G50, any consensus as to type?

[omgdave]

Hello all,
After reading many of the build diarys that most of you regular posters give links to, I am curious as to why you (you builders) chose to use the particular model of G50 in the Ultima that you built. Is/are there models that will last longer, handle more torque or just fit better with less fiddling?
If the answer is " I found one at a fair price at the breakers", that is fine for me. I am interested in your choices and reasons. Also, this might be info that could be usefull to other future builders.
Thanks,

Dave

[davefiddes]

There's actually a Faq Item about it.

The G50/52 box is the strongest box with the best gearing I think. It has a bigger ring and pinion which makes it a bit stronger too. Slightly more complex to mount but nothing serious.

I ended up with a low mileage G50/03 without an LSD because it was a good price at the breakers. May go through the pain (money and time) of fitting a Quaife ATB diff at some point.

[omgdave]

[quote=davefiddes]There's actually a Faq Item about it.

So there is! Had to search a bit -not too obvious- but there it is. How about the rest? Too late, or what?
Thanks, Dave.

From another one.

[jschwartz]

I got my G50/52 from Powerhaus II in Denver.
www.porschegears.com
Installed a 2.62 first gear ratio, now geared like a C4/C5 Corvette 1st-5th.
Very good trans 11,000 miles and a number of drag strip runs, no trouble. I don't run a trans cooler , but do use synthetic lube.
jeff
USA

[davejw]

G50/52 for about £2k. 30mph /1000 rpm makes the whole thing less frantic and means you can cruise sensibly. There is soooo much torque the higher gearing is not an issue but this box is designed for the starter ring gear to be on the flywheel and not the clutch cover (per G50/03) I know this as I changed from an 03 to a 52 and spent hours (over 16) milling out the inside of the bell housing to make it fit... It's also longer by about an inch and will need different rear mounts and a slight extension (by adjustment) to the linkage.

Worth the effort though...

As a point of interest, if you have a choice - try and get a clutch that does not have the rubber coupling as I managed to shear one on the way back from the Nurburgring and it was a real pain - moreso because Ultimas don't like being dragged onto a flatbed without loads of bits of wood and messing about...

[omgdave]

[quote=davejw]... but this box is designed for the starter ring gear to be on the flywheel and not the clutch cover (per G50/03) I know this as I changed from an 03 to a 52 and spent hours (over 16) milling out the inside of the bell housing to make it fit... It's also longer by about an inch and will need different rear mounts and a slight extension (by adjustment) to the linkage.

Worth the effort though... [quote]

Too bad about the clutch and the tow home- had to be fun running at the 'ring though!! So if I understand things right, the /52 box _will_ work, but with the extra fiddling that you did Dave, or was the machining (16 hrs.. ouch!) only because you swapped from a /03 to a /52? Taking into account the linkage and mounts,, etc., right?
Still a long way off from doing this, but I need to get a feel for what the hard parts will be, like getting an engine through California pollution checks. Still trying to get some info on what steps I will need to take, I need to make an appointment just to ask a question about where to start!

Thanks,

Dave

[gtrclive]

If you fitt the G50/52 I thought you keep the same rear gearbox mounts and linkage, but fitt the factory supplied 1" spacers to the engine mounts ?

[k wright]

gtrclive said:

If you fitt the G50/52 I thought you keep the same rear gearbox mounts and linkage, but fitt the factory supplied 1" spacers to the engine mounts ?

True, the factory engine mounts to accomadate the G50/52 are simple steel plates that move the motor forward 1 inch. They are placed between the motor and the motor mounts.

[steve_D]

You don't have to grind out the housing if you have the correct flywheel and clutch. The ring gear is on the flywheel and the starter is on the engine side of the adaptor plate.
Steve

[davefiddes]

If you have the starter on the engine side you need to machine a pocket in the gearbox bellhousing to allow the end of the starter to fly into.

[davejw]

Yes, I had to grind away the inside of the bellhousing (ever tried grinding alluminium??) to make the /52 fit to the existing /03 setup. The spacers on the back of the gearbox are needed (I forgot about those) but on the Sports, you also need to modify the wing mount as the gearbox fouls the diagonal bracing bar - not a problem for GTR owners!

For those who are contemplating doing the home mod, the best tool was a circular 4inch Makita concrete grinder (seriously as anything else gets clogged up), an arbour and lots of sandpaper of varying courseness. I used the ringear as my measure of 'ovalness!' and slid the clutch/flywheel assembly up the input spline to make sure I had enough clearance without removing too much metal. It was a pain but we finished at 19.30 and were on the ferry to the Nurburgring by 22.45 - arrived at 04.30 the next morning in time for track opening. Mad and certifiable but against all odds it performed faultlessly and did 3 further trips that year!

Cheers,

Dave.

[steve_D]

davejw said:

Yes, I had to grind away the inside of the bellhousing (ever tried grinding alluminium??) to make the /52 fit to the existing /03 setup.......For those who are contemplating doing the home mod, the best tool was a circular 4inch Makita concrete grinder (seriously as anything else gets clogged up), an arbour and lots of sandpaper of varying courseness. I used the ringear as my measure of 'ovalness!' and slid the clutch/flywheel assembly up the input spline to make sure I had enough clearance without removing too much metal......... Dave.

I did mine as I already had the clutch/flywheel.

