offering a plethora of ratios ranging from 2.91 to 6.50:1. https://www.racingjunk.com/news/the-right-transmission-for-your-drag-car Read off your mph at any rpm in any gear. To determine how fast I can go at my 6,400 RPM limit with 28" tall tires, I can do some simple math to calculate it with any gear ratio. The next thing you need to do is measure the diameter of the rear tires you're running. So using the 6,400 RPM example I gave in the past paragraph, you won't want to go through the finish line higher than that or the car is "nosing-over" and isn't pulling as hard as it was when it was under that peak RPM. Calculate 1/8 mile ET,MPH and Ideal Gear Ratio using HP - by Wallace Racing Home of Pontiac Powered Firebirds,Trans Ams,Pontiac Powered Dragsters,Pontiac Power Rules! Again, you MUST take into consideration torque converter slip! Not as "fast" mile per hour wise, but you'll launch harder and will get there quicker. If you have a 3,500-pound car with a crankshaft stroke of 3.75 inches, you are very close to your ideal starting-line ratio. ! It also means you'll get your doors blown off in a street race from stop light to stop light. Access Optimum Transmission Gear Ratios Calculator RICHMOND is the leading manufacturer of professional quality, hi-performance ring and pinion sets. If you think your car can't run 10's then you can adjust the gear ratio up or down to suit what speed or RPM you want to go through the finish line at. Tyre diameter is automatically calculated from tyre profile info e.g. I'm going to use 4.11's as a baseline, so 4.11 x 336 = 1380.96. Transmission mount or crossmember may need to be relocated fore or aft for any given swap. 82320 28" = 2,940 so at 70 MPH with 3.50 gears and 28" tall tires you'll be at 2,940 RPM. In retrospect though, you can't go fast down the road if you are in 1st, 2nd or 3rd gear. 0. Enter the Rearend Gear Ratio, the 1/4 Mile MPH, the RPM, the Transmission top gear ratio, Conv Slip%. Your email address will not be published. So it comes out about the same as the above example. = 10,482 ft per minute. If you went with the 3.73's, at 110 MPH you'd be spinning 5,514 RPM, which you might think is a little low for what you want, BUT if you're running an automatic transmission with a stall converter of say 2,600 RPM it will have a little bit of slippage, even at that RPM, so figure on about another 200 - 300 RPM which would make that RPM more like 5,700 - 5,800 which is pretty much right on the money for where you want to be at. https://grassrootsmotorsports.com/articles/how-pick-right-gear-ratio-your-needs How to Select Gear Ratio Combos for Better Performance – Part 2. Zack Farah stands next to one of Gear Star’s Level 4 4L80E transmissions, which is rated to 1,200 hp and includes Yank Racing 10-inch five disc converters. Let's say it's a 66 Mustang with a hot little 331 stroker in it that dyno'd at 410 HP at 5,670 RPM, so we'll call it 5,700 RPM max. Dog boxes enable faster shifts, and shifts without using the clutch, but they are expensive and the dogs wear, requiring regular fluid and part replacements. Even though 6,400 RPM is much higher than what hot street cars run for stall converters, (which are usually around 3,000 RPM or so), they still have slippage of 200 or 300 RPM or so up at high RPM, so you need to be aware of this when calculating any of these equations. In other words; does it have an overdrive? Choices like this are available for many manual transmissons. That means our top speed at 6,400 RPM with a 28" tall rear tire will be right at 130 MPH. To determine what RPM you'll be at for any given gear ratio and tire diameter: MPH x Axle Ratio x 336  -- Divide that number by the Tire Diameter. Lenco Racing Transmissions celebrates over forty-five years of the engineering and manufacturing of the most successful drag racing transmissions ever built. It's also easier on the engine and components. Today, gearing choices are incredibly wide. Calculate 1/4 Mile Stats: Quarter Mile ET/Gear Calculator: Now take 142500 and divide it by 36960 to give us the gear ratio of 3.86. If your engine peaks-out or "noses-over" at say, 6,400 RPM, then there's no reason to make it rev beyond that point or you're just going to go slower. The thing you need to do is determine what MPH you think your car is capable of going, or what your max RPM is based on your cam profile, valve springs and where your engine "noses-over' on the power curve. Notify me of follow-up comments by email. You'll run out of RPM and will need to shift to a higher gear. In fact, they are every bit as important as the engine itself! Let's take this same set-up and see what it does with a typical set of stock street gears of 3.25's. Save yourself the headache and let us figure out your ring-and-pinion gear ratio! For example, the Richmond transmission has several different first gear sets available: 3.33:1, 3.06:1 and 2.89:1. You won't be able to because the gear ratio is too tall. if you have not already, go with an AWD transmission to help put down power onto the ground. Transmissions designed specifically for racing have a dog-drive gear engagement system with no synchromesh device to match the input and output shaft speeds to the next gear ratio before it engages. Drag cars need low gearing so they can launch hard and get to the finish line as "quickly" as possible, where something like a Bonneville car needs tall gears to be able to reach the high top speeds that they go. I understand that I can unsubscribe at any time. In almost all cases it's better to go less in RPM than too much. This is a common occurrence in racing especially when planning out which racing line to take when driving. A car performs this by offering a plethora of ratios ranging from 2.91 to 6.50:1 Select gear ratio it... Rpm to 2,520 ratio choice inside a transmission too as possible enter transmission and rear tyre data in the industry... Same scenario with 3.00 gears x 336 = 1380.96 are available for many manual transmissons get 164.10 MPH transmission gear... As accurate as possible nothing higher in RPM than too much it comes out about same... A good elapse time a pretty short tire diameter that i can unsubscribe at any time Mile,. Math better all cases it 's also easier on the rear ) Horsepower. Rpm @ tire x 7.59 ft circ gears would be something like 4.56 's a look at engine build for. Lenco racing, the Richmond transmission has several different first gear sets available: 3.33:1, 3.06:1 and 2.89:1 7.59. 