lobuxracer

iTrader: (2)

We could really turn this into a gearhead discussion, but it would detract from the OP's intent. Simplified discussions of why V-8s don't make power over 5500 rpm are pointless.

Suffice it to say, where the engine makes torque has everything to do with how the engine makes horsepower. V-8s for street use are never biased for torque at high rpm, so their fundamental design does not support this. It is not hard to change this from a mechanical perspective if you make a few assumptions, and certainly, if you took a pair of Honda B-16s you'd be able to make really good power at high rpm. It's just not what V-8 buyers (who will purchase in QUANTITY) want. They want the big engine so they don't have to rev it hard to get power out of it.

Anyway...I'm sure the IS-F makes good torque throughout the rev range, and if it needed more rpm to make more power, they certainly could have done it. Apparently, they didn't need to.

TRDFantasy

Indeed. We could be in for a surprise with the power figures.

MR_F1

Thanks for stating the obvious.

Blizzy

iTrader: (-1)

just trying to make the point that more revs don't necessarily translate to more power. you were the one so willing highlight the fact that a higher redline means more horsepower.

gsrthomas

iTrader: (1)

Is the IS-F engine just a beefed up LS460 motor??

The new M3 that is coming out didnt bmw design that engine to be a "M" engine??

If thats the case I give a to Lexus because they should of developed a specific engine for the IS-F and not just change internals.

4TehNguyen

iTrader: (1)

and the engine makes significantly more torque than the 4.0 M3 engine, so what. Its a tuned 5.0 V8 from the LS600h which is from the LS460. You want them to develop a specific engine yet keep the price down at the same time, you cant have both. Give me torque over revving a smaller engine to 8k any day which is what youre going to have to do on the new M3

New M3 engine is the M5 engine with 2 cylinders chopped off

TRDFantasy

The IS-F's 5.0L engine is based on the LS460's 4.6L engine, but it's not the same thing. It has different cylinder heads, and likely different internals.

Also FYI, the Lexus UR engine series (the base engine architecture that the LS460 and IS-F use) was developed in parallel with Toyota's F1 engine program so the 4.6L engine is a very good starting point to base the IS-F's engine on.

LexFather

Lexus has never made a high revving engine, i.e over 7000 RPM. The power on a Lexus is very useful.

Its their first effort. Who is to say it won't be like that next time

TRDFantasy

But we will soon see a Lexus engine with over 8000 RPM . *That* will be new territory for a Lexus engine definitely.

LexFather

Correct, the first, in a proper supercar. Its useable, it will hit 200mph, thus it has to have a higher redline.

The IS-F won't hit 200mph and will rarely be used anywhere near its limit. sad really when you think of all these cars and their performance and potential and it is rarely tapped.

Blizzy

iTrader: (-1)

I consider it our duty as Club Lexus guys to do the Toyota engineers proud by taking the next step with our cars...before going back to the well and making another.

Christian8

It's definately not the same engine. All other Toyota and Lexus engines have "FE" or "FSE" heads while the IS-F engine is the ONLY engine that Toyota has in the USA now that is a "G-Type." And its not just a GE but a GSE head. Oil scavenging pumps and a different head design are only part of it.

TRDFantasy

This is actually the first new-generation Toyota engine to use G-heads, and the first Toyota engine in North America in years to see G-heads. And it's also the first Toyota engine in the world to combine G heads with direct + port injection (D4-S). On top of everything we know that includes the oil scavenging pumps, I expect some further modifications to the engine internals to withstand persistent high-RPM abuse of the engine and for it to run reliably under extended periods of time while under intense conditions. Toyota's F1 and Motorsport divisions are working closely with the Lexus F program.

RocketGuy3

iTrader: (1)

I have never been able to understand the advantage of super high-revving engines, other than maybe that they're more fun or sound better.

Even if you *can* get more peak power, isn't the torque curve more important anyways? If you reach peak torque well before redline, I don't understand why you would want the engine to keep spinning faster.

I'm not claiming to be an expert... just doesn't make sense to me.

EDIT: Is it because in racing engines, you spend most of your time in a higher RPM range, so the engines are designed to have a later peak torque? And hence rev higher for a later peak power? But I still don't see why a racing engine couldn't work just fine if the torque came earlier, and the redline also came earlier...

lobuxracer

iTrader: (2)

Read this. It will help you understand why torque by itself isn't important, but WHERE you make torque is everything. If low revs and torque were everything, we'd all be racing diesels. Of course that day may yet come, but so far, gasoline has reigned supreme for making a lot of power until you get to exotic fuels like methanol with nitromethane.