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Changing topics ever so slightly....
I may be the last one to install Fusion and log data but I see it has potential with the Yota PID pack installed to grab some details about camshaft positioning.
Couple that with a few other variables and we may gain a little insight on some previously uncharted territory.
I'll post up as time permits if Fusion allows it.
Glad you're still actively posting, redspencer! Just wanted to say your research has been very helpful with my own build, particularly with the suspension upgrades. Keep up the great work!
As I continue to wait for the weather to cool down so I can go back to having some new adventures with the IS350, my car reached a certain milestone today (which took exactly 13 years to get to):
I guess this means the engine is finally broken in?
I remember the weekday when my ride ticked over to 6-digits. Anti-climatic.
With the constant daily rain that Florida gets, having a tubed chassis setup and no fixed roof would certainly lead to many soggy afternoons.
I still have the Daizen steering rack bushings that needs to get installed so I'll likely get that done within the next few weeks. I'm also looking into replacing the front lip with something newer as the factory lip does have its wear and tear from the years of daily driving. I've always liked the look of the GFX front lip so I plan on adding that to the list (very likely a replica since the OEMs are rare to find nowadays).
A buddy of mine picked up a new Mustang GT loaded with all sorts of goodies (particularly the Performance Package) so it will be fun to see him with that car on the track at a future HPDE event. I managed to take this shot during a sun rise at the parking lot:
I also finally had a chance to put on a fresh coat of polymer wax on the recently purchased IS350C. Under certain lighting and angles, the car looks like it's on stealth mode!
Yeah, the tungsten pearl IS350 has unfortunately been neglected with car washes the past couple of weeks due to my busy schedule so it was filthy when I took that last pic (which was a day or two after initially waxing the Obsidian black car).
One thing for sure is that a black-painted car cannot stay clean looking for long unlike a silver-painted car (which is something I forgot about as I haven't had a black car since my old MKIV Supra days back in the mid 2000s!).
@redspencer I know I'll get a response from you, I'm going to track my IS250 (autocross first then some track) and I wanted to get a meatier tire for the rims I'm going to be running (ESR SR11's 18x8.5 in the fronts and 18x9.5 in the rears). The oem 225/40/18 and 255/40/18 are ok but I will looking for a meatier tire for this set up. I see you run 255/35/18 in the front and 275/35/18 in the rear. Any rubbing issues?? I have BC racing coilovers and only plan on lowering the car 1.25 inches in the front and 1.0 in the rear. How do you like this tire combination for the street /track and why did you choose this specific size combination??
@redspencer I know I'll get a response from you, I'm going to track my IS250 (autocross first then some track) and I wanted to get a meatier tire for the rims I'm going to be running (ESR SR11's 18x8.5 in the fronts and 18x9.5 in the rears). The oem 225/40/18 and 255/40/18 are ok but I will looking for a meatier tire for this set up. I see you run 255/35/18 in the front and 275/35/18 in the rear. Any rubbing issues?? I have BC racing coilovers and only plan on lowering the car 1.25 inches in the front and 1.0 in the rear. How do you like this tire combination for the street /track and why did you choose this specific size combination??
I believe I saw your recent post on the 'Lexus IS Freaks' FB page with you having a 6MT IS250 but I didn't have time to post a reply at the time. Not sure if anyone did reply to your post but good to see you're persistent by posting on this thread.
To answer your initial questions, a 255/35/18 up front will have approximately the same tire diameter as the stock 225/40/18 (635mm[new] vs 637mm[old]). Depending on the offset of your wheels, you may have minor rubbing under hard cornering if you leave your wheelwell fender liner untouched. With my +35 offset wheels, there were no rubbing issues with daily driving use but on the track, the outer edge of the tires would occasionally rub on the front outside edge of the fender liner. I resolved that issue by using a heat gun and pushing the affected plastic wheelwell liner inward which corrected the problem. From reading on the CL forums, this is a common fix for those lowering their cars and installing lower offset wheels to obtain that flush look.
