Question for you guys with gears.

[rad_rob]

So its been a while since Ive posted on here, but I wanted some input on gear ratio. I am in the process of building a 9" for my car. Im getting the 3rd member built and I have been kicking around gear ratio ideas. I know, I know....I should know this being where I work...but I thought what better way then to ask you guys who have tried different ratios.

SO...the car is supercharged, so I know that changes things a bit. Im kicking around 3 different ratios and have been unable to determine which one to choose. Its between a 3.70, 3.89, and 4.11. The wheels are 20" but Im not sure of which tire size is getting mounted on them. Based on a common 20" tire size...what would YOU guys do if it were your car. It will mostly be street driving with some occasional road trips. I know everyone runs the 3.73's in the 8.8.....but being that there is a 3.89 available...would you guys run that gear? I think the 4.11 is probably going to be a little too tall. SO.....Im knowledgable on the subject....just trying to get your opinions on what you would do if it were YOUR car. Thanks in advance!

 

[don_w]

With 20s, I would get as high a gear as possible. You'll have no sidewall to help with traction. So given your three options, 3.70 would be my choice. But even that may be too low.

 

[Black_GT]

With 20s, I would get as high a gear as possible. You'll have no sidewall to help with traction. So given your three options, 3.70 would be my choice. But even that may be too low.

+ 1

 

[rad_rob]

Thats a good point. I was pretty much phasing out the 4.11 option, but being that it was a popular selection for NA cars....I thought I would throw it in to the mix. Looks like I may just give that 3.70 a shot. If I dont end up liking it...its not going to be a problem for me to just switch the gears.

 

[don_w]

Thats a good point. I was pretty much phasing out the 4.11 option, but being that it was a popular selection for NA cars....I thought I would throw it in to the mix. Looks like I may just give that 3.70 a shot. If I dont end up liking it...its not going to be a problem for me to just switch the gears.

I run 4.10s with my KB no problem, but I also run 325/45-17 M&H drag radials on the street, and 28x11.50-15 M/T slicks at the track. So traction is not an issue for me. It would be a totally different scenario with low profile 20s.

 

[Hitman]

The higher the gear ratio is the greater the traction problem. I thought some of the people on here would know that. Friend of mine Has 79 Trans-Am with built 455. With the 4.11 he had a small traction problem. He went back to the stock gear (3.08, 2.73) and he has zero traction. Now the car will melt the tires all the way down the road.

I'm pretty sure that you will never see a difference in traction being as those ratios you were asking about are so close together.

 

[SoundGuyDave]

Huh? THAT makes no sense... Gears are a torque multiplier, and the higher the numerical ratio, the greater the torque gain, and thus traction problems. I'd double-check with your friend to make sure the ratios weren't reversed, or that there wasn't something else going on, like swapping between a posi and open differential at the same time.

 

[05stroker]

Huh? THAT makes no sense... Gears are a torque multiplier, and the higher the numerical ratio, the greater the torque gain, and thus traction problems. I'd double-check with your friend to make sure the ratios weren't reversed, or that there wasn't something else going on, like swapping between a posi and open differential at the same time.

+ 1 my 4:10s had no trac. at all for me and the 3:73 worked alot better with my auto.

 

[94tbird]

i used my 4.10s with a 26" tall tire for both street and track in my currie 9" . no issues. im now using a 28" tall tire for the track and street however

 

[Hitman]

ok. the higher gear ratio will yield more wheel speed once the tires break traction. I know this to be fact. But I'm not going to argue about it and I'm not double checking shit. I know what was in the car and I know what I put in the car. Put the higher gear ratio in yer car and come here to street race. And bring lots of money.

I rarely post in the technical threads. But when I do, it's because I know what I'm talking about. But there is always at least one bozo who doesn't know shit from shinola that tells me that it makes no sence.

 

[94tbird]

ok. the higher gear ratio will yield more wheel speed once the tires break traction. I know this to be fact. But I'm not going to argue about it and I'm not double checking shit. I know what was in the car and I know what I put in the car. Put the higher gear ratio in yer car and come here to street race. And bring lots of money.

i think you definitely need to double check here

 

[Hitman]

i think you definitely need to double check here

nah. Just keep thinking that. You will figure it out one day.

 

[94tbird]

already have. the opposite of your story lol

 

[Hitman]

already have. the opposite of your story lol

let's me know where you stand.

 

[SoundGuyDave]

ok. the higher gear ratio will yield more wheel speed once the tires break traction. I know this to be fact. But I'm not going to argue about it and I'm not double checking shit. I know what was in the car and I know what I put in the car. Put the higher gear ratio in yer car and come here to street race. And bring lots of money.

I rarely post in the technical threads. But when I do, it's because I know what I'm talking about. But there is always at least one bozo who doesn't know shit from shinola that tells me that it makes no sence.

WOW!!! Dude, take some Prozac or Ritalin or something! I sure as hell wasn't trying to call you an idiot or anything... Just questioning the information you were presenting, as it flies in the face of logic. If we were to street race, I would call for a five mile circuit, with about 18 turns, and the last thing you would see would be my tail-lights, at least until right before I lapped you. Lighten up man! You are absolutely correct, a lower numerical value will equate to higher wheel RPM after loss of traction for a given engine RPM, but let's face it: If you have enough torque to dust off a 3.08:1 ratio, the additional torque multiplication inherent in a 3.73 or 4.10 ratio would simply boil the tires, all other things remaining equal. Wheel speed once traction is lost is immaterial, as you have already lost the race, whether it's straight line or corner-carving.

The reason that I can pull on most other Mustangs at corner-exit is because of the torque multiplication of the 3.73 gears I run. I have to feather the throttle so that I don't blow off the rears, and that's ALSO because of the torque multiplication. Don't take it personally, it wasn't like I was calling you a "Bozo"...

 

[Hitman]

A supercharged 3V with 20's and a high(2.73, 3.08) gear ratio= tire melt. It doesn't take a brainiac to figure that out.

 

[Hitman]

WOW!!! Dude, take some Prozac or Ritalin or something! I sure as hell wasn't trying to call you an idiot or anything... Just questioning the information you were presenting, as it flies in the face of logic. If we were to street race, I would call for a five mile circuit, with about 18 turns, and the last thing you would see would be my tail-lights, at least until right before I lapped you. Lighten up man! You are absolutely correct, a lower numerical value will equate to higher wheel RPM after loss of traction for a given engine RPM, but let's face it: If you have enough torque to dust off a 3.08:1 ratio, the additional torque multiplication inherent in a 3.73 or 4.10 ratio would simply boil the tires, all other things remaining equal. Wheel speed once traction is lost is immaterial, as you have already lost the race, whether it's straight line or corner-carving.

The reason that I can pull on most other Mustangs at corner-exit is because of the torque multiplication of the 3.73 gears I run. I have to feather the throttle so that I don't blow off the rears, and that's ALSO because of the torque multiplication. Don't take it personally, it wasn't like I was calling you a "Bozo"...

Actually I get pissed when the same know-it-all mutherfuckers post dumb shit in every thread. Like Ron. When is the last time anything he had didn't break into a million pieces? That's what happens when you know everything and things aren't carefully thought out.

 

[94tbird]

ive got tons of drugs for ya, prozac, ritalin, morphine vicodin, take your pick haha

 

[Hitman]

were they prescribed to you or did you buy them illegally? Actually I was injected with morphine yesterday and medicated with hydrocodone today.

 

[SoundGuyDave]

Actually I was injected with morphine yesterday and medicated with hydrocodone today.

Well, that explains it...