I smell a rat!!!!!!!!!!!!!

[kingman]

Hi

After reading several articles on the new Z-06 regarding the claim of 500hp, and with every other hot machine coming out with between 400 and 500hp and only g-d knows how much the Viper coupe really has. The real question is.

Do you think that GM is under rating the hp? We will know for sure when they start putting them on the road so somebody can start putting them on a dyno!

I would guess that GM will do something or Bob Lutz is not the man l thought he is.

Alan

p.s. This wouldn't be the first time they did this or come out with a lightened version with an additional 15 hp when really they would push closer to 575.

 

[67HEAVEN]

1967-8-9 L-88:

Factory rating 430hp (gross)
Actual 560hp (gross)

1969 ZL-1:

Same

 

[warren s]

I just hope they hit the road and stay there with out being re-called.

 

[67HEAVEN]

No matter the challenge, the answer is already in the Chevy parts bin.

The next big block stands ready to come riding to the rescue if those other bad car makers pick on newest little brother.

572 cu. inches - 720 hp @ 6250rpm - 685 ft.lb @ 4500rpm

The 12:1 compression may present some fuel challenges, but hey........what a freakin' ride. :eek

Chevy Rules! Bring 'em all on. :bash

 

[Hib Halverson]

Hi

(snip)
Do you think that GM is under rating the hp? We will know for sure when they start putting them on the road so somebody can start putting them on a dyno!
(snip)

I suppose that depends on what we mean by "under rating". If "under rating" means, at a given rpm, the engine makes less power than rated, the idea that GM would do that with the LS7 is pretty remote considering the factory rating the Corp. would have much to loose given the gynormous PR hype on the run up to the car's intro. You can bet, the first thing some of the early Z06 buyers will do is break motor in then take the car to the dyno and I'll bet they'll make about 425 at the wheels. It'll be all over the Internet and the magazines, if GM does that.

Now, if "under rating" means taking the official power rating prior to peak power, that's very possible given that GM rates the engine at 6200 rpm and the rev limiter is said to be at 7000. Typically (LS1, 2 and 6 are examples) the peak power and the rev limit have been closer together. Perhaps the engine truly makes 500hp at 6200 but...does it make 525 at 6500-6700 rpm?

Someone mentioned the ZL-1 of the bygone musclecar era. That engine was rated at 430hp and, actually, that was an "honest" rating in that it actually made that power when tested at some rpm before peak power. Back in that period, the insurance industry set rates using way different criteria and advertised horsepower was of considerable interest to that industry (government-sanctioned organized crime that it is). Back then, there was a lot of pressure on the OEs to stop making such "dangerous and powerful" cars due to high insurance rates.

The ZL1 actually made 560hp@6800 rpm BUT, that was on racing gasoline, with fuel, spark, coolant temp and intake air temp optmized for best performance, with no accessories other than a water pump, headers and open exhaust.

What's interesting is the new LS7 is rated at 500 SAE net horsepower. If you were to test the LS7 the same way GM did back in the 1960s. it'd probably make 560hp...maybe even more.

 

[Edmond]

Weren't the C5 Z06's underrated? I read that they typically put out 15-20 more horses than advertised.

Could it be purposely to avoid the PR nightmare that Ford went through with the overrated Cobra's from a few years ago?

 

[kingman]

Only time will tell!

Hib

Excellent and well thought out points but Chevy already knows about everything there rivals are working on one way or another. I'm sure GM is already working on what is coming next.

The new GTO is going to be putting out 400hp, the Mustang is going to wind up being close.

No matter what the hp figures are, the 0-60 times will matter in the showrooms, and advertisements.

Most people that go around and only want to know how fast the car can go from 0-60 forget the most important thing!!!!!!!!!!!!!!

How long will it take to stop after reaching 60mph! And can it handle a turn!

Alan

p.s. weight is as important as hp and also the gearing.

 

[corvetteconti]

I hear the HP is really coming in at 512- 518.....
the 500 thing is all marketing and the Logo on the fender will have the 500HP on it - the Detroit & LA show cars do not!

 

[OLDGOAT]

Hib's comments are interesting on the ZL1 test conditions...racing gasoline and optimal conditions etc. With the bad gasoline we contend with now who can say what the actual street hp will be? I have asked about knock in other postings and been told that the computer and knock sensors will adjust and there will NOT BE knock on the base C6 or new Z06. Swell. OK, I get it. However, when the onboard computer adjusts the timing and other variables to allow the engine to run on the 92 octane ( supposedly ) junk gas from the local station what happens to the hp output?

I'm not trying to downgrade anything here just point out that in the real world the gas is terrible and this MUST influence hp. As far as running a 12:1 engine on pump gas? What are people using for octane booster these days?