On the rears, a 275/35/18 tire with a 18 x 9 +35 wheel fits within the wheelwell with no rub. However, the edge of the tire was extremely close to the fender lip so I had the rear fender lips rolled as a precaution (cheaper to do so than to replace torn up tires).
I chose this specific combination based on these factors:
1) Essentially, the wider tires you can fit, the higher overall lateral g's your car can achieve (provided you're comparing the same tire compound). There is essentially a point where significantly wider tires will have diminishing returns on lateral g gains and you also have to consider minor negatives with installing wider tires (typically higher rotational mass, increased rolling friction, etc.). 255mm tires up front were my chosen optimal width based on one of our CL members testing out a 255/35/18 tire and confirming this size did fit the 2ISX50 wheelwell. For the rears, I chose 275mm tires as my IS350 is FBO+Tuned as well as equipped with a clutch LSD. For track use, I need as wide of a rear tire as possible to optimize tire grip for the OS Giken to throttle steer me out of corners via the outside rear tire.
2) If you look at the trend in F/R tire width sizes for many of the OEM high-performance vehicles released within the past decade, they've gone from a 245F/265R setup (BMW E90 M3, BMW M2) to a 255F/275R setup (BMW M4, Lexus RCF/GSF, 2020 Toyota Supra). Many of these vehicles are built for daily driving/track use and also possess their own trick active differential for optimal cornering capabilities. Based on my research, current vehicle build, and F/R wheelwell size of the 2IS, a 255F/275R setup is my final setup. For reference, I previously used a 245F/265R setup and thought that worked well but I didn't want to miss an opportunity to add an additional 10mm of tire meat to each tire if the car and wheels were able to accommodate.
For your 6MT IS250, if you desire to stick with the OEM wheels, you can do a 245/35/18 tire size up front which will greatly improve cornering grip at the front. You can leave the 255mm tires at the rear and that width should be sufficient for your IS250. If the aftermarket wheels offer a significant reduction in rotational mass (for reference, my Enkei PF01s are 9-10 lbs lighter per corner compared to the OEM wheels), it's well worth going for the lighter wheels.
If you want to go for a square setup, you can look into getting a set of 18 x 8.5 +35 wheels and equipping them with 255/35/18 tires. This will let you rotate your tires (huge plus), maintain an optimal grip on the rear, and going slightly wider up front (255mm vice 245mm).
I believe I saw your recent post on the 'Lexus IS Freaks' FB page with you having a 6MT IS250 but I didn't have time to post a reply at the time. Not sure if anyone did reply to your post but good to see you're persistent by posting on this thread.
To answer your initial questions, a 255/35/18 up front will have approximately the same tire diameter as the stock 225/40/18 (635mm[new] vs 637mm[old]). Depending on the offset of your wheels, you may have minor rubbing under hard cornering if you leave your wheelwell fender liner untouched. With my +35 offset wheels, there were no rubbing issues with daily driving use but on the track, the outer edge of the tires would occasionally rub on the front outside edge of the fender liner. I resolved that issue by using a heat gun and pushing the affected plastic wheelwell liner inward which corrected the problem. From reading on the CL forums, this is a common fix for those lowering their cars and installing lower offset wheels to obtain that flush look.
On the rears, a 275/35/18 tire with a 18 x 9 +35 wheel fits within the wheelwell with no rub. However, the edge of the tire was extremely close to the fender lip so I had the rear fender lips rolled as a precaution (cheaper to do so than to replace torn up tires).
I chose this specific combination based on these factors:
1) Essentially, the wider tires you can fit, the higher overall lateral g's your car can achieve (provided you're comparing the same tire compound). There is essentially a point where significantly wider tires will have diminishing returns on lateral g gains and you also have to consider minor negatives with installing wider tires (typically higher rotational mass, increased rolling friction, etc.). 255mm tires up front were my chosen optimal width based on one of our CL members testing out a 255/35/18 tire and confirming this size did fit the 2ISX50 wheelwell. For the rears, I chose 275mm tires as my IS350 is FBO+Tuned as well as equipped with a clutch LSD. For track use, I need as wide of a rear tire as possible to optimize tire grip for the OS Giken to throttle steer me out of corners via the outside rear tire.
