knight_white99

iTrader: (5)

This was my first track day after getting the JWT TT kit installed from the guys at VRT. My apologies, this is a rather long post.

It was also my first track day with my new front and rear Rotora 14" big brake kit (6-piston front, 4-piston rear), as well as my new Rota 18x9.5" P45R wheels and 285/30-18 Hoosier R3S04 tires.

Good news and not as good news...

I didn't push the car too hard this first time out, since I wanted to be sure everything was working properly and I didn't want to break anything given that I have an important open road race coming up in two weeks.

The brakes feel great. I had the H6 race pads installed. Though I didn't push them too hard, they seemed very capable, with excellent initial bite and zero fade through 30 minutes of track time. I will say though that this track is not that fast, and I wasn't going full bore, so this is not a true test of the capability of these brakes. At least I didn't have to bleed them like I used to after ever other track day session when I had the stock rears!

The Hoosiers were awesome. Again, I didn't push too hard, but I had lots of grip, so long as I was smooth applying throttle coming out of the corners and didn't just floor the throttle. I had the VDC turned on for the first session (on purpose), and nailed the throttle a few times in third gear out of some corners. This caused the VDC nanny to activate, so I knew that full throttle third gear corner exits would take some finesse.

Now what the VRT guys want hear. The engine. Where to begin...

No doubt, the JWT kit makes good power. On the street, the instant, no-lag response of the turbos enables it slice through traffic like a machete. Point, shoot, and you are there, NOW. The car feels quite a bit more powerful than when I was N/A. Though the power seems to go a little flat on the top end after about 5000 rpm. It still pulls, but not nearly as hard as at lower rpm.

On the track, the car is fast, faster than it used to be, no question. Corner exit was noticeably stronger due to the substantially increased torque. This is great, since this is exactly what I was looking for. I had no trouble pulling away from a Lotus Exige on the track. This track is a relatively low speed track, maybe 100 to 105 mph or so at the end of the longest straight (3/10 of a mile). If I was going full bore, maybe I could be in 5th for a very, very short time, but it was just easier to run the track in 3rd and 4th gear. The Lotus should shine at a track like this, with more time spent in corners than straights. Maybe it was the driver, I don't know, but I thought the Lotus should kick my butt. He didn't. I wasn't going full bore, and he looked like he was pushing very hard, even out of shape in some corners. I slowed down for a while and let him pass, then followed him for a while. I was clearly faster, especially on the straights. In a race or time attack, pushing hard, I could have been maybe 4 or 5 seconds a lap quicker than him.

I did have a scare. In my second session, I was coming out of a corner, and suddenly, the car just went limp. It wouldn't rev above about 2800 rpm. It would just buck and lurch if I tried to apply more throttle. I thought I blew something up. But I checked the gauges, and everything seemed fine. Plenty of oil pressure, temps were okay, etc. I pulled into the pits, and the car stalled. I restarted it, and limped my way back to my pit area and shut the car off. I let it sit for about a minute, and tried to start it again. It started fine. I revved it a little, and it seemd to rev just fine, no issues.

I gave a quick call to Michael from VRT. He knew instantly what had happened. Apparently, this has happened to a lot of FI cars. The stock MAF sensor apparently can't handle full boost between about 2500 and 2800 rpm. The car goes into a "limp" or safe mode. That's exactly what happened. In order to reset the ECU, you have to shut the car off for perhaps 15 or 20 seconds, and then restart the car. Everything was fine after that.

In the third session, the car ran well for almost the entire session. Then, just before the end, the car had some stumbling at just over 4000 rpm. It seemed to be okay once you kept reving beyond that. In fact, in general, the car has a rather flat spot in the 5000 rpm range, but pulls harder at about 6000 rpm and above. I am thinking that might be due to my Nismo cams. Still don't know what was causing the stumble. The car ran fine on the way home, with no stumbling. Maybe temperature related? The oil temp got up to about 270 deg. F toward the end of the session - that is the highest that I have seen it go. Earlier sessions I was not pushing as hard and never got it above about 240. Also, it was hotter in the afternoon, perhaps 90 deg, maybe 110 or 115 track temp. I was running 100 octane fuel, and it didn't feel or sound like knock. It almost felt like it wasn't getting enough fuel. Still need to stew on this for a while. Michael thought maybe changing the water/coolant ratio might help aid cooling. Anyone else have any ideas?

One more thing. I was happy with the power gain, but Michael, I think I want to turn up the boost a little more. The boost gauge looked like it was only showing barely over 5psi. Is that right? Maybe I am now a power junkie, but as good as the car is now, I would love to have another 50, 100 or 150hp! The power was very controllable, and not intimidating in any way. The way my car is now setup, it could easily handle another 100 to 150hp and just be a rocket (like I know that your car is). Maybe it's my experience with true race cars that is showing, but the car is just starting to enter that sweet spot balance of power, handling and braking.

