Notices
RC F (2015-present) Discussion topics related to the RC F model

RC F teaser Brochure

Thread Tools
 
Search this Thread
 
Old May 13, 2014 | 09:55 AM
  #31  
LexFather
Guest
 
Posts: n/a
Default

Reply
Old May 13, 2014 | 05:23 PM
  #32  
eoph's Avatar
eoph
Pit Crew
 
Joined: Jan 2012
Posts: 247
Likes: 0
From: Alberta
Default

Originally Posted by 05RollaXRS
Yeah, "racing torque" is all about maximum torque available up in the topmost rpm (hence, the peak horsepower keeps climbing and comes in close to the rev limiter). For example, Lexus LFA makes its peak horsepower at 8700 rpm (9000 rpm for NE) and even at 9500 rpm, it is still making over 90% of its peak torque.

RC-F fulfills that very nicely. The M4 engine is just a normal turbo engine that makes the major chunk of all its torque in the midrange and completely runs out of steam after 6000 rpm. That is why the "in-gear" (low speed, tall gear) acceleration of M4 would be good and also part-throttle it will feel very peppy in the midrange.

However, BMW marketing was defiant and wanted to really use the mantra of "race bred" so they gave it a completely unnecessary 7600 rpm redline when it should have been no more than 7000 rpm. They wanted to market it as "high-revving" so they made pistons that can handle the engine speed, but not designed to flow well at high rpms for usable power (being a turbo engine).

I hope all magazines shift M4 at 7600 rpm in RC-F comparisons so that the M4 turns in much slower numbers.
I don't think it'll beat the M4 in straightline speed though. Over on the bimmer forums they're saying the M4 is underrated and probably makes 455hp based on the 118mph trap speed and weight, and mostly cause I don't think Lexus will have launch control. The Carbon package can probably only drop 50 lbs from the RC F max, mostly from losing the moonroof. Still, I like the RC F powerplant better with it's 'unending acceleration' feeling.
Reply
Old May 13, 2014 | 06:58 PM
  #33  
Joe Z's Avatar
Joe Z
Lexus Fanatic
iTrader: (10)
 
Joined: Nov 2004
Posts: 13,441
Likes: 1,076
From: Under an IS F since 2008
Lightbulb

Originally Posted by LexISguy
Nice close to the 480hp speculation everyone was mentioning. Throw in some future JoeZ products for 500bhp.. I will still like to see the final US specs...
Shhhhh... You'll spoil the surprise

~ Joe Z
Reply
Old May 13, 2014 | 06:59 PM
  #34  
4TehNguyen's Avatar
4TehNguyen
Lexus Fanatic
20 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (1)
 
Joined: Jan 2006
Posts: 26,218
Likes: 79
From: Houston, Texas
Default

adding headers and exhaust on this should unleash a lot more power like it does on the current 5.0
Reply
Old May 13, 2014 | 10:03 PM
  #35  
05RollaXRS's Avatar
05RollaXRS
Lexus Champion
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Oct 2005
Posts: 10,364
Likes: 2,762
From: Calgary, AB
Default

How did they get the 118 mph trap speed? I don't believe it has been tested yet.

Anyway, even if the RC-F is only able to match the straight line speed of the M4, for me it is either RC-F or bust. I think RC-F will be dynamically a better handling car around the track since it has a dedicated chassis as opposed to the baseline chassis of M4 being the much criticized 3-series chassis. The engine also like you said is much more exciting in the RC-F.

Put it altogether with the Lexus reliability, quality and durability, it is a tough combination to beat.


Originally Posted by eoph
I don't think it'll beat the M4 in straightline speed though. Over on the bimmer forums they're saying the M4 is underrated and probably makes 455hp based on the 118mph trap speed and weight, and mostly cause I don't think Lexus will have launch control. The Carbon package can probably only drop 50 lbs from the RC F max, mostly from losing the moonroof. Still, I like the RC F powerplant better with it's 'unending acceleration' feeling.
Reply
Old May 13, 2014 | 10:13 PM
  #36  
eoph's Avatar
eoph
Pit Crew
 
Joined: Jan 2012
Posts: 247
Likes: 0
From: Alberta
Default

Originally Posted by 05RollaXRS
How did they get the 118 mph trap speed? I don't believe it has been tested yet.

Anyway, even if the RC-F is only able to match the straight line speed of the M4, for me it is either RC-F or bust. I think RC-F will be dynamically a better handling car around the track since it has a dedicated chassis as opposed to the baseline chassis of M4 being the much criticized 3-series chassis. The engine also like you said is much more exciting in the RC-F.

