Converting a GT3 engine to reverse rotation? - Page 4

MarKoBrow · 07-06-2010, 12:04 PM

Quote:

Originally Posted by blue72s

Unlike the Subaru 'box, the GT3/G50 case does not have any room at the other side.

You are absolutely right and you can't flip the ring gear in a Subaru either, what I was suggesting is to get a ring and pinion made that would rotate in the opposite direction. the link that I provided was a company that makes a reverse rotation gear set for a Subaru transmission. Because the G50 and the Subaru trans both use a offset hypoid differential gear set, you simply can not "flip" the ring gear. the way to do this is get a New ring and pinion made that would run in the opposite direction.

Take a second and look at the link I posted

kenikh · 07-06-2010, 12:08 PM

^ Ah, got it. A custom ring and pinion set ain't cheap, but given where this thread is going, it seems the cheap alternative, for sure.

I'd bet you Matt Monson would have no problem building a one off reverse R&P set.

MarKoBrow · 07-06-2010, 12:11 PM

Actually earlier in the thread he had suggested some folks that could do it, he was the first person that came to mind when I read this thread.

Matt Monson · 07-06-2010, 01:15 PM

Echo
Echo
Echo

kenikh · 07-06-2010, 02:14 PM

Is that the the devil appearing?

Matt Monson · 07-06-2010, 06:03 PM

Kenik,
I hope not. I try to live a righteous life.

Did you see my comments on the Subaru box? That's the answer to your email that I never wrote back. Your engine would shred a Subaru box converted to 2WD.

kenikh · 07-06-2010, 06:15 PM

Quote:

Originally Posted by Matt Monson

Kenik,
I hope not. I try to live a righteous life.

Did you see my comments on the Subaru box? That's the answer to your email that I never wrote back. Your engine would shred a Subaru box converted to 2WD.

Missed it til now.

Yes, I had assumed as much. The good news is that I have a potential solution that will require modeling out. Now if I just had more time...

blue72s · 07-07-2010, 12:29 PM

Quote:

Originally Posted by Flieger

How about one of these?

I think that's a transverse type trans. I prefer longitudinal.

blue72s · 07-07-2010, 12:34 PM

Quote:

Originally Posted by Cupcar

Maybe a Quaife Q-Tek 6 speed shown on the left, which has all the dimensions of the latest 996 gearbox could be used. It is designed for mid-engine or rear engine use.

Quaife do make a variant of this gearbox as a kit to go with the non-GT3 911 engine, which is shown on the right with the gear lever. The kit also includes clutch and flywheel in addition to bellhousing.

Thanks, but the pic on the left is not 996-based. It's just an universal box – 190mm spiral bevel (not hypoid) and 80mm shaft centres.
The pic on the right is based upon the G50.00 (not G50.50) ie. 190mm dia crown wheel with 16mm hypoid offset and 85mm shaft centres. The GT3 uses the turbo-sized ring & pinion (9”) with 10mm hypoid offset, derived from the G50.50.

Cupcar · Cupcar's Garage

Quote:

Originally Posted by blue72s

Thanks, but the pic on the left is not 996-based. It's just an universal box – 190mm spiral bevel (not hypoid) and 80mm shaft centres.
The pic on the right is based upon the G50.00 (not G50.50) ie. 190mm dia crown wheel with 16mm hypoid offset and 85mm shaft centres. The GT3 uses the turbo-sized ring & pinion (9”) with 10mm hypoid offset, derived from the G50.50.

It is not 996 based, but has the external dimensions of the 996 according to Quaife.

proximity · 07-07-2010, 10:26 PM

Can you lower the engine/trans.? You can't flip the ring because it's hypoid, right? Isn't there a G50 variant you could flip the ring on(I have never worked on G50s)? Is this for a 914 or something else?
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Used Auto Parts | Used Car Parts

blue72s · 06:56 PM

Quote:

Originally Posted by MarKoBrow

what I was suggesting is to get a ring and pinion made that would rotate in the opposite direction.

You mean a reversed R&P set and still on the existing side of the casing and if so, doesn't that require reversed engine rotation? Secondly, such a conversion would result in "before-centerline" hypoid (not to be confused with reversed rotation). AFAIK most car manufactures use AFTER-centerline hypoid. I have no idea whether before-centerline hypoid works or not but if manufacturers don't use this type, there must be a reason.

MarKoBrow · 07-08-2010, 08:31 PM

Quote:

Originally Posted by blue72s

You mean a reversed R&P set and still on the existing side of the casing and if so, doesn't that require reversed engine rotation? Secondly, such a conversion would result in "before-centerline" hypoid (not to be confused with reversed rotation). AFAIK most car manufactures use AFTER-centerline hypoid. I have no idea whether before-centerline hypoid works or not but if manufacturers don't use this type, there must be a reason.

What it means is you would have a ring and pinion made with the pitch reversed. The position of the ring and pinion would remain the same and the pitch of both gears will be reversed, Therefore the rotation of the transmission would change but the rotation of the engine would remain the same.

blue72s · 07-10-2010, 08:48 PM

^ If you use a reversed R&P set (pitch reversed) you will be driving on the coast side, and coasting on the drive side of the R&P - it probably won't like that long term.

blue72s · 07-16-2010, 08:35 PM

Quote:

Originally Posted by Steve@Rennsport

Both Ricardo & Xtrac make custom transmissions for such applications and while not cheap, they are THE best.

According to this thread The insides of the Ford GT transaxle... , Ricardo will only do 25 units MINIMUM!

It is virtually impossible to get one of those companies to make just one transmission for you.

Jeff Alton · 07-16-2010, 10:28 PM

I'd take one for my Cayman so that leaves 23 more....

Just kidding of course.

johnman001 · johnman001's Garage

Quote:

So, Cayman gearboxes are not strong enough? There are 3.8 and Turbo conversion street cars, and there are a few being raced.

I would think it would be easier to make an adapter plate and flywheel than convert the engine to spin the other way.

Quote:

Originally Posted by Steve@Rennsport

OMG, no,...

These have many issues and once you see one all apart, its soon quite obvious what these really are.

The G50 6-speed is FAR stronger, especially a late Cup or RSR version.

Never having had one apart, I am curious. What are they?

Cupcar · Cupcar's Garage

Arn't the latest "normal" 911 and Boxster gearboxes built by a Japanese supplier with the same philosophy as a Timex watch that it gets thrown away when it needs repair?

The G50 based unit of the GT3, GT2 and Turbo is still built in Germany.

tctnd · 07-18-2010, 09:49 AM

You cannot reverse the rotation by altering the R&P pitch in any way. You must either flip the ring to the other side or flip the whole box over.
regards,
Phil

Matt Monson · 07-18-2010, 10:23 AM

Quote:

Originally Posted by blue72s

According to this thread The insides of the Ford GT transaxle... , Ricardo will only do 25 units MINIMUM!

It is virtually impossible to get one of those companies to make just one transmission for you.

Yep. And then there's the lead time. It took a year to make my ring and pinions...