boomn29

iTrader: (47)

The weekend started with a trip to Chicago late Thursday night; en-route to an 8am Appt at AMS Performance for some upgrades. Waiting at the shop was an upgraded 12 plate rear diff from Shep racing! I have been awaiting this for weeks, as I'm sooo sick of mid-corner understeer in the car. Also planned was an AMS Moustache Bar Eliminator to further reduce unneeded weight and improve shifting. As usual, everything at AMS went like clockwork, it's so nice to have confidence in a shop! More on the changes later.



Rain overnight and into Sat provided wet track conditions until about noon. I personally love driving the Evo on track in the rain and knew it'd be a great way to get used to the new Shep rear diff. I also was debuting new front Girodisc 2-piece rotors and Raybestos ST43 pads all around.
I did 2 sessions in the wet, both with Dunlops on (I planned ahead) and had a freakin ball! The first thing you'll notice is the diff creaks at low speeds if you are turning tight. If I hadn't read this on previous reviews, I would have been worried too! Along with that, the AMS Moustache Bar Eliminator added a bit of noise from shifts into the cabin area (my car is mostly stripped) but I really grew to like the feedback. I thought the shifts seemed faster and more crisp personally.
Back to the Shep Diff - If you've read any of the reviews or claims about Shep's rear diff, they are all true. It allows you the ability to finally create throttle-on oversteer but in a very controlled and predictable manner. Nothing snap or scary by any means. Before in the wet I could force it sideways but all the diffs/electronics would correct things. Whereas now I could pitch it and it'd carry that skid until the wheelspin caught up and it'd power out of the corner. If you've owned an STi and rolled back the DCCD; you know what I mean here. I'll splice up some vid later of the wet stuff.
Around lunchtime things started drying and I mounted up the Hoosiers. Since I was playing in the rain I had the #2 gridspot and stayed up front (and out of traffic) all weekend which was nice. Alot of the Vettes and such stayed in the pits so they had to work from the back of the 40 car TT field!
I was a bit cautious in the first dry session to warm up the tires and really see what this rear diff would do in dry conditions. The ST43 pads were definitely different, they definitely took longer to heat up as compared to the Hawk DTC60's I have been running and also squealed like all he11 for a good 2-3 laps. Once they were warm it seemed they needed far less pedal pressure to stop. This took some getting used to throughout the weekend. Rear diff reacted very predictably and I had some slight oversteer in several of the turns, enough that I had to countersteer a bit. I loved it! I ran a 1:35.2 which equaled my personal best from the July event. The next session I let things fly and set a new TTA track record with a 1:33.9. That also put me in 1st of 8 cars in class. Vid below.

Absolutely perfect day. However, I had a slight incident the night before when my jack rolled while rotating tires. No real damage other than some scratched paint - I thought. In the practice session the car wouldn't go past 3k w/o sputtering, which I assumed meant an intercooler pipe was bent or popped. Turns out I bent the inlet on the intercooler and the coupler obviously wasn't tight. So I bandaided that as best I could and went out in the next session just to put a time down. Ran a 1:35.6 which put me in 1st by just .1. The next session I let things fly again and broke my TTA record from the previous day - 1:33.1. That landed me 1st of 6 in class. Vid below.

Along with the new TTA track record, I set a personal best by nearly 2 seconds. I did this with rear tires that had 22 heatcycles by the end of the weekend! The ambient temps were great, but with newer tires there's definitely more left in the car. Overall, the transition from TTB -> TTA (where I get 19 more 'mod' pts) is progressing. I plan to 'max' the car out for TTA next year and make a good hard run!

Huge props to John Sheppard for an awesome rear diff. If I weren't maxxed out previously in TTB 'mod' points I would have had this long ago! I would have really liked to have it when I ran Redline Street here as the understeer was even more troublesome on street tires. Thx to AMS for the install and great/safe tune as always. Thx to Martin @ Girodisc for talking me through both the rotor purchase and especially the ST43 pad compound differences. Also thanks to AMSOIL & Hoosier.

boomn29

iTrader: (47)

Vids! I'm following 2 different cars, both TTU Z06 Vettes. Watch them pull away from me on the straights above 90mph! I ran nearly identical laptimes to each them however even though they are still 2 classes above me!

