LexFather

So whats your final guess?
I say 420.

lobuxracer

iTrader: (2)

My best source says 432 hp. I'll stick with that...

Manoj

My pick 412HP...... I don't mind how much high it will be... as i dont plan to use its entire HP anytime.... LoL

joonsta

I was thinking like 600...

Lexus is known to underrate their engine output numbers.

KJH

Bear in mind C/D reported months ago that the 5L V8 had made as much as 483 bhp in an (at the time) IS 500 mule. To me, part of the answer may depend on other F-series cars. If the LF-A makes around 570 bhp as recently reported and the GS-F 500 with potentially a detuned version of the LF-A's 4.8L V10 making about 500 bhp, Lexus can afford to stretch a bit on the IS-F 500 and give it 450+ bhp without having the power and performance compression issues that afflict the supercharged AMG cars significantly and the turboed AMG cars to a lesser degree.

If Lexus gets the same 82.6 hp/liter from the 5L motor it has gotten from the LS 460's 4.6L V8, the car would produce 413 bhp. To me, that seems overly conservative since the RS4 and new V8 M3 are both producing similar power with less displacement. Lexus repeatedly says the car will have more than 350 lb-ft. Given that the 4.6L motor produces 367 lb-ft, it stands to reason an out and out performance motor could have substantially more bhp/liter than the 4.6L motor and a slightly less torque peak that a higher horsepower peak would imply. If Lexus adopts the same approach with this motor that Toyota adopted with the new Tundra 5.7L V8, that is to say more power and torque than anything in its class, I think we'll all be happy campers.

is-fan

Hi All. I'm a new member here and just registered tonight. I'm stoked about the IS-F.

My estimate/quess is 437 hp, and I'll let you try to figure out how I came up with that number My torque estimate is 376 foot-pounds.

Does the person with the closest guess win a prize? LOL

MR_F1

This is a tough guess. The fact that Lexus says "400+hp" makes me want to think that they will do something wimpy like 415hp.
If it indeed has the same specific output as the 4.6L, then that would be about right.

However, The optimist somewhere deep down inside of me whats to think that the F division will do for Lexus, what Lexus they did for Toyota in 1989, just this time in the performance arena.
The fact that Yamaha is tuning the engine heads, and the designation is 2UR-GSE makes me think that this engine will be more than just "400+hp".
I want to believe this motor has serious potential and might just go toe to toe with Mercedes offering around 450hp. Furthermore, the torque figure on the hybrid iteration of this motor is 389 ft/lbs. In 'F' trim, that has performance tuned heads and according to the tach, redlines at about 7000rpm (as opposed to 6500rpm).

so at worst, I say 415hp/390ft-lbs
at best (and here is hoping), at least 450hp/400ft-lbs

I voted somewhere in between, 420-425hp

Carbman

That's easy, it's a simple mathematic extrapolation of the HP/liter ratio of the IS 350. Do I win a prize? I have no idea how you arrived at the torque number, inside info? I similar extrapolation of the IS350 torque number would put the IS-F at 395 lb.-ft. Joking aside, I like your estimates. I am no gearhead, but I suspect the G heads are high flow which would mean higher peak HP and rpms at the expense of some torque. I think Lexus could tune the engine for 450 easily, but given their emphasis on reliability, drivability, emissions and gas mileage they will probably opt for a lower number. I second your guess of 437HP and 376 lb-ft. If we are right this car is going to put up some pretty impressive performance numbers (if they can keep the weight below 3700 lbs.)

is-fan

You are right about my hp number being an extrapolation of the IS350 rating I agree that engine can easily be tuned for very high power and also that they will engineer the engine for higher power, with the sacrifice of some low end torque. With the 8 speed transmission, and the right gearing, the 375+ lb-ft of torque will be plenty. I have no inside info. I'm certain the IS-F will be very impressive. I think Lexus needs to beat BMWs new M3 in the power department, but I don't think they will go as high as the power of the C63 AMG Mercedes.

LexFather

Well this is the same engine in the LS 600hl and DETUNED I believe it makes 400hp and the electric motors make up the 38hp....

So this new 5.0 could really be a beast...Lexus has always had lower displacement than the Germans with equal or better acceleration.

FiveOhNine

I'd rather see 400ish HP and gobs of torque!

Though if they can make it 450+ hp and gobs of torque, I'd take that too.

Carbman

There was an article in the April 2006 R&T mag about future Japanese sports cars which said that Toyota was developing a new Supra and Lexus IS 500. Both would be powered by the same 5 liter V-8 putting out 450 hp and 383 lb-ft of torque in the Supra and detuned slightly for the IS 500 (IS-F). They blew the call on the Supra, but did get the IS-F and engine size correct. I am thinking they may have also gotten an accurate tip on the hp and tq numbers. If so, then 437 hp SAE and 376 lb-ft is a reasonable guess on the final numbers. That would beat the M3 and RS 4 in hp and tq and put them within striking distance of the C63 AMG in terms of hp, but no match for the Mercedes 443 lb-ft of torque. I think the real battle between the IS-F and C63 will come down to price and which has developed the better tranny.

One final hp thought.....you can bet your bottom dollar that Lexus marketing leaned heavily on engineering to make sure they beat the 420 hp number of the M3 and RS 4 (437hp would also give the IS-F bragging rights over the new 430hp Vette)

flipside909

Over 400 HP. Guaranteed!

is-fan

Hi flipside. Do you you have some more detailed information you can share regarding the power? It sounds like you know something more.

MR_F1

ok..........fair enough


what did you vote by the way?