Talk to me about lowering our cars for DE/track events

victorofhavoc said:

I disagree. I believe the bushing tolerances allow for the vehicle to be lower by a little. Enough to make a pretty substantial difference on track. Not enough to call it "hellaflush" or "slammed" or whatever the kids are calling it now. I strongly disagree on the stiffer comment. When done well, a car can roll and have great handling characteristics (miata is a perfect example), but it's certainly not true that a stiffer car is harder to drive at the limit. You're more likely to be moving faster and more likely to have a faster let-go when making mistakes, but the vehicle should feel more consistent and respond to correction faster, so it should be easier to drive...provided you understand the dynamics of the vehicle and don't have variable spring rates.




Bingo! Valving and spring pair are very important. The DCC shocks are supposed to adjust to some extent with a different spring, but in my experience so far, the DCC shocks just can't keep up. Your points on weight transfer and seat time are all spot on as well. If you lower this car within the spec of the bushings (I think as far down as the GTI CSS is plenty safe) by choosing a properly mated spring/shock the car will absolutely perform better than stock height. The key though, is another one of your comments on suspension travel. A lower vehicle doesn't have to have a shorter suspension travel on the right spring/shock setup.

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as far down as the GTI CSS = only about 20mm more

Interesting. What "coil overs" are you running with stock springs?

Godspeed!
Dave

Great conversation here!

Regarding ride height sensitivity, i have a few questions... please forgive my ignorance!

1) What is Euro spec ride height in comparison to what we get in USA?
2) Is Euro spec ride height achieved with different parts than USA cars get?
3) Is Euro spec alignment different from USA spec alignment?

replicate said:

as far down as the GTI CSS = only about 20mm more

Click to expand...

True. There's some variance between individual cars; my DCC Autobahn when stock was about 5-10mm lower than the 2017 gti sport it was sitting next to. Coincidentally I met two guys with 2017 gti sports who were parked next to each other, both stock, and one was very visibly lower than the other.

20-25mm may not seem like much, but that's about an inch lower. For suspensions, that is a lot, and it can very drastically change handling characteristics. There's also the big drag reduction from reducing the wheel well gap. So if you drop by 25mm and come close to reducing the wheel well gap to nothing, you gain approximately .01 drag coefficient reduction. You also have to compensate for reduced travel (if on stock dampers) by using stiffer springs, and stiffer helps a ton with weight transfer and putting power down when coming out of a corner.

Based on that, it would seem lower is even better, right? In some circumstances yes, but in most, no. All the bushings and angles of the dynamic and static parts are designed to work within a specific height range, with tolerance from the bushings being soft and inconsistency in the manufacturing process.

At the end of the day, these are just cheap econoboxes. They perform reasonably well, but their tolerances are also built in for mass production.

This has been an interesting debate.

The original ask, was whether a GTi should be lowered for the track? I’m assuming by default whether lowering a Mk 7 will improve your lap times?

Seat time, track pads and good brake fluid aside.

Tires will be your biggest handling gain and have the greatest impact on reducing lap times.

Going from the OEM Bridgestone all-season 225-40-18 to a 245-40-18 Michelin PS4S gained me 4.5 seconds around VIR (3.27 miles). Stock car/suspension. At the limit of grip the car pushed badly on both tires. Tire roll ate the outer edge on both tires.

Increased tire grip converts to performance gains everywhere around the track. Braking/acceleration, higher overall corner speed, higher corner exit speed which means higher v-max at the end of straights as you go deeper into brake zones.

SuperPro LCAs, 034 Fixed camber plates and a track alignment with 235-40-18 MPS4S’s was .5 seconds slower. The car definitely felt better, but it was a net zero gain dropping to a 235 wide tire. I was concerned with the 245 tires rubbing with the SuperPro LCA. I had a slight rub with the 245’s on heavy compressions before adding the SuperPro LCA’s.

From personal experience tires can be the biggest gain or loss. I’m looking at dedicated track wheels and NT01’s and reckon I will pick up another 2-seconds.
There is no question that a great set of adjustable coil overs will help reduce lap times once setup correctly.

In the Novice and Lower Intermediate run groups a stock Mk7 can more than hold its own. It becomes a little tougher as you progress up the ranks and everyone’s driving skills improve and you run with the Vettes, 911’s and M3’s. I really enjoy the challenge.

So it essentially boils down to whether you want the car to look cool with a reduced wheel gap or whether you want to run hard and be fast on the track.

And seat time is going to get you there the fastest every time. Then tires, suspension, brakes and power is absolutely last. Takes no skill to mash a peddle in a straight line.

Oh, and I forgot to say that above all else, have fun! If you are not having fun at the track, you’re doing it wrong. Lol

That’s my pennies worth folks.

Mini7 said:

This has been an interesting debate.


And seat time is going to get you there the fastest every time. Then tires, suspension, brakes and power is absolutely last. Takes no skill to mash a peddle in a straight line.

Oh, and I forgot to say that above all else, have fun! If you are not having fun at the track, you’re doing it wrong. Lol

That’s my pennies worth folks.

Click to expand...