 

[Hib Halverson]

Weren't the C5 Z06's underrated? I read that they typically put out 15-20 more horses than advertised.

I own a Z06 (04 SN 00039) and, on the dyno, it made slightly more than rated power, if we assume 15% parasitic loss. However, I've not seen an identifiable trend in that. I've seen far more Z06s that make about what they should on the dyno, given their rated power. I'd have to say that I do not believe the 01 and 02-04 LS6 engines were under-rated.

With the bad gasoline we contend with now who can say what the actual street hp will be? I have asked about knock in other postings and been told that the computer and knock sensors will adjust and there will NOT BE knock on the base C6 or new Z06. Swell. OK, I get it. However, when the onboard computer adjusts the timing and other variables to allow the engine to run on the 92 octane ( supposedly ) junk gas from the local station what happens to the hp output?

The idea that all pump gas is universally "junk gas" is urban legend. Sure there are "off-brand" gasoline suppliers with poor blending controls. There are station operators who mix grades of fuel or have tanks that water leaks and there operators who have poor control of contaminants, but, generally, the gasoline one buys from major brands sold by stations that move a lot of product is of acceptable quality.

Now, if we're going to talk about octane, then there is something to be concerned about. Right now GM calibrates Corvette engine for 93-oct. This has been the case for the last couple of years, however, through the 90s it cal'ed for 91. Unfortunately, 93 is not available in western states or in some southeastern areas. In those palces 91 is the predominate "super" or "premium" unleaded available there. Under high load and with high IAT, Corvettes running on 91 may see knock retard and a subsequent slight power loss...say 8-12 hp at WOT near peak torque.

Lastly, there is an advantage in unleaded racing gasoline under some of the above circumstances. Of course there's the higher octane, as much as 100-oct (R+M/2), but there's also better burn characteristics, too. It takes about 94.5 oct to keep most Corvette engines out of detonation in high-load, low-altitude, high-temperature. I usually mix Rockett Racing Fuel's 100 Unleaded with 76 91-oct. pump gas to get about 94 when I know I'm going to need all the power the engine can make.

 

[OLDGOAT]

Hib, thanks for the informative info. As you say here in Oregon the best octane available is 92 octane. I don't know why the West Coast is lower octane. Unfortunately it seems that bad gas is more than an urban legend here. We are about the last remaining state that has no self service gasoline. The suppliers are very upset about this and it seems to figure into our always high prices and low quality. Right now, sadly, I have only two relatively recent SUV's in which to judge gas quality. From one tank of 92 octane to the next my Explorer can either knock badly or not at all. Its V8 supposed to run on lower grades but the knock is very serious at less than 92 octane. I think that GM should consider calibrating Corvette engines for 92 octane rather than 93. I'd think the California market at least would warrant this change. It would also seem that some major brands might consider selling a higher grade in the 94-95 range with all the new performance engines now being offered. I just miss the old days when you could fill up and stand on it with no knock ever. Since knock is worse in high heat situations I guess Oregon is a good place to be......lol. I have wondered if ( now please don't laugh if this is foolish )...an intercooler type setup for a normally aspirated engine would reduce knock by cooling the intake charge? I'm sure this is one reason the new Z06 has the ram air hood inlet. Then there is water injection? There are ways to reduce knock and thus increase available power that have not been used up to now. One aftermarket supplier claims that their new air inlet for the C6 brings cooler air into the engine etc.

 

[Edmond]

OLDGOAT,

Why don't you guys have self service stations in OR? That doesn't make any sense at all! That will just keep prices high.

92 is usually the highest at most stations but there are some stations that have 93. On the flip side, I have only seen one full service station. It went by the Standard Oil name.

 

[warren s]

I cant wait until they (C6 Z-06s) Start hitting the race tracks. All this talk about horsepower numbers will be put into perspective once real owners start running them.

After all, we have all seen cars with less than 300 ponies running in the 12s and stock C5s Z-06s scraping the 11s.

We know what the cars weigh, and what the rear ends ratios are, some time slips can tell the real story.

 

[wx briefer]

Our club had the privilege of a visit from a top official of the plant. Let me just paraphrase a comment of his....'don't you guys release it unless it has ATLEAST 500HP if not more, even if it means a month or two of delay.'

So I would not be surprised at several more HP than advertised.

 

[ROCKETBLOCK]

I don't know what you guys are talking about here!!! I do know that I always enjoyed my 290hp 302ci engines in my 68 and 69 Z-28 Camaro...

 

[Robert YellowVette]

I don't know what you guys are talking about here!!! I do know that I always enjoyed my 290hp 302ci engines in my 68 and 69 Z-28 Camaro...

But that was under the old SAE gross hp rating, not the SAE net rating that we use now...

