Pics of my mid-mount transfer box

Paul_S · Post by **Paul_S** » Sun Dec 22, 2002 1:28 am

Here are some pics of my handmade transfer box for my mid-mount conversion project. I'm sticking a 3.0 V6 in the back of a bug. It doesn't look too good with the rust and welding spatter on it but it's quite accurate (less than 1mm out at the most) and still has to be cleaned, machined and painted. Once that is done it'll look like a casting.

I took the photos with the box lying on it's side. When it's mounted it will stand up on end.

This is the back of the case (the side you would see with the decklid open).

An angled shot of the case from the back.

The front of the case. (part that the engine and gearbox bolt onto) The left of the box is the top and the right is the bottom of the box. The large ring is for locating the tranfer box onto the gearbox. It still has to be machined down to size.

Here are the monster gears. They are over designed and heavy so I may try to lighten them if they cause any rotating mass hassles. They are made of EN 36B and are case hardened and have a ground finish. The distance between centers is 211.36 mm (8.32 inches) and the ratio is 1:1.5 which will give me a 120 km/h (75 MPH) cruising speed at 2600 RPM.

The transfer box consists of 95 pieces of steel that have been cold forged and welded together. It's a collection of angled steel, flat plates and round bar. It weighs 21 kg (46 lbs) without the internals! Yes very heavy but it WILL NOT break when I supercharge the engine up to 400 Nm (295 lbf feet) of torque.

It's amazing how much one can accomplish when you resign from your job and stay at home.

Paul

[This message has been edited by Paul_S (edited 12-22-2002).]

John Kelly · Post by **John Kelly** » Sun Dec 22, 2002 8:31 am

Nice work Paul! Reminds me of the type of work I used to see when I worked in the shipyards.

John www.ghiaspecialties.com

Paul_S · Post by **Paul_S** » Sun Dec 22, 2002 1:55 pm

<BLOCKQUOTE>quote:<HR>Originally posted by John Kelly:
Nice work Paul! Reminds me of the type of work I used to see when I worked in the shipyards.

John www.ghiaspecialties.com <HR></BLOCKQUOTE>

Hey I know those gears are heavy but they ain't THAT heavy!

I just had a look at your site. You do some really nice work John! It seems as if the "black smith" breed is slowly dying out. I see less and less real craftsmanship nowdays which is a pity.

[This message has been edited by Paul_S (edited 12-22-2002).]

John Kelly · Post by **John Kelly** » Sun Dec 22, 2002 3:18 pm

Hi Paul,

Thanks, if you have some time,check out this link for more of my metalshaping...also the metalshapers web site with lots of great metalworkers:
http://metalshapers.org/cgi-bin/communi ... 0093068868
www.metalshapers.org

John www.ghiaspecialties.com

spiny · Post by **spiny** » Thu Jan 02, 2003 4:04 am

that looks great - really nicely put together.

if i understand correctly, i take it you're going to mount the engine on top of the gearbox?

cheers, phil.

London Bugger · Post by **London Bugger** » Thu Jan 02, 2003 4:56 am

Might seem a dumb question but then that me

But what does the transfer box do, please explain

Rob.

Paul_S · Post by **Paul_S** » Thu Jan 02, 2003 10:58 am

<BLOCKQUOTE>quote:<HR>Originally posted by London Bugger:
Might seem a dumb question but then that me

But what does the transfer box do, please explain

Rob.<HR></BLOCKQUOTE>

The engine is going to sit on top of the gearbox where the back seats are.

Here is a diagram that will help explain the layout.

This is similar to how transvers mounted front wheel drive layouts work. (Engine on top of gearbox)

The engine has a short flexible drive shaft through a bellhousing to the transfer box. That drives the big gear in the transfer box on top. The little gear is below it and drives the input into the Beetle gearbox.

The transfer box solves several problems.
1. Transfers weight to the front wheels (no engine hanging out the back)
2. Changes the direction of rotation so that it is not neccessary to flip the ring gear.
3. Changes the ratio to better suit the V6
4. Makes the Beetle gearbox handle more power by running at higher RPMs. i.e. Low torque at high RPMs = high power. High torque at low RPMs = high power/broken gearbox

The only problem it introduces is a higher center of gravity which affects cornering ability but I'm building this as a freeway flyer so it's not a big deal.

