Poor-sha

Earlier this week I had a chance to try out the new DSC Sport RTx shocks with their controller. For those of you that want to lower your car this is definitely the hot ticket as it gives you more shock travel along with better control of the chassis than the stock shocks.

What was really cool though was that this turned in to an opportunity to use the DSC controllers ability to modify the suspension behavior based on PTM sub mode to really dial in the balance of my car.

For background, my car is running 305/660-18 front and 315/680-18 rear slicks. Those tires are a bit taller than the OEM sizes, have a lot more grip, and as you can see the fronts are much wider and rears much skinnier. I ran this setup towards the end of last year with the RT shocks and was happy with it though.

With the extra travel of the RTx shocks and the taller tires I started having issues with the tires getting in the wheel wells. I spoke to Mike and decided to play with stiffening up the suspension a bit to try and alleviate the rub. This is where it gets really cool.

For reference, remember this screen from the DSC Sport software that only comes up when you've selected the track map.




As you can see we have a block for each of the PTM modes and seeing 50/50/50/50 means there are no changes to the default shock curve for track mode. My next run out I just changed Sport 1 so 60/60/60/60 effectively making the shocks 10% stiffer. The car felt much better and the rub was gone so we propogated this change to the shock curve by changing the ma values there and reset the Sport 1 to 50/50/50/50.

Then I got thinking, the car is pretty loose with the current car setup. You can still drive it fast but with very cool ambient temps I'd like to be able to trail brake the car more. So went back to the PTM table and did this:

PTM Mode: LF/RF/LR/RR
Sport 1: 55/55/50/50 (stiffen up the front a little)
Sport 2: 60/60/50/50 (stiffen up the front more)
Race: 60/60/55/55 (stiffen up both a little and the front more)

Then I head out on track. During my session I could flip back and forth between these settings by just turning the PTM **** and in real time see what effect it had on the handling. It was like having cockpit adjustable sway bars in the car but all done through the shocks electronically.

I decided that I liked what was in Sport 2 so I ended up settings all the modes to that. There's lots of other applications for this.

- If I change to a different size tire
- I decide that I want to induce more understeer when I have less PTM intervention
- Maybe the front tires always get greasy in a session and I want more front grip halfway through.

I can do all of that by setting up the PTM modes in the software.

For those of you that don't want to tune or mess with the software, please don't feel like you need to learn how to do all this. The settings the controller ships with are fantastic for a car with stock tires. I'm running some different setups and really trying to push the capabilities of the car. Luckily I get great support from Mike and the rest of the guys at DSC Sport.

Poor-sha

I should add that I'm sure folks will ask about lap times. I also went in to the event with an alignment different than Mike normally recommends. I was running -2.7 camber in the front which really turned out to be too much with the Pirellis. Halfway through the second day I happened to look at the inside of the front tires and they were badly corded.

However, on the first day I still managed a 1:59.4 at VIR which is only .2 off my previous best. I'll be at Summit Point this weekend as well and we'll see what kind of clean laps I can get but the alignment is going to be unchanged - just a new set of scrubs.

0DSC Sport

Great job tuning the software the PTM modes is one of those real hidden gems makes tuning a delight and gives you flexibility in testing. It would not surprise me that alot of the tuning you were doing was also to the track VIR has changed so much since the new paving. We found that out at the end of last year in IMSA we ended up way completely different than the year before our notes were useless.
You will find there is a huge range to tune with the Tractive due to the piston design there is so much high speed range to tune and with the RTx you have more stroke as well

krisyk

Can you provide your thoughts/additional information regarding the shocks increased travel that provides the ability to lower the car more as it relates to the effects of the suspension geometry and any considerations or trade-off vs using a drop spindle like LGs?

0DSC Sport

Using the shocks with increased stroke allows users to maintain the factory uprights and geometry and provides added adj for ride height ie: larger tires lowering ect...
I have not made a geometry sweep of the LG but knowing LG I bet they work just fine and are a quality part!
In the case of the LG drop spindle I would go with either our RT or the new RTx both have the same valving and pistons the RTx offerers not only additional stroke but remote divider piston for the true track rats. the RTx is truly a proper race shock it will go endurance and not be effected by temp range like the factory mag shock.

fleming23

Poor-sha, did you leave the PTM modifications at the 60/50% or actually go into the GForce table and apply a multiplier there and return the PTM to 50/50? Would it not be better to leave the GForce table stock so the other modes (tour) are not impacted and only mess with the multiplier in the PTM table? Once we get the wifi release, this is something I intend to play with. Easy to make a change here and revert back if unhappy. I had not thought of doing it the way you described with each PTM level being a different setting so you can change on the fly, very good idea!

0DSC Sport

I really created the PTM mode in the DSC to make custom tuning all the easier and by using the ptm area it adds to all the other tables as well as Gtable . You will love the ease of tuning

cvp33

Shawn, great seeing that beast run at the track. Sorry we didn't get a chance to run together as I was chasing some gremlins. I did run a 2:11 on the Michelin ZP runflats with mostly clear track. I know I left a lot on the table especially through the uphill essess (109mph was my fastest here), the 14-17 complex and later braking. Day 2 was supposed to be used for me to start inching towards faster times there but unfortunately it didn't work out. I know the car had a 2:05 to 2:07 in it.

I can report that the DSC definitely did it's job. The car always felt planted, never unsettled. I can't imagine what that feels like with a superior shock set up as well. Nice job on the 1:59. Absolutely hauling azz!

CanadianVetster

If I lower my Z do I need to change the preset DSC controller settings?

0DSC Sport

Go into settings and locate. The tab zero travel this is done on a level surface with driver key on
It's not critical you will still have velocity control just if your looking at ride HT data it will be off

badhabit_wb

Poor-sha what differences did you notice in the rt vs the rtx shocks?

Poor-sha

The main thing I noticed was the additional travel. With the taller than stock slicks and as hard as I'm leaning on the car it was rubbing far more than before. We've been playing with the front shock mid and high speed velocity settings to try and prevent this. It's had the upside of also helping balance the car better with the more narrow rear slicks.

The RTx also should hold up much better on long stints with the remote reservoir sitting where it can get airflow in the wheel well. However, I've generally only been running ~20 min stints and I never noticed an issue with the RT shocks fading.

Sorry for the short review but I'm pretty smoked after spending 4 of the last 7 days at the track.

badhabit_wb

Thanks for the info that's really all I needed to know. I'm guessing with stock size tires I'll be fine with the rt's I have ordered. I just wanted to make sure because they're shipping this week and I didn't want to get the rt's and wish I had the rtx's