MrConflicted
Passed Driver's Ed
- Location
- Salt Lake City, UT
Hello all, many of you may have already seen this review on GTIreview.com, but since that site has intermittent issues, I wanted to go ahead and copy the review of there.
...
So for whatever reason, you’re here reading about one of most expensive modifications you can do to a GTI without adding any horsepower. Crazy, right? Well, maybe not. It turns out that the mechanical LSD (Limited Slip Differential) from WaveTrac may just be one of the single best mods you can possible do for your GTI. I personally drive a non-PP (performance pack) car, which like all front-wheel drive cars, has the notorious problem of under-steering. While you can help reduce this issue with springs, shocks and sway bars, the problem is inherent with FWD cars irregardless. As you try to accelerate, weight transfers off the front wheels, further reducing the traction of the wheels delivering power. This is further worsened when you have an open differential like the one that is OEM in the non-PP GTI.
The WaveTrac differential is a helical limited slip unit. Essentially, the gearing units prevent either wheel from moving much faster than the opposite. This means as power is applied, both sides of the axle are “locked” together, though in reality some difference in speed is allowed. The helical-type limit slip units are usually regarded as the middle of the line, working substantially better than “viscous” LSD’s, but not as good as “clutch-type” LSD’s. The reason for this is the gearing mechanisms’ performance is not reduced by heat, unlike the “viscous” style LSD’s, but fails when a single wheel loses all traction, unlike a clutch-type LSD. WaveTrac claims to have solved this inherent issues by implementing their “wave” gear design. But enough with the nerdy details, on to the review:
Upon normal driving of the car, I noticed no downsides to the LSD. No additional noise, no change in MPG, and no change in torque steer under normal conditions. However, if you are as hypersensitive as I am, you’ll notice the steering feels a tad bit more weighted as you steer, indicating the presence of the limited-slip. Now, when you start to lay into more, that's when the LSD come's alive.
The real place where this differential shines though, is in the corners. While previously my GTI would push with the application of power, the LSD forces the car to hold its line. It also increases lift off-oversteer, which is already noticeable in my car thanks to a ST Suspension 25mm rear sway bar. It might take you a moment to real-learn the car as when you apply power you’ll actually feel the front end of the car suck into the corner. It's a very mild torque steer feeling, but unlike typical torque steer, always pulls the wheel into the corner. (Typical torque steer is single directional). I can only imagine how much this feeling would be amplified with a more aggressive alignment setting, such as toe-out.
When you do finally lose traction you’ll notice the car doesn’t want to torque steer offline either. It simply feels as if its clawing at the pavement, with both tires, pulling the car forward. It’s a pretty insane feeling, and much improved over stock. The same type of feeling can be found in a straight line as well. While traction control would still engage in 1st on my stock power GTI, it was obvious the LSD was doing its job. Even when the car does lose traction, it isn’t a total loss. You are clearly still accelerating, and I can’t say the same to be true when 1 wheel is spinning. I'm not IS38 (low boost) and can fully hook 2nd gear with 235 PSS.
So how does this compare to the electronic diff of the performance pack? How can this be better than a torque vectoring unit? To be honest with you, it can, and it is, and here’s my rational: The PP electronic differential works great under IDEAL conditions: A loaded corner, with good pavement. It also works great under proper operating temps. However, the mechanical LSD doesn’t give a shit about pavement quality, operating temps, or constant changes in steering angle, it just wants both wheels spinning at the same speed.
This glory was apparent to me when I took the WaveTrac equipped GTI down canyon road with old, bumpy pavement on a wet day. With the open diff on a dry day the TCS would light up almost every corner, but with the LSD it rarely lit up. Maybe once during the 2 mile stint of “touge” style road did the TCS light ever flash, and not once did I ever really “feel” it intervene. Even more so, it was wet this day! The diff seemed to pull the car out of every corner flawlessly. Performance never dwindled, never diminished, and simply kept asking me to power out harder.
Update: Track Impressions
Having the unit for quite some time now, (almost 20K miles), I've noticed no changes in performance. I've also had the chance to take it on track. The LSD really does wonders out there. Where before I'd watch cars slip away from on corner exits, I can now hold the line and come shooting out. Particularly impressive considering my last track was on 8 year old RE-11s that might as well have been made of stone. I'll go into more detail once I have my next track day with proper slicks
Link to video: https://www.youtube.com/watch?v=jRzKYOA3QsY
(Don't mind my awful driving haha).
Final Thoughts:
This mod was 100% worth it for anyone who likes corners. If you have the means, do it. Track impressions to come, but I’m confident in a 2-3 second reduction in time on a 2.2 mile circuit close to home. If you’re doing this mod for roll racing, this might not be your best investment, but if you do canyon runs, autocross or track days, this mod is a must.
Side Note: Motul 75W-90 Gear Oil I used this gear oil along with my WaveTrac unit, as it’s the only “performance” gear oil supported by WaveTrac. The stock fluid that I removed was as thin as motor oil, but this 75W-90 stuff is thick as molasses at room temperature. This makes for a very notchy transmission when the car is cold. At operating temperature, however, the transmission feels close to stock. While this gear oil has increased the “notchyness” of the transmission, in return you are rewarded with confidence inspiring shifts. My guess is this thicker oil will really shine as the car further heats up on track.
