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This build thread is intended to help other CL members with ideas on what they can do with their 2IS IS350/IS250 for better straight-line and handling performance. I’m the original owner of my IS350 and I’ve had it for over 13 years now (since Oct 2006). My previous vehicle was a MKIV Toyota Supra so I’ve always been busy with the mod bug.
One of my favorite car enthusiast quote is "Straight roads are for fast cars, turns are for fast drivers”. Even though the 2nd Generation IS350 has exceptional acceleration for a car rated at 306 bhp (thanks to the high-compression of the 2GR-FSE, having 90 percent of max torque being available at 2,000 RPMs, and the aggressive 4.08 final drive ratio), the stock suspension tuning that Lexus gave the IS350 from the factory was very lack-luster from a performance driving perspective. Lots of understeer, body roll, intrusive VDIM, and too much steering assist made the IS350 a great straight line performer but a less than desirable driver’s car.
All was not lost though. With Lexus now focusing on performance with the debut of the Lexus IS-F, many of those same performance upgrades became available for the IS250 and IS350 in the form of F-Sport accessories. When I read that an ISx50 equipped with the TRD F-Sport suspension accessories upgrade could hit an impressive 71 mph on the slalom and 0.90g on the skidpad (which matched the handling numbers a BMW e46 M3 could do at the time), I knew that this 2IS chassis had potential which was what led me to the path I have taken with my IS350.
Below are my performance upgrades which I hope will be of use to our CL 2IS community. EDIT 1/23/2020: I also added the estimated cost for each upgrade (from what I can remember):
Suspension Upgrades: * TRD F-Sport Front and Rear Sway Bars ($450)- When I first upgraded just the rear sway bar, my IS350 had a tendency to oversteer which made the car fun to drive but it caused me to burn out my rear tires faster and my cornering speeds were not where I liked them to be. The addition of the front sway bar made the IS350 much more balanced from front to rear and allowed for more stable cornering. Lexus rates the front sway bar as being 42% stiffer than stock and the rear sway bar as being 150% stiffer than stock.
* TRD F-Sport Shocks ($700) and Springs ($300)- These two components work beautifully together on the track and greatly improve the agility of the IS350 over stock shocks/springs. I chose this route over adjustable coilovers because these were professionally tuned as a set by TRD USA at the Streets of Willow race-track in 2007/2008 so that saves me the time and headache of trying to dial in the right settings with adjustable coilovers.
* TRD F-Sport Chassis Brace ($350)- I noticed that this component reduces the polar moment of inertia which improves initial turn-in and slalom transition. I recommend the chassis brace to help fine-tune your setup once the majority of your suspension/handling upgrades are done.
* Tanabe Sustec Under Brace (two-point front lower brace) ($125)- On the streets, I did not notice any improvements w/ responsiveness from this upgrade. This component may have some impact on the track during high lateral g cornering but I cannot confirm or deny.
* Solid Billet Aluminum Rear Subframe Suspension Braces ($100)- This unique performance brace is stronger than the stamped steel factory support and is designed to further strengthen the subframe so that there is minimal flex to improve response and handling.
* GT Spec 4-Point Lower Tie Brace ($175)- I am very surprised that Lexus didn't offer an F-Sport version of this 4-point front brace to compliment the F-Sport Rear Chassis Brace!! Though the 4-point front brace isn't readily noticeable at low speeds, once you get to 35+ mph, I was pleasantly surprised at the additional responsiveness of the chassis I was getting through very minor steering inputs. Turn-ins felt sharper and the car felt a bit more stable. The only other chassis brace that impressed me this much was the F-Sport Rear Chassis Brace. I can see why Lexus incorporated a front cross brace to the 3IS, 4GS, and RC in order to improve rigidity and chassis responsiveness.
* Ultra Racing Front Tower Strut Bar ($175)- As much as I have been skeptical about putting a strut bar on a vehicle with a double-wishbone suspension over the years, I found having a solid single piece brace does provide additional improvement with steering responsiveness and assisting with the distribution of load when initiating a sharp turn. It should certainly help more than the three-piece strut bars with pivot points. Though not as impactful of a difference as the front and rear under chassis braces, every little bit does help toward that feeling of solid chassis rigidity.
* Center Tunnel Brace ($100)- I picked up a custom-built aluminum tunnel brace from a fellow CL member. As it is a natural crossing of chassis load between the front and rear, replacing the flimsy OEM tunnel brace with a beefier version should provide some benefits.
Drivetrain Upgrade: * OG Giken Super Lock LSD (TCD Spec) ($2500 + $1000 for install)- This is considered to be the Holy Grail of limited slip differentials. The IS350 is one of the lucky few models which sport the full set of 28 clutch plates inside the LSD as well as the 3rd generation TCD clutch plates which allow for an even more progressive lock-up compared to the original Super Lock LSD. This mechanical torque vectoring differential will literally pull you through every corner using the rear outer wheel and drastically changes how you would normally approach your driving line since you can get back on the throttle even before you hit the apex. As others have quoted on the internet: “The OS Giken is a cheat code. Absolutely unreal what you can do with a rear end with it”. This is easily my most favorite mod that I’ve done to my IS350.