Extremely well said. Can't agree more with power last if you want the most out of your car and track experience.

This thread is becoming full of sage advice! I appreciate everyone's contribution.

Fun is of the utmost importance to me too! I don't need the car to be lowered for esthetics, but as I get ready to install my Koni's I was just trying to get a bead on if I was doing myself a disservice by not increasing spring rates while I already have everything apart. At this point, I am going to stick with stock springs till I get to the point of regular/consistent lap times.

Mini7, do you hit the speed limiter at any point around VIR?

Mini7 said:

This has been an interesting debate.

The original ask, was whether a GTi should be lowered for the track? I’m assuming by default whether lowering a Mk 7 will improve your lap times?

Seat time, track pads and good brake fluid aside.

Tires will be your biggest handling gain and have the greatest impact on reducing lap times.

Going from the OEM Bridgestone all-season 225-40-18 to a 245-40-18 Michelin PS4S gained me 4.5 seconds around VIR (3.27 miles). Stock car/suspension. At the limit of grip the car pushed badly on both tires. Tire roll ate the outer edge on both tires.


SuperPro LCAs, 034 Fixed camber plates and a track alignment with 235-40-18 MPS4S’s was .5 seconds slower. The car definitely felt better, but it was a net zero gain dropping to a 235 wide tire. I was concerned with the 245 tires rubbing with the SuperPro LCA. I had a slight rub with the 245’s on heavy compressions before adding the SuperPro LCA’s.

From personal experience tires can be the biggest gain or loss. I’m looking at dedicated track wheels and NT01’s and reckon I will pick up another 2-seconds.

Click to expand...

What alignment spec are you currently running? I gained TONS of time from better alignment specs.

Honestly 245 vs 235 should not have lost you 0.5s. It takes an extraordinary driver to notice the difference between 235 and 245 if it's the same compound. Ambient temp, tire wear, tire heat cycle, and wind conditions can play a massive role in lap times.

I ran Direzza Z3 last year, which like the re71r are a more autocross tire. They were heat cycled out after 2 track days. They're sitting in my basement with more than half the tread life left and they're basically useless on track. Greasy after 10 mins on a cool day.

There are a lot of better tire choices these days than the NT01. Not hating on the Nitto, since they're a pretty solid tire, but you can get more precision and grip out of some more modern tires. I just got some Yoko a052 delivered the other day, and they cost me 143$/tire from tirerack. Great sales for specific sizes for a tire that's in the same class as the trofeo R and sport cup 2. It's not as fast as the two, but at half the cost it's good enough. It's also 200TW rated (which means nothing), so it qualifies for certain race classes as a street tire...

I'll throw in my .2c from ~15 trackdays with a lowered mk7 on several tracks, and someone who's certainly still improving. For background, I'm enjoying feeling pretty quick and having fun in the Intermediate run-groups, and hoping to move to "Advanced" this season and staying stock power. The goal with my setup (Neuspeed Sports w/ Bils B8s) was improved responsiveness while keeping good livability on the street. Can't deny there's some aesthetic improvement too but that's beside the point, hah.

On track it's very well behaved and I can say the goals are achieved. There's less of a delay between feeling the weight transfer and the car taking a set, with no dips or bounces throwing the car off-line to note -- the (pre-repave) dip inside of Summit Point main T9 comes to mind as one I would take with no drama. It feels very well controlled overall. Can easily use the curbs where recommended. Was something I was originally concerned about losing the bump travel and sitting fairly close to the bumpstops, but it's been a non-issue due thanks to the dampers I suspect.

This has all been with "where it ended up" camber in front (~-1.2' , and rear set at -1.5', with zero toe) and 300tw tires. No plans whatsoever to ever change the spring/damper setup, but (finally) more front camber this season.

All that said, I won't doubt a totally stock suspension would have been much more capable than I was, heck probably even now, while being more forgiving. But it's very fun as it sits. I'm expecting really nice results this season how with the front camber and 200tw tires, and to keep it there indefinitely... but the jury will be out until after the first couple sessions when the "rust" falls off .

Some good brake fluid, good tires and race brake pads, e.g. Carbotech XP10. Drive it like you stole it and push it as much as you can. It will be an understeering pig and you need to learn how to deal with it. After some time put some coilovers (leave them as high as you can) with camber plates on and stiff rear bar and enjoy less understeer. After some time add some DOT slicks, e.g. BFG R1 and learn to deal with a much smaller limit. After that move into wheel to wheel racing and figure out a way to get out of this nonsense.

reverend_sean said:

This thread is becoming full of sage advice! I appreciate everyone's contribution.

Fun is of the utmost importance to me too! I don't need the car to be lowered for esthetics, but as I get ready to install my Koni's I was just trying to get a bead on if I was doing myself a disservice by not increasing spring rates while I already have everything apart. At this point, I am going to stick with stock springs till I get to the point of regular/consistent lap times.

Mini7, do you hit the speed limiter at any point around VIR?

Click to expand...

I’ve hit 126-127mph on the back straight. That’s the highest I’ve seen. I don’t believe I’ve hit the speed limiter. Didn’t know our cars were speed limited.

victorofhavoc said:

What alignment spec are you currently running? I gained TONS of time from better alignment specs.

