LS numbers question

[anonymous-user]

I'm not the global pointy-head on this stuff but I think it goes as follows, all of the engines being clean sheet all-aluminium designs from 1997 at the earliest. 5.7 litre engines share capacity and bore spacing with previous Corvette engines but the similarity ends there. Except for the fact they're all pushrod....

LS1 - C5 Corvette, Monaro etc. 5.7 litres and around 350 bhp/350 ft lb. Warp factor 7
LS6 - C5 Corvette Z06. 5.7 litres in various power outputs around 385 to 405 bhp. (??) ft/lb. Warp factor 8
LS2 - C6 Corvette, late Monaro etc. 6 litres and around 400 bhp/400 ft/lb. Warp factor 8.5
LS7 - C6 Corvette Z06. 7 litres and around 500 bhp/500 ft/lb. Warp factor 10+

There ain't no substitute for cubes!

[Boosted Ls1]

Also less powerful LS1's were found in the z28's and pontiacs. Think they were about 320 bhp.

Boosted.

[anonymous-user]

Gazboy said:

Is a C6 Vette quicker than a C5 Zo6?

Z06 (C5) is a harder edged car and a few pounds lighter. It also had better tyres, stiffer chassis and revised suspension compared with base C5. In a straight line it may be too close to call in the real world although the older car might just have it. C6 comes in around $5,000 cheaper than Z06 (C5).

For the the record there are bigger differences between C6 and its Z06 brother than between C5 and its Z06 relation. Including a much bigger price differential.

[LuS1fer]

5USA said:

Gazboy said: Is a C6 Vette quicker than a C5 Zo6? Z06 (C5) is a harder edged car and a few pounds lighter. It also had better tyres, stiffer chassis and revised suspension compared with base C5. In a straight line it may be too close to call in the real world although the older car might just have it. C6 comes in around $5,000 cheaper than Z06 (C5). For the the record there are bigger differences between C6 and its Z06 brother than between C5 and its Z06 relation. Including a much bigger price differential.

Track figures show the C5 Z06 to be faster than the Z51-suspended C6. This is attributable to several things. The Z06 is lighter, it has a more rigid chassis as it's a hardtop, it doesn't use runflat tyres and the LS6 isn't as tightly reined as the LS2 via the computer allowing it an easier and fuller deployment of power before the computer steps in. It is also widely surmised and calculated that the C5 Z06 produced more like 425bhp than the 405bhp. Before anybody says the obvious "Why would any self-respecting manufacturer claim a lower power figure", I have no idea but both GM and Ford do, possibly to do with a "minimum power output" rather than a maximum power ouput. Various posted videos of C6 vs C5 Z06 (good old Americans are always the first to give a practical demonstration) have shown the C5 Z06 to have an easy advantage over the C6 but no more than a car length or two.

[vetteheadracer]

LuS1fer said:

It is also widely surmised and calculated that the C5 Z06 produced more like 425bhp than the 405bhp. Before anybody says the obvious "Why would any self-respecting manufacturer claim a lower power figure", I have no idea but both GM and Ford do, possibly to do with a "minimum power output" rather than a maximum power ouput.

The reason the figure is always the minimum is 'cos the Americans are likely to sue the manufacturer if their car didn't reach that figure on some good ol' boys dyno......you as a lawyer should know that!

[pentoman]

LuS1fer said:

5USA said: Gazboy said: Is a C6 Vette quicker than a C5 Zo6? Z06 (C5) is a harder edged car and a few pounds lighter. It also had better tyres, stiffer chassis and revised suspension compared with base C5. In a straight line it may be too close to call in the real world although the older car might just have it. C6 comes in around $5,000 cheaper than Z06 (C5). For the the record there are bigger differences between C6 and its Z06 brother than between C5 and its Z06 relation. Including a much bigger price differential. Track figures show the C5 Z06 to be faster than the Z51-suspended C6. This is attributable to several things. The Z06 is lighter, it has a more rigid chassis as it's a hardtop, it doesn't use runflat tyres and the LS6 isn't as tightly reined as the LS2 via the computer allowing it an easier and fuller deployment of power before the computer steps in. It is also widely surmised and calculated that the C5 Z06 produced more like 425bhp than the 405bhp. Before anybody says the obvious "Why would any self-respecting manufacturer claim a lower power figure", I have no idea but both GM and Ford do, possibly to do with a "minimum power output" rather than a maximum power ouput. Various posted videos of C6 vs C5 Z06 (good old Americans are always the first to give a practical demonstration) have shown the C5 Z06 to have an easy advantage over the C6 but no more than a car length or two.

I read that, with the late LS4 engined versions of the C4 vette (the very wedgey late '80s/early '90s one that Clarkson blew up with a helicopter), they had an underrated 330bhp so as not to overshadown the soon-to-follow C5 model.

