Mitsubishi 3000GT & Dodge Stealth Forum banner

1 - 20 of 24 Posts

·
No more VR4!
Joined
·
798 Posts
Discussion Starter · #1 ·
So with my two carrier bearings shot on the stocker it was time for a new driveshaft. I'm not a fan of multi-piece driveshafts in general, and the options for our cars I don't like since they're aluminum/steel hybrids. So I figured I'd go for a PST 1-piece.

I managed to get a great deal on a "refurbished" shaft PST had. The previous owner decided to swap it for a 2-piece, and they went through it with new U-joints and balanced it.

Installation is easy. The main difficulty for removal was having to drop the exhaust for access to the carrier bearing nuts (which isn't difficult per se, just annoying). Now I'll be able to remove the shaft without dropping the exhaust since there are no carrier bearings! :D

Driving so far is a world of difference. The car absolutely feels torquier, and seems much happier at low RPMs than with the stock shaft. I don't know how much of that has to do with the lower rotating weight to accelerate and how much has to do with getting rid of the shot carrier bearings that were probably losing a bunch of power, but the car absolutely feels better.

There is a very slight vibration in the 55-65 mph range. Honestly if I didn't know these 1-pieces had that issue, I wouldn't notice it. I definitely won't bother to intentionally re-clock it in an attempt to improve the vibration. But when I drop the rear suspension, it has a 75% chance of going back together differently at random, so I'll just do that.

The clunking I was getting is also reduced, but not eliminated. One thing I noticed under the car was it felt like the differential has more slop in it than it should. Today I noticed a bit of whining from back there. Not much, but a bit. So I probably need to think about rebuilding the differential when I drop the rear suspension to do my solid subframe bushings, rear steer delete, and Addco rear bar. Always something with these cars. :mad:
 

·
4G63 swap initiated
Joined
·
7,360 Posts
Was the one you bought from pst like a one time deal? Or do they always offer refurbs?
 

·
No more VR4!
Joined
·
798 Posts
Discussion Starter · #5 ·
I wouldn't call it the best on its own, but absolutely all the things that tighten up the car are collectively the best, moreso than all the power upgrades.
 

·
No more VR4!
Joined
·
798 Posts
Discussion Starter · #6 ·
Was the one you bought from pst like a one time deal? Or do they always offer refurbs?
This was a one-time deal from my understanding.
 

·
Premium Member
Joined
·
456 Posts
How fast have you gone with the CFDS? My ACPT 1 piece shaft has no vibrations until about ~120mph but then it becomes unbearable and you are forced to lift.

I will be changing drive shafts at some point, and had been looking at PST, so I am curious how they perform at high speeds.
 

·
No more VR4!
Joined
·
798 Posts
Discussion Starter · #8 ·
I've had it up to 100, which is as fast as I ever drive. Perfectly smooth up there. So no plans on testing it to 120. Sorry. :)

Have you tried clocking it differently on your car?
 

·
Premium Member
Joined
·
456 Posts
I've had it up to 100, which is as fast as I ever drive. Perfectly smooth up there. So no plans on testing it to 120. Sorry. :)

Have you tried clocking it differently on your car?
Yep, tried every way :) Now that I am getting new turbo's there is a chance I could potentially hit 120 on the 1/4th so the vibration which I have dealt with for the last 4 years actually needs to be fixed.
 

·
No more VR4!
Joined
·
798 Posts
Discussion Starter · #10 ·
Makes sense. For me this car is a daily driver and I'm planning on keeping it that way, so I don't have any desire to race it or really push the limits with it.

But I do want at least a 3.5L engine when it comes time to put a new engine in. :D
 

·
resident evil
Joined
·
17,080 Posts
I have had mine up to 140mph no issues
 

·
Resident Street Racer
Joined
·
5,605 Posts
My buddies vr4 has a 1 peice CF driveshaft and I honestly have never be able to tell based on driving his car and mine...only reason I know he has one is because I've seen it under his car...:p
 

·
Premium Member
Joined
·
160 Posts
I definitely noticed a difference after installing mine. The car seems way more responsive.
 

·
No more VR4!
Joined
·
798 Posts
Discussion Starter · #14 ·
My buddies vr4 has a 1 peice CF driveshaft and I honestly have never be able to tell based on driving his car and mine...only reason I know he has one is because I've seen it under his car...:p
I doubt if your car and your friend's car are 100% the same. As with most modifications that have a subtle difference rather than profound, you can really tell on a back-to-back comparison. The driveshaft differences are definitely subtle. You've also got a lot of other areas of potential slop in the drivetrain that are almost certainly different from car to car. In my case I absolutely noticed an improvement. However, I've also got more slop that appears to be differential backlash. I'm also realizing the trans output shaft or TC may have slop as well. The summary is I need to put the car up again in a couple of weekends to look more specifically - traveling next week for work. But I am going to adjust the backlash in the diff as my next step.

When I tell my friends about the difference I've seen, I quantify it that some is probably fixing a broken part and some is a genuine improvement. If I'd done this 3 years and 30k miles ago, I doubt I would have noticed as significant of a difference.
 

·
resident evil
Joined
·
17,080 Posts
I feel it changes the whole car. Like I have said before, I can go around a turn, snap into second gear and swing the whole ass around. I could never do that before the shaft change because its now a more direct link to the back nad has some elastic properties that the stock one doesn't have
 

·
No more VR4!
Joined
·
798 Posts
Discussion Starter · #16 ·
It definitely changes the whole car. The more I drive the car, the happier I am with it. However I still have some other looseness in the drivetrain - the rear halfshafts, probably need to adjust diff backlash, and I'm going to guess my output shaft and transfer case splines are loose as well.
 

·
resident evil
Joined
·
17,080 Posts
i need to drop the rear subframe and replace all the rack bushings. i did the diff bushings and they were really bad
 

·
No more VR4!
Joined
·
798 Posts
Discussion Starter · #18 ·
If you check my thread on the AWS Delete, Addco Rear Bar, and Solid Rear Subframe Bushings (see my signature) for the link), I did that all recently. It did quite a bit for improving the stiffness of the rear end. Not quite as much as the driveshaft did, but it definitely helped.
 

·
Elevate
Joined
·
1,121 Posts
you installed this with an addco sway bar? wondering about clearances etc since i have both parts on the way
 

·
No more VR4!
Joined
·
798 Posts
Discussion Starter · #20 ·
I had the Addco bar, but it wasn't installed until I dropped the rear subframe and went through it (AWS delete, solid subframe bushings, etc.). I've been driving it for a couple months now with both.

When you install the Addco bar, it has "optional" spacers that go under the bushings on the subframe. I put those in, and that gives sufficient clearance. Keep in mind that clearance will shift if the back end squats under hard accel, but I haven't had any issues with my setup. If you had a drag monster, maybe, but I'm not seeing any issues.

If you decide to put the spacers under, you'll need longer bolts. I had to special order them in a pack of 50 (only needed 4). You won't be able to find them in a hardware store, because they're Grade 10.9 and an unusual size. So if you go that route, PM me and I'll mail you the 4 bolts needed if you want to PayPal me a few bucks for shipping.

I couldn't be happier with the setup. The rear bar really makes the back end feel more planted. The CFDS makes the driveline feel tighter and more connected, plus it helps low-end acceleration since you've reduced rotating mass. I did the Addco bars backwards and haven't put the front end in yet, but I'm waiting until I have the time to drop the control arms and maybe the subframe to do it all at once.
 
1 - 20 of 24 Posts
Top