Transmision and Torque Converter Tuning discussion

[soutthpaw]

well Gas and Diesel are sooo different it is hard to talk about both other than in general terms.... That's what makes Diesels so awesome Maybe we will convince Jack to get a diesel

Lugging means you are trying to move too much weight with too little power...

as RPM increases even past the peak torque you still need less HP to move the weight because of the formula
here is a good example I found on the web
example 1: How much TORQUE is required to produce 300 HP at 2700 RPM?

since HP = TORQUE x RPM ÷ 5252
then by rearranging the equation:
TORQUE = HP x 5252 ÷ RPM
Answer: TORQUE = 300 x 5252 ÷ 2700 = 584 lb-ft.

Example 2: How much TORQUE is required to produce 300 HP at 4600 RPM?
Answer: TORQUE = 300 x 5252 ÷ 4600 = 343 lb-ft.

Example 3: How much TORQUE is required to produce 300 HP at 8000 RPM?
Answer: TORQUE = 300 x 5252 ÷ 8000 = 197 lb-ft.

Example 4: How much TORQUE does the 41,000 RPM turbine section of a 300 HP gas turbine engine produce?
Answer: TORQUE = 300 x 5252 ÷ 41,000 = 38.4 lb-ft

read it a few times and see if it makes sense... this is really the key to finding the best combination of RPM and Torque to get the best result..... you have to then look at how much torque the vehicle makes at various RPM then figure out what speeds the vehicle is traveling at using those figures
Remember Torque is an actual directly measurable value, whereas HP is a calculated figure...

Lets say my engine is in OD at 50 mph at 1600 RPM and making 500ftlb of torque (stock peak torque is at 1600)
500x1600/5252=152.3 hp
now at 2600 rpm lets say we get 450 ftlb torque
450x2600/5252=137.1hp

so even though we are making less torque we also need less power due to the higher engine speed......

sounds simple right...
except for a couple of things... we are not using Wide Open Throttle WOT most of the time when driveing... so now you look at how much throttle and hence fuel u need to get the power to move the vehicle ; so you will need less throttle to get the same amount of torque at peak torque rpm than you will at higher RPM and as the engine is spinning less times a minute you are injecting less fuel per minute at the slower speeds

Confused yet
so in the real world it comes down to trial and error!