My Questions

James Vette

CCCUK Member
Is american horsepower and torque ratings the same as ours? A neighbour was saying my car had low power for a 5.7 V8 so I was confused. Also I had to put E10 in today (I found an E5 pump last time) so will this cause problems or is it ok every now and then? Thanks bit worried. Any additive recommendations and where to buy them?
 

teamzr1

Supporting vendor
To answer these
1. you have to find out if the UK is using "brake HP" test results that is with just the engine with nothing attached to it such
as with a belt off crank for power steering, generator, etc, no full exhaust system, no tranny, etc

Today GM tests engine design output as to SAE process that uses an engine dyno, and some exhaust and measures and results are at the flywheel
SAE testing has to be done with an SAE engineer watching the tests, and multo engines have to be tested and then the average of those results as what
GM can report as to engine HP and Tq. GM began doing this with the start of C6 Z06s LS7

Europe due to higher SMOG rules adds crap to the exhaust system and costs maybe 25 flywheel HP less than here in USA

2. Your Corvette's engine was designed to use leaded gas, way before that crap Ethanol was forced on us and reduces HP and fuel mileage
and in your case will F up your valvetrain, carb, mufflers, etc

Best case is stay away from E10 (here in the USA they forced E15 being sold :(
If you cannot find leaded gas, use a lead additive or spend the money to have the heads reworked that have internals Ethanol
will not F up like the valves

More on what makes up SAE engine dyno testing standard check my forum

SAE Testing
 

antijam

CCCUK Member
Your car is a 1971 I think James? If it's the base 350 cu in (5.7 litre) then the rated horsepower was 270HP. In today's terms that is pretty pitiful and I suspect your neighbour was comparing the power with modern equivalents.
As an example of typical modern power ratings Ford's current EcoBoost 2.3 litre produces 310HP - less than half the size of the 'Vette but 40 more HP.
The power of the '71 'Vette may be unremarkable but by 1975 the same engine was so strangled by emissions equipment, the power was down to 165HP - 29HP per litre ! !
 

teamzr1

Supporting vendor
James will have to see which engine and tranny for his 1971 C3 as to the build code (suffix below) and then match it to GM 1971 specs
As HP ranged from 270 to 425 flywheel HP depending on engine and tranny it has

1971C3.jpg

Then he needs to take this 170-page GM archive I obtained and is attached to this post
I suggest he reads it in depth and make a couple of copies of it as it goes far into detail of design and build specs for 1971 C3

Enjoy the read !
 

Attachments

  • 1971-Chevrolet-Corvette.pdf
    5.1 MB · Views: 9

Chuffer

CCCUK regional rep
Is american horsepower and torque ratings the same as ours? A neighbour was saying my car had low power for a 5.7 V8 so I was confused. Also I had to put E10 in today (I found an E5 pump last time) so will this cause problems or is it ok every now and then? Thanks bit worried. Any additive recommendations and where to buy them?
The HP issue has been addressed but as for E10 fuel , occasional fill ups cause should cause no real problem but avoid as much as possible . Either fill up with super unleaded 98 RON that is E5 or better still Esso Supreme Synergie 99 RON if avialble in your area which is Ethanol free dispite the pumps saying E5 . Various additives are available such as Millers to counteract the negative effects of ethanol . Look on line .
 

Roscobbc

Moderator
James - don't be concerned about horsepower - whether it is American pre' 1972 quoted HP (so as already noted the figure is taken without any connected accessories, like water pump, fan, alternator, enclosed air filter and open exhausts. Add some manufacturers exaggeration and you'll see the 'advertised' figure.
1972 onwards and co-insiding with emission regulations and drastically reduced compression ratios and the manufacturers 'advertised' figures were down by about a third. Were they slower? - not really, certainly the 'cooking' engines were much the same - the high output engines suffered and many were canned by manufacturers.
Your neighbour commenting on the lack of HP from 5.7 litres is badly missing some logic. Torque is the major factor on engine performance - the simple fact is that more 'cubes' will in most cases generate more torque which is perhaps more important than HP. Yes, a Ford Ecoboost has more horsepower - but how much torque does it have? - over how much of its rev band does it provide that torque - the turbo will assist here but can it make do with a 3 speed auto or 4 speed manual (no it needs multiple ratios).
This is the seemingly gutless power spec's for a 1978 Mustang 302 - rubbish HP - but look at the torque

Year1978
Power (hp)139 hp @ 3,600 RPM
Torque (lb/ft)250 lb/ft @ 1,600 RPM
Compression8.4:1
Displacement302 cu / 4.9 liters
 

teamzr1

Supporting vendor
Thanks for the replies.

