98 Z28

I know they have different gears for first and second gear, but what about third? Is it just not possible to make another ratio for 3rd gear (say making 3rd like an over drive? Also for FI (say 650 rwhp) wouldn't a gear set like 2.1 for first and 1.4 for second be better for traction with a rear end gear like 3.73s? Thanks

performabuilt

iTrader: (25)

Not sure about the other gears but in the case of third because its direct drive and does not actually use a planet and rather just transfers power straight through I do not see how you could get a different ratio for it, because really its not a gear at all ,its very much like if you had a steel rod directly from your converter to your drive shaft

98 Z28

That would make sense why there are no third gears to be changed.. I'm thinking about going with a th400 with the lower gears or higher what ever is the correct way to say it for the street, being able to due 60mph in first gear would be nice. I would think would have better traction on the street too, but i could be wrong.

performabuilt

iTrader: (25)

Well going to a higher ratio to get better traction probably is not the best way to do it, I would keep the trans you have and spend the money on traction mods instead and keep the overdrive if you have it and have a much more streetable and quicker car

back4more

i have to agree with performa we ran into this issue with my old dragster the theory is true that with a higher ratio you do have less torque. However you do have more wheel speed, therefore if you go to a semi-slick track now you have a worse situation. think about it you dont do a burn out in 1st only do you? and you never see a compound low gear stick shift spinn the tires do you? the point is wheel speed.

gator's 99TA

iTrader: (2)

once you make bigger power, the best way to put the power to teh ground is to reduce the first gear (numerically). thus why so many love the powerglide or TH210

performabuilt

iTrader: (25)

Different points of veiw I see lol. I know guess im old school but the way we did it back in the days of big blocks we would build till we couldn't possibly hook up then we would work on the tires and suspension until we could , the back to building lol. A never ending circle,

gator's 99TA

iTrader: (2)

with todays tire technology, there is no excuse for hooking lol. you are right. its just a different way to skin a cat.

98 Z28

Definetly a lot of good info you guys have.. Here is what i'm planning on doing... I want to procharge my car with a built ls2 with l92 heads and intake and of course the supporting mods for it. I'm shooting for about 650rwhp its mostly a street car (i might take it to the track once in a while once its done) and i know its more than over kill for the street .. I already have a strange 60 rear end with 3.73's. Thats why i was thinking about going with the th400 with the 2.10 first and 1.4 second (because the smallest gears i can get in the rear end are 3.54's). I wanted to stay with the 4l60e but i just dont want to spend the money on it and know there is a chance of it breaking especially being driven hard on the streets with that much power. And i don't want to go to the 4l80e just because its gonna cost anywhere from 3-4k. lol i know you have to pay to play but i dont need overdrive that much since the car is only driven in the city and only when its nice outside. Any recommendations would be appreciated.

98 Z28

So by that do you mean the 2.1 and 1.4 gears would be better, Right?

code4

iTrader: (30)

There are only 2 choices in gear ratios for the th400 that I am aware of;
2.48 1st 1.52 2nd 1.00 3rd (stock)

2.75 1st 1.57 2nd 1.00 3rd with an aftermarket planetary, this is what I went with for my build but don't have it on the road yet to see how I like it.

Edit; I just saw tci added a 2.10 gear set.

gator's 99TA

iTrader: (2)

um i believe the stock first gear is 2.48 in a th400 right?

code4

iTrader: (30)

Yea, 2.52 is th350 I believe plus I just noticed that tci added a new planetary with 2.10 1st gear.

98 Z28

Ohh i found them on the web but they are i'm not sure if expensive is the right word to describe them... they are close to $1400 just for the gear and on another site they had the 2.1 and 1.4 for like $1700 Might as well buy the 4l80e instead of the gears lol.. Guess the standard TH400 gears are the only option.. I'm curious to know why it would cost $1400 for a gear... Ohh well was a nice thought to be able to do over 60 in first gear...

98 Z28

Did you see tci's price on them thats the highest yet? $2161.30... there better be no wheel spinning at all in first gear with gears that expensive..

back4more

well now you just threw something else into the equation. the procharger is a centrifugal supercharger, which do not spool up to a higher rpm so when you do build the trans i would suggest a lower gear in order to spool the motor up. you could cover it up with a high stall converter true, but then you loose top end effeciency, so... in all honesty it is all combination.

gator's 99TA

iTrader: (2)

i told you guys that TH210 are expensive. lol. guys are going 6 second passes with those trannys

back4more

well those 210's not only have different gear ratios but he uses 4l85e five pinion planets he also puts the aluminum drums in all of which booko bucks. Well the th400 is a super strong unit stronger than a power glide and they go 6's.

Frost

iTrader: (45)

You sound a lil mixed up there buddy Peak boost on centri will coincide with peak RPM. There is no spooling up; it's physically tied to your engine. The higher the stall, the more boost you will have when you mash the happy pedal.

back4more

no what i meant is you need rpm to make boost, so.... you through a 2.10 first gear and the rpm of the motor climbs slower because it has to struggle less boost, less power down the pavement. now through something with say a 2.75 first your in a rpm range your making lots of boost = more happiness. (i know a centri supercharger is just a belt driven turbo you can change pulleys on.)