Audi 6 speed ford modular 4.6

[Jim Cowden]

I am fitting a 4.6 modular to my RF40.
I have looked at a few and the engine position is tight and position compromised.
I feel if I flip the audi trans it would make a big difference.
Has anyone fliped the 6 speed and if so is there any lube problems ECT that I should know of.

Jim

 

[Andrew East]

Hi Jim,

I have assembled a RF 4.6 with an audi 6 speed and concur with your comments regarding engine fit being tight, but the 4.6 fit is tight even with 5 speed. One issue with the six speed in an RF is the length of the gearbox which requires a small cutout on the bottom of the rear clip because the gearbox length. I had to make the same cut out on bottom of the clip on my 302 6 speed.

I suppose I am interested as to where you were hoping the gain some space by flipping the gearbox?, although I do not feel qualified to comment on any lubrication issues in flipping the audi box.

Andrew

 

[Jim Cowden]

High Andrew
The drive shaft angles plays a lot on how you set up eng height to a point.
I have noticed the 4.6 mod is fitted with a rake down to the front.
There is a resonable amount of d/shaft angle down to the g/box.
I have studyed it and came to the conclusion that it would be suited to a G50 as it is flipped and the shafts are higher.
Then why not flip the 6 speed this will raise the shaft angles at the inner end and allow the rear of the engine to be lowered to give it an up hill rake of about 2 deg.
The shape of the box when flipped looks like it will clear the frame.
All the frame work from my lower inner arm points back is coming of with the air hacksaw when Im ready.

There is also the issue of the direction of the diff, I know there are some switched on gearbox men on this site that maybe able to help.

Jim

 

[Jim Cowden]

deleted post

 

[Ron Earp]

I think it'd help with engine placement. But, wouldn't you end up with six reverse gears and one forward gear? I'm not sure if the ring gear can be flipped on these boxes or not.

Ron

 

[WesS]

i had fran at rcr put my 4.6 into a 40. look at rcr manufacturers section, look back about one year and you'll see a yellow 40 with the mod engine in it. unfortunately the rear deck would not close without serious modification. heads are just too big.
also if you look on the australian gt40 manufacturers website, you'll see a 4.6 in b. garvey's car. look back a year or two. lot of work.
instead i yanked the 4.6 out and put in a 4.0 lexus. much more efficient engine and DOHC's.
wes

 

[Jim Cowden]

Hi Wes

They fit in the RF I think if I could lower the trans and leave the eng height at the front alone I would be happy.
It will come down to the d/shaft angles that is were the G50 has an advantage as the shafts are high out of the diff.

Jim

 

[JohnC]

Deleted content - asked engine question in transaxle section

 

[Russ Noble]

I think it'd help with engine placement. But, wouldn't you end up with six reverse gears and one forward gear? I'm not sure if the ring gear can be flipped on these boxes or not.

Ron

That is right Ron. You would get six reverse. I've no idea about swapping across the ring gear either.

Cheers

 

[Mike]

Lurker and first post here....but I have to ask! If I understand you correctly, you simply rotate the trans 180 degrees so the top is now on the bottom? In that configuration you still haven't changed the rotation of the input shaft......have you? If not then shouldn't you still have the same amount of forward and reverse as before? Just curious.

Mike

 

[Jim Cowden]

No mike I wish, you get 6 reverse
these trans were designed to fit north south normal configuration.
The porsche box works because you flip it and turn 180° front to back if you know what I mean.

Jim

 

[Mike]

Hi Jim,

I know about the Porsche since they are a similar to the way the old VW's were done for a mid engine.

I'm still having a real hard time getting my head around the top to bottom flip though. Assume there is a cad file showing the centerline of the input shaft that traverses through the length of the trans, that line is the rotational axis....correct? Assuming the input shaft rotates in a clockwise direction looking at the trans from the input shaft end, the rotation of the input shaft will not change by simply rotating the trans upside down...will it?:dead:

Anyway here is a jpg showing what I mean.

Now don't get me wrong, I know nothing of the transaxles but I am trying to learn and that is why I'm here on this forum. You have excellent technical info period!

Mike

 

[Steve Kulper]

Hi Mike,
It's the output shafts that are the issue, looking from the rear of the GT40 with the tranny in the mounting position in the Audi position ( gear selectors on top of gearbox) now rotate the gear box so the left side output becomes the right side output and vice versa. So you are rotating it on the input shaft axis not the output shaft axis. I hope it makes sense.

Steve

 

[Jim Cowden]

High Steve good description

Yes I had to think about as well.
I find the best way Mike is use your hands (imaginary g/box).
One hand on the input shaft rotating clockwise.
The other on the L/H drive flanges, it is rotating in the forward drive direction.
Now roll it over without letting go of anything while rotating your hands slowly and now it is going in reverse.

It is because the pinion is on the opposite side

Now if you plan on doing this in public tell them you are practicing tieche .

Jim

 

[Lynn Larsen]

I once made a post on how anyone can do this. It involves putting your arms into a crucifix configuration and rotating your fingers to indicate tire rotation and using a wall to represent the ground. Start out facing the wall, then flip yourself over (facing away from the wall) maintianing the same rotation with your fingers. This has worked for me every time I have done it (every couple of years just to convince myself that the laws of physics haven't changed. BTW, to emulate a Porsche, you'll have to stand on your head, LOL

Mike, you'll get 6 reverse speeds!

 

[Mike]

Thanks guys,

Jim this is one of those things that even when you see that it works, you still don't believe it. I followed your example and can see what you are talking about. Just to be sure I replicated it on my cad system.....so now it is through the thick part of my head! lol

I appreciate the patience and the help in understanding. Now, how are you going to fix it?

Mike

 

[AdrianBurton]

You would fix it by flipping the ring gear inside the trans.

a

 

[Eric A.]

You would fix it by flipping the ring gear inside the trans.

a

I don't think that there is room in the case to flip the ring gear. The other option is to run a reverse rotation cam in the engine. This brings on a whole new set of problems however, as the gears run backwards and wear becomes a real problem. If you need to run an inverted box, go with a Porsche.

 

[AdrianBurton]

Sorry, I guess my answer was a bit criptic....
If there is room in the case you would flip it, it may even require machining, if it could be done. As Eric said, you might be better off going with the porsche box

 

[Pete T]

You can't flip the ring gear on these. It is a hypoid type gear set. This means that the pinion is offset from the ring gear centerline. When you flip the ring gear, it's centerline moves to the opposite side of the pinion. So the ring gear centerline would be moved below the pinion and wouldn't fit into the case.

The 915 and 930 use spiral bevel gears which means that the ring gear and the pinion gear are on the same centerline, (same as the Beetle) so it can be flipped.