Who says stock Yank motors don't make power...

[RoverP6B]

85bhp/litre from pushrods without any forced induction, and GM sandbagging on true output by 70bhp... take that, those of you who insist all great engines are DOHC!

http://www.lsxtv.com/news/danzio-performance-basel...

[RoverP6B]

Honda had to push their engines to upwards of 8000rpm and they made virtually no torque. You can get 100bhp/litre out of pushrod V8s too, but only really by boring them out, destroking them and making them rev to kingdom come. This is a great big thumper of a V8 - and don't forget, a C63 AMG with Performance Pack, from a marginally bigger engine (6208cc vs 6162cc), made only 487bhp - this thing is nearly 50bhp up on that.

[RoverP6B]

Once again - small, short-stroke engines with very little torque. Compare it to the comparable - big, torquey motors of over 5 litres' displacement.

[RoverP6B]

Read the article. 525 lb-ft peak torque. That also translates to 85ftlb/litre. By contrast, a C63 AMG Performance Pack makes only 71ftlb/litre. BMW E92 M3 made 75ftlb/litre but at much higher revs (being a much smaller engine). AMG's M120 7.3 V12 in the Zonda makes 71ftlb/litre. BMW E65 760i makes 73ftlb/litre. Rolls-Royce Phantom variant of that engine makes 78ftlb/litre, as does the Lamborghini Aventador. The only remotely comparable engine is the 6,262cc Ferrari V12 in the F12, which makes 81ftlb/litre. The FF is barely detuned, so that also counts.

Then, there's the simple fact that a GM small-block OHV engine is physically tiny for its displacement - probably the only comparable engines in terms of physical bulk would be some of the very small V6s of the 1990s.

[RoverP6B]

Horse Pop said:

What they're doing with a supposedly outmoded technology like a NA pushrod V8 is pretty amazing really.

Am I not correct in saying DOHC has actually been around for longer than OHV? Pretty sure DOHC was around before the First World War, whereas I think OHV only really appeared in the 1920s...

[RoverP6B]

CrutyRammers said:

This crap again? The Honda engines made the same amount of torque as any other engines their size, but they extended the power band upwards by about 3000 rpm as well. They did make less torque than larger engines producing the same power at lower rpm, as you'd expect.

There are certainly benefits to pushrods, packaging, weight, and parasitic drag being the ones I'm aware of.

Compare a Honda VTEC 2.0 to a VW or Vauxhall engine of the same size - I think you'll find the Honda motor is wider of bore, shorter of stroke, enabling it to rev higher and make that power. You have to rev them much harder to get to the torque than with most 2-litre fours.

Mr2Mike said:

One thing you aren't taking into account. The power and torque figures for American engines (whether original or tuned by the aftermarket) are notoriously full of BS.

Yes, that's the point. It turned out GM were sandbagging - the engine made a lot more power and torque on the dyno than the book figures.

ZX10R NIN said:

Hate to burst your bubble on this one but the 6208cc Merc lump makes 525BHP 464lb/ft Torque it's detuned when it's put in the C63, so you're case doesn't stack up.

The M156/M159 goes as far as 618bhp in the SLS, but it never makes more than 470ftlb AFAIK - compared to 525ftlb for the near-identically-sized GM pushrod lump.

Max_Torque said:

Did you miss the "as std" part? Those are "LS based racing engines" according to the web site, and even then, they only make roughly the same power as the fully EU type approved (Eu6 emissions, driveby noise etc etc) production AMG engine! If we are allowing race engines, the (inlet/rev restricted) SLS AMG GT3 engine makes 552bhp, and the (downstroked) 5 litre M159 AMG race engine makes 650bhp even with the mandatory 7500rpm limiter necessary for sports cars!!

I think Troubleatmill rather went off at a tangent. The bog-standard LT1 is making 530bhp N/A, fully emissions/noise approved etc.

Toltec said:

Not sure what the op is trying to prove, if I was building a Cobra or LMP replica a then one of the modern American V8 crate engines would be perfect.

Trying to combat the prejudice evident on this board against American cars and engines!

Benbay001 said:

RoverP6B said:

You can get 100bhp/litre out of pushrod V8s too, but only really by boring them out

I spot a flaw.