Honestly 245 vs 235 should not have lost you 0.5s. It takes an extraordinary driver to notice the difference between 235 and 245 if it's the same compound. Ambient temp, tire wear, tire heat cycle, and wind conditions can play a massive role in lap times.

I ran Direzza Z3 last year, which like the re71r are a more autocross tire. They were heat cycled out after 2 track days. They're sitting in my basement with more than half the tread life left and they're basically useless on track. Greasy after 10 mins on a cool day.

There are a lot of better tire choices these days than the NT01. Not hating on the Nitto, since they're a pretty solid tire, but you can get more precision and grip out of some more modern tires. I just got some Yoko a052 delivered the other day, and they cost me 143$/tire from tirerack. Great sales for specific sizes for a tire that's in the same class as the trofeo R and sport cup 2. It's not as fast as the two, but at half the cost it's good enough. It's also 200TW rated (which means nothing), so it qualifies for certain race classes as a street tire...

Click to expand...

-2 degrees and zero toe up front. Still needs more camber. And -1.8 in the rear with a smidge toe in.

I looked at my Harry’s LapTimer today and I was actually .8 slower with the 235’s. The stop watch doesn’t lie. The comparison was on the same tire but slightly different section width. Conditions were very similar. The events were two weeks apart. Michelin Pilot Sport 4S. Great rain tire but at 300 TW there are faster tires out there. I’m interested in the 052’s. Heard that they are a good tire. NT01’s give great life and don’t heat cycle out and grip down to the cords. For sure not the grippiest R-Comp but definitely provides good value.

tripleS said:

I'll throw in my .2c from ~15 trackdays with a lowered mk7 on several tracks, and someone who's certainly still improving. For background, I'm enjoying feeling pretty quick and having fun in the Intermediate run-groups, and hoping to move to "Advanced" this season and staying stock power. The goal with my setup (Neuspeed Sports w/ Bils B8s) was improved responsiveness while keeping good livability on the street. Can't deny there's some aesthetic improvement too but that's beside the point, hah.

On track it's very well behaved and I can say the goals are achieved. There's less of a delay between feeling the weight transfer and the car taking a set, with no dips or bounces throwing the car off-line to note -- the (pre-repave) dip inside of Summit Point main T9 comes to mind as one I would take with no drama. It feels very well controlled overall. Can easily use the curbs where recommended. Was something I was originally concerned about losing the bump travel and sitting fairly close to the bumpstops, but it's been a non-issue due thanks to the dampers I suspect.

This has all been with "where it ended up" camber in front (~-1.2' , and rear set at -1.5', with zero toe) and 300tw tires. No plans whatsoever to ever change the spring/damper setup, but (finally) more front camber this season.

All that said, I won't doubt a totally stock suspension would have been much more capable than I was, heck probably even now, while being more forgiving. But it's very fun as it sits. I'm expecting really nice results this season how with the front camber and 200tw tires, and to keep it there indefinitely... but the jury will be out until after the first couple sessions when the "rust" falls off .

Click to expand...

Do you run with Potomac Audi and Summit point? I’ve haven’t run with them at Summit, but do their events at VIR. Great bunch of guys and I have made a number of friends over the last two years running with them.

Very relevant topic for me as I'm approaching my first HPDE class with this car (2nd overall) with PCA at Laguna Seca. My (daily) GTI is lowered .75" with the H&R OE Sports. (I also have Koni sports, front/rear sways, and soon some SP LCA's)

I really enjoy the setup on the street, but I know it's not going to be perfect on the track. Just hoping I didn't screw it up too badly.

Since I've already gone overboard, and since I consistently hear guys shredding their front tires, I'm also strongly considering the SP front camber mounts to go with the LCA's I've had sitting around).

Apart from the initial cost, any reasons not to? (Inside tire wear on a daily? Slows learning? etc? I already need an alignment so that's not a factor)

Thanks.

Hammersticks said:

Very relevant topic for me as I'm approaching my first HPDE class with this car (2nd overall) with PCA at Laguna Seca. My (daily) GTI is lowered .75" with the H&R OE Sports. (I also have Koni sports, front/rear sways, and soon some SP LCA's)

I really enjoy the setup on the street, but I know it's not going to be perfect on the track. Just hoping I didn't screw it up too badly.

Since I've already gone overboard, and since I consistently hear guys shredding their front tires, I'm also strongly considering the SP front camber mounts to go with the LCA's I've had sitting around).

Apart from the initial cost, any reasons not to? (Inside tire wear on a daily? Slows learning? etc? I already need an alignment so that's not a factor)

Thanks.

Click to expand...

Generally toe will kill tires faster than negative camber. I would go up to -2.5 degrees on the street. I ran -2.5 on my Mini and the inside inch would eventually show more sign of wear but by that time the whole tire was at or past the wear bars and needed replacing. Basically the tire is past its safe wet weather use for the street.

IMHO -2.5 is still not enough for the track. I’m still eating the shoulders at -2 just not as bad.