Which Gear box for more than 700HP and more than 800Nm?

[GT40LS7]

Hi all

According to the factory G96/00/01 G87/00 could handle over 700 hp.

According to California Motorsport, those gearbox could not handle more than 500 hp.

That make 40% more for the factory.

Where is the truth?

Thanks for all your experence short or long with overwhelmed gearbox. What are your issues if you had.

Best regards to all

DJE

[GT40LS7]

Please find a picture of what we designed for a shifter for a G96, i know some people would be interesseted by a such picture

[356Speedster]

I wouldn't go for a Carrera or Boxster gearbox personally, especially not with 700bhp and the accompanying torque! Those boxes were designed for much less of both... As you appear to be going cable shift (based on your lovely shift mech), you probably want to look at turbo or GT boxes, IMO.

[GT40LS7]

Thanks

[F.C.]

GT40LS7 said:

Hi all

According to the factory G96/00/01 G87/00 could handle over 700 hp.

According to California Motorsport, those gearbox could not handle more than 500 hp.

That make 40% more for the factory.

Where is the truth?

Thanks for all your experence short or long with overwhelmed gearbox. What are your issues if you had.

Best regards to all

DJE

It's not the power that kills gearboxes it's the torque.
In a light chassis this is less of a problem as the tyres give way to the torque before the gearbox does.
ETS If you really want to, a Ricardo box from a Ford GT fits quite nicely.

Edited by F.C. on Wednesday 12th March 23:31

[AlexCim]

F.C. said:

GT40LS7 said:

Hi all

According to the factory G96/00/01 G87/00 could handle over 700 hp.

According to California Motorsport, those gearbox could not handle more than 500 hp.

That make 40% more for the factory.

Where is the truth?

Thanks for all your experence short or long with overwhelmed gearbox. What are your issues if you had.

Best regards to all

DJE

It's not the power that kills gearboxes it's the torque.
In a light chassis this is less of a problem as the tyres give way to the torque before the gearbox does.
ETS If you really want to, a Ricardo box from a Ford GT fits quite nicely.

Edited by F.C. on Wednesday 12th March 23:31

Exactly, it's all about how you treat it. It's like how you can catch a 600 lbs fish on 12 lb line (that's a true example BTW), if you do it the right way.

I went with the factory suggestion (considering they build the most Ultimas.... and don't want a mass of unhappy customers either.....) and got a G96/01 with a Quaife LSD. If I break it in future, I'll rebuild it to stronger to match my driving style.

[crossram]

Yes but what size leader did they use, and was it a barbed hook?

You can light foot 2000 HP but is that really practical? This is not the proper way to rate transmissions,

[macgtech]

The point is exactly as mentioned above - if you run road tyres, you are limited by the amount of torque you can put through the driveline, as you break traction far earlier than if you are running semi slicks or slicks.

[crossram]

Yes but there more factors, I have seen this topic discussed before and in the end nobody knows for sure most of the discussion is speculation.

Currently FFR in the US is shipping a car called the 818 it uses a front transaxle in the rear to drive a SubaruXRX some of these engines produce 800 HP so the question is how much can that transaxle take. Being the car is light some say a lot, but who knows.

[ROWDYRENAULT]

the factory has set multiple world records on one gearbox with a 720hp sbc. I believe that its a g50/50. I have 20,000 miles on a 565hp 575 ft lb LS motor with a G50/03 which is not as strong as a 50/50. The point is if you put either one of those combos in a 3500 lb car I think we would all agree that oily parts would be on the pavement in short order. In the end the gear box has to overcome the inertia presented by the weight of the car. the higher the weight of the vehicle the lower the tolerance for torque. lee

[F.C.]

To be honest I can't remember seeing anyone on here complaining their G50 had st its pants on street rubber.
There's a lot of un-modded G50's being run at over the 500ft/lb mark.
I believe there's some modded ones handling in excess of 600.
My mechanic looks after a twin turbo Ultima with a Ford GT box, the engine is running close to 1000hp, (sorry I don't know the torque figure but its a trick scratch built SBC) the owner rags the thing to hell and back with super sticky rubber fitted, (I have seen some of the shredded carcasses) and his gearbox has covered a good few thousand miles now with no apparent problems.
So if you really want an un-breakable (in non slick terms) box then the Ford GT's Ricardo would seem the way to go.
Other than that there's the straight cut stuff, Allbins etc,

[andygtt]

GT40LS7 said:

Hi all

According to the factory G96/00/01 G87/00 could handle over 700 hp.