That's what GM and countless tuners have been doing ever since the OHV V8 arrived on the scene. Just like an LS7 is a handbuilt, bored-out, blueprinted race version of an LS3. You can destroke these motors to make them rev, fit tougher valve springs and VTEC-like revs are entirely possible, but you wouldn't want to live with it on a daily basis, because it's going to be about as civilised as an irritable, hungry tiger.

Max_Torque said:

a bendy, heavy push rod between the camshaft and the valve limits valve acceleration, which is why no true high performance engines use them

Which is why they don't just make pushrods out of any old heavy, soft metal. As for true high-performance engines, the 5.8 litre NASCAR pushrod V8 makes 850bhp @ 9000rpm or thereabouts...

Max_Torque said:

So the "basic numbers" aren't there. Std 6.2 LS engines make about 430 bhp.

The LS is no longer the latest tech... it's been replaced by the LT... and the new LT1 is making 530bhp from the same 6162cc block and bottom end as the LS3. 100bhp just from the heads and direct injection.

[RoverP6B]

AER said:

LT1 makes 460hp in the US-homologated C7 Corvette. If 530hp was street legal and reliable, do you think they might have sold it as such?

That's what GM say. The truth is it's making 70 more bhp than estimated. GM aren't alone in sandbagging - it's well-known that BMW and Porsche BHP claims are often rather conservative.

[RoverP6B]

GravelBen said:

Its always funny when people post photos of a stripped down LS next to other engines complete with manifolds and ancillaries to try and show how compact the LS is.

Ignore the ancillaries and manifolds, just look at the size of the block and heads... especially the LS next to the Ford Modular DOHC V8.

[RoverP6B]

Evoluzione said:

There are a few good reasons why the Meercans still use carbs, 2v per cyl and inches - one is because they're 20yrs behind everyone else.

They don't use carbs, haven't in donkey's years, except in NASCAR, and even there I think fuel injection is making inroads. As regards cubic inches, I find them (like most Imperial units) much more useful than the equivalent metric units.

[RoverP6B]

swerni said:

Again, substantially more HP than claimed - what have you done to it, if anything?

Regarding those saying the dyno test wasn't representative - you've got to have an alternator and battery to run the ECU, ignition, injection etc, and the lack of an exhaust only compensates for the lack of a proper induction system having air rammed into it by the car's motion...

[RoverP6B]

R8VXF said:

That will be at the wheels if I know Surrey Rolling Road, factor in the 15-20% driveline losses on top of that figure...

So we're looking at 662-704bhp at the crank? Based on the median of those two figures, that suggests 35% more power than claimed, or else their dyno is overreading significantly, or a bit of both.

swerni said:

I wouldn't call 12- 13% substantial.

I wouldn't when it's on top of 150bhp, but on top of 505bhp, you're going to feel that extra 60bhp... but can you comment on R8VXF's comment above?

[RoverP6B]

stevesingo said:

That is not a wheel horse power figure! Unless you are so delusionally blinded by your love of OHV V8 engines. Manufacturers do not homologate engines at 80% of their true power, why would they. If GM could homologate the engine in the Corvette at 700hp, they would. Think of the marketing value in such a figure.

I was just responding to the other poster who said take the figure quoted and then add in the 15-20% driveline losses on top of that. Manufacturers often sandbag over power output - Porsche is well-known for so doing, and BMW F10 M5 owners have reported their cars topping 600hp on the dyno when the book figure is 552PS. Chrysler, meanwhile, with its Hellcat range, quotes 707hp and 650ftlb, but dynos are picking up quite a bit more than that (MotorTrend got 635whp and 591wtq on K&N's pretty accurate dyno, so reckon on 747hp/695ftlb at the crank - a subsequent MT dyno test elsewhere saw consistent results of 666-672whp/604/606wtq, which is probably down to dyno optimism - in all cases, it was running Chrysler's 8-speed TorqueFlite autobox, which is a license-built copy of the ZF 8HP) - and a Jalopnik article has stated that (according to an anonymous Chrysler insider), with a MAF sensor and wideband O2 sensor rather than its usual MAP sensor, they're able to reduce emissions significantly, such that power raises (to as much as 825bhp) could be in the offing... all unverified at the moment, of course, but it'll be interesting to see how they get on...

swerni said:

Ever driven a 500+ BHP car weighing 1400kgs? 60bhp is going to make very little difference.

No, I haven't. I would still have thought you'd feel it...