Why is the RCF so heavy
#166
Lexus Test Driver
This also doesn't help the RC-F's case with the post-2014 track layout being a faster track configuration with slightly more runoff available at certain parts of the course.
As I noted above, on some tracks, the IS-F had the edge, on others, the RC-F had the edge. As you know very well, tires play a huge role on a vehicle's lap time. With the RC-F's 255F/275R tire width, one would expect it to do better than the IS-F's 225F/255R tire width configuration. It's unfortunate that Lexus never provided an option to fit 255F/275R tires on the stock 2012 IS-F wheels which it could easily fit. Keeping all other chassis/suspension/differential variables constant, we'd see a different picture in these comparisons.
I will not go into hypotheticals here. What if RCF had 285/30 PS4S? Tires will not compensate for the power, chassis rigidity (which is higher for the RCF), lower CoG, suspension and dynamic advantages the RCF has.
I absolutely agree and I didn't plan on posting anything but the comment above stating that the RC-F is light years ahead of the IS-F is an erroneous comment (IMO) and I provided the data for Fuji Speedway and VIR with the IS-F posting faster lap times to refute this claim of track superiority.
It's more appropriate to call the F80 M3 as being light years ahead of the E90 M3 as it consistently posts significantly faster lap times on essentially all track layouts. The RC-F doesn't have the same distinct dominance over the IS-F that the F80 M3 has with the E90 M3. It is certainly why many IS-F owners never felt the need to trade in their cars for the RC-F.
Simple reason, turboes. If you review the data, RCF loses out on the straights to the M4 where it gets a 2 - 3 mph advantage. We picked RCF because we wanted an N/A high-revving engine. My two choices were either E90 M3 sedan (2013) or a 2015/2016 RCF. RCF engine is free-revving, revs quite high and sounds glorious at that 7450 rpm cut-off. I could have purchased an M4 for cheaper than RCF because lots to choose from, but I chose the RCF because of the engine (interior/exterior).
Last edited by 05RollaXRS; 03-02-18 at 06:52 AM.
#167
OG Member
iTrader: (1)
Originally Posted by Lexus
"Lexus has upgraded IS F with new performance, convenience and design features. The key mechanical improvement is a new, compact Torsen Limited-Slip Differential (LSD) that supersedes the previous Brake LSD function. Torsen-equipped IS F is two seconds faster per lap at Fuji International Speedway, the vehicle's development home."
Motortrend provides the specific IS-F Fuji Speedway lap times but incorrectly source the two second improvement to the 2011 MY: http://www.motortrend.com/cars/lexus...us-is-f-drive/
Originally Posted by MotorTrend
"The new model laps the 2.8-mile Fuji Speedway in 2 minutes, 3.4 seconds — nearly two seconds faster than its predecessor — thanks to Yaguchi’s subtle, yet substantial, modifications."
The only known lap time documentation that I could find for the RC-F was on a thread that you posted years ago which compared the times of a TOM's tuned RC-F (2:02.8) to a stock RC-F (2:03.7): https://www.clublexus.com/forums/rc-...edway-lap.html
#168
Lexus Test Driver
As requested on the FSW lap times, here is the press release (dated Sept 2009) for the 2010 IS-F which received an upgrade in the form of a Torsen LSD: https://www.pressroom.com.au/press_r...navSectionID=2
Motortrend provides the specific IS-F Fuji Speedway lap times but incorrectly source the two second improvement to the 2011 MY: http://www.motortrend.com/cars/lexus...us-is-f-drive/
The only known lap time documentation that I could find for the RC-F was on a thread that you posted years ago which compared the times of a TOM's tuned RC-F (2:02.8) to a stock RC-F (2:03.7): https://www.clublexus.com/forums/rc-...edway-lap.html
Motortrend provides the specific IS-F Fuji Speedway lap times but incorrectly source the two second improvement to the 2011 MY: http://www.motortrend.com/cars/lexus...us-is-f-drive/
The only known lap time documentation that I could find for the RC-F was on a thread that you posted years ago which compared the times of a TOM's tuned RC-F (2:02.8) to a stock RC-F (2:03.7): https://www.clublexus.com/forums/rc-...edway-lap.html
All of the lap times I put above, were by publishers/drivers who were unrelated to Lexus and had limited seat time.
This is a good comparison video of RCF vs LC500 on the same track, same publisher, different day that shows difference in on-limit handling characteristics of two cars where the LC500 consistently pushes nose out while RCF points nose inwards and slides tail out (where C&D VIR shows RCF as slower):
Last edited by 05RollaXRS; 03-03-18 at 10:47 AM.
#170
Thanks for posting. Good information. That is nearly an official lap time with a press release by lexus to show improvements over the non-LSD model of 2 seconds/lap. It is like LFA's 7:14 Nurburgring lap times. TOM's lap time used their own two drivers and it seems like two drivers are testing out TOM's chassis components rather than a before/after. Yaguchi never revealed what their own RCF lap time was. Just said, it was faster around the track than the ISF in their lead/follow laps.
All of the lap times I put above, were by publishers/drivers who were unrelated to Lexus and had limited seat time.
This is a good comparison video of RCF vs LC500 on the same track, same publisher, different day that shows difference in on-limit handling characteristics of two cars where the LC500 consistently pushes nose out while RCF points nose inwards and slides tail out (where C&D VIR shows RCF as slower):
https://www.youtube.com/watch?v=eRByWIewuZA
All of the lap times I put above, were by publishers/drivers who were unrelated to Lexus and had limited seat time.
This is a good comparison video of RCF vs LC500 on the same track, same publisher, different day that shows difference in on-limit handling characteristics of two cars where the LC500 consistently pushes nose out while RCF points nose inwards and slides tail out (where C&D VIR shows RCF as slower):
https://www.youtube.com/watch?v=eRByWIewuZA
#171
Lexus Test Driver
It is the telemetry equipment called video Racelogic VBOX
That works great for stoplight-to-stoplight racing. If you look at high speed acceleration (best of) for each car, the AWD parasitic loss and power difference becomes apparent. 0 - 200 km/h (124 mph) or 0 - 150 mph where RCF gets to 2 seconds quicker. Also, RS5 lapped consistently slower on every track (in part because of 58/42 weight distribution).
That works great for stoplight-to-stoplight racing. If you look at high speed acceleration (best of) for each car, the AWD parasitic loss and power difference becomes apparent. 0 - 200 km/h (124 mph) or 0 - 150 mph where RCF gets to 2 seconds quicker. Also, RS5 lapped consistently slower on every track (in part because of 58/42 weight distribution).
Last edited by 05RollaXRS; 03-04-18 at 01:39 PM.
#172
So what is the most extreme weight reduction anyone has achieved by changing the (Battery, Suspension, Brakes, Exhaust & Tires)?
Thread
Thread Starter
Forum
Replies
Last Post
MLindgren
SC430 - 2nd Gen (2001-2010)
4
05-12-17 06:35 PM