05RollaXRS

From description:

ISFPOWER

iTrader: (20)

Davew77

There's a lot of Mustangs... haha

They looked pretty much even. So a FBO RC F should be faster then. It matters little to me though. I wouldn't want a 4 door even if it was faster.

mjeds

what is FBO?

bnizzle87

Full Bolt Ons....Intake, exhaust, headers.

Deanrcf

iTrader: (1)

the RCF has crazy top end where the weight doesn't matter so much. its just engineered to breathe better up top

DJsISF

I have pulled on a few RCFs here in socal. Don't know if they are on the board though. I guess maybe its a drivers thing. I'm headers, exhaust, and tune. For that matter Ive pulled other ISF with the same mods lol

DJsISF

this is true however in real world scenarios all lexus did was improve the flow of the stock headers. Basically go off the designs that tuners did to improve ISF breathing.. That's why RCF don't pick up big gains from header installs like the ISF does. RCF already flows sufficiently. Just my .02

SlowXIsf

to clear things up a bit, the isf in the vid has a cel from headers and is in limp mode. i have exhaust and intake and stay neck and neck with the FBO and tune isf.

LRCSALES

iTrader: (1)

i second that. im a die hard coupe fan.

Deanrcf

iTrader: (1)

although headers are mentioned below, I'm pretty sure Lexus did more than just update the headers to get the extra power and top end pull:


New or redesigned parts include:

• Cylinder heads and cam covers
• Crankshaft: crank pin diameter, connecting rod big-end bearing size and crank counter-weight size are all reduced, to reduce reciprocating weight
• Crank main bearings and caps
• High-strength forged connecting rods
• Pistons and piston rings
• Titanium inlet and exhaust valves
• Intake manifold and throttle body
• Redesigned Variable Valve Timing-intelligent Electric motor (VVT-iE)
• Revised Lexus D-4S dual injection system
• Four-into-one exhaust headers and heat insulators
• Oil pan and baffle plate
• Alternator clutch system
• Engine and transmission oil coolers
• Spark plugs

Digging Into the Metal

• The new cylinder heads improve the 2UR-GSE engine’s breathing with improved porting and a high-flow/high tumble ratio. In addition, intake surge-tank capacity has been optimized, as have the intake manifold runner length and diameter.
• The new oil pan baffle shape reduces agitation and hence friction, while new air-to-oil coolers for the engine oil and transmission fluid increase track suitability.
• The Lexus D-4S dual-injection system has been redesigned, with higher injection pressure of 2,611 psi and improved fuel atomization.
• The throttle diameter was increased by 10 percent, from 3 to 3.3 inches (84 mm).
• A new intake camshaft profile increases valve lift and suits the Atkinson cycle, while improvements to the electronic VVT-iE system have expanded its range of operation for increased fuel economy and performance.
• New four-into-two exhaust headers help reduce interference and hence further improve engine breathing. The larger-diameter exhaust system is designed to reduce backpressure and sound amazing, especially under acceleration. At the same time, the main muffler keeps things from getting too rowdy at lower speeds.
• As a final touch, the new 2UR-GSE engine has a one-way clutch on the alternator pulley.

When I built my VQ i had the cams, valves and springs upgraded to allow me to rev safely 500 extra rpm and to make power doing so

DJsISF

yes...they obviously did more than change the headers design....my point was the so-called top end you are referring to does nothing to leave an ISF behind. I have raced several RCF and a GSF with gutted cats. Did any of them pull on me with this magical top end? Nope. That was my point in a nutshell. you just listed an entire engine upgrade list that doesn't amount to very much.

DJsISF

and by no means I'm I disrespecting the RCF. I think it is a badass car! Would I trade in my ISF for a much more expensive car and get absolutely no increase in speed and might actually be slower, No. I don't think many people would..

IMCHIA

I may or may not know the owner of that RCF.

However, I just wanted to just wanted to give you guys some input on ISF vs RCF... stock for stock RCF is slightly quicker. My best friend has an ISF and this is how we compared:

Stock RCF vs ISF with Exhaust and Intake - We were even each and every match (we've done over 30 runs). With maybe a slight advantage for the ISF as I weigh an additional 90 lbs more than he does.
Stock RCF vs ISF (Intake/Exhaust/Headers) - No competition. ISF Clearly faster.
RCF with Exhaust vs ISF (Intake/Exhaust/Headers/Tune) - Very close - driver race. I would give him the slightest of edge here as well.

At the end of the day, no way is a stock RCF slower than a stock ISF. That's pretty much clear. As SlowXISF mentioned, the FBO ISF in this particular video (not my best friend's ISF) may not be at its full potential. The owner is trying to work to clear the code.

This is RCF with Exhaust vs ISF (w/ res delete). Judge by the video - the ISF was a bit behind the RCF when honking but jumped a bit, however the RCF pulled hard on top end.

Davew77

So limp mode for a Lexus only slows the car down a little bit? That's very abnormal. A vehicle's limp mode usually makes a dramatic difference in the way it performs. Like by cutting the throttle by 25%, limited the RPM by as much, preventing use in higher gears, etc... But you guys are telling me that Lexus limp mode only slows the car down by a couple of tenths in a 1/4 mile run? I don't buy it...

The OP also states that the IS F has a tune. So it shouldn't be throwing any CEL codes at all. Unless the OP is lying.