Russell

[Boosted Ls1]

vetteheadracer said:

LuS1fer said: It is also widely surmised and calculated that the C5 Z06 produced more like 425bhp than the 405bhp. Before anybody says the obvious "Why would any self-respecting manufacturer claim a lower power figure", I have no idea but both GM and Ford do, possibly to do with a "minimum power output" rather than a maximum power ouput. The reason the figure is always the minimum is 'cos the Americans are likely to sue the manufacturer if their car didn't reach that figure on some good ol' boys dyno......you as a lawyer should know that!

Quite interesting this as I know of 2 brand new crate ls6 engines which only made 395 on the dyno in other words down 10 hp but this was with ancilliaries fitted. The ancilliaries may have sapped some hp. They also had aftermarket performance plug and play ecu's so I have to wonder what was going on. Only thing I can think of was inlet tract length may be critical.

Boosted.

[ringram]

I read a US car mag dyno'd a C5 and 02 Camaro and the camaro put down more power!
Ill try and dig the info up. Superior tune I guess.

Here you go, one of them anyway.. Drivetrain apparently..

http://forums.corvetteforum.com/showthread.php?t=119

>> Edited by ringram on Tuesday 10th January 21:44

[Boosted Ls1]

Gazboy said:

Boosted Ls1 said: Quite interesting this as I know of 2 brand new crate ls6 engines which only made 395 on the dyno in other words down 10 hp but this was with ancilliaries fitted. The ancilliaries may have sapped some hp. Isn't there a chap on here somewhere who works for Ford R&D- he mentioned that they test all their engines with all ancilliaries fitted????

I'm not sure Gaz but I sometimes hear claims which don't stack up. One of these angines was tested at a very prestigious car manufacturer with unlimited dyno facilities, in fact they had many dynos and wall to wall instrumantation. Despite all the skill and experience they had it wouldn't go past 395. I don't believe the claims of 425 hp out of the crate or 475 with just a change of rocker ratio as suggested on a posting some time back.

Boosted.

[LuS1fer]

It's always hard to get an accurate figure and there are variations between engines but stock C6 Z06's have been running 11's over the quarter mile and this would just not be possible according to the accepted hp calculations if it only produced 405bhp but I haven't got any hard dyno figures to hand.

[pentoman]

I find it weird how these pushrod engines can even make that sort of power.

OK so they're fairly large of displacement but how can a 60's (older?) based engine with pushrods (which means it'll be poor at high revs) and 2 valves per cylinder be making BMW M5 (old shape) levels of bhp/litre?

Is all that M-power thinking and technology pointless? Could you just get there with an old American V8 that probably costs about $3000?

Why do Mercedes need AMG to build them a 5.5 V8 that only makes 367bhp?


I'm missing something?

Russell

[Boosted Ls1]

pentoman said:

I find it weird how these pushrod engines can even make that sort of power. OK so they're fairly large of displacement but how can a 60's (older?) based engine with pushrods (which means it'll be poor at high revs) and 2 valves per cylinder be making BMW M5 (old shape) levels of bhp/litre? Is all that M-power thinking and technology pointless? Could you just get there with an old American V8 that probably costs about $3000? Why do Mercedes need AMG to build them a 5.5 V8 that only makes 367bhp? I'm missing something? Russell

Makes you wonder doesn't it?

The Lsx range of engines are way more advanced internally then the older stuff and were designed from scratch in the 90'ies. Performance in all departments was clearly the goal. So many small things were improved in one fell swoop. Only common part between old engines and the lsx is the big end shells. They also have modern efi which helps and a 6500 rpm limit for the vette, more so for the ls7.

Boosted.

[anonymous-user]

Boosted Ls1 said:

The Lsx range of engines are way more advanced internally...... They also have modern efi which helps and a 6500 rpm limit for the vette, more so for the ls7. Boosted.

Exactly. Mechanically simple although very high tech in terms of materials, electronics and production. KISS has been for many years and remains the way forward in just about every area of consumer technology.

[Keep It Simple, Stupid]

[pentoman]

But could we assume, then, that one of these small blocks, given JUST overhead cams and four valves per cylinder (no other fancy gubbins), might fairly easily make 100 bhp/litre and run for 100,000 miles problem free?

Impressive if true but I remain a little unsure.

[Boosted Ls1]

pentoman said:

But could we assume, then, that one of these small blocks, given JUST overhead cams and four valves per cylinder (no other fancy gubbins), might fairly easily make 100 bhp/litre and run for 100,000 miles problem free? Impressive if true but I remain a little unsure.