* Titan Motorsports Rear Differential Solid Ear Mounts ($250)- A necessity for the differential housing when upgrading to the OS Giken TCD. The solid aluminum differential ear mounts replace the squishy OEM bushings and virtually eliminates wheel hop.
Wheel and Tire upgrades: * Enkei PF01s ($1200)- I recently picked up a set of Enkei PF01 track wheels. Specs are 18 x 8.5 +35 (Front) and 18 x 9 +35 (Rear). Each wheel is approximately 10 lbs lighter compared to the OEM 18” wheels so I’m saving approx. 40 lbs of unsprung weight with this upgrade. Responsiveness of the IS350 on the streets is noticeably improved.
*Michelin Pilot Sport 4S ($1100)- I’m currently using Michelin Pilot Super Sport tires with 255/35/18 (Front) and 275/35/18 (Rear). I chose this set-up to match the tire widths of the RC-F and GS-F.
Steering Upgrade: * 2012 IS-F Steering ECU ($450 + $125 for calibration at Lexus)- This is another Top 3 favorite mod that I recommend to everyone. Since I daily drive my IS350, the improved steering feel and road feedback greatly enhances the driving pleasure of driving around town. For high-performance driving, the accuracy of steering inputs and the heavier weight due to less power steering assist is greatly improved over the stock steering ECU. The available IS-F Sport Mode VDIM parameters are also much more lenient compared to the stock IS350 stability settings.
*FIGS LCA Polyurethane Bushings ($330)- These were recently installed on my IS350 and I've noticed an additional improvement to the steering feel and feedback during normal driving and especially while cornering. The front tires feel very planted to the ground and the chassis communicates with the driver even more on what is going on with the tires on the road. I highly recommend the IS-F Steering ECU/FIGS LCA Bushings combo if you want to dramatically improve the steering feel.
Brake Upgrades: * EBC Slotted Rotors ($300 per axle) and Project Mu RC09 Club Racer Pads ($200 per axle) (or EBC Yellowstuff [$100 per axle])- I’m a big fan of these brake pads and rotors. Very strong fade resistance on the track. I find the EBC Yellowstuff fantastic for daily driving and light track work/autocross. If you need to go to the next level, my recommendation is going with Project Mu Club Racers. I was able to maximize braking threshold on the track with no signs of fade during my twenty minute sessions.
* Castrol SRF Brake Fluid ($70)- A necessary upgrade if you plan on taking your IS to the track. I used to run ATE Type 200 fluid but the wet boiling point rating caused some issues for me on the track when the fluid was over a year old. The Castrol SRF has among the highest wet and dry boiling point which should help prevent the fluid from boiling over when I need it the most.
Engine Upgrade: *RR-Racing ECU Tune w/ 7200 RPM Rev Limit ($550)- This is probably my second favorite modification done to the IS350. Not only do you get the benefit of an additional 15rwhp and Torque, you can also take advantage of the peak horsepower at a much broader powerband range from 6000-7200 RPM.
At a recent Autocross event, spectators and other drivers were commenting on how fast the Lexus was and kept asking me if there was a V8 under the hood or if the motor was supercharged! With the additional power/torque and the additional 500-700 RPMs to play with from the ECU tune, the IS350 would launch from a dig like a bat out of hell and maintained a very strong powerband up to the 7200 RPM redline. As long as initiated my shifts a little bit early (1,000 RPMs prior to redline on 1st gear and 500 RPMs prior to redline on 2nd gear), I would consistently be able to upshift at around the 7k mark without bouncing off the redline.
A really big benefit gained from this tune is the ability to stay in gear much longer which helped tremendously when I was able to stay in 2nd gear at speeds close to 70 mph when I previously had to shift to 3rd gear at 60ish mph. The IS350 was screaming through the course and the combination of the F-Sport Exhaust and the ECU Tune turned the car into an acoustic masterpiece. The amount of compliments on how great the car sounded were endless.
* TRD F-Sport Engraved Exhaust ($1200)- A nice aggressive sounding exhaust without the drone. A perfect Dr Jekyll and Mr Hyde set-up.
* Megan Racing Midpipes ($450)- I picked up these midpipes as I needed to free up the exhaust flow bottlenecks that I was having when I had just the PPE headers and F-Sport exhaust. These midpipes are an excellent choice for those that are looking for a 2.5" diameter setup and don't want the associated raspiness that the invidia midpipes are known for. The additional exhaust note is deep and a bit louder at WOT while staying quiet when coasting at low RPMs.
