RobsZ28

iTrader: (3)

I have a 98 Camaro with a 4L60e and a torque converter with 3600rpm stall. I'm wondering if a worsening 60' while increased horsepower is a sign of a poor torque converter efficiency.

My car with stock ls1 and bolt-ons made 305rwhp got 1.796 60' times
I added a ms3 cam, bumped the hp up to 357whp and got 1.821 60'
Now I have a fully build forged bottom end and heads/ nitrous cam/intake I'm at 425whp and just got 1.886 60'

The only part that is still in the car from 305hp setup to the 425 setup is the torque converter. I'm just looking for what could me causing the poor 60'. It's not losing traction, the car did the 1.796 with completely stock suspension and now the car suspension has improve with adjustable shocks. The car makes 100rwhp more and weights 400lbs less but has a worst 60' and is only .7 and 8mph quicker.

I'm at a loss and would like others thoughts and opinions.

Boostedhatch

Yes probably converter and might to a gear change.

mrvedit

What brand converter and what is your rear end ratio.

RobsZ28

iTrader: (3)

The converter is a Edge Racing Pro series w/3600 stall
The rear end is a 9" with 3.70 gear, but I'm on a 28" tire now versus the 26" tire and 3.23 gear that was in the 10 bolt.

PBA

What are the camshaft specs at .050" lift? The duration and the lobe separation? Assuming these times are the combined average for each event, and not drastic changes in the weather, then the main reason that I see here for the slight loss is the Ford 9" eats a lot more horsepower than the 7.5" rear end. I have seen this a few times over the years. The camshaft specs might tell us something.

farmington

iTrader: (14)

motor has lost some bottom end torque due to the cam change. Need more converter (4000?)

RobsZ28

iTrader: (3)

Converter is too tight, took the car to the track made some test run, data logged the runs. I just ordered a new FTI 3800 converter

01ssreda4

iTrader: (96)

Your 60ft should improve nicely with the new converter. I mean, it cant get any worse can it

farmington

iTrader: (14)

dont forget that the 9" rear eats up a lot more power than the 10 bolt did. More rotating mass to accelerate

Jake's Performance

iTrader: (2)

Rotating mass isn't the reason a 9" has more parasitic loss.
Its nothing for a Sportsman class racer to worry about and certainly not a street car.

01ssreda4

iTrader: (96)

It does show power loss due to rotating mass but not much. The main problem with the 9 inch is the gear mesh. The relationship of the pinion and ring gear cause more drag then other designs.

Jake's Performance

iTrader: (2)

The rotating mass in most 9"is probably less than a 8.5"10 bolt or 12 bolt. Definitely less than a Dana 60.

I agree on the mesh but again most of the people who worry about it, are mentally masturbating. It doesn't matter on the typical street/strip car.

01ssreda4

iTrader: (96)

Hot rod did a test between the 12, s60, and 9 inch. It IS worth something on a dyno. While this amount probably doesnt matter to most people for some it does. I recently swapped a 28lb truetrac for a LW 8lb spool. I did it only for the weight/drag savings, no other reason. But I realize im not the norm. I bring it up because its a mentality, if you approach all your mods with the thought of weight, drag, etc and you put it all together at the end of the day it all adds up and gives your car an advantage over the next guy who didnt think that way.