Old vs. New

[Nightrage]

Sorry Ken, the title has nothing to do wih you

I've been thinking lately about the differences between older muscle cars and newer sports cars. I think the muscle car era died in the early 70's with fuel emissions. Sure F-bodies were muscle cars but now they're sports cars (at least in my opinion). I've been thinking about the differences in pretty much everything about older cars and newer cars. I read an article in Hot Rod magazine about how just changing the spark plugs, wires, swapping to an MSD ignition and changing the fan got them almost 30 horsepower on i believe it was a Plymouth Satellite or a Plymouth Fury. I've heard a lot of people discuss how dissapointed they were with their MSD ignition in a newer car. I'd assume that's because older technology is so inferior that older ignitions weren't properly burning all of the fuel. Also, fuel injection vs. carburetors, which would you choose? Some people claim that carburetors are better for making big power but i've also heard people argue in favor of fuel injection being superior.

Do catalytic converters really decrease fuel economy? Someone claimed that they cause the loss of anywhere between 3-5 MPG. There's something else that has me confused. Why is it that some of the older cars that have an advertised 350- 400 horsepower and somewhere in the 400+ range of torque that weighed less than our cars usually ran a similar time or sometimes a lower time in the 1/4 mile? On dream car garage, the skinny guy (don't know their names) ran a bunch of muscle cars at the track that were supposed to be making huge power. Most of them ran low 14's to very high 13's. If my car has an advertised 275 horsepower and 325 ft. lbs and something else has an advertised 375 horsepower and 400 ft. lbs, shouldn't they be faster? Especially if they weigh almost 500lbs less? Could someone make sense of this for me?

P.S.: anybody else get this?- Every time an older muscle car guy sees my car and talks to me about it, i get the following question, "That's front wheel drive isn't it?" Silly humans, you and your 4 speed manuals. Bow before my mighty 6 speed! MWAHAHAHA! lol

[Injuneer]

Catalytic convertors do not decrease fuel mileage. In fact, it is because of the need to maintain a very rigid, fairly lean A/F ratio, to allow the catalytic convertor to work, that electronic fuel injection with closed loop A/F ratio feedback was developed. Your car is almost always operating at 14.7:1, which allow the catalytic convertor to minimize total emissions (CO + HC + N2O) while returning decent fuel mileage. It is true that you could gain even better fuel economy with a mixture closer to 15.5:1, and that would net you about a 5% (1 mpg on an F-Body) improvement in fuel mileage. It is also possible to run "lean burn" engines (18:1) and that technology has been applied to small 4-cyl engines, requiring a new generation of O2 sensors, etc. If you were to apply lean burn technology to a large V8, its conceivable that you could see a 25% increase in overall fuel economy. But it isn't the catalytic convertor that is the limiting factor.

"Old cars" had engine rated in "gross" HP. The engine was put on a test stand, stripped of all accessories, intake, exhaust, etc. and the flywheel HP measured. That's where the early muscle cars got their 425HP engines. Current standard is "SAE net", which requires that the engine be run on the test dyno EXACTLY as it is installed in the car.... actual intake and exhaust, all required accessories, etc. That's where the seeming 25% reduction in HP comes from.

My 1966 GTO 360HP 3x2bbl 389ci 4-speed ran about 14.5 in the 1/4-mile. My 1994 Formula 275HP fuel injected 350ci 6-speed ran about 14.0 in the 1/4-mile. Different way of measuring the HP.

And just to loop back to the gas mileage discussion, my 1966 GTO got 9 to 10mpg. My Formula averaged 23mpg over its first 5 years of life.

[Nightrage]

Wow, thanks a lot! I never new how they dyno'd older motors. How about fuel injection versus a carburetor? I'd imagine that fuel injection is superior in every way as it's computer tuned and there are fuel injectors out there that can spray with an unholy amount of force lol. I know a few people, my stepdad included that would have a perfect running car if not for an out of tune carburetor.

[Jeff_in_Atl]

Wow, thanks a lot! I never new how they dyno'd older motors. How about fuel injection versus a carburetor? I'd imagine that fuel injection is superior in every way as it's computer tuned and there are fuel injectors out there that can spray with an unholy amount of force lol. I know a few people, my stepdad included that would have a perfect running car if not for an out of tune carburetor.

I put a Holley projection FI kit on my 85 Mustang and picked up ~3 (2.8 measured) mpg from the stock Holley 600 carb. It cranked AND stayed running when it was cold with the FI. I have no numbers to prove it but I'd swear it was faster with the FI. Both passed emissions fine.

[wolfdogs]

Nightrage moves to the top of the list.

Note.

[Noggin]

Also, fuel injection vs. carburetors, which would you choose? Some people claim that carburetors are better for making big power but i've also heard people argue in favor of fuel injection being superior.

I've brought this up with one of my friends (I make no claims to know squat about carburetors) and he's pointed out that the stock cars all use carburetors, often with restrictor plates. This is something I've thought about though.

My thought process leads me to believe that a low pressure carburetor would not be able to force fuel into the engine until the start of the intake stroke. Opening the valves would blow exhaust back into the carburetors (Is this what causes a backfire?) if the valves opened too soon. However, as you pointed out the pressure on an injector is much higher, perhaps this lets the valves open before the exhale is completed, and perhaps even give an extra kick to the exhuasting gasses?

And carburetors just don't seem all that accurate to me. Of course thats what the A/F adjustments are for though. So how do they make so much power? Is it simply from massive displacement and high compressions by means of beastly sized walls?

Do catalytic converters really decrease fuel economy? Someone claimed that they cause the loss of anywhere between 3-5 MPG.

If you ask a stereotypical "ricer" that question, then heck yeah they decrease it. Thats one of the first things to get knocked out. Ask me, and I'd say, "Dunno, but I would think it would. It has resistance to air flow, and would make it harder for the car to breathe." But I also suspect that there is sooo much more going on in the exhaust than one would first think. As I understand it, if you time everything right each exhaust valve opening causes a shockwave that travels down the exhaust manifold. If you make the lenghts of each header-tube the proper length, as a shockwave travels down one tube, it'll reach the opening of the next and kinda suck out the air from it too. This creates a negative shockwave which travels back up to the head, and if timed right, will reach there just as the valve opens and suck the exhaust right out of the cylinder.

Maybe some will beat me and call me stupid, but it makes sense to me. But what do I know, I drive a Sentra (Spec-V 'yo!) with tinted windows so I'm automatically a ricer.

There's something else that has me confused. Why is it that some of the older cars that have an advertised 350- 400 horsepower and somewhere in the 400+ range of torque that weighed less than our cars usually ran a similar time or sometimes a lower time in the 1/4 mile?

Other than for reasons already stated about techniques of dynoing engines, I would think that drivetrain losses have become much better by now.

[Nightrage]

Nightrage moves to the top of the list.

Note.

Uh....my brother went on my name? didn't work, oh well. I'll take the Hulk Hogan big boot to the face like a man lol. Just don't sick your wolfdogs on me. Their fangs look like they're about 3" long

This forum is so awesome. The knowledge contained here is so vast that i can't imagine any question ever going unanswered. Ken was right, you guys really do rock