I just replaced my generic $15 el-snappo tranny mount with a Prothane polyurethane mount, and I've noticed a loss in performance. Before the swap, I was running with a snapped, plastic, recycled bubblegum aluminum wrapper and plastic tranny mount, and acceleration was fairly decent for being a 305 LG4, but after replacing it with the Prothane, I noticed a big difference, reduction, in performance...

With my old, snapped tranny mount, it would shift down instantly and accelerate with all it's might. With the new tranny mount, the car shakes and vibrates for a second or two, then shoots out. Did I mount this puppy wrong? Psychologically, I feel better not hearing/feeling the tranny poking through the floorboard every time I shift hard, but the loss in performance is getting to me...

Any advice?

 

The smoother the car the slower it feels. The only way to really tell is by measuring the time it takes to cover a distance. But the tanny mount should have no effect on power. But if the added height of the poly trans mount is now causing the exhaust to rub against something and therefore causing a false knock, the ECM could then retard the timing and kill the power.....but that is a remote posisbility and I would lean to the smoother feels slower theory.

 

You were feeling an abrupt slam of the nose raising with the broken mount because TQarm could drop between shifts then rotate hard upward and abruptly hit the floorboard stooping the upward rotaation of the rear axle and giving the sense that the car hard more umph to the rear tires than it does.

In otherwords, you were tearing the sh*t out of your car to get a cheap thrill. Its a slingshot effect that only feels like you hard more speed when it as actually no different. Its the same feeling as if you were to double clutch the car by raising the rpms and dropping the clutch in the same gear. It'll hit you for a second but really is only trying to catch back up to if you had just left it engaged in the first place.

If you tranny mount were not broken to begin with, the TQarm would never had dropped behind and had to catch back up.

 

Yes, I have been abusing and neglecting my car for some time now. I'm not proud of it, but it's a good argument for the reliability and durability of our cars.
It has, by far, been the most reliable car I've ever had. It's been my daily driver for 5 years now, and it has never left me standing...


As far as the tranny mount, James and you probably nailed it right on the head there. It never occurred to me that it can feel slower when everything is operating properly (and things aren't shaking around causing a distraction).

 

Update:

I must have been looking for something that wasn't there... I have purposely been pushing my car, testing the acceleration at different RPM's, speeds and gears to see if I really had a problem with excessive vibrations and performance loss.

After a few more days of testing, I can tell you that my bird is performing better than ever! The new tranny mount, new tires, and brake pads, all of which are higher quality parts than those used before, have made a huge, huge difference in performance. I have a new found respect for my bird, and I can only imagine what you guys and gals feel for your cars with all the go fast (and stop fast) goodies that you have...

 

'ats the ticket, take care of her, she'll be a classic soon. Its alright to drive something fast when its mechanically sound, just know that worn or broken parts and can lead to other worse problems