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The next track weekend at this road course will be around the beginning of November so that leaves you plenty of time to plan a proper road trip.
Just wondering if you or someone else has ever installed a FSB on these cars? I know the overall take is that we don't have "struts" so no need on using these. That is just a generic term tho IMO. but I think it would hold value when trying to stiffen up suspension/chassis flex, seeing as its still a part of the front subframe.
I basically have your same setup (minus Fsport shock/springs & Giken LSD). I love the feel of the car and how everything has tied together so far. Still seems that the front could be tighter tho. Just my opinion. Maybe I should just be happy with how far ive come with it... lol. How much would you recommend getting the Billet Aluminum Rear Subframe Suspension Braces? Was it worth the money in your opinion?
Just wondering if you or someone else has ever installed a FSB on these cars? I know the overall take is that we don't have "struts" so no need on using these. That is just a generic term tho IMO. but I think it would hold value when trying to stiffen up suspension/chassis flex, seeing as its still a part of the front subframe.
I basically have your same setup (minus Fsport shock/springs & Giken LSD). I love the feel of the car and how everything has tied together so far. Still seems that the front could be tighter tho. Just my opinion. Maybe I should just be happy with how far ive come with it... lol. How much would you recommend getting the Billet Aluminum Rear Subframe Suspension Braces? Was it worth the money in your opinion?
Since our front suspension is a double wishbone set-up, spending the money on a tower bar would have little to no impact to suspension performance (they are essentially all show/no go parts). Strut bars are typically useful for vehicles with a MacPherson strut suspension.
If you really want to make a big difference to the responsiveness of your IS from the front end, I highly recommend swapping out the OEM bushings of the LCA to 90+ durometer polyurethane versions like the ones FIGS or RR-Racing offers:
Yes, I highly recommend the Billet Aluminum Rear Subframe Braces (I believe Cusco also offers an alternative version). There is a surprising amount of flex from the flimsy OEM braces and one IS-F owner even noted that his IS-F would flex when parked on a steep driveway. I noticed that the rear end stays more planted with less chance of upsetting the rear suspension geometry. For the amount of $$ you'd pay for a tower bar, the rear subframe brace would be a significantly better investment.
Lol. Thanks for the video and thanks for the quick response. That's exactly what I was contemplating in my head. Just bouncing ideas off. Sometimes I second guess myself. Already have the FIGs installed. Got those a while back along with the ISF steering ECU, steering wheel damper, and front lower braces (TOMs).. HUGE difference.. then just recently put on the rear chassis brace and lowered it on eibach pro kit springs (IS250) with Koni FSD Gold dampers. Came with sport suspension and the OE dampers were starting to give.
Yeah, beefing up the lower body chassis with stiffer braces really makes a difference on this platform since there are a few structural weak points that need to be addressed (such as the 2IS thread we had a while back where owners were getting random dents on the roof after hitting a pothole). When I research other vehicles (such as the E46 M3) having cracks in the rear subframe, it makes me take notice and to try and prevent this from happening with my IS350.
Nope, no SPC front adjustable ball joints for me. Since the car is only lowered about an inch, camber is still within specs.
It's good to see another 2IS owner on the forum with a track-focused tune.
Redspencer's Track-Tuned IS350 w/ OS Giken LSD Build Thread
Originally Posted by 4grDrvr
I basically have your same setup (minus Fsport shock/springs & Giken LSD). I love the feel of the car and how everything has tied together so far. Still seems that the front could be tighter tho. Just my opinion. Maybe I should just be happy with how far ive come with it... lol. How much would you recommend getting the Billet Aluminum Rear Subframe Suspension Braces? Was it worth the money in your opinion?
I'm not exactly what you mean by "tighter", but I'll throw my .02 in. The reason that all of the various braces help your suspension is that they reduce uncontrolled suspension movement. The reason a front STB doesn't help is because movement of the strut towers has very little effect on the suspension movement on these cars.
With the rest of the hardware you have I think you can consider a couple of things for the front end of the car: First of all tires. Both size and the tire. There is no need to cripple the front end of the car with narrow 225 width tires. You can also get a stickier tire.
Look at the rest of the suspension bushings. The lower rear makes the most difference and you have those, I'd follow those with the front lower and then consider the upper bushings. Then there is alignment. Toe and camber can both affect your handling.
Last of all if the car has a-lot of miles you need to look at replacing ball joints and tie rod ends.
It's been a while since I've done any upgrades to my IS350 so I decided to let the mod bug get a hold of me again!
After spending some time contemplating on what additional components can help enhance the handling and responsiveness of my vehicle at the upper cornering limits on the track, I decided to place an order for the GTSpec 4 point lower tie brace.
