Larry Cable

Can you say more about the different modes, and how they compare to the stock PASM algorithms and how those differences will translate into handling behaviors of the car on road/track?

Tom@TPC Racing

All three modes are active, in that it will react immediately to your inputs. The difference between the 3 modes is the peak of the curve for stiffness. For example, if the operating range of the shock is 1-10 (10 being full stiff), then Mode 1 would be at 7 at for its maximum stiffest when inputs demand the stiffest dampening value for an event such as heavy braking to reduce front dive. Mode 2 would be 8, and Mode 3 would be 9.

Mode 1 is good for street driving, wet track, and bumpy track. Mode 2 is good for most tracks. Mode 3 is good for very smooth tracks.

The modes are selected via the PASM button. Each time you press the button it will graduate to the next mode. The LED light on the button is lit solid in Mode 1. The LED light will blink twice in Mode 2, and three times in Mode 3. DSC will remember mode that was used when the ignition is turned off. It remains in the same mode the next time your start the engine.

F1CrazyDriver

Thank you for pm . I'm interested but waiting on feedback. Any improvement on track that you can provide overlay data?

Tom@TPC Racing

After spending Friday, Saturday, and Sunday there, I am exhausted coming to work this morning! I did more wrenching on customers cars(brake pads, brake bleeds, sway bar changes, alignment, etc.) than I did driving. I missed two of my session because I was working on cars. Its all good, customers come first as long as I can perform the required task on site.

Anyway, I am very happy to report that my car is significantly more planted and more confidence inspiring than at the previous track event. Which was at the same track back in April and I'm running the exact same Bridgestone RE11 street tires. The car was good before, it just moved around more than I like, and now its just hooked up! The changes made were Bilstein Damptronics 500/720 springs, rear upper mounts, DSC, side muffler delete & opening rear bumper vents. I don't have data acquisition so the only data point I have are mph at different parts of the track. I saw 2-3mph increase at the slower turns, and 5mph increase at T10 which also led to a 8mph increase at the brake marker for T1. I like to think a fraction of the high speed improvement was attributed to opening up the rear bumper vents. Does it matter to me even if the vents didn't do anything? No. It just makes me feel happy that they are no longer fake. With the DSC using accelerometer input for individual corner dampening management the woolsey roller coaster feeling of the down hill slight off camber drop turn(between T4-5, aka The Chute) is reduced. I am also catching cars that were dusting me at the same track 3 months ago. Those cars are on R-comp tires. I used Mode 2 of the DSC all weekend. The car felt very balanced overall, the only thing worth noting(not a complaint) was slight push exit T6, which was easily manageable but it still was resolve by a driving tip I got from my friend KJ, who is an instructor/racer. KJ, like an angel speaking over my shoulder, said to give the throttle just a littlest of little breather to rotate the car(whereas before I'd the gas pedal pinned to the floor). BAM! No more push. I got the tire pressure nailed down to 34psi left/35psi right. The side muffler bypass did a great job of keeping the rear tire pressure stable so even on street tire I was able to tango with the cars on R-comps throughout the entire run session. In conclusion, I am completely psyched about the car as a complete package. I'm sure some of the mph improvement was my driving as a direct result of a better feeling, more confidence inspiring car that makes me feel sublime behind the wheel. Regardless, I'll take any improvement I can get from the car and/or driver. The only regret is I didn't try the different DSC modes as recommended by Mike Levitas(DSC developer). Will do that when I come back here in 2 weeks. Next mods on my wish list are stiffer motor mounts, rear diff work, and 18" wheels with R-comps.

In regard to the motor mounts, I'm completely for the obvious advantage, but has anyone logged the ignition timing before/after swapping mounts to see if the ECU retards timing thinking that there's detonation as a result of vibration?

manuxc

Tom,
my GT3 had solid mount for engine (like cup part), with still RS engine mounting plate (not the red cup part) and stock gearbox mount (very flexy indeed ....)
Yes , I can feel vibrations a lot more, but ECU doesn't seem to change anything to timing

Tom@TPC Racing

Thanks you for the info.

Tom@TPC Racing

Now I know for sure why the rear bumper vents are blocked off on street cars. The rear section of the car gets very dirty in no time! It actually dirtier than it appears in the photo. I am okay with it since I am more about function/performance than looks.

Alan C.

Tom, great information. Thanks for sharing.

Ur20v

Hopeful that means the vents are now venting and the dirt is being drawn out. i.e a pressure drop under the car. I guess you did to much at once to see if the car felt stable because of this and not down to the other group of mods you have done.

Tom@TPC Racing

I just want to clarify that the car was not unstable the first time it was on track back in April. Before the last round of mods, the car moved around under braking and transitions more than I like due to the softer suspension; the movements were mechanical, not aero. The movements were manageable, but the car wasn't as grippy as it is now. I really do think the vents are working to release some pressure because the rear gets dirty after one drive. But there's no difference that I can feel in terms of stability accelerating at the front straight between ~80-150mph.

I could tape the vents off from the outside and do one lap just to see if the mph change between the exit of T10 to brake marker of T1 at Summit Point when I go back in two weeks...if there a 2mph gain then I'd consider this experiment a success.

MJSpeed

^ The vents do help increase speed and reduce pressure. If not Grand-AM wouldn't have made the teams close them, especially in the .2 bumpers.

Tom@TPC Racing

MX RACER

Well thanks to Tom I now have no side mufflers and open vents!!

Thanks for all the help Tom!!

Tom@TPC Racing

Well done! My pleasure to help.

Tom@TPC Racing

...and enjoy the cup car exhaust note!