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My Motor and Transmission Mount Saga

742 Views 15 Replies 5 Participants Last post by  Olszewski
Today I spent all day working on my 23 GT 6spd. Since installing the Racechip GTS last year I have been fighting excessive traction and wheel hop issues in 1st and 2nd gear. The first thing I did was install Whiteline lower trans mount inserts KDT970 KDT970 Trans mount insert – Whiteline USA ( They worked good but the shake at idle was more than I wanted. I then bought Powerflex Yellow PFF26-120 Hyundai Veloster N, I30N, ELANTRA N (2017+) Engine Lower Torque Arm Bushings | PowerflexUSA but I decided to try something different. I put Whiteline insert in the rear spot and installed the Powerflex yellow in the front position. The vibration at idle is gone and there is no wheel hop at the moment but that also could be the new 235/45/17 Continental DWS06 vs the 225/40/18 Michelin PS4, I changed the upper motor mount insert and the tires at the same time.
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Powerflex yellow is the way to go all around for balance between engine movement and NVH (remember it's worse with the AC on in the summer), although messing with lower bushing is kind of pointless once you find something with the NVH you want - you'll really notice a big difference after installing the upper bushing inserts. I spent way too much time and money trying to find the best combo of NVH and engine response and I've finally found it. Powerflex yellow lower bushing (both sides), upper engine bushing insert PFF26-125 and upper transmission mount insert PFF26-123 are the ticket.

I can now launch the car on any surface with no wheel hop to speak of, grab gears as fast as I want, and drive smoothly in stop and go traffic, all with no wheel hop or engine movement.

Turns out with just a poly lower mount, the upper mount can and will still move over an inch and a half. I could grab the hook for the engine crane and move it like 1/2" with just my hand.

Edit - looks like I got to it before you could finish typing - disregard this post
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Today I also installed the Powerflex upper engine mount PFF26-125 Hyundai Veloster Upper Engine Mount Insert | PowerflexUSA. This was easy and works perfect, with no additional vibration.

The upper transmission mount PFF26-123 Hyundai Veloster Transmission Mount Insert | PowerflexUSA was another story. I installed it and had odd noises under hard acceleration in 1st and 2nd gear. I was not sure if it was the new BOV but once I realized it was in fact the upper trans mount I remember it needed to be ground down a little because it hits the mount. Well after removing the steel plate 3 times and grinding almost an 1/8 inch off the side that was hitting I gave up. I test drove it after each attempt, but I swear it got worse the more I took off. I decided to just remove the upper trans mount insert and everything was perfect again. The lower trans inserts and the upper engine mount do a great job and don't add any extra vibrations. I will just keep it like this for now.

It is hard to tell but it looks like the right side is almost touching from top to bottom in this pic.
View attachment 91522
Make sure to pull some material off the back corners too. Both my car and Hamster-GT's car had this issue. I ground 1/8" off the corners and 1/16" off the side and that did the trick, though my FE is making far less power than your GT surely is.
All the advertisements show the black cylinder piece, mine didn’t come with it. Plus every powerflex item I have ever purchased has come in black. I don’t believe all these other pretty colors exist. View attachment 92591
Mine was yellow and came with the black piece to distribute the load. Yours being black, it hides. It’s there in your pictures
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