Maybe but at great expense and the americans like things cheap and simple. Also I think GM got their fingers burned with the quad cam before the lsx so they won't go there again. The ls6 made similar bhp and torque to the quad cam so we can see how well development with 2 valves per cylinder has come. Not quite sure where this leaves the Northstar engine, out on a limb?

LSx is a range of at least 6 engines, maybe 7 sharing many components so development costs for the high performance engines is subsidised by all the truck and more ordinary engines.

Boosted.

[vetteheadracer]

pentoman said:

I'm missing something? Russell

Yes you are!
Full details are here

http://en.wikipedia.org/wiki/Horsepower

Extract that explains the differences.......
SAE Horsepower
In the United States the term "bhp" fell into disuse after the American Society of Automotive Engineers (SAE) recommended manufacturers use "hp (SAE)" to indicate the power of the engine, given that particular car's complete engine installation. It measures engine power at the flywheel, not counting drivetrain losses.

Prior to 1972 most American automakers rated their engines in terms of SAE gross horsepower (defined under SAE standards J245 and J1995). Gross hp was measured using a blueprinted test engine running on a stand without accessories, mufflers, or emissions control devices. It therefore reflected a maximum, theoretical value, not the power of an installed engine in a street car. Gross horsepower figures were also subject to considerable adjustment by carmakers: the power ratings of mass-market engines were often exaggerated, while those for the highest-performance muscle car engines were frequently underrated.

Starting in 1971 automakers began to quote power in terms of SAE net horsepower (as defined by standard J1349). This reflected the rated power of the engine in as-installed trim, with all accessories and standard intake and exhaust systems. By 1972 U.S. carmakers quoted power exclusively in SAE net hp. The change was meant to 'deflate' power ratings to assuage the auto insurance industry and environmental and safety lobbies, as well as to obfuscate the power losses caused by emissions-control equipment.

SAE net ratings, while more accurate than gross ratings, still represent the engine's power at the flywheel. Contrary to some reports, it does not measure power at the drive wheels.

Because SAE gross ratings were applied liberally, at best, there is no precise conversion from gross to net. Comparison of gross and net ratings for unchanged engines show a variance of anywhere from 40 to 150 horsepower. The Chrysler 426 Hemi, for example, in 1971 carried a 425 hp gross rating (often considered to be underrated) and a net rating of 375 hp.

DIN Horsepower
This is the power measured according to the German standard DIN 70020. It is measured at the flywheel, and is in practical terms equivalent to the SAE net figure. However, be aware that DIN "horsepower" may in fact be expressed in PS (Pferdestärke) - see "Metric horsepower" below.

[anonymous-user]

Boosted Ls1 said:

Not quite sure where this leaves the Northstar engine, out on a limb? Boosted.

IIRC part of the reason for pushrod design was, with with low mounting/flat oil pan, to give the C5 a very low hood line. Cadillacs have a higher hood so plenty of room for the taller Northstar engine. It's said to be a very smooth motor though I've never tried one. It presumably cost more to build as it has more bits in it.

I see no reason why a 4-valve DOHC design should necessarily wear out any quicker provided it's properly built/lubricated and chain driven to avoid the dreaded rubber belt change. 100 bhp per litre is not so special these days with modern materials and manufacturing processes. Lotus and Toyota have both separately and together had production car engines heading towards that level for a long time. Other makers too. Setting up an N/A engine for big and reliable bhp per litre must be doable but flexibility is likely to go down the pan. vvt technology assists both fuel economy and engine flexibility at the cost of further complexity.

[franv8]

I think everyone focusses too hard on the pushrod OHV in the small block. Apart from that, these engines benefit significantly from the work that goes into the port and inlet tract design.

GM spent $2 Billion developing the LS range of engines (and that was just the LS1...), without getting intellectual and looking at the techno moving bits, appreciate that this engine makes good and relatively economical power. And despite its displacement, it is also a compact engine installation too. Remember adding 4 overhead cams makes for a massive engine, look at the engine bay of a 5.7l ZR1 vs a small block equipped 'normal' Corvette.

[pentoman]

5USA said:

[quote=Boosted Ls1] 100 bhp per litre is not so special these days with modern materials and manufacturing processes. Lotus and Toyota have both separately and together had production car engines heading towards that level for a long time. Other makers too. Setting up an N/A engine for big and reliable bhp per litre must be doable but flexibility is likely to go down the pan. vvt technology assists both fuel economy and engine flexibility at the cost of further complexity.

True but on a large engine?

BMW have had problems with the E46 M3's engine, the E36 M3 never made 100bhp/liter in real life, and they've had to make something pretty special to get the new M5's 5.0 to 100bhp/litre.

[LuS1fer]

Did the NSX also not cease production because for all it's electrojoggery, it couldn't meet new emissions regs?