TH400 - stick with stock 2.48 or upgrade to 2.75 first gear
#1
TECH Fanatic
Thread Starter
Join Date: Nov 2001
Location: CA
Posts: 1,064
Likes: 0
Received 0 Likes
on
0 Posts
TH400 - stick with stock 2.48 or upgrade to 2.75 first gear
this will go behind at 408ci, 3.73 gears, transbrake with 4000 stall and a 200 shot. Is it worth it to upgrade to the 2.75? Will this make driveablity without OD "better." Will it help when foot braking when spraying or will I get too much spin.
I read that the 2.48 bogs HARD on launch.
I read that the 2.48 bogs HARD on launch.
#4
TECH Veteran
iTrader: (4)
You guys should stick with the 2.48. The 408ci motor plus the nitrous will make so much torque, then add the multiplier of a 2.75 1st gear and you'll never hook and if you do, you'll wish you had whellie bars on the car. I highly recommend you stick with a 2.48 1st gear!!
#5
2.75's
Originally Posted by ATVracr
I'm getting the 2.75-1.57 upgrade on my th400 coming from Coan soon. I have a 346 H/C and will be hitting it with the 200 shot also.
I dont see how it would hurt drivability, still 1to1 in 3rd thats all that matters really.
I dont see how it would hurt drivability, still 1to1 in 3rd thats all that matters really.
#6
11 Second Club
iTrader: (2)
Join Date: Mar 2002
Location: Hawaii
Posts: 618
Likes: 0
Received 0 Likes
on
0 Posts
Going to a wider gear spacing can hurt you at the track by putting you outside the powerband after a shift. Closer gear ratios can be a benefit because it allows you to cam for a shorter more intense powerband. Then you dial the rest of your setup by choosing the right rearend gears & tire size. I'm sure you guys understand all of this already. I'm posting this for those that may not realize it.
Trending Topics
#12
11 Second Club
iTrader: (20)
Join Date: Jul 2002
Location: Jonesboro, Ga
Posts: 1,988
Likes: 0
Received 0 Likes
on
0 Posts
Sorry to bring this thread back from the dead, but was just searching.
Would the 2.75 be better for a turbo car to help it get out of the hole considering the low compression and lag? Especially on a larger turbo such as a T-88, or T-76.
Thanks,
Josh
Would the 2.75 be better for a turbo car to help it get out of the hole considering the low compression and lag? Especially on a larger turbo such as a T-88, or T-76.
Thanks,
Josh
#13
TECH Fanatic
iTrader: (1)
Originally Posted by distortion_69
Sorry to bring this thread back from the dead, but was just searching.
Would the 2.75 be better for a turbo car to help it get out of the hole considering the low compression and lag? Especially on a larger turbo such as a T-88, or T-76.
Thanks,
Josh
Would the 2.75 be better for a turbo car to help it get out of the hole considering the low compression and lag? Especially on a larger turbo such as a T-88, or T-76.
Thanks,
Josh
Not really, no. What you need for a turbo motor is a torque converter with a high stall-speed. For the turbo you need to be able to bring the RPMs up in a brakestand to spool up the turbo. While standing still gearing has no affect on this ability - it's the torque converter letting it happen.
#14
TECH Resident
iTrader: (43)
Join Date: Jan 2003
Location: Dayton, OH
Posts: 920
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by distortion_69
Sorry to bring this thread back from the dead, but was just searching.
Would the 2.75 be better for a turbo car to help it get out of the hole considering the low compression and lag? Especially on a larger turbo such as a T-88, or T-76.
Thanks,
Josh
Would the 2.75 be better for a turbo car to help it get out of the hole considering the low compression and lag? Especially on a larger turbo such as a T-88, or T-76.
Thanks,
Josh
#15
11 Second Club
iTrader: (20)
Join Date: Jul 2002
Location: Jonesboro, Ga
Posts: 1,988
Likes: 0
Received 0 Likes
on
0 Posts
I'm running stock cubes, so I know it won't be quite as ridicolous off the line as a 400+ cubic inch motor. However, the tranny I'm considering does have a transbrake, which should get me leaving pretty damn hard regardless of the first gear ratio.
Thanks a ton the advice,
Josh
Thanks a ton the advice,
Josh