2) If you look at the trend in F/R tire width sizes for many of the OEM high-performance vehicles released within the past decade, they've gone from a 245F/265R setup (BMW E90 M3, BMW M2) to a 255F/275R setup (BMW M4, Lexus RCF/GSF, 2020 Toyota Supra). Many of these vehicles are built for daily driving/track use and also possess their own trick active differential for optimal cornering capabilities. Based on my research, current vehicle build, and F/R wheelwell size of the 2IS, a 255F/275R setup is my final setup. For reference, I previously used a 245F/265R setup and thought that worked well but I didn't want to miss an opportunity to add an additional 10mm of tire meat to each tire if the car and wheels were able to accommodate.
For your 6MT IS250, if you desire to stick with the OEM wheels, you can do a 245/35/18 tire size up front which will greatly improve cornering grip at the front. You can leave the 255mm tires at the rear and that width should be sufficient for your IS250. If the aftermarket wheels offer a significant reduction in rotational mass (for reference, my Enkei PF01s are 9-10 lbs lighter per corner compared to the OEM wheels), it's well worth going for the lighter wheels.
If you want to go for a square setup, you can look into getting a set of 18 x 8.5 +35 wheels and equipping them with 255/35/18 tires. This will let you rotate your tires (huge plus), maintain an optimal grip on the rear, and going slightly wider up front (255mm vice 245mm).
Hope this helps!
I forgot to mention the offset to my wheels are +30 In the front and +35 in the rear. I'm hoping I don't get any rubbing with a meatier tire setup .
The Redspencer IS350 underwent a minor facelift by receiving a new GFX replica front lip spoiler. I took a few shots of the car at night and I definitely like the new look (hopefully it will also add a bit of downforce as well)!
In your opinion, how'd that rep lip fitment could out (1 to 10)? My full OEM GFX kit is on-point and still a 10 to this day, even after hitting it on everything when I was lowered. LOL!
I went with a GFX front lip replica from Ikon Motorsports as I've read fairly positive reviews from others on CL with many of the replica parts offered for different Lexus vehicles. I actually was tracking this specific replica from Ikon for several months as it was temporarily discontinued for the longest time with no ETA of ever being back in stock. Luckily, it was made available again earlier this month and I ordered a pre-painted version.
Fitment-wise, I was not initially happy with my purchase and would give it an initial score of 7/10 (or 8/10 if I'm feeling generous). Though the tabs went in smoothly and I was able to secure the front lip using the majority of the OME mounting points, there were two issues that I had:
1) If you look closely at the pictures above, there is a very small gap where the lip begins to wrap around the bumper and exists on both ends. I don't think these gaps exist on the OEM GFX lip but that was a nuisance for someone OCD like me. I've convinced myself that those are tiny air vents which will assist in stability at high speeds. Hehe.
2) Though most of the OEM mounting points are used to secure the front lip, this replica does not include a mounting tab on the ends of the lip like the OEM version does. This means I will need to utilize two small screws on each end of the lip to secure it to the wheel well (which looks to be a common method for securing replica lips). At the moment, I've only used double sided tape to secure the ends of the lip but I'll likely drill two small holes on each end of the lip to insert the screws.
Other than those two items, I'm pretty happy with this replica, especially since it likely costs 1/3 to 1/2 the going rate for a painted OEM GFX lip. The 1G1 paint matches my car and the lip fits properly at all other points of the bumper. Once I properly secure the ends of the lip with the small screws, my score will be bumped up to either an overall 8/10 or 8.5/10.
Surprisingly, Ikon has really good customer service as I was at the brink of returning this lip for a refund and after presenting the above two issues, they approved my refund request and provided a pre-paid shipping label which surprised me (I fully expected to have to pay for the return shipping).
After weighing the pros and cons of keeping the GFX replica or going back to the factory standard lip, I've decided to keep it and will let it run its course. If it doesn't survive track use, I still have my factory one stored away for future use.
09-10-19 | 02:33 PM
