G50 Trans Mods

[Woody]

HI Has anyone done there own modification to a G50 transaxle as far as the extra oiling / spray bars / and oil pump goes? and does it really help.
Where is the oil needed most? is it sprayed directly to the crown wheel or plumbed right through the trans to feed all the gears on the main shaft.
Now that the trans is inverted, or upside down, how much oil do you run is it best to over fill it.
I intend to do the mod myself and had planed to pump the oil into the old sump plug hole which is directly over the crown wheel. But if an internal spray bar is recomended I'll venture further.
Appreciate any comments
Woody.

 

[Russ Noble]

Hi Woody,

I'm not sure that a spray bar is necessary but running a cooler is not a bad idea. So if you are going to run a cooler its just as easy to feed the oil back in through a spray bar anyway. It's not rocket science and can't do any harm. If nothing else return the oil onto the pinion.

What I would consider essential behind your 427 though, is a billet sideplate. Forget the cooler, forget the spraybar, make the side plate your first priority. This is the weak point on all Porsche trans which we use, particularly a non turbo trans which you have.

My trans is a 930 but there are similarities. There are photos of side plate, spraybar, etc on my build thread posts #134, 155, 162 and the odd one of some trans internals in there somewhere too, I think.

 

[Jac Mac]

Pete, Welcome aboard BTW, Wanni/Gearfox gave us all some insight into gear spray systems & made the point about spraying any gears on exit from rather than prior to mesh to avoid hydraulic pitting, IIRC he stated at the time that this was for road use systems where higher mileages/long life were a factor... race systems might require a more direct setup.
In the inverted G50 setup since the ring gear only has to carry the lube thru about 90° of rotation to reach the pinion as opposed to 270° in the Porsche application its actually better off in the inverted position, assuming of course that there is oil there to be picked up.

 

[Woody]

Russ
I found the photos ,thanks, the new side plate is in the lathe, we should have it chopped out early next week.
Appreciate your comments.
Jac Mac
Interesting comments, I wouldn't have thought of that Thanks:thumbsup:

 

[Tim Kay]

...if this helps, side pic and underside pic of trans cooler install (G50\52) setup by California Motor Sports

 

[Doc Kaler]

BTW, I have a Patrick Motorsports billet sideplate with the tapered bearing race pressed in, the output shaft seal installed PLUS the Hall effect speedo assembly to fit a G50-series (not the 12-stud G50.50) to sell. PM me with an offer. Probably best if in the USA for shipping costs.

 

[Woody]

Doc
Thanks for the offer but I've nearly finished my plate, But if you dont mind can you answer a few questions. I'm just a new comer and are not sure what BTW is? or
how do I PM you? Also What is the hall efect speedo assembly?

 

[Jac Mac]

Docs probably still asleep about now Pete

BTW--- by the way, To send a PM (private message) just click on the user name of the person , & a window will pop up with the options, one of which will be to send a PM, click on that & follow the instructions, Dont feel dumb, most of us are older farts around here & learning new skills faster than the grey matter can absorb them!!
You will find a whole lot of 'shortened expressions which make life easy if your typing skills are like mine, LOL-laugh out loud, FWIW- for what its worth, IMHO- In my humble opinion...........

Hall effect speedo has a pickup similar to the 'Hall effect' ignition pickups that reads off the ring gear or a wheel on it to drive an electronic speedo.

 

[Woody]

Thanks Jac mac I wondered what that broken wire was stickin out of the trans. LOL :laugh:
After reading Russ'es build log, that only took a week! I'm thinking of upgrading my G50/01 to 50/50 is it worth the expence?

BTW awesome job Russ and I'm not joking It realy did take a week to read through:thumbsup: BRILIANT

 

[Doc Kaler]

Hi Woody,

BTW, I'm glad you're mastering abbreviations!

My LS will be in the 600HP range so the G50.50 with it's larger Ring/Pinion setup AND the billet sideplate are my choice, albeit probably about twice as expensive than other G50's.

 

[Jac Mac]

Pete, I cannot speak for 'porsche reliability', Im an 'ALL FORD' guy, guess we will find out over the next few weekends if 930's are up to the job, thats if those North Island couriers actually send Russ's head gaskets down, could be a bit of sabotage job going on there, only way they can beat the SI stuff is make sure it doesnt make the grid, especially after last weekend!!

 

[Russ Noble]

Well Woody, the 930 in my car is just about the ONLY thing that hasn't needed looking at since I got it going a few months ago!

You say you are going to mainly track your car. If you've got decent rubber I would think you might be asking a bit much of the non turbo box behind a 427. G50/50s are almost impossible to find. The G50/52 is just as strong but slightly longer in the tail. There are several ways to successfully shorten them.

Look at the ratios for the G50/52 (and /50) I think you'll find first is miles too low for track use, even with the tallest aftermarket gear you can fit! So you've effectively got a four speed box. Might as well get a 930, arguably stronger, and save yourself a bundle too. You can get a decent first for that, but the highest available second in the 930 is a wee bit low, so maybe you could get better increments with the remaining four in the G50. I haven't checked.

