Thread: Best gear for 1/4 mile

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lol i watched that happen the other day. A 1990ish model camaro was doing his burn out before he staged and his driver's side axle came out from under the car.

To make a long story short, they had to get a jack to lift the car off the tire so they could slide the axle back in, needless to say, that car didn't race that day.

that usually happens because people are too cheap to buy c-clip eliminators

Why would anybody put a 6500 top ranged cam into a turbo-charged motor pushing 10 lbs. of boost, and 700 hp??

I smell poo....

Well, it wouldnt be ideal, but on paper it sort of makes sense:S. a turbo is only able to make decent boost around 3000rpm+. Match that with a small block turning 7000RPM, and you have a peak powerband near 6500. However, with only 10lbs of boost tops, you would probably have more backpressure from the turbo than you would gain from the 10psi with a radical cam, so it does strike redundant. Or am I the only one who thinks this way?

First figure out what the original gearing is or the gears that are in it now. You can do that by geting on a flat serface and putting a peice of bright tape on the drive shaft then rolling the car backwords and counting how many times the drive shaft rotates per one full tire rotation. After you figure out what gears are in it run it and see what RPM you finish through that Traps. second in no mater what application the higher the numbers of gears the more tourqe is going to get to the wheels Ex: 3:73 is going to deliver more tourqe to the rear wheels than a 3:08 will. becouse the rear wheels will make 3.73 retations for every one time the engine completes a power stroke. where as a 3:08 gear will be 3.08 rotations for ev.... weel you get it anyway it all depends on the application your using. i ran a 3.08 with a 400hp 350 and a 3 sp trans and swiched to a 3.73 gear and it made all the difference in the world. after all if your going to drive it on the street you cant go to wild with the gearing

Originally posted by CIzA5IHIOvIzId3
. second in no mater what application the higher the numbers of gears the more tourqe is going to get to the wheels Ex: 3:73 is going to deliver more tourqe to the rear wheels than a 3:08 will. becouse the rear wheels will make 3.73 retations for every one time the engine completes a power stroke. where as a 3:08 gear will be 3.08 rotations for ev.... weel you get it anyway

Exactly right ,except backwards.

Update on the gear setup in this car. Had some miscomunication, my buddy had 3.55 gears and 4.11 gears. I just found out the gears in the car are actually 3.55, so somthing is wrong somewhere. With his tire size and a 3.55 he should have been around 150 MPH but he was only at 132. So that tells me somthing is slipping. Either the torque converter or transmission, how do you tell which one is slipping?

Not sure i ran 3.23 in my car stock ten 4.11 well then to 3.55 thought about highway driving then thought well im never on the highway 4.11 with a sbc chevy th350 trans 3,500 rpm at 60mph . In the 1/4 mile its sick

I'd start with 4:56's depending on tires diameter and go as much as 5;14's
It is a mild small block v-8 or not? When u don't have much torque gears
really help. ET not mph gets u there first.

Ron

Google "quater mile time estimator" or something like that and you will find a few pages that allow you to "experiment" with tire and gear combos to see which works best for your car. They use weight and HP to calculate everything and from what I have heard they are pretty accurate. One I was on actually gave you an ideal gear ratio based on HP and tire size.
CHAZ

Chevydrivin,in the past when Iv had a tranny slip or a converter fade away I can usualy tell by my 60ft time falling off like say a 1.49 insted of 1.35 this is a slight slip and befor some body says you SPUN off the line NO it hooked hard pulled front wheels did every thing it should do.Also if you have a real bad slip at high RPM'S say at the 1/8 mile point ETC,IV had the car go up on the REV-LIMITER.I trashed that converter,you can tell if the tiers are spining off the line by putting shoe polish on the rears and whatch the car leave the line you can tell if thats whats slipping not the tranny or converter.also if you spin off the line you will pick up alot more MPH at the traps.put some runs on the car and start comparing time slips thats the best place to start.get a summit / jeg's log book or even a note book to keep records.

I have a way of calculating the correct rear gear for your application given the tire size and maximum engine rpm. BUT take into consideration THIS.....the formula I use only takes into consideration maximum engine rpm with a one to one transmission output and tire size. That considered, you need to look at it this way, with a one horse power engine capable of 4,000 rpm and the tire size of 30" and a gear ratio of 4-50, you will eventually reach a maximum speed of 100 mph. It may take all day, but you will get there, relatively with a 1,000 horse power engine capable of the same maximum rpm of 4,000 you'll reach the same 100 mph with the same gear ratio of 4-50 but you'll get there before you hit the end of the driveway
So all these things being understood it is up to you to consider you're power to weight ratio, maximum horsepower and torque and how far into the upper rpm ranges you want to push your engine.
All that being said, I need your tire size and maximum engine rpm and I will assume that you are running an engine with 375 to 400 horsepower, the higher horsepower and torque, the higher you can run your gear. I will also assume at this point you are running a 26" X 9" tire and if it is a small block you're probably capable of running 7,000 rpm. Which would give you an appropiate ratio of 4-30 which should run you through the quarter at approx. 125 mph and also give you a halfway decent streetable.
Shaggy

Hi Guys
Richmond Gears has a calculator on there web site for guys like us trying to figure out what gears would suit our needs the best. You just have to punch in your HP, Tire Size and RPM you want to go threw the lights with and it spits out the gears you would need, or dam close to it anyways.

www.richmondgear.com

I used there web site to buy the gears i needed and it worked out great for me.

OPPS..oh ya...you need to know the weight of the car also. But dont forget, thats rear wheel HP on there web site. So you will have to figure out what your rear wheel HP is and not your engine HP.

Thought this post was dead. It was a converter problem. Got a new converter, and ran it, blew up a turbo, got a spare turbo, then spun the rod bearings as stated in the spun bearings post.