Robr

I took the S3 to an autocross event a couple of weekends back. I won't go into comparison to my previous vehicles as it would be apples and oranges. It was a lot of fun, but the understeer was a real issue. When I first bought the car, I had read that it was possible for the haldex system (starting with the 2017 model) to transfer 100% of power to the rear wheels. I later learned this was marketing speak and there is almost never a circumstance where this is possible. It was extremely evident on the autocross course. Does the RS3 have the same haldex system? Any recommendations on how to improve the understeer on the S3?

ducrider61

jaegerlc

I'm using the reverse staggered tires from an RS3 (255/30 front, 235/35 rear) -- supposed to address the issue. I am not enough of a driver to say one way or the other.

uniqueMR

Glad to hear

SteveO987

Here's the problem with the "transfer 100% of power to the rear wheels" statement:
I had an MK6 Golf R. They made the same type of claims about sending "100% power" to the rear wheels. The caveat was that the transmission would only ever transfer UP TO 50% of the power going through it to the rear wheels at any given time. So the statement was more like, "transfer 100% of 50% of the available power to the rear".

Sure it was transferring 100% power but it was not 100% of engine output.

As for auto-crossing and understeer:
I took the RS3 to an auto-cross with mild expectations. I'm very familiar with how the Haldex equipped cars handle. I was pleasantly surprised by how well the car behaved when being pushed through hard corners and the slalom.
I was running the reverse stagger wheels with stock Pirelli tires and the RS fixed suspension. Zero issues with understeer when running the car through the course.

I'd recommend playing around with tire pressures first to see if that helps with your understeer (it's the easiest and cheapest option). You can always try borrowing some different wheels / tires to see if that helps as well.

whitby

Sad. My old RS4 had a proper rear bias AWD.
Now Audis seems to be going to FWD with the ability to send some power to the rear when the front can't handle it

Kurac

Diztek

stiffen the rear sway bar. rear only. that will reduce understeer.

qwijibo

If you are participating in SCCA autocross make sure you check the class rules before making mods. If you are now running Street class, nearly any hardware performance or handling alterations will change you to Street Touring where the competition will be tougher. Other than practice (and remembering to turn the traction control off), one of the best ways I've found to drop time is tires. Switching from OE Continentals to Michelin Pilot 4S made a significant difference in getting around while keeping it in Street class. They are pricey, but great all around tires that IMO earn their top reviews on the track and in daily driving.

superswiss

In my personal experience the RS3 isn't any better at least not with the MagRide suspension. The MagRide is actually part of the problem. I have not yet had the opportunity to compare an RS3 with fixed suspension, but I have personal experience with the R8 V10 and the R8 V10 Plus. The former has MagRide and the latter has a fixed suspension. The fixed suspension makes all the difference. Even in the R8, the MagRide kinda sucks. Same for the standard Lambo Huracan. Lambo fixed it in the Performante.

As for the 100% to the rear claim, that is indeed a marketing spin to make the system sound better. It's not wrong, but you have to understand what it is referring to. It's what's known as traction based torque distribution. AWD systems in principle are designed to send the torque where the traction is. This is simple physics. With the Haldex clutch fully locked and 100% traction all around, each wheel gets 25% of torque. Now if the front wheels start losing grip, more torque automatically flows to the rear as long as they have grip and 100% will flow to the rear if the front wheels have 0% grip. In order to send more torque to the rear, you have to shift the weight to the rear to unload the front wheels. For example during hard acceleration the system will indeed send more torque to the rear, because the rear tires naturally have more traction at that point. But if you do that in a corner, then the front wheels will wipe out and the car understeers. So in order to induce oversteer and rotate the car you have to do the opposite. Lift off the throttle to make the tail light and rotate before getting back on the throttle. You basically wanna dive into the corner, then trail brake to rotate and once you are past the apex get back on the throttle to let the car pull you out.

In contrast, the quattro system in the RS4 and higher, mechanically forces 60% of the engine torque to the rear under normal conditions. It does this via different sized gears in the center differential. So with a 100% grip all around 60% goes to the rear and 40% goes to the front. The system then deviates from this default torque split based on traction and can even control the split around corners using the brake based torque vectoring system. While cornering, the inner wheels receive a braking torque to induce a yaw moment and by proportioning how much the front inner wheel vs the rear inner wheel is slowed down the system can indirectly influence the torque split of the center differential and unless the rear wheels don't have grip it's always rear biased. The difference is very noticeable compared to the Haldex system. In addition the RS model with this system also have the active torque vectoring rear differential adding yet another level of RWD dynamics, and you can even powerslide if you are skilled enough. I take my RS5 sideways regularly for example.

The main noticeable difference between the systems is that the Haldex pulls the car around the corner while the torsen/crown gear system pushes it around the corner like RWD.

Audi's transverse platforms have always been FWD-biased Haldex systems. The longitudinal platform cars still have the rear biased quattro system, except for the Ultra models with Quattro Ultra, but that system is designed to save fuel and not to be fun.