I used a carbide burr in an air grinder. To stop it clogging you just need to dip it in parafin every few minutes. I didn't have any parafin but WD40 seemed to work fine. To finish the surface I use a flap disc in an angle grinder. Took about 4 hours.
Steve

[omgdave]

davejw said:

It was a pain but we finished at 19.30 and were on the ferry to the Nurburgring by 22.45 - arrived at 04.30 the next morning in time for track opening. Mad and certifiable but against all odds it performed faultlessly and did 3 further trips that year! Cheers, Dave.

Dave,
You _have_ to share the details of what it is like to run on the North Circuit!! You know, peeling the faux factory decals off some Sport Bike poseurs as you motor sedately past in 4th, flashing your brights and signalling to pass the odd and sundry M5, that sort of thing... C'mon Dave!!
The best I can brag about is 2 laps in the (current equivalent) Showroom Stock class at Laguna Seca, for runs at famous tracks. Start a new thread, " Racing Spews, or as fast as I wanted to go before bending the car", or something.
The rest of you also, tell some stories or link to some video of tracks that I will prolly never put wheels to- club tracks, airports, any GP track, historic UK tracks, anything!

Bated breath,
Dave

[omgdave]

davejw said:

It was a pain but we finished at 19.30 and were on the ferry to the Nurburgring by 22.45 - arrived at 04.30 the next morning in time for track opening. Mad and certifiable but against all odds it performed faultlessly and did 3 further trips that year! Cheers, Dave.

Dave,
You _have_ to share the details of what it is like to run on the North Circuit!! You know, peeling the faux factory decals off some Sport Bike poseurs as you motor sedately past in 4th, flashing your brights and signalling to pass the odd and sundry M5, that sort of thing... C'mon Dave!!
The best I can brag about is 2 laps in the (current equivalent) Showroom Stock class at Laguna Seca, for runs at famous tracks. Start a new thread, " Racing Spews, or as fast as I wanted to go before bending the car", or something.
The rest of you also, tell some stories or link to some video of tracks that I will prolly never put wheels to- club tracks, airports, any GP track, historic UK tracks, anything!
(edit)
Only U-car stories, thankyouverymuch!

Bated breath,
Dave

>> Edited by omgdave on Monday 23 February 01:22

[454]

davejw said:

30mph /1000 rpm makes the whole thing less frantic and means you can cruise sensibly.

That gearing sounds ideal, is it exactly 30mph / 1000rpm i.e are you turning 3000rpm at 90mph ?

If so I'll be keeping my eye out for one for my car

edited to add :

Also saw the G50/20 mentioned in the FAQ's, does anyone know what the ratios are like on this one and if it takes a lot of mods to fit ?

>> Edited by 454 on Tuesday 24th February 13:03

[steve_D]

454 said:

......Also saw the G50/20 mentioned in the FAQ's, does anyone know what the ratios are like on this one and if it takes a lot of mods to fit ?

I have the G50/20 6 speed.
Will look out the ratios I have but it seems there may even be EU/US differences.
In the process of fitting it over last few days. Seems the housing is a different shape below the rear rubber mount so the standard frame does not fit. Factory are sending me a replacement which should work.

You will need the alternate flywheel/clutch. It puts the starter ring gear on the flywheel rather that the back of the clutch. With this you do not need to clearance the inside of the bell housing. The down side may be that the starter is now on the engine side of the adaptor plate. I believe, but could be wrong, the location is difficult to access and you may need a heat shield to prevent the starter getting cooked.

From other peoples comments it seems that the /20 may not be an ideal choice. The amount of torque we have makes the taller gears quite acceptable and if you were looking to be different then try the 4 speed.
Steve

[OutOn]

I hope this helps you a bit. These are the Porsche gearbox ratios I managed to get. Remember that for the G50 box (964 & 993) it looks to use different ratios depending of market. Below are the ones used in Most Europe and US.

Getrag 6 speed 996 C2/Boxster S (as factory supplied):
1 3.82
2 2.20
3 1.52
4 1.22
5 1.02
6 0.84
diff ratio 3.44

G50 6 speeds 993 C2
1 3.82
2 2.05
3 1.41
4 1.12
5 0.92
6 0.78
diff ratio 3.44

G50 6 speeds 993 turbo
1 3.82
2 2.15
3 1.56
4 1.21
5 0.97
6 0.75
diff ratio 3.44

G50 5 speeds 964 turbo
1 3.15
2 1.79
3 1.27
4 0.97
5 0.76
diff ratio 3.44

4 speeds 930 turbo (1976)
1 2.25
2 1.30
3 0.89
4 0.66 (0.63 from 1978?)
diff ratio 4.22?

I´ve got the ratios for the Getrag not supplied by the factory too. I mean 996 turbo, 996 GT3, new 996 GT3, 996 GT2, 996 GT3 RS, new 996 GT3 RS.

Cheers guys and sorry if this has been covered to death here before...

[davejw]

OMGDave - here is a link to some pics of the Ultima at the Ring. There are 6 pages in the guy's set but I think most of the shots are on 4 and 5.

www.sportbilen.se/index.php?page=bildspel.php?cat=ringen03_2&go=0

It's great fun but also a bloody liability as it attracts loads of attention and everyone wants to have a go at it and with the lack of rear visibility the bikes can be quite an issue. Parking is also a nightmare but.... get a decent lap and it's so much fun. Really hard work and the speeds require loads of respect as you never know what's around the corner!

Dave.

PS Don't follow it or you will choke to death.

At Hatzenbach (series of tight left and right combinations) it shoots huge flames out of the exhaust as you come off the gas after accelerating hard! A decent fuel pump is also a must the original Carter's couldn't cope.