Put it altogether with the Lexus reliability, quality and durability, it is a tough combination to beat.
Some dude privately tested his M3: http://f80.bimmerpost.com/forums/sho...d.php?t=984354
I think the RCF is more like the next gen M3, may not be the fastest a straightline, but touches all the right spots. It'll definitely be more interesting modded as well, the new M3/4 has an even smaller turbo than the 335i, so I don't see the top end problem being fixed easily with a tune.
Reply
Old May 13, 2014 | 10:31 PM
  #37  
05RollaXRS's Avatar
05RollaXRS
Lexus Champion
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Oct 2005
Posts: 10,364
Likes: 2,762
From: Calgary, AB
Default

Originally Posted by eoph
Some dude privately tested his M3: http://f80.bimmerpost.com/forums/sho...d.php?t=984354
I think the RCF is more like the next gen M3, may not be the fastest a straightline, but touches all the right spots. It'll definitely be more interesting modded as well, the new M3/4 has an even smaller turbo than the 335i, so I don't see the top end problem being fixed easily with a tune.
12.2 seconds seems to be about right for 400 meters (402 meters or 1/4 mile would be around 12.3 - 12.4 secs). The RS5 and C63 507 did 12.2 seconds in recent MT test. I would expect the RC-F to be dipping down in the low low 12s. I believe RC-F will have the same brake torquing technique the IS-F had (allowed brake torquing from around 3500 - 4000 rpm).

BMW actually went through to great lengths in encrypting the ECU so tuning would be very difficult on the new M4.

Last edited by 05RollaXRS; May 13, 2014 at 10:42 PM.
Reply
Old May 14, 2014 | 05:17 AM
  #38  
4TehNguyen's Avatar
4TehNguyen
Lexus Fanatic
20 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (1)
 
Joined: Jan 2006
Posts: 26,218
Likes: 79
From: Houston, Texas
Default

thats the tradeoff you get doing turbos, if you want fast response and reduced lag you have to go with small turbos but that also means those small turbos cant provide enough boost at high rpms. Just the reverse if you want bigger turbos for better high end, youll have lag at the low end. F it, I want a V8 so you dont have to deal with that. Tune isnt going to fix a mechanical limitation, its going to need bigger turbos to fix the top end but thats going to mean more lag
Reply
Old May 14, 2014 | 07:11 AM
  #39  
05RollaXRS's Avatar
05RollaXRS
Lexus Champion
20 Year Member
Liked
Loved
Community Favorite
 
Joined: Oct 2005
Posts: 10,364
Likes: 2,762
From: Calgary, AB
Default

Originally Posted by 4TehNguyen
thats the tradeoff you get doing turbos, if you want fast response and reduced lag you have to go with small turbos but that also means those small turbos cant provide enough boost at high rpms. Just the reverse if you want bigger turbos for better high end, youll have lag at the low end. F it, I want a V8 so you dont have to deal with that. Tune isnt going to fix a mechanical limitation, its going to need bigger turbos to fix the top end but thats going to mean more lag
If you watch the video in the link Eoph posted, in the lower gears the massive "hole" at the top rpm past 6000 rpm is somewhat masked due to torque multiplication of lower gears. However, once it gets into the taller gears and gets over 180 km/h, that massive hole is blown wide open. It took forever for the M4 to get from 180 km/h to 250 km/h. It was struggling to reach redline in higher gears.

Last edited by 05RollaXRS; May 14, 2014 at 08:05 AM.
Reply
Old May 26, 2014 | 06:42 AM
  #40  
LexISguy's Avatar
LexISguy
Lexus Champion
 
Joined: Sep 2007
Posts: 2,279
Likes: 2
From: Pembroke Pines, FL
Default

Originally Posted by Joe Z
Shhhhh... You'll spoil the surprise

~ Joe Z
ooops My Bad
Reply
Old May 26, 2014 | 06:45 AM
  #41  
LexISguy's Avatar
LexISguy
Lexus Champion
 
Joined: Sep 2007
Posts: 2,279
Likes: 2
From: Pembroke Pines, FL
Default

Originally Posted by 4TehNguyen
adding headers and exhaust on this should unleash a lot more power like it does on the current 5.0
At first we might see an air intake then the goodies will come up down the line....
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Giggzz
GS - 3rd Gen (2006-2011)
11
Aug 23, 2007 01:56 PM
5gears-IS
Car Chat
8
Oct 20, 2005 05:12 AM
GFerg
Car Chat
15
Jul 20, 2005 12:55 PM
ARISTO*7
Car Chat
16
May 29, 2005 07:21 PM




All times are GMT -7. The time now is 12:36 AM.