TH400 questions with a turbo 4.8L build
08-10-2011, 02:38 PM
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TH400 questions with a turbo 4.8L build I'm doing a turbo'd vortec LS based motor and a TH400/3400stall build in my notchback. I have alot of what i need to get started but i got quite a few questions about the transmission i'll be doing. The car wont strictly be a track car but more of a track/ weekend/ cruise/ meat kind of thing
- How much power/torque will a stock TH400 hold in a 2800LB car? I wont be putting one in the car unless its built... I'm just curious.
- If i go with a RMVB in the th400 I've heard you cannot downshift the car while on the highway (55mph +) because you have a risk of messing up the drum in the trans.
- With a TH400, how would the RPM's on the highway be at a cruising speed of around 70MPH? I have 3.73 gears in my 8.8 now but i'll probably be trading a guy with a 3.08 gear'd rear end and i'll more than likely be using a 28" tall tire.
- How much to get one built up with a transbrake and everything?
Anything else i can think of i'll be posting up. Thanks in advance 'errbody
- How much power/torque will a stock TH400 hold in a 2800LB car? I wont be putting one in the car unless its built... I'm just curious.
- If i go with a RMVB in the th400 I've heard you cannot downshift the car while on the highway (55mph +) because you have a risk of messing up the drum in the trans.
- With a TH400, how would the RPM's on the highway be at a cruising speed of around 70MPH? I have 3.73 gears in my 8.8 now but i'll probably be trading a guy with a 3.08 gear'd rear end and i'll more than likely be using a 28" tall tire.
- How much to get one built up with a transbrake and everything?
Anything else i can think of i'll be posting up. Thanks in advance 'errbody
Last edited by notoriousdoa; 08-10-2011 at 02:43 PM.
08-10-2011, 04:42 PM
#2
A stock TH400 will typically start to run into issues between 400-450 HP with the third gear clutches (directs). As light as your combo is, it would probably live at over 500 HP for a while.
You don't want to do much downshifting with a RMVB setup. No engine braking and trans internals can overspeed. It also shocks sprags when you come back up on the throttle.
There are online calculators that will give you an approximate RPM. 3.08's and 28" tall tires, rough guesstimate of 2400-2600 rpm at 70 mph.
Check pricing on my website and email or PM if you have any questions. Pricing depends on options mostly.
You don't want to do much downshifting with a RMVB setup. No engine braking and trans internals can overspeed. It also shocks sprags when you come back up on the throttle.
There are online calculators that will give you an approximate RPM. 3.08's and 28" tall tires, rough guesstimate of 2400-2600 rpm at 70 mph.
Check pricing on my website and email or PM if you have any questions. Pricing depends on options mostly.