Now take that last bit with this in mind: I will also say that I was very lazy for this track day. I didn't even remove the spare tire, and I had a passenger EVERY session! LOL... So maybe after removing the 170 pound passgenger, the 40 pounds of spare tire, changing out the 70 pound Stillen exhaust for the 15 pound JIC titanium one that I have ordered, running less than half a tank of gas and removing the 37 pound passenger seat for time attacks, maybe I really won't need the extra 100hp!

Comments, questions and analysis welcome!

EM-EFER

iTrader: (6)

Great write up. Glad to hear your happy with your kit.. and that your getting rid of the stillen exhaust

Mike Wazowski

iTrader: (113)

Nice write up.

Are you using a manual boost "****" controller or an electronic boost controller?

knight_white99

iTrader: (5)

Right now, just the stock boost with no adjustment. Michael (from VRT) is going to send me a manually adjustable boost ****. So right now, I can't change boost.

1nate7

iTrader: (19)

It was a pleasure meeting you yesterday. I might be skinny, but I still added 190 lbs. I had a blast riding with you and your car is very well balanced and skillfully driven.

I'll try to get some pics up today. Most of them didn't turn out very well due to my old camera, harsh lighting conditions, and general lack of photograpy skill.

BriGuyMax

iTrader: (4)

stock short block? How were your coolant temps?

knight_white99

iTrader: (5)

I stand corrected - 190 lb. passenger! And not even one scream. LOL...

It was a pleasure to meet you too, Nate, and you can be a passenger anytime! Thanks again for the help, too. We wouldn't have made the first session without your help changing wheels.

And don't worry about the pics - any pics are better than no pics!

Hope to see you out there in your own car and those Stop Techs soon!

knight_white99

iTrader: (5)

I only have actual temp info for oil temp (added Autometer gauges for boost, A/F and oil temp). Still running the stock dash water temp gauges, which if yours is like mine, comes up to just under halfway and then never, ever moves. Not very useful.

Mike Wazowski

iTrader: (113)

ok, then you are just running the stock boost. I was just trying to get a feel for why you were seeing only 5 lbs on your boost gauge.

1nate7

iTrader: (19)

Pics of knight_white99's car. With the exception of the track shots, larger pics are available by copying and pasting the link location and then deleting the -med.

Mike Wazowski

iTrader: (113)

looks good

blowdry

Nice to see a F/I car tracked. You'r car looks intimidating on the track and at a stand still. Nice job.

JoeDirtPharmD

iTrader: (9)

Steve - are you joining us on the Alpine drive tomorrow?

knight_white99

iTrader: (5)

I would love to Don, but I think it will need to be another time. Too many things to do this weekend (work related). I'll catch you guys next time. I really want to try that stretch of road. Have fun and stay safe!

WheelDude.com

iTrader: (58)

The car looks awesome Steve!!! I'm glad to see it all come together and that you had a great time at the track. Sounds like it was alot of fun

-Dan

knight_white99

iTrader: (5)

Hey, thanks Dan! Yeah, it's pretty good when I can run faster than a Lotus Exige at a non-horsepower track. The car is really coming together, and wheels worked out great. I am very pleased with them.

Anyone who likes these wheels, contact Dan at Subydude. He was awesome in helping me ensure that the wheels fit over the brakes and to choose the right offset. Great customer service!

raceit

iTrader: (1)

Just curious, did you reenforce the motor? Meaning upgrading rods, pistons, etc. for strength? I'd hate to see you blow your motor...
Looks great btw!

p.s. what wheels are your running? 5zigen GN+s? 275.17s?

knight_white99

iTrader: (5)

Not a built motor. That's why the boost is kept low.

Re-read the second paragraph of the first post to answer your wheel/tire question.

SinCity350Z

iTrader: (19)

Nice write up! The 4000rpm thing was most likely lack of gas, just as it felt. Keep a good eye on your gas gauge when tracking. When its around 1/4 tank you can start to experience a little starvation coming out of corners. It happens to me too. Gas goes fast when tracking a TT car .

knight_white99

iTrader: (5)

Hi Mike, how are things in Lost Wages? Congrats on the Modified Mag feature!

The tank had pleny of gas, about 1/2 full at that point. That's why I couldn't understand it. And it happened on the straights. Felt like it was stumbling - symptoms of either lack of gas or spark. Didn't make sense. But it cleared up on the drive home. Weird.

But you're right, the car sucks gas like a pig now! I used over 1/4 tank in one 30 min. session. LOL...

Does your car go flat at about 5K rpm, then pick up again about 6K rpm?