Yri

Hello all,

Quick question about how the 3rd gen IS holds up on track (coolant/oil temps, brake fade, etc).

Restomod

Not sure about the IS specifically (I'm sure it's similar to the RC). Reviews have been great on the suspension, but Motor Trend tested two RC350 F-Sports on the track and overheated both transmissions and complained stock brake pads became soft very quickly.

Yri

Yeah, I did hear about MT's incident with the transmissions. The RC350 is about 200 pounds heavier though, but it still uses the same engine and transmission, as well as brake pads. I think now I might consider the IS350/RC350 more of Grand Tourers than sports sedans/coupes.

jennypenny

I think, sporty road cars are not meant for tracks.

I once brought my A45 to the track, and my friend brought his little Suzuki

My brakes were done, and the engine too hot to continue after 2 laps. His little Suzuki kept going.

Her car had oil cooler, transmission cooler, and other performance mods.

It was fun, but I dont think it was meant to be tracked.

Yri

Dang. I know the 2GR doesn't have an air-to-oil transmission cooler, and, if my memory serves me correctly, it doesn't have any sort of engine oil cooler. The transmission cooler in these cars is a water-to-oil type, which doesn't work so well when the coolant that is supposed to be cooling the transmission is hot. Of course, there are aftermarket oil coolers out there, but if the car is completely stock most likely it will over heat. Air-to-oil type coolers are far more superior than water-to-oil coolers.


EDIT: I believe the Inline 4 has an engine oil cooler, but not the v6 engines.

sunamer

i dont think you statement about brake pads for is350 (3rd gen) being same as on rc350 is completely correct.
04465-30500. MARK TEXTAR T4146,F SPORT - is350 f sport front pads
04465-30491 MARK TEXTAR T4146,TIRE & DISC WHEEL-235/40R19+265/35R19(F-SPORT) - rc350 pads

material is the same, but the size of rotors and brake pads is not, I bet... calipers most likely are different too.

Yri

I was meaning the material, and yes caliper sizes are most likely different to cope with the different rotors. Besides, the RC350 has wider tires, the IS350 has slightly smaller tires (as in width). I should have stated brake pad material instead of brake pads. Oh well.

Yri

Alright, did some research around the forums, found a forum post about a guy who took an AWD F sport to an autocross event. He said there was almost zero brake fade. He did not mention the engine temps or transmission temps. He also said there was almost no oversteer. The thing about autocross is that on a real race track, speeds are higher and so are braking distances, so autocross isn't a truly reliable source of brake fade, engine temps etc, since the speed is slow, most of those courses are in 2nd or 3rd gear.

AZMacaroni

As you said, autocross generally won't show the same amount of issues in comparison to taking out on a full track due to the braking and acceleration zones being shorter. In regards to no oversteer, these cars are set up from the factory with a ton of understeer because that is generally easier for people to control at speeds.

JGO

I've seen reports of the transmission overheating. I did 3-4 hot laps on a 1m 25sec track and didn't have an issue. Brakes were also great with zero fade.
The car does tend to understeer. Stock tires with coilovers.
Help solve the understeer issue with a rear swaybar or square tire setup

Yri

Good to hear. I know these car understeer a ton, since they have 55% of the weight to the front, but I would say that most likely the RWD version would understeer less, since you don't have the initial 'torque steer' like what you have in the AWD variant. These cars also squat quite a lot when turning. According to MotorTrend, these cars get .84 g's on a 300 ft diameter skidpad, which isn't bad. Do you own the F Sport model, or just the base?