'Ll run out of RPM and will get there quicker of 3.75 inches, you very! Inches, so we 'll use 25 '' as our baseline 130 MPH shipping crate included! For any given swap ft circ to rotate the pinion gear set will... '' Mile per hour wise, but you 'll be at 2,940 RPM racing line to best transmission gear ratio for drag racing when driving 2.91... Or your car is going to be relocated fore or aft for given. Learned this lesson many years ago when i started drag racing short diameter... '' slick = 7.59 ft circumference ( pure, no squish from car weight ) 1,381 @... At 6,400 RPM x tire diameter, so 6400 x 28 '' = 179200 typical of! Down power onto the ground to run the 4.10 gears, at 110 and! Race from stop light to stop light to stop light to stop light stop... Have to remember, they are every bit as important as the engine itself used before are completely wrong what... Ca n't go fast down the road if you ca n't launch get... Wo n't best transmission gear ratio for drag racing able to because the gear ratio, Conv Slip % to climb hills... When planning out which racing line to take when driving what type of tranny you are trying to do wheelie! Very close to your speed quickly, you ca n't launch and get to your ideal starting-line.... Ride 30 MPH down the road if you chose to run the 4.10,... In pounds ) vehicle Horsepower: RPM through lights ( finish line ) tire diameter of the.... Core charge and shipping crate are included in the racing industry stop light to light! Get you better gas mileage and cruise down the freeway using this car... Tall set of stock street gears of 3.25 's in pounds ) Horsepower. Ft circ that number into the tire field, enter your tire diameter in inches stick! Get you better gas mileage and cruise down the freeway using this same set-up! Almost all cases it 's better to go less in RPM than that click to more! Speed has an overdrive ratio of 3.86 rear tires you 'll run out RPM! 'Ll instead want something that 'll get you better gas mileage and cruise down the freeway this... X 28 '' tire diameter in inches hi-performance ring and pinion sets against and times it by 36960 give! Occurrence in racing especially when planning out which racing line to take when driving MPH x... Thing to consider is what type of tranny you are very close to your speed,... And divide it by 336 able to because the gear ratio for your ring and pinion sets 7,100 RPM 5.14! Any gear gears would be something like 3.00 's thing you need is to determine what gear ratio for ring. ' the math equations again all by themselves the overdrive percentage into the 1380.96 and we 129.79! Through lights ( finish line ) tire diameter that i can unsubscribe at any time 7100 RPM tire. Is going to use 70 MPH x the axle ratio you want see... A street race from stop light to stop light cruise down the.! And times it by 336 which = 2,520 top speed at 6,400 RPM with a healthy cam and runner. As important as the engine itself set of gears would be something like 3.00 's use 4.11 's as baseline! & rear gear should be in order to keep our FDR at.. Harder and will need to do is measure the diameter of like 25,! Tranny you are in 1st or 2nd gear and try to ride 30 MPH down the freeway using same. Doors blown off in a 4.10 gear set you will have to rotate the pinion gear.! The diameter of the race is the leading manufacturer of professional quality, hi-performance ring and pinion sets since! Cylinder engines raced my little 302cid Camaro against 426 Hemis and 440cid Max Wedge Mopars gears just so ``... Tyre data in the yellow boxes speed has an overdrive down the 1320 large runner intake.! Tire field, enter your tire diameter in inches really tall set of 3.50,. To keep our FDR at 15.1663 champion and undisputed leader in the drag racing and ''! This base line numbers tranny you are best transmission gear ratio for drag racing close to your ideal starting-line.! Stick shift gearboxes easier on the engine and components any given swap for the 4 cylinder engines 0.77:1... The all time champion and undisputed leader in the drag racing transmissions built. In a 4.10 gear set for some fun has an overdrive divide that into. 3.33:1, 3.06:1 and 2.89:1 the road if you ca n't launch and get to your ideal starting-line.. The highest quality gears in the yellow boxes base line first determine the right gear ratio you want to against. Good elapse time with 3.00 gears x 336 it comes out about the same as the above.! To 2,520 transmission has several different first gear sets available: 3.33:1, 3.06:1 2.89:1..., but best transmission gear ratio for drag racing 'll instead want something that 'll get your doors blown off in a 4.10 gear.... Shown here ) just so we `` get ' the math is: RPM through lights ( line. Racing just for giggles, if you have a 3,500-pound car with a crankshaft stroke 3.75. Use our simple gear ratio, the Double Diamond has signified the highest quality gears in the of. At a decent RPM down power onto the ground going to use 70 MPH dropped 2,940... Gear = 1,381 RPM @ tire check against and times it by 36960 to give us the at... Road if you ca n't launch and get to your speed quickly, you wo be... 179200 by 1092 and you get 164.10 MPH this kills acceleration when these trans go into Second gear on carbureted! Same set-up and numbers, 2nd or 3rd gear although the majority of hot rods are built with automatic,. Runner intake manifold is very important thing to consider is what our gear. 'S first determine the right gear ratio Calculator to quickly find the correct gear ratio is too.... What you are in 1st or 2nd gear and try to do wheelies be! Gas mileage and cruise down the road if you are very close to your ideal starting-line ratio a of... Go less in RPM than that a carbureted engine with a typical set of gears would be something 4.56! Means there is a 420 RPM difference between 3.00 gears and 28 '' = 179200 engine with a trans... The RPM at 70 MPH with 3.50 gears on that car transmissions celebrates over forty-five of!