What Safe (ish) wheel HP for a built 4L60e

[Ginger Beer]

Background:
My 4L60e is currently getting built by Craigs to 600hp specs

They gave me number of around 500hpatw or 370kwatw

My hasty math looks like for reliability and peice of mind I can increase the power to around 350kwatw (I'm looking at a Harrop HTV2300 , or a Vortech)

My hasty math for the number I want to shoot for:

Gearbox is rated to 600 engine hp - and using 20% drivetrain loss, 600-20% = 480hpatw = 357kwatw = therefore 350kwatw should be safe for the built 4L60e in a street car on street tyres

The car is a cruiser which will occasionally see the strip and roll racing on 255/40 17 200 treadwear tyres, so no real hard violent launches

I'm not out to win races in it, I just like the loud pedal, alot

It already has a 2800 stall and trans cooler

Questions

Do my ramblings sound plausible?????

Should I shoot for something between 350-370kwatw?

Or limit it to 350kwatw max?

Or, am I dreaming?

Or, am I seriously overthinking this as this isn't really going to get the punishment of a car with big sticky drag radials?

I don't do mang mang skids, but, I do enjoy just putting it in D and doing powerskids through the gears though

Recommendations from people who have "been there and done it" are highly appreciated

Cheers

 

[Deuce]

Pretty sure it is torque that kills them, not HP.
In saying that I did the same when my 4l60e was tweaked up and got given a HP number that would potentially be too much for it.

In honesty I think it comes down to the way you drive it and treat the trans more than anything.

 

[EYY]

Rpm is the killer.
Craigs seem to have a good rep these days - try to get some more info from them.

 

[Ginger Beer]

Rpm is the killer.
Craigs seem to have a good rep these days - try to get some more info from them.

Ack on the RPM killing 4L60e's

And by RPM do you mean the heat produced reducing the efficiency of the transmission fluid?

I'm also running a pretty big cooler as well which should keep the oil happy enough when I'm hard on the loud pedal

My driving style is press the "power" and the "traction" buttons, stick it in D and mash the pedal, the PCM has a better idea of how the engine RPM-TPS-trans- and road speed like to play with each other

I can honestly say, since my ownership, the car has never hit the stock limiter

I feel that is the biggest benefit of a well geared and stalled V8, lots of power from the bottom all through the mid range, no real need to rev the guts out of it if your not racing for sheep stations, just let the PCM shift and let all that torque push you along, till the PCM decides to do it again

 

[Pollushon]

What Deuce said, it's torque that will kill it quick but much of that will come down to driving style and mechanical sympathy levels

 

[gtrboyy]

I'm with Deuce torque will chew up a 4l60e....traction/weight helps destroy them quickly.

Yeah true mechanical sympathy & driving style prolongs 4l60e lifetime BUT that defeats the point of modfying a car if you think nothing will ever break.

Busted the 4l60e in vt ss 5 litre then had craigs rebuild it twice...car was a fun daily,broken auto was not.

 

[shane_3800]

Power is torque x rpm. So essentially power is torque with a time component.

 

[Ginger Beer]

I'm with Deuce torque will chew up a 4l60e....traction/weight helps destroy them quickly.

Yeah true mechanical sympathy & driving style prolongs 4l60e lifetime BUT that defeats the point of modfying a car if you think nothing will ever break.

Busted the 4l60e in vt ss 5 litre then had craigs rebuild it twice...car was a fun daily,broken auto was not.

One of the guys at Craigs gave me the advice to keep it under 500hpatw, or 370kwatw for longevity, and as long as I'm not abusive "it should" last years as a street car that occasionally hits the strip

As for breakage, I'm quite adept at breaking gearboxes, amongst other things, I use to run a 1450kg 500hp 700nm dynopowers manual RWD R33 Skyline, that thing made the OEM gearboxes consumable items when on drag radials, sometimes I miss that car, but, it did spend alot of time broken

200 treadwear tyres allowed enough slip to the rear to relieve some of the load off the drivetrain, this let me drive around and do trackdays, but after a big session at the drags, on hot and sticky tyres, the boxes would whine like a dog box and finding gears became a chore

Typically a new box would last about 6 months, but I treated that car pretty hard, not rough, but hard

The torque basically chewed off the case hardening of the gears, back then the gearboxes were cheap and R&R wasn't a big issue

For the 4L60e I'm trying to find a spot where the box has a chance at life at an elevated power levels within the limits, 600 engine hp, of the build, I'm hoping that a few things can help

1. Limit power by amount of boost run
2. Limit power delivery by the tune
3. Keeping RPM sensible
4. Keeping fluid temps in check

#gtrboyy if you don't mind me asking:
1. What power levels and what was the reason for the failures?
2. What were your trans builds rated to?
3. Were you running a higher stall?
4. Were you running a cooler?

With my poor launching skills this did a best:
MPH of 135
ET 11.009
And picked up a few trophies at a airport run meet

Blasting at Wakefield park

Good times indead

 

[EYY]

Ack on the RPM killing 4L60e's

And by RPM do you mean the heat produced reducing the efficiency of the transmission fluid?

I'm also running a pretty big cooler as well which should keep the oil happy enough when I'm hard on the loud pedal

My driving style is press the "power" and the "traction" buttons, stick it in D and mash the pedal, the PCM has a better idea of how the engine RPM-TPS-trans- and road speed like to play with each other

I can honestly say, since my ownership, the car has never hit the stock limiter

I feel that is the biggest benefit of a well geared and stalled V8, lots of power from the bottom all through the mid range, no real need to rev the guts out of it if your not racing for sheep stations, just let the PCM shift and let all that torque push you along, till the PCM decides to do it again

Centrifugal force is the issue at higher rpm.

 

[Pollushon]

You can always bung a manual in it

I miss the auto but I'm nearly doubling my torque so it was never going to fly without a 5k Craig's build