So after 3 long weeks, I finally got my car back from the shop. As some of you may have read, my drive shaft split in half and my VAC street-style aluminum differential cover shredded at the ear mount.
Let's start with replacement parts:
Current suspension/drivetrain mods:
Settings used during testing:
Defiv Quick Review
The questions on everyone's mind is does it fix the wheel hop? My answer to this question is "it depends". There are many factors to induce wheel hop. Let's list them below:
I took the car out around 6 a.m., the temperature was around 30 degrees F. I drove around normally in an open flat road until I got to 170 in the oil temp gauge then I proceeded with the following:
After that, I did the same tests around 2 p.m. when the temperature was around 60 degrees F. Again, I got my oil temps above 170 and did the same set of tests earlier on the same road:
So yeah 30 degrees makes a big difference on launching. If Rick put the kit on my car as a free "test" and had me decide to pay after trying it out with the same results as I did above, I would still pay him to keep it on my car.
How does it feel? Any noise, vibration, harshness (NVH)?
One thing I noticed is I hear a slight high pitched whine when I'm not on the throttle, more noticeable on the freeway than street. The source of this sound is from the rear which I'm assuming at this time is the Quaife differential running through the metal bushings. There are no vibrations I can attribute to this but the rear feels considerably more planted and solid.
Also, launching can be further improved by raising the rear a bit as its lowered enough to not have any gaps. It's not super tucked in but there is no gaps at all in the rear. The front has a 1 finger gap between the fender.
VAC Resolution
Just FYI, I emailed Mike@VAC and explained him the situation with the VAC differential cover. The shop that worked on my car noticed that the RACE vs STREET versions of this cover has noticeable thickness difference in the ear area. I had the street version.
What I asked Mike was a refund to the VAC cover, replacement of the drive shaft and pay half of the labor which was 8 hours total. What I got back was just a refund to the VAC cover stating that there is no absolute proof that the cover failed first. So that's that. I wished VAC would've at least covered half to cover the price of the drive shaft and labor.
That's all I have. Just glad to have the car back.
Let's start with replacement parts:
- Brand new OEM differential cover (PN: 33 11 7 518 412)
- Drive shaft lock nut kit (PN: 26 11 7 567 770)
- Defiv lockdown kit
- M14x1.5x133mm bolt to replace the stock "short" 120mm (PN: 33 31 1 092 591)
- Gear oil
- Sealant
- Rogue Engineering transmission mounts - might as well!
Current suspension/drivetrain mods:
- Bilstein PSS9 Coilovers
- Full M3 suspension except the Rear Lower Camber Link
- Megan Toe arms
- Quaife LSD
- HPF Stage 2 Clutch
- Pilot Super Sports (235/35/19F and 275/30/19R)
Settings used during testing:
- Front tire: 36 PSI cold
- Front strut: 7/9 (9 is softest)
- Rear tire: 34 PSI cold
- Rear strut: 6/9 (9 is softest)
Defiv Quick Review
The questions on everyone's mind is does it fix the wheel hop? My answer to this question is "it depends". There are many factors to induce wheel hop. Let's list them below:
- Launching on first gear
- Dropping on second gear
- Temperature
- Tire pressure
- Coilover settings
- Pavement
I took the car out around 6 a.m., the temperature was around 30 degrees F. I drove around normally in an open flat road until I got to 170 in the oil temp gauge then I proceeded with the following:
- First gear "soft" launch - dropped the clutch around 2.5K RPM, slight and short wheel hop, the tires eventually hook but there are vibrations in the rear
- First gear "hard" launch - dropped the clutch around 4K RPM, slight and long wheel hop
- Second gear drop - no wheel hop but no traction either due to the cold
After that, I did the same tests around 2 p.m. when the temperature was around 60 degrees F. Again, I got my oil temps above 170 and did the same set of tests earlier on the same road:
- First gear "soft" launch - no wheel hop, lots of grip through 1st and 2nd
- First gear "hard" launch - very slight and short wheel hop
- Second gear drop - no wheel hop and lots of traction
So yeah 30 degrees makes a big difference on launching. If Rick put the kit on my car as a free "test" and had me decide to pay after trying it out with the same results as I did above, I would still pay him to keep it on my car.
How does it feel? Any noise, vibration, harshness (NVH)?
One thing I noticed is I hear a slight high pitched whine when I'm not on the throttle, more noticeable on the freeway than street. The source of this sound is from the rear which I'm assuming at this time is the Quaife differential running through the metal bushings. There are no vibrations I can attribute to this but the rear feels considerably more planted and solid.
Also, launching can be further improved by raising the rear a bit as its lowered enough to not have any gaps. It's not super tucked in but there is no gaps at all in the rear. The front has a 1 finger gap between the fender.
VAC Resolution
Just FYI, I emailed Mike@VAC and explained him the situation with the VAC differential cover. The shop that worked on my car noticed that the RACE vs STREET versions of this cover has noticeable thickness difference in the ear area. I had the street version.
What I asked Mike was a refund to the VAC cover, replacement of the drive shaft and pay half of the labor which was 8 hours total. What I got back was just a refund to the VAC cover stating that there is no absolute proof that the cover failed first. So that's that. I wished VAC would've at least covered half to cover the price of the drive shaft and labor.
That's all I have. Just glad to have the car back.