05RollaXRS

Not true. Still lots of issues persist in the F30 with N55. Lots of people stalling and overheating. Here is just one sample of an F30 with juice box 4 on N55 having lots of issues of going into limp mode and overheating. However, I don't want to make this thread about the 3-series. This is about RC-F.

http://www.1addicts.com/forums/showthread.php?t=718467

ISF001

With the optional carbon fiber roof and hood/bonnet, it should be able to drop 200 pounds?

I am still hoping for HP in the 470 area.

eoph

That probably saves less than 20 lbs total......I'm even willing to bet the 3968 lbs target is with the CF package.

jdmSW20

iTrader: (12)

that means even with the added power, its still going to be a boat weight wise

LexFather

More like 10 lbs lol

FYI the CF roof on bmws only saves about 8lbs

05RollaXRS

If people don't have problems with the IS-F's 3850 lbs weight then the RC-F's weight increase of 50 lbs would be negligible.

Besides, all cars these days weigh over 4000 lbs from RS5 to C63 AMG. The M4 will be 170 lbs lighter than the E92 M3, which would make it around 3600 lbs (since the E92 M3 weighed 3750 lbs). Not to mention the M4 is longer, wider and taller than the E92 M3.

Even the so-called "Godzilla" now weighs over 3910 lbs and rarely it ever gets deemed as a liability outside magazine tests.

jat0223

iTrader: (1)

The isf doesn't weight 3850 lbs. It weighs 3780 lbs, compared to 3968 lbs, that's a pretty substantial weight increase.

I think the RCF might be faster than the isf thanks to its torque vectoring differential, but the difference will be very small. I don't think the extra 34hp and torque vectoring differential Will be enough to compensate for the extra 188 lbs and create that much of a difference between the cars.

05RollaXRS

Your post is full of assumptions, which unnecessarily skew the facts in the IS-F favor.

- You assumed the RC-F is going to have 450 HP. How is 450 HP same as Lexus' actual claim of "over 450 HP"? When the IS-F was introduced, Lexus said it will have "over 400 HP". No one knows what the actual figure of the RC-F would be until Lexus announces. Your assumption of only 34 HP increase is inaccurate, but nonetheless tips the power-to-weight ratio in favor of the RC-F by 1 lbs/hp.

Most importantly, the RC-F will have a broader torque band, which is why the rev range has been increased by at least 500 rpm. The higher torque at the higher rpms is exactly what automatically produces higher horsepower figure .

- The goal of the RC-F weight is to be "under 3968 lbs". Again, no one knows how much over 3900 lbs would it be.

- The IS-F has weighed well over 3800 lbs in many tests. I could put several tests up, but here is one sample where it tipped the scale at 3839 lbs.

3839 lbs (2011)

http://www.caranddriver.com/reviews/...ad-test-review

3819 lbs (2008)

http://www.motortrend.com/roadtests/...fications.html

3825 (2009)

http://www.roadandtrack.com/cm/roada...-IS-F_data.pdf

- Again, reality is, no one knows how much faster will the RC-F be than the IS-F. However, it has been improved on everything. Not just through slapping a torque vectoring diff. Suspension, chassis etc. everything has been improved according to the chief engineer as it is based on the CCS-R. Lexus' own figure are pointing towards at least 0.5 seconds quicker in a straight line. Around Nurburgring, I am sure the RC-F will crack the 7:5X. I believe the difference will be very substantial.

jat0223

iTrader: (1)

I thought we were all going by assumptions here since nothing is concrete at the moment. So going by*the targets that*we know, the RCF won't be that much faster than the current isf unless they beat the targets by a lot. Also, manufactures post curb weights so you can't compare the real weight of the isf to the target curb weight of the RCF like you did on your post.

Anyways I'm hopeful that they will beat their targets by a lot, but we have to be realistic here.