G50 Transaxle info wanted

[Grant Tuscan]

Does anyone have any information regarding using a Porsche G50 transaxle in a mid engined application as in the Ultima?
I understand it has to be inverted to get the drive in the right direction - does running the box upside down present any problems? How strong are these boxes and how much power can they reliabley handle? Which version of the G50 is best? I am exploring the possibility of fitting a G50 in a Lotus Esprit V8 to replace the weak Renault 30 box which is fitted as standard. Are there any G50 specialists in the UK? How different are the dimensions of the Renault and Porsche transaxles? Constructing an adaptor plate/bell housing to mate the G50 to the Lotus engine - is this feasable? Would there be problems regarding the gear linkage to the esprits centraly mounted gearstick (Ultima gearsticks are mounted on the right I believe)?

If anyone has any thoughts on any of the above points I would value your input - sorry for the dull listing!

[rev-erend]

Give Ted Marlow a call at Ultima on 01455 631366; when I was up at the factory he had fitted a BMW 4.0 V8
to the G50 box. He would be a good source of inform of might do the work / know someone who could.

Also Ultima's are also available with a central gear stick !

[domster]

Okay, I'll try and answer a few points. First, yes the Ultima is available with a centrally mounted gearstick, but this is the six speed cable operated 996 (latest 911) gearbox, not the G50 as found in late 3.2 911s, 964 C2s etc.

Ted can get these for a better rate than Porsche dealer prices, brand new, apparently.

The G50 runs fine in the Ultima upside down, although there is a small modification - breather pipe if I remember.

The best people to speak to are Quaife at www.quaife.co.uk as they do a reconditioning kit with helical internals or something. Can't remember but it's on their web site under gear kits. They can also put an LSD in it if it doesn't have one. I think only the earlier 3.2 ones miss this. I'm sure most 1990 onwards ones had an LSD as standard, but don't quote me!

Power wise, check with Quaife. I think a version of the G50 went into the 3.6 turbo, with 360 bhp, but not sure if it was modified for the application. I would doubt 400+ would be safe without modification. Standard 3.2s had 231 bhp.

Later versions of the G50 are best. If the turbo ones were miodified with stronger casing and internals that could be an option, but remember that the earlier turbos used a different 4 speed box.

Re dimensions, they must be similar as I know of an Ultima with a Renault box.

Adaptor plates and bell housings will need a friendly engineering shop at a guess. Not sure about that one. Sounds feasible but quite expensive.

I am not sure about the linkage situation - you may be okay. The Ultima doesn't have a central tunnel, but the esprit does. You big problem may be making sure that the upside down selector linkage doesn't cause clearance/fit problems.

Remember that the centrally mounted Ultima box is a 996 cable unit, so no transmission tunnel needed. For a rod change this would be needed.

All to the best of my limited knowledge - hope it helps!

Domster

[ultimapaul]

Sounds like Domster has given you most of the answers. I believe the new 6-speed box is made by Getrax (is that spelt right?) so they may be able to help. I've driven the Can-Am with that box and it is a delight to use

[thom]

quote:
Getrax (is that spelt right?)

Getrag

[ro_butler]

Check the lotus forums for this but, I think the main problem with the renault gearbox was the length of the shafts used (can't remember why, gearbox in front of engine?). These long shafts flex under load slightly disengaging the cogs and chipping the teeth leading to premature failure.

So not sure if the renault box is crap, but the lack of reliability in an esprit is nothing to go by.

Rob.

[k wright]

The Ultima chassis is available with a G50 transaxle and mechanical linkage that may be positioned in one of three locations: right, center or the left side of the passenger space.

ken

[boosted ls1]

Kennedy Engineering in the US have a load of info on these boxes plus other options. They may send you a catalogue which gives the power/torque rating for each box plus its weight and suitability. My free catalogue arrived in just days! LS1's in Ultima's use this box, I think. If you send me a fax number I can send you some extracts.

[ultimaandy]

I remember other lotus's with this conversion so I would advise contacting the lotus owners club (or like) as they will be able to put you in contact with someone who has or does the conversion.

Porsche box's don't seem to have a problem running upside down as long as you run the right oil. After all they are installed in our cars with 500+ of torque and huge 335 tyres.

If you have trouble with bellhousings I expect Kennedy engineering in the US could help as they seem to have a kit for all applications......in fact that could be were I saw the lotus.....I think I'll check.

[srreck]

Does anyone have any information regarding using a Porsche G50 transaxle in a mid engined application as in the Ultima?
I understand it has to be inverted to get the drive in the right direction - does running the box upside down present any problems? How strong are these boxes and how much power can they reliabley handle? Which version of the G50 is best? I am exploring the possibility of fitting a G50 in a Lotus Esprit V8 to replace the weak Renault 30 box which is fitted as standard. Are there any G50 specialists in the UK? How different are the dimensions of the Renault and Porsche transaxles? Constructing an adaptor plate/bell housing to mate the G50 to the Lotus engine - is this feasable? Would there be problems regarding the gear linkage to the esprits centraly mounted gearstick (Ultima gearsticks are mounted on the right I believe)?

If anyone has any thoughts on any of the above points I would value your input - sorry for the dull listing!

Gardner Douglas www.gdcars.com offers Cobra replicas and a Lola T70 with G50 gearbox and chevy V8.
I have heared G50 are good to 500Lbs of torque, but suffer premature gear wear on hard torque conditions.

[brammo]

The G50/52 variant of this box can be "souped up" to handle about 650 ft/lbs of torque. There are a bunch of billet upgrades, including strenghthening the case, and GT3 chromoloy LSD diff. Add a high torque clutch and maybe external oiling and you are ready for a lot of HP. The six speed dual turbo porsche box (4WD) can also be modified to handle a ton of torque. The twin turbo version glorified on Ultimaclub (kurt dobsons) handles 1300 hp but they managed to keep the torque just under 650 ft/lbs.

We can get these modified for you or can send you links to a number of folks who prepare the G50 variants for this usage in the US.

With a 2100 lb car, 650ft lbs of torque (my car has this as well) and you definitely can tell where your organs are, and how they feel against your spine on acceleration!

Craig
[e-mail] www.brammo.com

>> Edited by brammo on Thursday 22 May 07:57