As most of you know I am not exactly a fervent Lexus fan. However I do like to think I can view all cars on the merits they possess. So when my good friend combfilter decided to take a shot at driving on a real road race track with his slightly modified IS350. I was all on board to see just exactly how his car would stack up. After all events such as this, the driver can make a substantial difference, often beating cars that score better on paper.
Location
The location was Texas World Speedway, an older NASCAR track built in the 1970’s complete with a road race circuit. Today the track is mainly regulated to SCCA, private events and motorcycle races, but is still an excellent venue for car clubs to let it all hang out. This event would be hosted by a Texas group on Supraforums.com with several highly modified cars in attendance. However this event was it was not solely limited to Toyota based vehicles. Staged on the 2.9 mile road race circuit layout and utilizing the front portion of the huge 2.5 mile banked oval, speeds should easily approach 130 mph. With this in mind it was pretty obvious that my buddy had his work cut out for him.
The Driver
Now combfilter isn't a neophyte to the race circuit, regularly tripping the lights fantastic at the Texas Motorplex just south of Dallas. His IS350 consistently takes on and defeats BMW 335i's with ease with consistent low 13 second passes.
combfilter's IS350 vs BMW 335i at Texas Motorplex
However since this was his first time on a true road circuit at such high speeds, and he wisely opted for an instructor to sit with him until there was a comfort level for the track. If an instructor is available then by all means take advantage of it, because they can assist you in choosing the correct lines on the track making it far easier to drive quickly.
The Car
The 2007 Lexus IS350 is known as more of a touring sedan rather than by a track pedigree. The 306hp V6 has ample power to keep up adequately with most of the competition, but the suspension is geared more for a soft ride rather than track prowess.
The solution, to that was a set of Eibach springs with the stock struts to firm up control and at this time the stock sway bars were kept intact. A free flow Borla exhaust was added to lower back pressure and allow the V6 to sound a bit more authoritative. Since the track is pretty abusive to tires and this is more of a learning day, off came the custom rims and tires and back went on the stock tires.
The Event
The rules of the event dictated you must run the track in groups contenting with traffic all of time. While this keeps times down a bit, it also creates and awareness of your surroundings. No superman antics here or you may collect your neighbor and end up in the guard rail. The groups consisted of 8-10, with combfilter’s lineup featuring a Mini Cooper, a Z06 Corvette and even a turbo Supra sprinkled in for variety.
After the first ½ day the instructor had completed his assignment and the group was allow to dice amongst each other. For those of you contemplating such an event you need to take it easy for the first few laps, because there can be tremendous differences in the way you car handles at speeds over 80 mph, this is something you have to learn on your own. You will also need to inspect the tires thoroughly after each session noting wear and looking for defects. A tire failure over 100 mph can be catastrophic as you can see below from a Z06.
Speed can be deceiving believe it or not this is 130 MPH on the oval
Combfilter's first 130 mph pass Texas World Speedway
And again in traffic:
Combfilter in Traffic at 130 MPH
Overall Impressions And Observations From The Driver
Quick notes on what I disliked about the is350 on the road track.
1. it has quite a bit of body roll when you really push the car hard into the turns. A lot of this is the weight of the car and the roof. Unlike 3 series, our roofs are actually safe if you roll it over, but they are heavy because of this. We know the IS isn't really a track car but they could improve on this.
2. this isn't really Lexus fault, but the car should really come with some pilot sports or something better than the potenza/and even worse the turenza's. They did an ok job, but i know that after the driver, the tire is the 2nd most important thing when it comes to track days.
3. The car seems to have quite a bit of understeer. This surprised me.
Quick notes on what I liked about the car
1. I've always loved the power of the IS. Vettes, Supra, WRX's etc could not pull on it unless we got into the oval bank section. Matter of fact I found myself passing quite a few Supra's and Vettes during the sessions.
2. I was actually kind of impressed with the way the car's automatic transmission adjusted to very abusive driving conditions. It was great
3. braking on the IS was absolutely great. The brakes never faded or gave any fuss. They were amazing. Big surprise there, I figured after the 3rd lap they would be fading like a sumbish, but that wasn't the case.
Conclusion
While the IS350 may not be a road race car by any means it is pretty obvious if you address the soft suspension and body roll issues with a good aftermarket kits you have just resolved 50% of any issues you might have on the track. Driver and tires are almost always the major factors in driving fast, without competence in either category you can lose up 10 to 20 seconds per lap on the 2.9 mile road course.
BTW, combfilter’s lap times ran right at the 2:10 to 2:13 mark per lap which is quite respectable and in the middle of the pack.
Not a bad job at all for the first time ever on a road course.
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