* JoeZ Intake Pipe ($125), 2IS TRD F-Sport Lower Intake Box ($80), and Ram Air Duct- I am using a Joe Z intake pipe which improves throttle response throughout the entire RPM range and an estimated 4-5 rwhp improvement. I also utilized the 2IS F-Sport lower intake box to give the 2GR-FSE a nicer growl at 3,500 RPMs and above as well as additional airflow from behind the headlights. I recently replaced my 3IS350 F-Sport Intake pipe which includes the sound generator/creator. The Lexus sound generator that's part of the 3IS350 F-Sport Intake pipe adds additional acoustic sound from the engine bay to the cabin at mid/high RPMs though it is subtle (due to the sounds emitted from the header/exhaust combo). After doing several datalog comparisons between the two pipes, I found that the JoeZ intake pipe has a 3-5 higher MAF g/s reading than the 3IS F-Sport pipe so it has been replaced for performance purposes. The F-Sport Lower Intake box utilizes a secondary intake hole which also increases the peak MAF g/s readings. For more info on the Ram Air Duct that I built, see posts #734, 739 and 741.
* PPE Headers ($1000 + $300 for ceramic coating; $400 for install)- These are the RR Racing speced PPE headers that I also had ceramic coated in high temp black. Provides an additional surge of acceleration throughout the entire RPM range. I haven't noted any loss in power at the lower RPM range.
Other Upgrades: * Prestigious Society Navigation and Video Enhancement Module ($300)- Allows your passengers to watch DVDs on the road if you have both Navigation and Mark Levinson.
* iJDMTOY LED Daytime Running Lights ($60) - No more yellow DRLs
* F-Sport Shift **** ($60) - Cosmetic upgrade
* F-Sport floor mats ($80) - Cosmetic upgrade and slightly lighter than the original floor mats
* F-Sport Front Grille ($60) - Cosmetic upgrade
* Lexus Aluminum Sport Pedals ($100) - Cosmetic upgrade
If you have any questions, comments, or additional mod suggestions, please let me know.
Nice write up. Ever thought if getting the GT Spec lower 4 point brace?
Do you know if the GT Spec 4 point brace will have a noticable impact to the overall rigidity of the chassis? There's a variety of front/mid/rear chassis braces made by different manufacturers and its difficult for me to determine which chassis-related components will actually make a difference for the $$ invested.
The F-Sport Rear Chassis Brace mod is very noticable to me in terms of responsiveness of the vehicle so it gets a rating. I'm unsure if the Tanabe front under brace makes a difference so that gets a rating.
I had the F Sport chassis brace, the Tanabe front lower brace, F Sport away bars, Jun TW center tunnel brace, tuned Parts rigid bars, GT Spec 4 point lower brace, GT Spec shock tower brace. You've pretty much gone this far...the rest don't cost very much more. I just decided to get the most I could to feel the tightness. Although I was on coils and extremely low I don't feel that I pushed the car anywhere near what you're doing and being so low negated some of what could have been handling improvements.
Thanks for listing your aftermarket chassis component upgrades for consideration. I plan on keeping my IS350 for the long run so I'll definitely do some research regarding the additional chassis brace parts as another potential performance mod in the future (most likely the GT Spec 4 point brace and Jun TW center tunnel brace).
I should have known better that spending money on car mods is a never ending cycle!
Wheel and Tire upgrades: * Enkei PF01s- I recently picked up a set of Enkei PF01 track wheels. Specs are 18 x 8.5 +35 (Front) and 18 x 9 +35 (Rear).
Are you using TPMS sensors in the PF01s? If so are they OEM sensors or aftermarket? Looks like about a 90% chance I'll be getting a set of these wheels for my car, just trying to see what my options for TPMS are.
Are you using TPMS sensors in the PF01s? If so are they OEM sensors or aftermarket? Looks like about a 90% chance I'll be getting a set of these wheels for my car, just trying to see what my options for TPMS are.
Yeah, they are the OEM TPMS so you'll be able to switch them over just fine. You'll love these lightweight wheels!
Originally Posted by Gville350
What happened at your last track session? Forgot to follow-up via PM to see how it all went!
I unfortunately didn't make it to the track that weekend. I stayed at the hotel in Daytona Beach and was ready to race the next morning but I ended up having insomnia throughout the night so I decided it would be best to skip the event rather than risk an unforseen incident due to my lack of sleep. There will always be other track days.
At least I did get a nice shot of the car at the beach
redspencer to your rub on the fronts since your using 245 tire widths and the rear on 255/40?
With the 245/35/18 tires up front, there has been no rubbing issues. Based on what I've read from other 2IS owners, it's typically the increased diameter of the tire that will cause rubbing issues on the front wheel well. A 245/35/18 tire is about 9mm shorter than a stock 225/40/18 tire. Back when I was experimenting with a 235/40/18 tire (8mm taller than stock), I had minor tire rub up front when braking and turning simultaneously.
There's another CL member that recently tested out a 255/35/18 tire up front with a similar offset wheel as mine (+35) and he noted that there was no tire rub since the diameter of the tire was near identical to stock diameter (1.5mm shorter than stock). I may go that route as well once my 245s wear out.
There's still plenty of room in the rear for 265s using a 18x9 +35 wheel without worrying about any fender rub. Unfortunately, I'm not 100% sure if I'll be able to squeeze 275s in the rear without having to roll the fenders...
10-06-14, 08:49 AM
Redspencer's track-tuned IS350 w/ OS Giken Super Lock LSD Build
rating. I'm unsure if the Tanabe front under brace makes a difference so that gets a 
rating.
