Road Atlanta Tracking Testing the GT-RRR 's...really Options

[Sharif@Forged]

Derek's Freedown Autosports GTR made a stop at Forged Performance for some custom Cobb AP Dyno Tuning. After adding nearly 90whp+ from his stock basline run, we headed off to Road Atlanta. "Underpressure" also brought his JRZ/Hoosier clad GTR, to really make things interesting.

Derek went all out for this test....him and another team rented out Road Atlanta. There were at most, 6-7 cars on the track at a time...and usually just the 3 of us. Derek's GT-R was driven by professional Koni Challenge driver Tom Long, and was equipped with active rear wing, bone stock suspension, and a set of larger Michelin PS2's. The Forged Performance GT-R was driven by me, running stock all weather run flats, and Eibach springs. Underpressure's GT-R was testing out the JRZ triple adjustable competition coilovers, and a set of upsized Hoosiers.

What a great time. We spent the better part of the day, chasing each other down, and making a nice Nascar-style train up the back straight. All three cars were evenly matched in the power department, but it became really clear that Underpressure's car had far more grip, and more corner entry-exit-and-everything speed around the track. Derek's GT-R, although run on street tires, was expertly handled by his hot-shoe driver.

Tom Long put in a 1:33'ish laptime..just playing around. Underpressure I am guessing was about 1:31-132, and I brought up the rear with a 1:37 with the run flats.

I have some more commentary...but here are some pics.







This post has been edited by Sharif@Forged: Dec 15 2008, 11:45 PM

[Arch5]

and...and...and?????

Edit: Jumped the gun on ya. :D

Sounds like a blast. Good to see you guys pushing the cars nice and hard.

This post has been edited by Arch5: Dec 16 2008, 01:10 AM

[underpressure]

Um... I was walking away from Tom

[Kris@GTRBlog]

Nice one Sharif, looks like a lot of fun!

[Sharif@Forged]

After a few laps around Road Atlanta, one thing became abundantly clear: These run flats SUCK! These tires are absolutely horrible and unsuitable for anything more than a casual 6/10th cruise around the track. The understeer and tire squeal was incessant. I guess I really wasnt expecting much from them...oh well.

Second thing I noticed, is that the stock GT-R suspension is way too soft for track use, and the transiant reponse is very slow and lazy. I am putting a good set of coilovers, and sway bars on the top of my list.

The stock brakes held up fine for about 3-4 laps, and then the pedal got very mushy and fade increased dramtically. Add pads, rotors, and lines to the shortlist of track prep items.

IMHO, good sticky tires, brake pads/rotors/lines, coilovers, and sways, and there is no reason that a stock weight GT-R can't put in consistent low 1.30's with a competant driver, and dip into the 1.20s with an ace driver. These are incredible fast times for ANY car at Road Atlanta.

[Sharif@Forged]

Um... I was walking away from Tom

Corrected...I saw you pull away, but I thought he was having issues with the wheels. Oh well...you guys were both hauling...fun to watch!

Will, give us your assessment on the JRZ's and your overall experience.

This post has been edited by Sharif@Forged: Dec 15 2008, 11:42 PM

[underpressure]

nice ninja edit lol

Will be back over at the shop about 9am. Going to lend the downpipes to the guys for testing. Have a female coming over in the morning to the hotel so not going to be there at 8am.
If they need the car early I'm staying at the same hotel as them, rm 117. They are welcome to take the truck/trailer/car to the shop in the morning.

Lots of fun today. That pic of you thru 12 shows alot of body roll btw. lol

Update has been added to the JRZ thread under the suspension group.
http://www.nagtroc.org/forums/index.php?sh...c=26531&hl=

This post has been edited by underpressure: Dec 15 2008, 11:48 PM

[Neoseven]

Thanks for reporting. Looks like sticky rubber is the next order of business for me, well, at least after I test again to see what I can do on the Bridgestone vs. Dunlop runflats.

