Today's 160 mph 2.4 Liter Targa is...

[Jeff Higgins]

A 287 RWHP 2.7. I'm currently in a discussion on another forum with its owner. It's twin plugged, 10:1 compression, running PMO throttle bodies and some form of EFI. That's all he can tell me - he just "writes the checks", and besides, the guy who built it has "spent a lifetime honing his skills" and would prefer his "secrets" not be shared on the internet. This is a street motor, on pump gas.

I'm trying to convince him it's really 187, not 287, which is still respectable for a 2.7. He's having none of it. The engine builder told him it's so, so that's just the way it is. Besides, he's spent a lot of money on this...

[Noah930]

With or without the thermal reactors?

[Ayles]

I have the Dyno sheet on mine, built and tuned by Dick Elverude carbed euro 3.0 with 289 at the crank. And it’s in a Targa

[colingreene]

Wicked Sixes built Magnus walker a 2.5 that makes 287 at the tires...

[pwd72s]

Considering how much horsepower can be found in cars being made today, why are these numbers a big deal?

[Heel n Toe]

Originally Posted by pwd72s

Considering how much horsepower can be found in cars being made today, why are these numbers a big deal?

Good job, Debbie Downer.

Why not say something really dumb like "a Dodge Challenger would be faster"?

[sc_rufctr]

Originally Posted by colingreene

Wicked Sixes built Magnus walker a 2.5 that makes 287 at the tires...

That's crazy... I'm imagining a bill somewhere around $60,000 for an engine like that!

[slow&rusty]

I'm confused at the OP, your subject title says 2.4L but the body of your thread says 2.7L, which is it?

[Chocaholic]

Sellers always enjoy shoppers who tell them they’re lying about their car.

[masraum]

Originally Posted by Heel n Toe

Good job, Debbie Downer.

Why not say something really dumb like "a Dodge Challenger would be faster"?

Or a mustang

[oldE]

Originally Posted by slow&rusty

I'm confused at the OP, your subject title says 2.4L but the body of your thread says 2.7L, which is it?

The 2.4 l Targa became a meme around here, hence the reference.

As for the hoopla about the horsepower ratings being squeezed out of these motors today, consider forty years ago, you had to hang a turbo off the things to make those numbers.

Impressive indeed.

Best
Les

[GH85Carrera]

Originally Posted by pwd72s

Considering how much horsepower can be found in cars being made today, why are these numbers a big deal?

Look at modern Porsche engines designed in recent times. Lots of power from a 4 cylinder engine. But they start with a clean piece of paper, well a fresh computer page. They get to design in modern manufacturing tolerances and methods. Not starting with an engine designed in 1960 with a slide rule and pen on paper.

[mepstein]

Porsche was getting 230-240 out of the 2 liters years ago. I hear the guys are getting 250-270 these days. Pricy I'm sure.

[Bob Kontak]

Originally Posted by GH85Carrera

Look at modern Porsche engines designed in recent times. Lots of power from a 4 cylinder engine. But they start with a clean piece of paper, well a fresh computer page. They get to design in modern manufacturing tolerances and methods. Not starting with an engine designed in 1960 with a slide rule and pen on paper.

Four valves and variable valve timing make a big difference.

[island911]

Originally Posted by pwd72s

Considering how much horsepower can be found in cars being made today, why are these numbers a big deal?

Because, as Jeff sez, 10:1 CR.

Modern motors are running much higher compression ratios for higher thermal efficiencies. In-cylinder injection is another big part of high numbers (controlling the burn/chem kinetics in a higher CR engine.)

And then there's the thermal physics of air-cooled motors. -steady state power is dependent on how fast you can remove excess heat.

[Jeff Higgins]

There is only one way that these old air cooled motors can come anywhere close to these wild horsepower claims - exceedingly high rpm's. An engine is essentially an air pump. Horsepower is a function of its ability to pump air - the more it pumps, the more power it makes. Only two ways to make it pump more - make it bigger or spin it faster.

In this particular case, using the +15% correction factor, this 2.7 is making 330 horsepower at the crank. By way of comparison, the 2.8 RSR motor claimed just over 300 at the crank, at 8,500 rpm. Some simple math reveals that this 2.7 (with less compression than the 2.8 RSR) would have to be spinning close to 10,000 rpm to make that kind of power. Magnus's 2.5 would have to be spinning even faster.

I just find all of these wild claims rather humorous. I think one's willingness (or eagerness) to believe them runs in inverse proportion to one's actual experience with, and knowledge of, these motors. Yes, we do see some very high specific outputs from some modern engines, but look at the rpm's at which those numbers are produced. Our motors are simply not happy at those rpm's. Then, to make claims for these old motors actually exceeding these amazingly high specific outputs from these modern engines demands that they spin even faster. It's simply not possible.

Oh well. These folks seem to believe there is still some hidden "magic" to be found, allowing 2.7's to make 287 RWHP - at 6,800 rpm... They have no understanding as to why that simply isn't so, and get all pissy when challenged. They don't know enough to even carry on an informed conversation. Their engine builder has a secret...

[island911]

"An engine is essentially an air pump."

I cringe when ever I hear/read that. I know what you're saying but...

First there is the importance of fuel/air mixing and the control of the chemical kinetics. --the "bang" produced is of utmost importance.

Second, what you are talking about is limiting torque losses (preserving MEP) at higher rpm ... which comes back to the chemical kinetics.

Overall I agree with you that the HP claim on pump gas, naturally aspirated and 10:1 CR is dubious. I expect that their secret is that they are lying about the HP number, or lying about the work-around. Perhaps fuel used and CR. Perhaps it's unsustainable steady state /cooling.

[wildthing]

There's only one thing left to do really... loser pays for the dyno test.

[Jeff Higgins]

Originally Posted by island911

"An engine is essentially an air pump."

I cringe when ever I hear/read that. I know what you're saying but...

First there is the importance of fuel/air mixing and the control of the chemical kinetics. --the "bang" produced is of utmost importance.

Second, what you are talking about is limiting torque losses (preserving MEP) at higher rpm ... which comes back to the chemical kinetics.

Overall I agree with you that the HP claim on pump gas, naturally aspirated and 10:1 CR is dubious. I expect that their secret is that they are lying about the HP number, or lying about the work-around. Perhaps fuel used and CR. Perhaps it's unsustainable steady state /cooling.

Oh, I agree - the "air pump" analogy is horribly simplistic. It is somewhat useful, however, for forming an image for those who are not so mechanically inclined. You know, the sort who believe these kinds of horsepower numbers.

Far too many engine builders these days are reminiscent of the butcher with his "thumb on the scale". They feed a portion of the hobby wherein folks have a great deal of money to throw around, but no real basis for understanding what is happening. They get a motor out there that they have convinced a less than savvy customer has some pretty unrealistic numbers, he brags it up at the cars and coffee, and the next guy with a fat checkbook comes a'knockin'... And the honest engine builder, who gave his customer real numbers, goes hungry.

[island911]

I get 50 hp extra with cleaning the intake with ShamWows - ask me how!