When does power break the drivetrain

[86MLR]

I'm contemplating getting some form of boost

When do people start breaking gearboxes, axles and other driveline parts.

I'm looking at not surpassing the limits of the drivetrain

I've killed boxes before by throwing too much torque at them

250nm, 300nm, 350nm

I've had a search but I cannot find much info, apart from one post where the member stated he was eating gearboxes at 375 nm

Car is a daily that gets thrashed, sees some khana and the occasional, Read: rare, track day

No slicks, only summer tyres like RE003, RS4, Starspecs

235 tyre size, I assume that plays a part.....

Cheers for any relevant information

[86MLR]

I should have kept looking

250nm max capacity

At least now I know my max goal for torque

[86MLR]

From some quick calcs the AZ6 is good till 228hp?

Damn

Unless my info, or calcs are wrong, there is a good chance they are, I hope they are......

I was hoping it would be good to at least 300-350hp atw, or at least 330nm.

[Verl0r4n]

Are you sure? I thought the product code was 6MT which isnt listed there ?

Edit: wait nvm, are they really that old?
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[Verl0r4n]

Perhaps those figure are calculated using the stock clutch which is known to be weak.

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[CSG Mike]

There is no rule of thumb.

It depends on your setup, your tune, and how you drive it.

[86MLR]

Originally Posted by CSG Mike

There is no rule of thumb.

It depends on your setup, your tune, and how you drive it.

Coming from Nissans with the Skyline box, anything over 500nm on semi slicks as your going to have issues, unless you drive like miss daisy.
Back in the day my OEM gearboxes were a consumable item.

Just spooling it up on full throttle would kill it pretty quick.

Edit: In the end the 33 was running 750nm, I was always on the hunt for new and used boxes, I couldn't justify the outlay for a built box when a new OEM cost 1.5k and I could pick up used for a couple of hundred.

I'm to old and jaded to be swapping out boxes every couple of months.

I just don't want to go down that path again, I want to find the limits of the OEM driveline and then make power accordingly.

[Grady]

Originally Posted by CSG Mike

how you drive it.

Most important.

[bfrank1972]

Yup. Examples:

If you constantly pound on it at the drag strip with drag radials, speed shifting all the way down, you'll be able to break things much faster with much less torque.

If you're lowered a lot, with a lot of rear camber, without supporting mods, you will increase stress on your axles/cv joints.

If you're running a positive displacement supercharger with tons of mid range torque, and 'stomp on it' a lot, you'll potentially increase shock stress on your engine internals + drivetrain.

[Sleepless]

3 years of JRSC with 265whp, 10+ track days a year in advanced group... no problems

[riboyster]

You'll start running into problems at 300whp. First you'll need a better clutch. Then you'll bend rods around 320. Then the trans will go around 400.

[CSG Mike]

Lets throw some monkey wrenches into all the misinformation and assumptions.

I've broken many transmissions at even 280whp. Why? Because transmission failures are not dictated by horsepower, but by torque and load.

I've broken axles both NA and FI. Axle failures are dictated by shock load, tire grip, and articulation of the CV joint. Big power can accelerate this in an unrelated manner, because guys with big power also tend to run stickier tires, which can exert a much higher shock load to the axles.

Clutches are also rated in torque. The stock clutch can hold 325-350whp, depending on the setup.

[CSG Mike]

Originally Posted by 86MLR

Coming from Nissans with the Skyline box, anything over 500nm on semi slicks as your going to have issues, unless you drive like miss daisy.
Back in the day my OEM gearboxes were a consumable item.

Just spooling it up on full throttle would kill it pretty quick.

Edit: In the end the 33 was running 750nm, I was always on the hunt for new and used boxes, I couldn't justify the outlay for a built box when a new OEM cost 1.5k and I could pick up used for a couple of hundred.

I'm to old and jaded to be swapping out boxes every couple of months.

I just don't want to go down that path again, I want to find the limits of the OEM driveline and then make power accordingly.

Easy solution? Run the Harrop supercharger, off-the-shelf, with their provided tune.

No fueling modifications necessary. No need for an upgraded clutch. Trans will hold just fine. Axles will be okay unless you're drifting or drag racing (and would fail NA over time; unrelated to the SC).

[riboyster]

Very true. Most people pushing 300hp have enough tq for it to happen though.