I know I've been saying it awhile but I have finally come to create a project log for my AWD build. First off I want to say that I've officially completed the AWD conversion for a 3.0L and have been driving it around for a few days. I have several hundred km's on it with no signs of failure yet. Since I'm breaking in a new clutch it has not undergone and serious abuse yet. Soon though, real soon
I've been working on this project for ~3 months. For this project I started with a 1991 Dodge Grand Caravan LE with a factory 3.3L w/ AWD. I'm not particularly thrilled by the lackluster performance of the 3.3/3.8 engines. To be fair, most of it is due to A-604. I am, however, a fan of the 3.0L engines and their potential. The addition of a 5-speed transmission was enough for me to go through with this project. AWD was just icing on the cake. Since nobody had 100% confirmed that the PTU will fit behind a 3.0L I figured I'd try it out. Lostaboost had done a lot of the heavy lifting as far as the diff is concerned. If it weren't for him I probably wouldn't of tried in the first place. I did things a little differently which I'll try to explain. I took a fair amount of pictures so if you don't see something or want me to explain something further I will try my best
Here's the van with the 3.3L before I pulled it out. Holy crap was that painful. I'll gladly pull 5 3.0L engines before one 3.3L.
Donor car. It was cheap and paid for itself even though I had to travel 8 hours to get it. Factory 3.0L 5-speed under the hood.
I couldn't resist cleaning it up. I ended up having a couple dropped valve guides so I yanked the heads, had them replaced, did a little porting, cleaning, etc, etc.
PTU mounted to the 5-speed transmission. Instead of drilling and tapping the case I opted to weld on extensions and re-drill holes into the adapter plate. It ended up working out ok. I did have to grind a bit from the PTU to make the bolts fit. I used the upper left bolt as the guide just like lostaboost.
Here's a closer look at the modified adapter plate.
I shaved just a bit out of the PTU. I actually had 1 PTU snap on me when I was putting a bolt in. I'm not sure if it was pinched or if I just took to much material out. The second PTU I didn't take near as much out and I shaved the bolts to make it fit more easily.
Just a comparison to show the difference between the AWD diff (left) and 5-speed diff (right).
This was one of the initial mock-ups just to show myself that it would work.
Here is the modified AWD diff. This is where I did things differently than lotsaboost. Instead of modifying the ring gear I opted to modified the diff. So I had the machine shop add a ring so my ring gear would sit centered. It was recommended to me that the amount I was taking off would not provide a large enough lip to center the ring gear. It's hard to tell but I had 35 thou taken off the diff. What I did was checked the wear pattern for the stock diff, then compared it to the wear pattern for an unmodified diff and determined how much I needed to take off. After machining it was pretty darn close to a stock wear pattern. It's a bit of a rough measurement but as far as I'm concerned, if I'm able to do a 5k launch in a 4000 lb van and not shear the teeth off then this should be acceptable. Worst case scenario I put an auto in
One thing I noticed when I had everything bolted up is that the diff bolts came real close to the case, REAL close. So close that I actually had to grind them to make them fit. Again, it's a little hokey and there are better ways to do things, but I feel that I'm not affecting the integrity of the bolt.
The 3.0L exhaust is very close but not quite the same as the 3.3L exhaust. It sits lower and protrudes closer to the firewall. All I did was chop out the cat and weld in a slightly shorter straight pipe. It is really tight back there with maybe 1/2" of clearance between the exhaust and the k-frame so I have urethane mounts keeping the engine in place. With stock rubber ones it would surely smash and break the exhaust. It still might but so far it is holding up.
So there you have it. It's a far cry from the 10+ pages of updates on TD but it is a start. I believe in sharing this knowledge and I'd love to see more AWD projects down the road. I'm certain there's more things that can improved upon from what I've done. I'll keep updating this thread as progress goes on.
I'm about half-way through breaking in my new clutch. I've got some small issues to work through but I should be attempting some wicked launches shortly. If it survives on the street I'll be taking it to the track. I'll also be installed MS2 shortly to see what kind of gains I can get. My engine is mildly modified but I expect to see some decent numbers. Even without launching this van feels considerably faster through first and second than my old 3.0L duster. At least it feels that way And if I can't get good numbers NA then I'm going to slap an m90 on it