Sharif, I see you were talking about the stock brakes fading, I experienced this, but not that bad. I actually found the stock brakes sufficient, except they don't really look to hold up that well. Of course, I was only doing 4-5 laps sessions at Buttonwillow so who knows what they would have been doing after another 2 or 3 laps. I do know they get extremely hot, thus my installation of brake ducting to help cool them down faster on the track. I understand Derek's car was running AP Racing rotors. How did they perform compared to stock, and what pads did he decide to use?

[Arsinek]

i cant see any pics from work, boohoo.

[jaspergtr]

Have a female coming over in the morning to the hotel so not going to be there at 8am.

... alot of body roll btw. lol

i've trimmed the post to relevant data - pics?

[DerekFSU]

It was a good time. Will's car is sick loud and sounds great. Sharif's car did really well considering it's tires, chalk one up to the driver on that one. You could literally hear Will's car going faster as he dialed in the suspension on those JRZ's. As the it got better, he came through turn 12 (a VERY fast corner) faster and faster hitting higher rev's after each adjustment. Eventually hitting a higher gear due to the higher speed being carried through the corner.

Will, as for walking away from Tom, let's just say it's a good thing he didn't drive your car for a time

Sharif has a GREAT shop. I've never seen that many higher end street performance cars in one shop in my life. VERY clean, well run, and efficient. Musta been 30+ really nice cars getting worked on. His use of the new Cobb tuning software was also spot on. Great guy, great shop, and great operation.

Dyno tuning and testing continues today.

Here are a few pics and a 1 1/2 laps around with the 3 cars. Please forgive the video quality as I forgot to switch it to HD and also forgot the add the mic. Turn your speakers down so the windnoise doesn't wake up your neighbors.

http://www.whitisconsulting.com/videos/3gtrsroadatlanta.wmv

Attached thumbnail(s)

 

[DerekFSU]

UNFORTUNATELY, the aero tuning took all the track time so we were unable to try different pads. We'll do so in a few weeks during our next test. The AP rotors worked great with the Pagid pads. There was an issue with strong vibrating while braking at 10/10th's. Back off to 9/10's and it went away. Seemed like warped rotors but wasn't. Could be a hub issue but really won't know till we can do some more tests. These pads and rotors were definitely better than stock.

[Neoseven]

underpressure, what tire size you running now? Are those 19" wheels?

[Kunani]

That wing looks sexy....

[MDracer76]

LOL!! Good stuff Sharif!

[Bullo]

Looks like fun times.
Is that track open all year long?

[DerekFSU]

Looks like fun times.
Is that track open all year long?

Pretty much. It's pretty active with NASA, SCCA, and other groups so getting on it is relatively easy.

[Bullo]

Pretty much. It's pretty active with NASA, SCCA, and other groups so getting on it is relatively easy.

I want to tow my car down South.

[trumperZ06]

After a few laps around Road Atlanta, one thing became abundantly clear: These run flats SUCK! These tires are absolutely horrible and unsuitable for anything more than a casual 6/10th cruise around the track. The understeer and tire squeal was incessant. I guess I really wasnt expecting much from them...oh well.

Second thing I noticed, is that the stock GT-R suspension is way too soft for track use, and the transiant reponse is very slow and lazy. I am putting a good set of coilovers, and sway bars on the top of my list.

The stock brakes held up fine for about 3-4 laps, and then the pedal got very mushy and fade increased dramtically. Add pads, rotors, and lines to the shortlist of track prep items.

IMHO, good sticky tires, brake pads/rotors/lines, coilovers, and sways, and there is no reason that a stock weight GT-R can't put in consistent low 1.30's with a competant driver, and dip into the 1.20s with an ace driver. These are incredible fast times for ANY car at Road Atlanta.

Nice Video !!!

You look a little ragged coming out of turn five !!!

Otherwise nice lap... good late appexing.... 1:37 is very good on stock tires.

Properly set-up with good rubber/ low 1: 30's easily ....

but I wouldn't expect dipping into 1:20's.... without major engine mods.

CONGRATS... well done.

This post has been edited by trumperZ06: Dec 16 2008, 11:51 AM

[DerekFSU]

Nice Video !!!

You look a little ragged coming out of turn five !!!

Otherwise nice lap...

Ragged?