Vid from Saturday: (spliced from 2 different sessions)
http://www.youtube.com/watch?v=JXN2DDOCvz8

Vid from Sunday:
2nd lap is my fastest of the weekend. Shot with my crappy GoPro. Apologies for the sucky mic on this.
http://www.youtube.com/watch?v=vxAskb4PUjI

Mark@AMS

iTrader: (1)

Awesome! Good Job!

racer145

iTrader: (1)

Great job on the new track record! That is really moving for a TTA car. By the time next year rolls around you will have a seriously fast car for the class.

Wish I could have been up there in the front with you so we could have pushed each other even more. We gambled on some setup for the weekend on my car and it turned out to be a real handful to drive. I will have things back to like they were before for the upcoming Putnam Park event.

Would you recommend the new pads over the DTC 60's for Time Trial use, or does it take too much time to get them in the right temp range?

boomn29

iTrader: (47)

Thx - it's coming into form!

Gotta give props for ya trying some crazy changes. It's the only way to discover if something works! I tried a big RSB and a much stiffer rebound setup last time at Autobahn and it was slower! And now I know!

Would I recommend the ST43's over the DTC60's - I dunno yet. I still think I need to get used to them. As they're bedded to my rotors, I'll def give them another weekend (at Putnam) before I truely give them the thumbs up or down. It's hard to retrain the braking process ya know. I had been saying I threshold brake repeatedly and I wasn't kidding. Lately with the DTC60's I was literally pushing as hard as I could and with ST43's - once warmed up sufficiently after they stop screeching - def do not need that much pedal pressure. That's a plus I think. It seems they roll on a bit better too which should make them easier to modulate once I get the hang of the torque curve and all....

jid2

iTrader: (62)

ST43's are good stuff - like you said once they get up to temp they really bite nicely.

GTWORX.com

iTrader: (35)

Good job!

- Andrew

boomn29

iTrader: (47)

Still not sold on them, but gonna stick with them for the next event. I usually don't like to hammer the first lap out at 100% so it's not too much of a pain for me.
However if someone was running A6's (I have before) you wanna hit it your FIRST lap and these could be an issue especially early in the day.

As always; appreciate the good thoughts everyone!

rawkus

iTrader: (16)

Smoking fast time... Not going to lie, I am a little upset that you have a faster time then me! I know our cars are completely different, but I wanna go to Autobahn RIGHT NOW!!

We are taking the car to Gingerman soon to test a new part and I will let you know what our times are there... I'm still blown away! Nice Job!

Dan

Hiboost

iTrader: (9)

Nice work, can't wait to check out the videos as the customer I'm at has Youtube blocked (by me rofl) so I don't want to break my own rules. I really enjoy my ST43 brake pads on Girodisc 2 piece rotors as well, never noticed a delay in warmup of the pads and after they are seasoned they seem to stop really well within 1/2 a lap of driving and are still quite grabby before they reach temp. I guess you could drag your brakes for 10 seconds to get them up to temp quicker.

boomn29

iTrader: (47)

Thx for the compliment Dan!
It was about 15 degrees cooler with less humidity last weekend as compared to RTA! Of course I had Hoosiers to your streets; but you're not on a stock turbo either! lol.

G/L at Gingerman. I'm sure you'll slaughter the times I put up there last month with NASA. 1:32 on the old config and 1:39 on the new config. I'd like another shot at those carousel turns now with the new Shep Diff though!

jid2

iTrader: (62)

Yeah it's not that the ST43's don't have bit cold they just have more when they're hot. You could use the first lap as a brake dragger like others said. Keep the tires cool but put some heat in the brakes.

rawkus

iTrader: (16)

I'm on the ST43's as well and have not noticed weak braking when cold, in fact I had a problem with ABS and could lock up the brakes so easily when cold it was scary.

BTW, I loved your line through the switch backs, made that Corvette look dumb.

Dan