TRDFantasy

We all know it's over 400HP, that much is certain .

My vote goes for over 430HP, and 390 - 410 lb-ft.

mr. haison

It will have 415hp so it can be 1hp over the new M3, but I wish it will have 400lb of torque.

4TehNguyen

iTrader: (1)

the 5.0 from the LS600h makes around 385 ft lbs torque, IS-F specs say over 350 ft lbs. so in the ballpark of 350-375 is a good estimate

GoHuskers

My source from japan said few months ago that it will have 436 hp and 375 ft-lbs of torque.

olorin

Did some calculations this afternoon. Excuse the lack of hp and ft-lbs.

Let's take two existing engines:

• 4.6-litre V8 from the LS460
• 3.5-litre V6 from the IS350

The specific output of the LS460's engine is as follows:

283kW: 62kW/L
498Nm: 108Nm/L

For the IS350:

228kW: 65kW/L
375Nm: 107Nm/L

My speculation entails extrapolation of the highest specific figures, for starters. This leaves us with:

65kW/L x 5.0L = 325kW
108Nm/L = 540Nm

Given the IS350's 228kW at 6400r/min (of 6500 usable revs), and the IS-F's red line at 7000r/min (see here), I conclude that 436hp is fairly conservative.

My estimation is 330kW/540Nm.

Rickster31

Yeah.. what he said... lol

FiveOhNine

I would prefer more tq, but if it can lose a few hundred pounds more than the IS350, I can deal

is-fan

Hmm...Those numbers are within plus/minus one of my unscientific guestimates. I guess we will have to wait and see. I read somewhere on here that there would be an August press release regarding the IS-F. Maybe they will release more information about it then.

Here is a related topic on autospies:

http://www.autospies.com/news/How-Mu...ut-With-17730/

TRDFantasy

Let's not forget that the 5.0L 2GR-GSE isn't just an enlarged 4.6L. Apart from having a higher redline and slightly more displacement, the engine has unique cylinder heads (G heads, which haven't been seen on a new Toyota engine in years) compared to the "F" heads of the 4.6L 1UR-FSE.

In Toyota terminology, "F" cylinder heads refer to economy narrow-angle DOHC. "G" heads refer to performance wide-angle DOHC. Plus, seeing as this is not a regular Lexus, but a high-performance Lexus, the engine may be tuned more towards performance, and less towards fuel economy.

For a rough comparison, the race-spec 3.5L V6 2GR-FSE that was to be used in the IS350 GT2 cars in ALMS makes over 470HP and about 330 lb-ft. Now although this is a race-spec engine, it has a lot less displacement than the IS-F's 5.0L, and the IS-F was developed with a lot of motorsport and racing input.

With all this in mind, estimates of 415 - 425HP do seem overly conservative.

olorin

Has Lexus issued any press releases with the engine code explicitly stated? Or are we guessing?

Allen K

iTrader: (4)

I honestly don't care how much HP this car puts out as long as the handling is on par with its competitors...

TRDFantasy

Yes. Lexus Europe has explicitly stated that the engine code is 2UR-GSE. The PR thread from the Geneva Auto Show can be found here:

https://www.clublexus.com/forums/sho...IS-F+europe+PR

lobuxracer

iTrader: (2)

I seriously doubt the included valve angle will be more than the 15 degrees we see on the F heads. All the bike engines (including Yamaha's) have extremely narrow included angles on the valves these days, and bikes are not having any issues with specific output. The only reason the engineer's don't like this in cars is because it makes the hood line higher. Maybe the engineers will win one this time and get the head design more modern than the last G heads that used 1960's pentroof technology.

TRDFantasy

I agree; the valve angle may actually stay the same as the F heads, but historically in Toyota terminology G heads have referred to a more wide angle design. Also having too much of a wide angle may cause real fitment problems inside the engine bay. Then again, the IS has that raised hood so who knows.

I am guessing the G heads for the IS-F were designed collaboratively with Toyota (and some motorsports input) and Yamaha. I am quite confident these G heads will be a modern design. Considering the fact that the 2UR uses a lot of tricked out tech like dual injectors per cylinder and electronically driven intake VVT, there is huge performance potential that can be extracted out the engine; more so than what Team Lexus did with the 2GR-FSE in the IS350 GT2 cars.

lobuxracer

iTrader: (2)

I'm still pretty convinced Toyota typically builds an engine with twice the stock output, tests it extensively for durability and performance, then detunes it to half the power they made in development. I've seen far too many Toyota engines fully capable of supporting twice their stock output with few if any changes to the long block. Just one of the reasons I buy their stuff!

Also, FWIW, the IS350 makes 51 hp per cylinder. If we just added two cylinders with no other changes we'd get 408 hp. But that engine would only be 4608cc. If they went +4mm on the bore, it would be 5009cc. Dead on 5 litres. The alternative would be to keep the same bore but add 7mm of high rpm killing stroke for 4997cc. Stroking it will drop the 20 m/sec red line to 6660 rpm, keeping the 2GR stroke puts redline at a familiar 7500 rpm exactly. Oh, yeah, the IS350 has a lot more rpm capability than we can use with the OEM rev limiter. I think they're concerned about the valve train though, not mean piston speed.