Let me know if you want to sell your G50.

 

[Dave Deerson]

I just wanted to add a point or two on the 930 box. To put the taller first in a little attention with a die grinder is needed to get some clearance between the case and the larger drive gear,no big deal really,I just wanted to give a heads up to whomever may do it. Then about second gear, I don't totally agree Russ. I am not at the shop at the moment,so I don't have my notes as to what ratios I have. But with my chosen ratios I feel I can use all the gears comfortably at both long and short courses(I can now actually use 1st for hairpins!!). Now,maybe your tires may give you a different final,as I am using 25 1/2in tall slicks,and the available ratios may indeed not work for you. All in all I feel the 930 to be the best value. Granted by now I have somewhere around $8000 in it($2400-purchase price,$1500-limited slip, and $3900 for the new dog ring gear conversion from Albins),but I basically have an LG500 for a 1/3 of the price!

 

[Russ Noble]

Dave,

I'd be interested to know what ratios you have. When I was talking to Albins a couple of years ago the highest 2nd they had was 1.21, that's not much taller than the stock one at 1.3. My tyres are the same diameter as yours.

At Ruapuna, my local track here, the quite long midfield section is too fast for second but too slow for third. It would be advantageous to stay in a higher second all the way instead of chopping and changing 2/3/2/3/2/3 all the time. Particularly since a lot of it is twisty and there is only one short straight that I can put down all the power I have in the lower 2nd anyway, and then only for a short time as I have to grab 3rd momentarily before another downshift into 2nd.

The standard 3rd is about ideal for the rest of the circuit and 4th needs to be somewhere between .75 and .72 I think.

Your comment about the LG500 echos my sentiments. Of course an LG600 would be perfect.....

Sorry about the thread drift Woody

 

[Julian]

I think there's a lot more that can be done with the G50 than perhaps credit is given here. FWIW, here's the low down on the G50/52 in my Ultima...

1st 2.06; 2nd 1.50; 3rd 1.13; 4th 0.86; 5th 0.68 with a 3.44 R&P and GT2 chromoly LSD @ 80/80 lock, billet side paltes etc. Its hung behind a 427CI Aluminum Dart (Chevy) with 600HP.

The box uses a custom fit stock 2nd used as a first and allows me to hit 62 mph at 5500 rpm in first for a no shift 0-60 around 2.7 secs. Theoretical top speed when the rev limiter cuts in at 6k is 206 mph.

I'm hoping to find out whether that can become reality at the Mojave Mile in March.

 

[Russ Noble]

I think there's a lot more that can be done with the G50 than perhaps credit is given here. FWIW, here's the low down on the G50/52 in my Ultima...

The box uses a custom fit stock 2nd used as a first

Joules, I think you've just confirmed what I said, in that 1st is useless (you don't use it in anger) and that 3rd gear (effectively 2nd) has a better ratio than the 930 2nd. And of course the G50 syncros are better if you want to stay syncro.

 

[Woody]

All good stuff guys thanks. I defiantly need to research this a lot further.
Russ
If I find another box I'll let you know as for now my head's swiming and I need a beer.

 

[Woody]

Ok Russ now you have me thinking 930. For my G50/01 I spent many hours making the axles and drive flanges and $$$ on heavy duty CV joints. Are they interchangable to a 930, are the flange bolt patterns the same and is the trans the same width, so the axle length still works. And how does the cost of a 930 compare to a G50 roughly :huh:
Any comments welcome.

 

[Russ Noble]

Woody, I'll take width measurements off my 930 tomorrow. I think the CVs interchange, they do with Lim's G50/52. I would think a G50/01 would be the same but I'll measure the bolt PCD for you too.

The 930 that I am using, I lucked out and bought locally here in ChCh for $4000 complete with LSD. I've spent about another grand on it, alloy for the billet sideplate (we used 7075, not cheap in big lumps!), some plates to tighten up the slip, a syncro ring and a couple of bearings.

Unless you've got contacts in Europe and reasonable shipping, the best place to find a 930 is probably Stateside. An average 930, probably needing a rebuild similar to what I did, seems to go between $US2000 and $US3000 depending on condition, LSD etc. Maybe a little more now. By the time you get it landed here that will probably translate into $NZ4000 to $NZ6000. Unless you've got a friendly shipper, and can mitigate the GST a bit too.....

If you haven't seen it, try this for a bit of background... http://www.gt40s.com/forum/gt40-tech-powertrain-transaxles/19746-930-failure.html

 

[EGLITOM]

this file shows my modified G50/05. I have choosen this one because it has the long 3.33 final ratio. i modified first and second gear to longer ratios in order to achieve low rpm drops. third to fith is stock and pretty closed ratio already. This fits perfect with my high rpm engine (peak power at 7200 - 7400 Rpm)
Other than that i have a Quaiffe ATB Diff and a oil cooler setup installed. The oil is taken from the diffhousing and reenters at the endcap, so flowing through the whole gearbox. No spray bars installed.

TOM