I would like to thank Jess Wilson on the flawless job he did on installing this unit for me. He is an absolute professional. Thanks again for reading my review on the WaveTrac LSD!
...
So for whatever reason, you’re here reading about one of most expensive modifications you can do to a GTI without adding any horsepower. Crazy, right? Well, maybe not. It turns out that the mechanical LSD (Limited Slip Differential) from WaveTrac may just be one of the single best mods you can possible do for your GTI. I personally drive a non-PP (performance pack) car, which like all front-wheel drive cars, has the notorious problem of under-steering. While you can help reduce this issue with springs, shocks and sway bars, the problem is inherent with FWD cars irregardless. As you try to accelerate, weight transfers off the front wheels, further reducing the traction of the wheels delivering power. This is further worsened when you have an open differential like the one that is OEM in the non-PP GTI.
The WaveTrac differential is a helical limited slip unit. Essentially, the gearing units prevent either wheel from moving much faster than the opposite. This means as power is applied, both sides of the axle are “locked” together, though in reality some difference in speed is allowed. The helical-type limit slip units are usually regarded as the middle of the line, working substantially better than “viscous” LSD’s, but not as good as “clutch-type” LSD’s. The reason for this is the gearing mechanisms’ performance is not reduced by heat, unlike the “viscous” style LSD’s, but fails when a single wheel loses all traction, unlike a clutch-type LSD. WaveTrac claims to have solved this inherent issues by implementing their “wave” gear design. But enough with the nerdy details, on to the review:
Upon normal driving of the car, I noticed no downsides to the LSD. No additional noise, no change in MPG, and no change in torque steer under normal conditions. However, if you are as hypersensitive as I am, you’ll notice the steering feels a tad bit more weighted as you steer, indicating the presence of the limited-slip. Now, when you start to lay into more, that's when the LSD come's alive.
The real place where this differential shines though, is in the corners. While previously my GTI would push with the application of power, the LSD forces the car to hold its line. It also increases lift off-oversteer, which is already noticeable in my car thanks to a ST Suspension 25mm rear sway bar. It might take you a moment to real-learn the car as when you apply power you’ll actually feel the front end of the car suck into the corner. It's a very mild torque steer feeling, but unlike typical torque steer, always pulls the wheel into the corner. (Typical torque steer is single directional). I can only imagine how much this feeling would be amplified with a more aggressive alignment setting, such as toe-out.
When you do finally lose traction you’ll notice the car doesn’t want to torque steer offline either. It simply feels as if its clawing at the pavement, with both tires, pulling the car forward. It’s a pretty insane feeling, and much improved over stock. The same type of feeling can be found in a straight line as well. While traction control would still engage in 1st on my stock power GTI, it was obvious the LSD was doing its job. Even when the car does lose traction, it isn’t a total loss. You are clearly still accelerating, and I can’t say the same to be true when 1 wheel is spinning. I'm not IS38 (low boost) and can fully hook 2nd gear with 235 PSS.
So how does this compare to the electronic diff of the performance pack? How can this be better than a torque vectoring unit? To be honest with you, it can, and it is, and here’s my rational: The PP electronic differential works great under IDEAL conditions: A loaded corner, with good pavement. It also works great under proper operating temps. However, the mechanical LSD doesn’t give a shit about pavement quality, operating temps, or constant changes in steering angle, it just wants both wheels spinning at the same speed.
This glory was apparent to me when I took the WaveTrac equipped GTI down canyon road with old, bumpy pavement on a wet day. With the open diff on a dry day the TCS would light up almost every corner, but with the LSD it rarely lit up. Maybe once during the 2 mile stint of “touge” style road did the TCS light ever flash, and not once did I ever really “feel” it intervene. Even more so, it was wet this day! The diff seemed to pull the car out of every corner flawlessly. Performance never dwindled, never diminished, and simply kept asking me to power out harder.
Update: Track Impressions
Having the unit for quite some time now, (almost 20K miles), I've noticed no changes in performance. I've also had the chance to take it on track. The LSD really does wonders out there. Where before I'd watch cars slip away from on corner exits, I can now hold the line and come shooting out. Particularly impressive considering my last track was on 8 year old RE-11s that might as well have been made of stone. I'll go into more detail once I have my next track day with proper slicks
Link to video: https://www.youtube.com/watch?v=jRzKYOA3QsY
(Don't mind my awful driving haha).
Final Thoughts:
This mod was 100% worth it for anyone who likes corners. If you have the means, do it. Track impressions to come, but I’m confident in a 2-3 second reduction in time on a 2.2 mile circuit close to home. If you’re doing this mod for roll racing, this might not be your best investment, but if you do canyon runs, autocross or track days, this mod is a must.
Side Note: Motul 75W-90 Gear Oil I used this gear oil along with my WaveTrac unit, as it’s the only “performance” gear oil supported by WaveTrac. The stock fluid that I removed was as thin as motor oil, but this 75W-90 stuff is thick as molasses at room temperature. This makes for a very notchy transmission when the car is cold. At operating temperature, however, the transmission feels close to stock. While this gear oil has increased the “notchyness” of the transmission, in return you are rewarded with confidence inspiring shifts. My guess is this thicker oil will really shine as the car further heats up on track.
I would like to thank Jess Wilson on the flawless job he did on installing this unit for me. He is an absolute professional. Thanks again for reading my review on the WaveTrac LSD!