I have a done quite a few searches and haven't really come up with a solid answer.

If I get on the throttle quickly or let off the throttle quickly it feels that the entire drivetrain is loading/unloading violently. It honestly feels like everything is moving several inches (even though I know it is not). The way I have been avoiding it is to roll on/let off the throttle very gently. The mounts appear to be in decent-ish shape (checked them when I was doing my timing belt)

I have a hard time believing a car would come from the factory like this and I am trying to figure out if my mounts need to be replaced. Granted my Evo is old, and has quite a few miles on it, so I would not be surprised that the mounts are tired. I just want to make sure that I am not "barking up the wrong tree" so to speak.

2003 Evo 8 with 173k miles on it, all stock never modified.

My other car does the same thing it but it is no where near as bad.

 

Could you snap a quick video? What exactly do you mean by "drivetrain", i.e. just the motor, or are you feeling stuff all the way to the rear diff? What kind of clutch do you have?

 

I was having compressor surge problems last year that made it seem like my drivetrain was moving that much.

 

By drivetrain, I mean the motor/trans, I feel it in the front of the car. It will be difficult to snap a video because it is only noticeable while driving under load and quickly letting off the throttle to decelerate or vise versa. Clutch is stock and does not slip at all.

If I had to describe it in a less than technical way, it feels like all the mounts have gone soft/squishy and the motor/trans is allowed to rock forward (when torque is applied, and backward until it settles in the neutral upright position when the torque is taken away.

 

my car holds steady-ish 18 psi through all gears with my rigged up test boost gauge (before tapering off around 6k of course). Although that might be a red flag that something else is happening since it is not slightly higher, but that will be addressed later.

 

is your downpipe close to hitting anything when you get under and look? it could be contacting the oil pan or the bars that brace the car.

 

I did not see any rub marks / or damage when I pulled it off during the timing belt fiasco to lock the balance shaft in place. I also do not hear a clunk, bang, or metal on metal sound when it the slack gets taken up / released

 

Why not Just get a upgrade front Motor Mount. WIll help the motor From Rocking.

 

I was more or less just trying to see if this was something normal before I tried replacing them.

I have seen torque dampers advertised but I wasn't really convinced. (like the one I linked to below)

http://www.maperformance.com/weapon-...l#.UNM9Wm9QWGI

 

It will move a little, but should not be as bad as your talking. i know alot of people upgrade the buschings in the drive shaft as well to help tighten everything up.

I would not do a torque Damper i would just do something like
https://secure.buschurracing.com/cat...2a0c0c26219488

 

My previous evo and my current evo both do this in lower gears.

You are loading up all of the slack and + twisting in the drivetrain when you are on the throttle. By releasing the throttle, the loading up is reversed through the entire drivetrain (transmission gears, differential gears, mounts, driveshaft, axles, etc.) as your engine then becomes a brake and is just generating compressed air. Harder mounts will reduce the amount of travel but will increase the sharpness. Softer mounts will increase the travel and have less of a sharp hit between on-off throttle.

In the lower gears, your engine is doing more braking due to the ratio than in the higher gears.

edit: or I am just full of ****.

 

It's all the slop in the drivetrain. If you ever get under the car, grab the driveshaft and rotate it back and forth, it can move about 15-20 degrees back and forth before the gears engage in the rear differential and t-case/trans. At least on my car it can, and there isn't anything broke or messed up in my car either.

 

Thanks for the all the feedback, sounds like what I am experiencing is partially normal and partially tired stock rubber mounts. I think I will try this (see link) first, and move to replacing the other mounts if I am not satisfied.

https://www.evolutionm.net/forums/ev...t-install.html

I currently daily drive mine and I don't really want to have the fillings rattled out of my teeth while the car idles, (somewhat rough idle, which I have been reading is normal)

My idle is stable at 750, albeit a bit on the rough side. I have cleaned the maf, checked all my hoses and connections, changed spark plugs, gapped them to .028 (.028 - .031 is factory spec correct?), and I also cleaned my IAC, however I cleaned it in the dark so I will likely pull it off and re clean it again soon.

Long story short, step one is to remove drive train slop, if I need to go harder mounts all around so be it, and then I will go from there. Step two, (haven't quite gotten there yet)

 

I've replaced my front motor mount and rear diff/moustache bar bushings. Still quite a bit of slack left in the drivetrain but it's a bit better, it only slightly increased the noise and vibes in the cabin. I am looking to install some driveshaft carrier bushings after the first of the year to see if that helps anymore.

 

which front motor mount did you use, and what durometer bushings?