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LuxBug (my V6 mid-engine Beetle)

[This message has been edited by Paul_S (edited 01-02-2003).]

goatmaster187 · Post by **goatmaster187** » Thu Jan 02, 2003 11:01 pm

Is this something that has been done before, if so on what?

vwfye · Post by **vwfye** » Thu Jan 02, 2003 11:23 pm

man, and i thought there was alot to converting my notch to midengine, but that is some serious design and execution! wow

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konzept type 3 w/mid engine'd 2332cc of topless fun!!!
64 Notchback
73 Square w/1904cc

London Bugger · Post by **London Bugger** » Fri Jan 03, 2003 2:57 am

Wow thats pretty amazing! You look like you really know your stuff Paul!! It seems a good way of doing a mid engine conversion without having to mess with the gear ox and running gear!!

Rob.

Richard Olafsson · Post by **Richard Olafsson** » Fri Jan 03, 2003 5:00 am

I know you aren't designing a race car but that engine is going to sit very high! The Essex isn't exactly a light engine either so you are really going to suffer in corners. Transverse gearboxes are designed to allow the engine to sit low, the VW one wasn't!
Just wondering why you are so against just flipping the gearbox around the other way.

You are obviously talented when it comes to fabrication, just wondered why this route?

Rich

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http://www.ricola.co.uk

spiny · Post by **spiny** » Fri Jan 03, 2003 5:15 am

would it really make that much difference?
if the beetle is lowered then the engine wouldnt sit that much higher than in an equivalent hot rod for example ?

i'm no engineer mind you

phil.

Paul_S · Post by **Paul_S** » Fri Jan 03, 2003 10:04 am

<BLOCKQUOTE>quote:<HR>Originally posted by Richard Olafsson:
I know you aren't designing a race car but that engine is going to sit very high! The Essex isn't exactly a light engine either so you are really going to suffer in corners. Transverse gearboxes are designed to allow the engine to sit low, the VW one wasn't!
Just wondering why you are so against just flipping the gearbox around the other way.

You are obviously talented when it comes to fabrication, just wondered why this route?

Rich

<HR></BLOCKQUOTE>

The engine is going to sit 211.63 mm (8.33 inches) higher than if I mounted it directly to the gearbox. I'm relocating the sump to the side.

The cornering won't be too bad once I've lowered the car and tweaked the suspension but it won't do for track racing.

I did think of turning the gearbox around but there isn't much space and that would require major cutting and refabrication. When you start cutting the body work away (forks and part of the tunnel) you have to do a total redesign of the structure to keep it strong and rigid. That is a lot more work than building a transfer box setup in my opinion.

Paul

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LuxBug (my V6 mid-engine Beetle)

[This message has been edited by Paul_S (edited 01-03-2003).]

Richard Olafsson · Post by **Richard Olafsson** » Fri Jan 03, 2003 12:27 pm

It's not just the height of the engine base, the V6 will also have a higher centre of gravity. I think they have cast iron heads so CofG would really suffer...
I know mid-mounted would be a lot of work if kept longitudinal, but I'm not sure what you will gain handling-wise compared to hanging the engine out back (apart from stealth)
Rich

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http://www.ricola.co.uk

Paul_S · Post by **Paul_S** » Fri Jan 03, 2003 1:07 pm

<BLOCKQUOTE>quote:<HR>Originally posted by Richard Olafsson:
It's not just the height of the engine base, the V6 will also have a higher centre of gravity. I think they have cast iron heads so CofG would really suffer...
I know mid-mounted would be a lot of work if kept longitudinal, but I'm not sure what you will gain handling-wise compared to hanging the engine out back (apart from stealth)
Rich

<HR></BLOCKQUOTE>

Yip, the center of gravity will be a lot higher than just the crackshaft center line. It's roughly equivalent to having someone really top heavy sitting in the back seat. The V6 is 72 kg heavier than the stock 1600.

If I stuck the engine on the back it would look ugly and would produce some scary oversteer in the corners.

What I do gain is cross wind and high speed, straight line stability. In the past I have have been hit by sudden gusts which have made the car do involuntary lane changes! I do about 3100 km of freeway cruising every month so this is on the top of my priority list.

What I also gain is gearing better suited to the engine.

Paul

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LuxBug (my V6 mid-engine Beetle)