9XX build thread

[Ricky.REP]

And optimised transmission software!

Cheers Ricky

[wrekka]

I think I remember Doug saying that the standard box can cope with about 1200nm, with the toughened spec what are we talking then roughly? Cheers

[C6NVS]

I think I remember Doug saying that the standard box can cope with about 1200nm, with the toughened spec what are we talking then roughly? Cheers

Can of worms there wrekka !!

I think the answer for the toughened spec is 'more than standard, reliably, in extreme use'... and against the spec I have chosen I have been told toughened handles 200nm+ more than standard.

There exists a full range of views as to what the standard box can handle, starting at 800nm and this is the first I've heard of a suggestion as high as 1200nm, but I can't say that is not possible (I'm not an expect on the ZF6HP26A).

Some of the GB re builders I have spoken to (incl. a few in Australia where the same box is used on the Ford FPV platform) suggest 900nm is the long term reliability limit. Against this we have cars running 1000nm+ over many miles without breaking.

I've heard of standard boxes being replaced on stock cars, as well as modded cars, but without knowing the exact failure and the cause, it is all speculation as to the failure.

I think the answer to 'what can the standard box handle' depends on how it is used, in what conditions and for how long. Standard can handle anything until it breaks, just as with the toughened spec, but with a view that uprated > OEM.

With the upgrades I am doing (against a goal of 1200nm+), and the way the I will use the car (hard), I would expect to have to replace a stock box at some stage in the future.

If I had the luxury of choosing to run the standard box till failure, then maybe I could have added an example to the limit discussion, but unfort circumstances don't allow.

[classba]

I don't think anyone/ company is willing to guarantee x amount of torque handling for the stock GB before it breaks!!! The stock box is being asked to cope with twice as much torque so you go figure that out. Like Bretto has stated, the stock box may cope with the extra torque but for how long ( no body knows).

I like to tackle all possible bottle necks in a tune and IMO, the GB is a weak link.

[wrekka]

Yeah see what you mean. Standard gearbox does very well compared to the old c5!

[C6NVS]

Yeah see what you mean. Standard gearbox does very well compared to the old c5!

Being a former C5 chocolate box owner, I would have to say that is certainly the case.

[C6NVS]

Quick update.
Not wanting to hijack my own build thread and turn it into a 'how strong is the C6 gearbox' thread...but here are the findings of the two GB's that we have had opened so far:

Car1: 1 owner stock car to 30k miles, I then owned and stage 2 remapped ECU/TCU circa 735ps to 40k miles
GB1: Assessed internals as in very good condition, but TC replaced as it's condition was not suitable for rebuild

Car2: 3 owner stock car to 30k miles, def not as well looked after as Car1 and had signs of hard life, I then owned with no tuning or moding to 40k miles
GB2: Showed wear in friction plate Clutch A (with a TCU log - friction plates slipping / over limit), but TC in condition suitable for rebuild.

Moral of the story, I think the GB's are strong, it is probably more about the individual cars and how they have been driven / looked after. Both boxes has some signs of wear, but both against different parts.

More updates soon !!

[Ungjaevel]

Any comment on the oil quality / particle count in both boxes?

[classba]

Any comment on the oil quality / particle count in both boxes?

My car is the Car 1 from above.....When I changed the gearbox oil at 41000 miles, the oil was very clean with NO metal particles on the bottom of the oil pan. The car was running stage 2 at the time.

It now has 44000 miles on the clock with the uprated gearbox, torque convertor etc running 855 PS on a 20 degrees Celsius day with NO issues.

[SuprSi]

Awesome, so just to recap, what's next on the to-do list? 855ps is pretty insane to start with!

[classba]

Awesome, so just to recap, what's next on the to-do list? 855ps is pretty insane to start with!

To clock 200 mph by GPS.

[bam_bam]

Awesome, so just to recap, what's next on the to-do list? 855ps is pretty insane to start with!

To clock 200 mph by GPS.

I imagine that will be complete before this weekend is over...

[classba]

Awesome, so just to recap, what's next on the to-do list? 855ps is pretty insane to start with!

To clock 200 mph by GPS.

I imagine that will be complete before this weekend is over...

Lol.... you never know....possibly Bam Bam

[doodlebug]

You sticking uprated tyres on?

[C6NVS]

You sticking uprated tyres on?

Got this covered.

Also good to note, tyre ratings are for tested maximum 'sustained' speed (i.e. tested for 10 minutes). If I last >10 minutes @ 200mph, it could only be between two autobarhn petrol stations !!