AWE tuning Drivetrain Stabilizer
My next chassis mod on the A4 is what is commonly called a DTS or a drivetrain stabilizer. The craftsmanship of this piece is simply beautiful. Sold by AWE tuning and Autospeed it connects the two sides of the unit body together under the transmission. It acts as a structural brace, then from the middle of the bar it bolts to the transmission via a rubber mount. This acts as third transmission mount triangulating the two stock mounts. Also due to its orientation it helps eliminate fore aft movement along with the engine snub mount and the rear differential mounts.
I bought my DTS used and spent an hour cleaning it top to bottom.
The DTS uses a GM transmission mount so you can replace the rubber one that comes with it with a polyurethane unit. The cheapest place to get them is from the Summit Racing web store, 30$ w/ s+h.
The installation instructions from AWE can be had from their website, it lists the bolt sizes in case you need to get new ones. Be sure to get grade 8 ASE or 10.9 metric at least.
GM polyurethane transmission mount part numbers:
- Energy Suspension:
- ENS-3-1108G
- Prothane:
- PTP-7-1604-BL
Handling both of the mounts the Prothane mount is obviously more solid. It should have come with that mount. The one that comes with the bar has huge cutouts that go deep into the mount and the solid part inside is very very soft.
The machining is beautiful.
This.. this is how things should be...
Assembly and installation
Installing the DTS is not at all difficult. There are a few things of note that I'll detail here in case it may be of use to you. The first issue I ran into was that the Prothane mounts take a different sized bolt than the ones that comes with the bar. The write up where I got the idea mentioned this but I couldn't find it as I was leaving to do the install. Get those first of course. You may also want to open up the inner holes, on the bar, for that mount just a hair. The holes on the prothane mount are set just a bit wider than the holes in the bar, a file should do the trick.
Bar to mount bolts for the Prothane mount:
- (2) Hex key 7/16 - 14 (3/4" length)
The second issue was that the subframe bolts that you need to take out are supposed to be used only once and should be replaced with new bolts from the dealer, at least for the really long ones. I believe that ECS does sell them but they don't list part #'s. Also if you're taking that loose you could theoretically fill the subframe mount with goo while its still on the car. I haven't tried it but I think its thick enough to keep from dripping out.
That bolt is part number: (#'s for the 97 A4 1.8t Q)
- N 908 235 01
and the smaller 4 bolts:
- +N 019 530 3
The third issue was that one of the small bolts on the passenger side stripped out as I had the torque wrench on it. I had to drill it out with an 11/32 drill and tap it to the next size up from the stock 8x1.25 to a 10x1.25. Getting the car high enough to fit my massive drill wasn't easy. Be very careful torquing those bolts.
First impressions:
I didn't have the right bolts for the mount-to-brace connection when I first installed the DTS so at first it was only acting as a brace. As a brace I noticed increases in drivetrain and suspension noise and, along with that, a reduced amount of rattles and such. Personally I'd rather hear the gears than squeaks and rattles. The car does feel a bit stiffer but I've already got an S4/A6 shock tower bar so it probably isn't as pronounced as it would be if I didn't.
After driving with it for a while it does indeed make a big difference in tightening things up. Less so I think for me though since I've fixed the real problem, the other drivetrain mounts. The gear whine that the bar has made audible in first and second sounds lovely. It sounds pleasantly racecar without being overly obtrusive. Is it worth it? Yes, but only after you replace the mounts.