Porsche G50/52 Gearbox

[356Speedster]

Gulf LS3 said:

obviously it wont be doing 265 mph but it will cruise quietly and economically on the motorway unlike your G96 Ultima!!

'Eh? The G96/50 has a higher 6th gear ratio than all other Porsche 'boxes I've researched (G50/52 included), being geared for 200mph, so at 80mph it'll be about 2,600rpm, which is still very low revs for m-way cruising. Sounds like your confusing the TT 'box with the G96/01 'box you put in the orange striped car last yr.... yes, that was very low geared and missmatched

[F.C.]

356Speedster said:

'Eh? The G96/50 has a higher 6th gear ratio than all other Porsche 'boxes I've researched (G50/52 included), being geared for 200mph, so at 80mph it'll be about 2,600rpm, which is still very low revs for m-way cruising. Sounds like your confusing the TT 'box with the G96/01 'box you put in the orange striped car last yr.... yes, that was very low geared and missmatched

I think that was the point. Geared for 265 means high overdrive for cruising. And first 4 for track work.
Though I may worry a little that the engine may suffer the "black death" with such low RPM motorway speeds.

[738 driver]

Modern engine and fuelling system should take care of the blackness.... car in qusetion is so light it only needs a teaspoon of fuel per mile when cruising.......

....tis really engineering abuse but should be good fun and tons of smile factor...

[F.C.]

738 driver said:

Modern engine and fuelling system should take care of the blackness.... car in qusetion is so light it only needs a teaspoon of fuel per mile when cruising.......

....tis really engineering abuse but should be good fun and tons of smile factor...

SBC / LS is hardly the pinnacle of modern engineering, i.e non-variable valve train to make the most of lean burn low rev situations, could see it being worse for the "cammier" large overlap N/A engines out there.
ETS have to agree with the "smiles per mile" factor

Edited by F.C. on Sunday 29th April 23:00

[356Speedster]

F.C. said:

I think that was the point. Geared for 265 means high overdrive for cruising. And first 4 for track work.
Though I may worry a little that the engine may suffer the "black death" with such low RPM motorway speeds.

Still seems an odd, mismatched package tho'... on a track you don't want the kind of gaps between gearchanges that that T56 has, especially as there's not that many local circuits that'll make use of such long gears. Then if m-way cruising is a requriement, why build a 7-type car? Doesn't tally to me, but each to their own, I guess. Sorry, we've gone O/T, back to the OP's G50....

[738 driver]

^ the LS is far more modern than the Forums' subject ......Although a very basic engine design to achieve almost 30mpg from a very streetable 6.0 ltr 500 HP engine has to be acknowledged as a step up from 8mpg SBC's of similar output ?

[F.C.]

738 driver said:

^ the LS is far more modern than the Forums' subject ......Although a very basic engine design to achieve almost 30mpg from a very streetable 6.0 ltr 500 HP engine has to be acknowledged as a step up from 8mpg SBC's of similar output ?

LOL you're right of course.

[Leogasp]

More infos can be found here: http://www.pistonheads.com/gassing/topic.asp?h=0&a...

[JohnMcL]

Anyone got comments about the new transaxles from Griffin? See https://griffingearboxes.com/Mid-Engine_Transaxles...

Bolts straight onto LSx without adaptor. 5 or 6 speeds. Loads of ratios. Stock starters.

Seems like the final solution but I would welcome input from from all you experienced guys before going ahead.

John McL.

[V8Dom]

356Speedster said:

'Eh? The G96/50 has a higher 6th gear ratio than all other Porsche 'boxes I've researched (G50/52 included), being geared for 200mph, so at 80mph it'll be about 2,600rpm, which is still very low revs for m-way cruising.

really ??? wow let me have the ratios and ill input them into my gear ratio calculator i made the other year?

http://www.spatz-tech.com/ultima/Doms_Gear.xls

Edited by V8Dom on Thursday 2nd August 23:06

[356Speedster]

Hi Dom. I made a similar gear calculator too The G64/51 has the same 6th gear & final drive, but it's 2nd to 5th ratios are shorter, with a bigger "step" from 5th to 6th, therefore, feeling a little like an overdrive gear.

Now, who's going to be the first person to find a 7-speed 991 'box and get that in an Ultima

[738 driver]

The newish sand racer boxes from the states look promising... 7-8000 USD all the ratios we need, very tough and accept GM patterns, clutches, starters and similar sized to the 930 4 speed.
Dont be misled, the sand racers, jumping V8 powered buggies during long endurance type races need the toughest stuff available.
No one has broken one in two seasons up to now.... am watching closely.

[V8Dom]

Interesting read..

i have a question about g50/52 gearboxes..

do they have lsd?
if so what percentage
my car ive now removed 1 drive shaft. if i put in gear it still rolls forward and back although i can hear the diff trying to stop it turning( bit light hand brake on slighly)

is this normal?

Edited by V8Dom on Sunday 18th September 18:23

[Storer]

Dom

I have the same box but you can fit various LSD in it. I have never tried moving the car with a driveshaft removed so don't know what it should do.

My suggestion would be to get a new driveshaft or new joint (probably a pair) and fit them, then retry the car. If the car drives properly, job done. If not then investigate the box.

These boxes are fixable but not cheap to do. Porsche parts are pricy.

The company I used to replace my LSD and refresh reset tolerances was http://www.sportsandclassic.com/index.php

Mike was very good and the box has been fine since.


Paul

Hope that helps

[F.C.]

V8Dom said:

Interesting read..

i have a question about g50/52 gearboxes..

do they have lsd?
if so what percentage
my car ive now removed 1 drive shaft. if i put in gear it still rolls forward and back although i can hear the diff trying to stop it turning( bit light hand brake on slighly)

is this normal?

Edited by V8Dom on Sunday 18th September 18:23

If you have the "standard" plate type Porsche lsd then you ought to have some resistance if in gear.
Also remember the lsd works differently forwards and backwards. On a Porsche you want the lsd to slip more on the overrun to help stop the back end stepping out.

[mikko k]

I did have one G50/52 box for sale. Sold.

Edited by mikko k on Wednesday 16th November 18:27

Edited by mikko k on Friday 2nd December 09:33