 

[OLDGOAT]

enjoying the old chevs a s they knock themselves apart

hey Rocketblock, I owned two 69 Z28's and enjoyed them as well. Both were original 302's and stock. Whether gross hp, net, SAE ,or who knows what the cars always felt much more powerful than 290 hp and would rev through the roof. Problem was no low end torque and a car weighing 3600 lbs or more. Both of them were VERY sensitive to gasoline octane. I sold them when I got tired of octane boosters and worrying about detonation damage. It's no fun driving a car that is knocking itself apart. In terms of engineering, handling, and fit/finish these cars were and are very primitive. In terms of styling they were and are sublime.
Edmund, the idiot voters here in Oregon keep defeating measures to allow self serve gas. Don't ask me why. It's nuts. I cannot legally put gasoline in a car in Oregon as a customer. So I have to watch the pump attendant try and figure out how to avoid spilling on or scratching my car while they do it. Oregon is a quirky place. Very liberal politically in some areas and conservative in others. But it's green, pretty, and smells good when the Red Chinese smog coming across the Pacific is not excessive. I thought one reason all our manufacturers are moving over there is because they can totally avoid environmental pollution controls( and wage/hour laws, child labor laws, safety laws etc etc ). So they pollute over there and it's so massive it makes it here. Where's my soapbox........that's an oldgoat for you.

 

[67HEAVEN]

....the cars always felt much more powerful than 290 hp and would rev through the roof. Problem was no low end torque and a car weighing 3600 lbs or more.

OLDGOAT,

As you know, and I well remember, the 302 was developed purely for homolgation for Trans Am racing. On the track, hi revs were the order of the day. As you said, the 302 would rev through the roof and there is pretty much general agreement that a stock 302 was putting out between 350 and 400hp SAE gross well above 6,500 rpm, depending on state of tune and fuel.

Tall rear gears and cruising around town in second gear made the 1st Generation Z-28's a very enjoyable and formidable ride.

 

[OLDGOAT]

yup, it was fun.

 

[DavidWP]

What's interesting is the new LS7 is rated at 500 SAE net horsepower. If you were to test the LS7 the same way GM did back in the 1960s. it'd probably make 560hp...maybe even more.

Okay, here’s the deal.

Back in the late ‘60’s and early ‘70’s, the switch was made by automobile manufacturers from advertising Gross Horsepower Ratings to advertising the more realistic Net Horsepower Ratings. For Corvette, the last year that the Gross Horsepower Ratings were shown was 1971. The Net Horsepower Ratings were also shown:

To avoid, I hope, the flywheel power versus rear wheel power ratings confusion that usually rears its head at this point, let me state positively and absolutely that the power ratings advertised by automobile manufacturers are ALWAYS rated at the flywheel. They are ENGINE rating numbers and not POWERTRAIN (Engine, Transmission, Differential Gear) ratings. The ratings at the rear wheels are another story.

Also confusing is the fact that the early ‘70’s engines lost power due to lower compression ratios required to accommodate unleaded fuel needed for catalytic converters. That is not part of this discussion, either.

We are talking about the difference between an engine with virtually no accessories, no intake restrictions and no exhaust restrictions (GROSS FLYWHEEL POWER) versus an engine with all the accessories, full intake system and full exhaust system (NET FLYWHEEL POWER).

Also, we are just doing this for fun so don’t get mean. If you find errors in my logic, get helpful and let’s produce a better answer.

Okay, for the two people still with me (SWC and Runge), here are my assumptions:

1971 Standard Engine – 210 Net Horsepower and 270 Gross Horsepower
210/270 = 0.7778

1971 LT1 – 275 Net Horsepower and 330 Gross Horsepower
275/330 = 0.8333

1971 LS6 – 325 Net Horsepower and 425 Gross Horsepower
325/425 = 0.7647

So let’s be conservative (and make the huge assumption that a modern, electronically controlled, fuel injected engine would act anything like a carbureted early ‘70’s engine on the dyno) and use the 0.8333 ratio on our 500 NET FLYWHEEL HORSEPOWER 2006 C6 Z06 engine.

500/0.8333 = 600

SIX FREAKING HUNDRED HORSEPOWER!!!

600

Okay, I can’t resist either, let’s use the Big Block number 0.7647 and see what we get. (Yes, I know the LS7 in the 2006 Z06 is NOT a “Big Block” – remember, we are having fun here.)

500/0.7647 = 654

SIX UNFREAKING UNBELIEVEABLE HUNDRED AND FIFTY HOLY S**T FOUR HORSEPOWER!!!!

654

Remember, these are assumptions. If ANYONE has access to real GM dyno numbers – I am led to believe they still do GROSS numbers – they would make very interesting reading.

David
I love this stuff!!