The rear portion of my IS has already received multiple enhancements to stiffen the chassis and while I've greatly improved the steering response by adding the FIGS LCA bushings and the '11+ IS-F Steering ECU, I feel that there's still opportunities for reinforcing the chassis in the front end of the car since all I currently have is the Tanabe Sustec Brace.
I became particularly motivated in doing this upgrade after scoping out the OEM front suspension cross brace on a 3IS250 loaner car which is standard on the 3IS, 4GS, and RC models:
I'll be attending another track day on November 7th so I'll have a great opportunity to see what changes to the driving dynamics are made with the addition of this future mod once I've received and installed it.
Interesting about that 3IS front cross brace. I had to look into that myself and found this pic. Had to post it for everyone because I didn't even have a clue what/where it was :
I assume that since the 2IS underpinnings are far different of that of the 3IS, this brace couldn't merely be a bolt-on would it?
I think the dimensions should be very close since the 3IS is only 0.5 inches wider than the 2IS. Implementing the 3IS cross brace would require some welding on the black brackets behind the cross brace in order to bolt the cross brace properly.
Believe me, I was tempted to test the 3IS cross brace for compatibility if it wasn't for the slight design change of the two black brackets behind the brace.
Lol. Great minds think alike. I've been thinking this one through myself. Trying to figure out how we 2IS owners can take advantage of the somewhat front cross member brace on the 3IS. Red you and I have the same braces now overall. Got the lower rear body chassis braces ordered/installed like you suggested. Never would have guessed that OE tubular brace would have flexed that much! Thanks love them!
As for the black brackets you are referring to that ties the 3IS cast aluminum under carriage to the forward end of that cross member brace. I'm almost betting that no welding is necessary. Haven't had time to find one yet. But I'm thinking the aluminum undercarriage that it mounts to, is common (or very similar to our 2IS) and can be a direct bolt on or even if it isn't the same bolt pattern that it could be drilled (spot drilled) to fit. Then the question is does the 3IS cross member brace fit our chassis or does a custom brace need to be fabbed? We need to find that forward black bracket(s) in a junkyard and do a test fit. If I'm not mistaken we have a similar black bracket of our own in the same place, just no mounting support for another brace.
I'm with you though Red I will find a way to get that brace on our cars. I think it will be just as big of a difference as the rear chassis brace, but for the front of course
Lol. Great minds think alike. I've been thinking this one through myself. Trying to figure out how we 2IS owners can take advantage of the somewhat front cross member brace on the 3IS. Red you and I have the same braces now overall. Got the lower rear body chassis braces ordered/installed like you suggested. Never would have guessed that OE tubular brace would have flexed that much! Thanks love them!
As for the black brackets you are referring to that ties the 3IS cast aluminum under carriage to the forward end of that cross member brace. I'm almost betting that no welding is necessary. Haven't had time to find one yet. But I'm thinking the aluminum undercarriage that it mounts to, is common (or very similar to our 2IS) and can be a direct bolt on or even if it isn't the same bolt pattern that it could be drilled (spot drilled) to fit. Then the question is does the 3IS cross member brace fit our chassis or does a custom brace need to be fabbed? We need to find that forward black bracket(s) in a junkyard and do a test fit. If I'm not mistaken we have a similar black bracket of our own in the same place, just no mounting support for another brace.
I'm with you though Red I will find a way to get that brace on our cars. I think it will be just as big of a difference as the rear chassis brace, but for the front of course
Good call with possibly swapping out the 2IS black brackets with the 3IS black brackets. The dimensions of the black brackets appear to be identical so this would eliminate the need to weld a mounting point to the 2IS black bracket in order to bolt on the brace. The only question is whether or not the cross brace would fit the 2IS chassis as you mentioned...
The GTSpec 4-point lower tie brace came in earlier this week and I had a chance to install it today. I was very impressed with the build quality of this product and the brace was much lighter than I anticipated (approximately 3 to 4 pounds).
The process was pretty straightforward and the only tough part was torquing the 22mm bolts to 150 ft/lbs by hand while laying on the floor in awkward positions.
The GTSpec 4-point brace looks great in combination with the FIGS LCA bushing and the Tanabe Sustec Brace:
What was my driving impression after taking an hour's worth of a spirited drive post-mod? I must say that 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!! I honestly delayed in getting this 4-point brace because I wasn't expecting to feel a noticeable difference in driving dynamics which is what happened when I previously installed the Tanabe Front Sustec Brace. Boy was I wrong!
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. I highly recommend this upgrade!
06-27-15, 07:42 AM
