6CYL Swap "The Real Truth"

[Dredder]

Well I have been researching the 6cyl differential swap for quite sometime now. There's a lot of misinformation about this topic. I have spoken to a few people that have done this swap personally and the answer was still the same. Well, I finally decided to prove myself and other that this swap is not as difficult as people try to make it out to be.

Here's the truth:
3.25 LSD from 5 series
Output flanges from 318ti is direct bolton to 6cyl differential. This way you no longer need to construct a hybrid axles as stated in the notebook section.



Output flanges 318ti left Vs. 6cyl right.
As you can see the 318ti extra seal. 6cyl is a little longer not by much maybe less than 1/4"


318ti output flanges fully assembled into 6cyl differential. Notice the 6CYl output flanges for comparison


318ti output flanges fully assembled sideview closeup


6cyl output flanges still intact. Notice the seal. Its as secure as the 318ti output flanges see above.

[Dredder]

Ill make a write up once i get my mcoupe cover.

[96cali]

nice! thanks dredder.

[aceyx]

318ti LEFT, 6cyl RIGHT?

[Dredder]

right...

[hellrot332ti]

I think i spoke with you on B.F c about this. I have the 3:73 LSD and i actually had to change my rear end in my apartment complex parking lot. Its real easy. Dont even have to remove a wheel or the axles. I too just popped the Ti axle input flanges into the 6 cylinder diff. Since the 6 cylinder diff is physically larger it taked some ingenuity (hammer) to get it in. Works great though and i love it.

[Dredder]

Originally Posted by hellrot332ti

I too just popped the Ti axle input flanges into the 6 cylinder diff.

Are you talking about image number#1 or image number#2 (4bolt patern - upper top left).

I recall talking to you on BFC and Kiley_sean in this forum. If I'm right, All i need to do is swap the output flanges from 318ti to 6cyl differential and Im good as gold.

[L84THSKY]

I've got my 3.45LSD with M-coupe cover waiting for install. I would appreciate the naked truth on what the install will be like. Too many people have said too many confusing comments.

Originally Posted by Dredder

Ill make a write up once i get my mcoupe cover.

[Dredder]

Originally Posted by L84THSKY

I've got my 3.45LSD with M-coupe cover waiting for install. I would appreciate the naked truth on what the install will be like. Too many people have said too many confusing comments.

Will do. Im in the same boat as you are L8. From the people I've talk to all they did was swap flanges and its a direct bolt on. From my experience so far, it looks like they are right. Everything is going as planned. I will document everthing down to the last bolt.

[GDB]

so no cutting is required?

[Dredder]

Originally Posted by GDB

so no cutting is required?

So far. But the size of 6cyl requires pounding the underbelly where the diff sits. The 6cyl is just a little larger. Shouldn't be too much

[hellrot332ti]

Yeah it looks like it isnt gonna fit when you bolt it up. Jack it up with a floor jack in place, put your bolts in the driveshaft and then start the 2 front bolts(towards front of car) Now lift it up and you will see that it hits the underbelly of the car before the diff cover mount bolt lines up. You must beat about a 3\4 inch deep dent in the floor of the trunk. Keep jacking it up unitl the diff cover bolt lines up an hit it thru with a hammer. Now put the 2 rear bolts in and bolt up the axles. Tighten everything up and youre ready to go. Took me about an hour in the parking lot of my apartment. The beating of the dent took the longest. Looking forward to a write up and pics from dredder.

[L84THSKY]

I agree about the inner portion of the flanges both seating the same depth. What I wanna see is how much width is lost flange face to flange face of the entire diff. Even in your pics, you can see how the 318ti flange sits deeper, from the outside view. That extra depth is going to leave a gap from flange to CV joint, when you attempt to bolt the halfshafts on.

Originally Posted by Dredder

Will do. Im in the same boat as you are L8. From the people I've talk to all they did was swap flanges and its a direct bolt on. From my experience so far, it looks like they are right. Everything is going as planned. I will document everthing down to the last bolt.

[hellrot332ti]

Originally Posted by L84THSKY

I agree about the inner portion of the flanges both seating the same depth. What I wanna see is how much width is lost flange face to flange face of the entire diff. Even in your pics, you can see how the 318ti flange sits deeper, from the outside view. That extra depth is going to leave a gap from flange to CV joint, when you attempt to bolt the halfshafts on.

You have to remember that the 6cyl diff is physichally larger than the stock unit. Its so much bigger that it doesnt look like it will fit and your stock rear cover is also alot smaller. This actually makes its a tighter fit between the CV and the flange. So tight that you have to start the edge of the CV against the flange and kinda roll it on.

[Dredder]

Originally Posted by hellrot332ti

You have to remember that the 6cyl diff is physichally larger than the stock unit. Its so much bigger that it doesnt look like it will fit and your stock rear cover is also alot smaller. This actually makes its a tighter fit between the CV and the flange. So tight that you have to start the edge of the CV against the flange and kinda roll it on.

Thanks for the advice.....My diff cover probably wont get here until next week sometime, busy with the holiday season. Once its here maybe I'll find sometime to get it installed.


p.s. "F.Y.I. this differential upgrade was not required when I had my 6cyl engine installed. The stock differential is still going strong after 10k+ of driver the car hard. The only negative with stock diff is it revs high in the freeway."