GTI vs Golf R on track

[theclutch]

Fwiw, here is a video of me chasing a fellow instructor up at Thunderhill East last January. He was driving a project car for the shop we both use. It's a GTI with an IS38 and running a downpipe, so he had a bit of a power advantage on my APR stage 1 high torque car. We are both on Ohlins, both have Stoptech 4-pot brakes, a Wavetrac, and a thicker rear sway, so very similarly modded cars. I was on 255/35R18 Dunlop ZIII tires while he was running 245/40R18 Hankook R-S4s. His car has a 200 pound weight advantage and a 40+hp power advantage, but he was consistently spinning his wheels if he wasn't very careful with the throttle.

Tell me if you agree with my observations. It seems that he definitely had a faster car. It seems that you were catching up only because you were out-braking him. His exit speed appears to be faster. But I couldn't really tell if he was cornering faster on entry/mid corner because he going in so slow in every corner.

So the GTI was running a Wavetrac and it was still spinning the inside wheel? I wonder why. You said you also installed a Wavetrac on your Golf R. I assume this is installed to replace the front open diff? And the rear diff is still an open diff? If you hadn't added the Wavetrac, how would it have handled on the track? I don't see myself spending to add a Wavetrac. I would either get the GTI with the VAQ or the Golf R and leave it as is except for doing Stage 1+ for either cars (so I say that now).

Since I already have a Protuned Stg2 Mk6 GTI, I was more inclined to get the Golf R for something "different".

The reason why I would go to the 7.5 GTI:

1. Newer infotainment screen (I just realized the GTI doesn't have a full LED dash like the Golf R)
2. Bigger brakes - I don't see myself ever spending on a BBK
3. DCC adjustable suspension - I would otherwise have to spend $2000 on adjustable STA coilovers for my Mk6
4. Is my perception that since it's lighter, it would be more agile and more fun everyday just like my current GTI
5. VAQ diff

I would go with the 7.5 Golf R:

1. Newer infotainment screen and LED dash
2. Bigger brakes - I don't see myself ever spending on a BBK
3. DCC adjustable suspension - I would otherwise have to spend $2000 on adjustable STA coilovers for my Mk6
4. Since it would be more different from what I have now
5. The higher HP potential and the much faster 0 to 60 and quarter mile times

With the DSG on both cars, it appears that the Golf R is 245 lbs HEAVIER than the GTI (3373 vs 3128 curb weights). That's a lot of weight. I recall 20 years ago that I didn't "upgrade" to the E46 M3 from my E36 M3 since it was around 250 lbs heavier.

I should just buy both cars for an extended test drive and get rid of the one I don't want!!!

 

[theclutch]

Does anyone here have data of using XDS on track? Or is it better to keep it all the way off

Of all the videos and threads I've read on this, unfortunately NO ONE has actually timed themselves with a before/after. Some say keep it off since it could overheat the brakes dependent on the track. On track, some say keep it on if you already have an LSD and keep it off without. But again, no one has times to prove either way...

 

[Andrewbens]

Of all the videos and threads I've read on this, unfortunately NO ONE has actually timed themselves with a before/after. Some say keep it off since it could overheat the brakes dependent on the track. On track, some say keep it on if you already have an LSD and keep it off without. But again, no one has times to prove either way...

other thing I’ve seen with xds if you have a long track day the red paint melts on the caliper so it’s better to keep it off.

 

[Cliff]

Tell me if you agree with my observations. It seems that he definitely had a faster car. It seems that you were catching up only because you were out-braking him. His exit speed appears to be faster. But I couldn't really tell if he was cornering faster on entry/mid corner because he going in so slow in every corner.

So the GTI was running a Wavetrac and it was still spinning the inside wheel? I wonder why. You said you also installed a Wavetrac on your Golf R. I assume this is installed to replace the front open diff? And the rear diff is still an open diff? If you hadn't added the Wavetrac, how would it have handled on the track?

He was walking me on the straights, but other than that we were closely matched. I was probably doing a better job of trail braking than he was. The Wavetrac tempers the car's tendency to understeer on-throttle, as does the UM Haldex tune, allowing me to transition to full throttle sooner.