According to California Motorsport, those gearbox could not handle more than 500 hp.

briefly maybe they can, but long term reliably? not a chance you need the G50 for that power... a friends sedately driven ultima had the above box brand new supplied by factory and it only lasted 2 years and under 10k before it was shot., it never did a single fast start as well and had under 500ftlb.

there is a G96 that can take the power, the ones from the GT3 and GT2's but they are hens teeth and very expensive even second hand.

[UltimaCH]

I imagine the use of a high quality oil and more frequent oil changes will also help to preserve a "weaker" type box.
Otherwise going for a G96 TT box is an excellent solution, cheaper and easier than searching for hens gold teeth

[crossram]

Oil has nothing to do with it


Unless you have solid tests done using engines that were dynode to exact specs it's all speculation.

[F.C.]

crossram said:

Oil has nothing to do with it


Unless you have solid tests done using engines that were dynode to exact specs it's all speculation.

Agreed there has not been much said about mapping torque around a given gearbox's torque sweet spot so to say.
This was something that I had in mind with my S/C set up, In the end when it was mapped I reduced the boost to 3 PSI for road use and a "useable" Circa 550 BHP at the wheels and a similar torque figure.
I am now trying to set up a reliable variable boost and map set up.
This will be a telling time for my gearbox. my intention is to limit torque to 600-650 ft/lb if at all possible.

[JoulesCanAm]

I have a G50/50 with billet side plates, oil spray bar etc. and I have had no issues with it behind an SBC with 600HP/590ft/lb TQ and majority of time on track with slicks.

The Ricardo is a strong gearbox, big and heavy though, plus it is no longer supported and I hear Ford GT guys buying up used ones and stashing for future spares.

Fran Hall at race Car Replicas is using a modified Corvette transaxle in his new LMP kit, might be worth giving him a call, I heard he has some pretty reasonable pricing on it too (comparatively that is!).

Julian

[Swiss_Toni]

The gear lube matters and matter a lot!

If you are at or over the torque specification and you use lower end gear lube the gearbox may not break but will definitely wear quicker.

I run Motul 140W90 competition gearlube in my Hewland NTL and when I did the usual fluid change and quick inspection at the beginning of the year it looked pristine.

Though I do also make sure the gear box lube has a minimum of 60°c before putting meaningful torque through it (800 nm or 590 ft lbs).

Regarding the torque rating keep in mind that this doesn't necessarily the limit where the gearbox blows into a million pieces. What it likely means is that certain components will have accelerated wear or have higher risk of damage and of course failure. In other words you may get pitting on 2nd gear or in the pinion(on the tooth face) which you need to monitor to take care what you torque you put through it and when.

[tjlees]

In my dealings with VMAX, nineexcellence have very successfully upgraded a 996 to handle >1300NM of torque (and speeds in excess of 228mph!!).

http://www.nineexcellence.com/performance/9ETuning...


NineExcellence is highly regarded over in the porsche forum and is reasonably priced. To upgrade my Porsche turbo to around 588bhp, they quoted me £6k which included a new Plenum, full replacement 100 cell cat titanium exhaust and a days worth of retune.

With that type of power/torque the stock porsche gearboxes will need upgrading if you are going to use it as nature intended. See http://www.californiamotorsports.net/996.htm for some bits you could possibly add to strengthen the gearbox on a DIY basis.

[Corsair613]

ROWDYRENAULT said:

the factory has set multiple world records on one gearbox with a 720hp sbc. I believe that its a g50/50. I have 20,000 miles on a 565hp 575 ft lb LS motor with a G50/03 which is not as strong as a 50/50.

As a point of information (received last week from Richard Marlow): the factory has used the G50/03 for all their record runs and have it in all of the demo cars. Good enough for me.

Ken

[F.C.]

Corsair613 said:

As a point of information (received last week from Richard Marlow): the factory has used the G50/03 for all their record runs and have it in all of the demo cars. Good enough for me.

Ken

That box is good for about 160 mph in standard form in a Chevy powered Ultima, you will need to modify the gearing to get anywhere near the top speed the factory quotes,
I suspect the G50/03 is in more plentiful supply and obviously cheaper to obtain because of this, also a G50/03 has a 7.5" ring gear which is not as strong as the G50/50 or 52 which have 9" ring gears, both the 50 and 52 have final drives equating to 210 (ish) MPH.
This may not seem relevant now but when your cruising on the motorway at 70 mph you'll wish you had another couple of gears!!