James just install a 100-150 HP shot of NOS for like $400 and then take your fricking neighbour for a drive and not mention the NOS and
jump on WOT and watch his face.

The real crap was starting in mid 1970s, my 1977 was a real SMOG pig and was common by unknown factors to find those bricks called CATs
sitting on the side of roads :)
Sneaky way is cut the top of the CAT, peel back to gut the F'er, then weld back, install and cannot be seen as gutted and the exhaust smell is better :)
 

CaptainK

CCCUK Member
Not many people moan at me about size of engine versus power output etc. I mean technology moves on very quickly. The only one I've had is jokingly from a mate that drives a "performance diesel". Yeah ok his modern turbo diesel is slightly quicker than my Vette. Do I care? Its a comparison between cars with an age gap of 50 years. Let's take a look at what "performance diesel" was doing 50 years ago when my Vette was born. Oh, there wasn't any.... and the diesels of the time would be ridiculously slow. Fact is, my Vette can happily keep up with most modern cars, and that in itself is quite impressive considering the age gap - and my Vette is a base model as well, with the lowest output engine for the year.

Now let's look at this "old car versus new car" thing in my field of expertise - computers. You don't see ANY computers from 50 years ago being able to keep up with even a basic modern computer. And why would you expect it to? You wouldn't. So why would you expect a 50 year old car to keep up with a new car? But yet, this 50 year old car happily keeps up with modern cars, and in a fair few cases will happily beat them too. So I call that a victory for the Vette personally.
 

Roscobbc

Moderator
Capt - one could actually transplant a 'modern' diesel in your Vette or even replace with something studid like a Toyota engine and unless the hood was raised the majority of people wouldn't have a clue. Irrespective of whether its a 327, 350, 427, 454 or LS lump the car has got something that is immeasurable.............coolness!
 

Chuffer

CCCUK regional rep
Continuing the theme of perceived puny power outputs of big old Yank lumps , this stunning land yacht wafted into our sleepy little village this morning . The owner was visiting a near neiDSCF2792.JPGDSCF2793.JPGDSCF2794.JPGDSCF2795.JPGghbour so I just had to walk over for a chat . A stunning and totally original Summertime Blue 1976 Cadillac Coupedeville with only 32, 334 miles . Virtually still in showroom condition and still got all the under hood and trunk stickers and warning labels ! So many electric toys and driver aids that you barely get on modern Euro -Boxes , and they all worked !! The spec was unbelievable for 45 year old car . How does 8.2 litres with just 190 bhp sound ? But the maximum torque is 370 lbs at a lazy 200 rpm . Now that`s real stump pulling power ! :D
 

Nassau65

CCCUK Member
Stunning apart from the half vinyl top.
Those half vinyl were the height of fashion and style at that particular time. If you ordered a full size coupe, you had to have it, especially in white.
me personally I love full size sedans/coupes. Coupes especially with the half vinyl padded tops.
 

Nassau65

CCCUK Member
Continuing the theme of perceived puny power outputs of big old Yank lumps , this stunning land yacht wafted into our sleepy little village this morning . The owner was visiting a near neiView attachment 14363View attachment 14364View attachment 14365View attachment 14366ghbour so I just had to walk over for a chat . A stunning and totally original Summertime Blue 1976 Cadillac Coupedeville with only 32, 334 miles . Virtually still in showroom condition and still got all the under hood and trunk stickers and warning labels ! So many electric toys and driver aids that you barely get on modern Euro -Boxes , and they all worked !! The spec was unbelievable for 45 year old car . How does 8.2 litres with just 190 bhp sound ? But the maximum torque is 370 lbs at a lazy 200 rpm . Now that`s real stump pulling power ! :D
My kind of car. Always loved full size coupes Coupe de villes, eldorado’s and continental MK’s
 
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