 

[jay745]

Does anyone here have data of using XDS on track? Or is it better to keep it all the way off

I'd keep it off, it overheats the brakes. I try to take the temp on my brakes at least once every track day when I come off just to see where I'm at and if anything is sticking. I measured a friends mk6 who had XDS set to the hard setting (2 for mk6) and his right rear caliper was almost 100 degrees hotter than the left.

 

[theclutch]

I'd keep it off, it overheats the brakes. I try to take the temp on my brakes at least once every track day when I come off just to see where I'm at and if anything is sticking. I measured a friends mk6 who had XDS set to the hard setting (2 for mk6) and his right rear caliper was almost 100 degrees hotter than the left.

The XDS brakes the rears and not the fronts? Or it does both?

 

[jay745]

The XDS brakes the rears and not the fronts? Or it does both?

Actually come to think of it, that was probably stability control since it was the rears. Turn that off too though lol

 

[MrFancypants]

Does anyone here have data of using XDS on track? Or is it better to keep it all the way off

I’m apparently the oddball here, but I love XDS, especially on the track. I’m at the stock ~220 bhp though, so I’m sure it’s usefulness decreases as horsepower goes up. I’m running 1:50.X at Road Atlanta and I have zero traction issues anywhere and no problems with brake fade.

If you’re at or over 300 bhp your equation is a bit different.

 

[MrFancypants]

The XDS brakes the rears and not the fronts? Or it does both?

Fronts only. If you’re smooth on throttle application you can feel the front inside brake caliper doing its work. If you‘re ham fisted on the throttle you’ll feel the front inside spin up. Getting the most out of XDS is definitely a skill.

 

[Gvazquez]

Idk this whole xds thing sounds subjective. I didn't know it only did the front either. I wonder how its dynamics change when you have a BBK. I guess I would rather understeer than cook the brakes up.

 

[GTIfan99]

I could have bought either, but chose GTI to build street/ track car. Lighter, which translates to less consumables, awd doesn't really help much, especially a haldex based system, and if I ball up a 26,000 dollar car, it sucks, if I ball up a 40k car, it sucks morer.

 

[MrFancypants]

Idk this whole xds thing sounds subjective. I didn't know it only did the front either. I wonder how its dynamics change when you have a BBK. I guess I would rather understeer than cook the brakes up.

A BBK should make it more effective. Larger diameter rotors increase potential braking power, so they can deal with more horsepower.

I can appreciate why people don’t like XDS. If you’ve tuned your car and your software doesn’t have a linear throttle map it can be difficult to modulate the throttle as precisely as you need to to get XDS to work properly. Another issue with XDS is that it doesn’t give the driver a lot of feedback; you kind of have to try to feel it out through the seat of your pants, looking for a combination of the feeling of the inside front tire gripping and braking while the nose of the car kind of gets pulled in the direction you’re steering it.

A mechanical limited slip is definitely a lot more predictable and easy to use, and offers much better feedback.

 

[GTIfan99]

Idk this whole xds thing sounds subjective. I didn't know it only did the front either. I wonder how its dynamics change when you have a BBK. I guess I would rather understeer than cook the brakes up.

I own both a non-PP and a PP mk7 GTI. XDS only cooks the brakes of the non-PP car. PP cars with VAQ don't have the same issue with XDS cooking the brakes. XDS appears to fill the gap in delay of the VAQ and they work very well together.

 

[GTIfan99]

A BBK should make it more effective. Larger diameter rotors increase potential braking power, so they can deal with more horsepower.

I can appreciate why people don’t like XDS. If you’ve tuned your car and your software doesn’t have a linear throttle map it can be difficult to modulate the throttle as precisely as you need to to get XDS to work properly. Another issue with XDS is that it doesn’t give the driver a lot of feedback; you kind of have to try to feel it out through the seat of your pants, looking for a combination of the feeling of the inside front tire gripping and braking while the nose of the car kind of gets pulled in the direction you’re steering it.

A mechanical limited slip is definitely a lot more predictable and easy to use, and offers much better feedback.

I think you're using XDS and VAQ synonymously. They aren't the same thing.

Some mk7's have VAQ, a haldex based LSD, and all mk7's have XDS, a brake based ediff.

 

[MrFancypants]

I think you're using XDS and VAQ synonymously. They aren't the same thing.

Some mk7's have VAQ, a haldex based LSD, and all mk7's have XDS, a brake based ediff.

I’m not talking about VAQ at all, only XDS.