Why Build A Cad engine?
The short answer: For the Affordable Street Performance.
The long answer:
Torque: Horsepower is good, But Torque
Torque moves mass. Torque is what gets a car to moving fast from a dead stop, not Horsepower. You don't believe all this? Actually since hp is a measurement of torque my statement is almost an oxymoron. But it was needed to get my point across.
Ok, Try this. Take your car to its torque peak in first gear, and nail it. Notice the belt in the back? Now take it to the power peak, and nail it. Quit a bit weaker, is it not?
When someone says an engine is 'torquey', they mean that it has a lot of low RPM torque. This type of engine is quicker to accelerate with on the street, because downshifting isn't as necessary. This helps make it more responsive, Massave amounts of torque will make it nech breackingly responsive and can be very practical for street raceing or driving in traffic.
HP at the flywheel = torque times RPM deviled by 5252
HP at the wheels = HP at the flywheel times 0.83
HP at the wheels deviled by 0.83 = HP at the flywheel
Torque can be multiplied by gearing. Power can't. So from a
Street Raceing perspective, Any Automobile, in any gear, will accelerate
at a rate that exactly matches its torque curve. (allowing for increased
air and rolling resistance as speeds climb). Another way of saying this
is that acceleraction will always be hardest at torques peak in any given
gear, and an automobile will not accelerate as hard below that peak, or
above it. Because Torque moves mass it is the only thing that a driver
feels, and in this contex horsepower is just sort of an esoteric measurement.
300 foot pounds of torque will accelerate you just as hard at 2000 rpm
as it would if you were making that torque at 4000 rpm in the same gear,
yet, per the formula, the horsepower would be *double* at 4000 rpm. Therefore,
horsepower isn't particularly meaningful from a driver's perspective. The
two numbers only get friendly at 5252 rpm, where horsepower and torque
always come out the same. I'm not sayimg horse power is a bad thing or
hat its not important, In contrast to a torque curve (and the matching
pushback into your seat), horsepower rises rapidly with rpm, especially
when torque values are also climbing. Horsepower will continue to climb,
however, until well past the torque peak, and will continue to rise as
engine speed climbs, until the torque curve really begins to plummet, faster
than engine rpm is rising. However, as I said, horsepower has nothing to
do with what a driver feels.
Basically, for street raceing horsepower numbers aren't worth much. Horsepower is a measurement of torque over time. So it will not necessarily give you the information you need to determine how fast the car can excellerate when you punch the throttle. Actual torque is the key. When looking at advertise HP numbers. You need to properly interpret what they mean. As well as what effect they have. For Example Putting in a cam that "adds 100 HP" doesn't do much in a street car if it moves the power peak so far up the RPM range you cant often use it on the street. If your gearing weight are in order there are only 4 ways to make a dramatic increase in low- to mid-RPM performance or "TheTorque "the twisting force" curve"
2. The magic numbers
in my humble opinion, assuming everything else on the automobile is in order. Real street performance starts at 350 hp and 450 ft or toque. Now we have all seen the local hot rodders spouting engine figures like these. Everyone and his brother clams to have this kind of power under their hood. I can tell right now the average fast daily driver on the street, has less than 350 horses probably less than 300. There are a few faster ones out there. You can spot them because they will either be running a blower or fueling their car with something other than pump gas. The nicest thing about the big Cadillac engine is it doesn't take any special parts to get this huge torque and power. In 1970 the Cadillac 500 had 400 hp and 500 ft of torque stock from the factory! " The fuel injected model was rated at 425 hp" That's right no raceing cam no tricked out parts just a 850 cc quadjret 10:1 compression and 500 cubic inches. With the big cad all you need is the right "recipe" of stock parts to get the magic numbers on pump gas!
3. Cubic Inches
you may have heard the old saying, "the only way to beat cubic inches is with cubic dollars" The cad with its 500 cubic inches is the largest regular production 8 cylinder ever made. Ever herd of a sroker motor? That's where someone builds a given engine to have a larger displacement. The 454 is often stroked to a 490. The 396 to a 433, the 350 to a 388 and so on. This is done in an effort to make more cubic inches, which in turn makes more power. Why not start with 500 in the first place? The 500 can be stroked to 529, 540 I have even seen a 570cubic-inch stroker kit for the cad 500.
4. The Stock Factor
Go ahead and pick out what you think is the fastest classic muscle car ever made. Ok now what kind of engine is under the hood? A 454? 396? Hemmi? A boss? With this engine in mind pick up a chiltons Manuel and compare your engines power specks with that of a 1970 Cadillac 500. Surprised! Yep that old boat anchor was even rated more powerful in its stock form than the legendary 454. All that power with out an aftermarket cam or other special parts. Now look at the torque rateings. Nothing even comes close to the cads 550 ft pounds at 3000 rpm's. We all know its torque thas responsible for that slap in the back when you nail it!
5. Pump Gas Performance
while you have your book open take a look at the compression rations of the engine you picked out. Is it higher than the Cads 10.1? If so that engine will not run on today's pump gas. Not with out lowering the compression. Which would make the engine even weaker. The Cad can make massive amounts of strippable power on pump gas.
With an aluminum intake manifold The Cad 500 weighs only about 40 lbs. more than a Chevy 350 small block. Its power to weight ratio is unreal; you would have to spend three times as much to build a small block with as much torque output as the Cadillac. With all factors being even It could not be done on pump Gas. Nor would such a fantom small block be streetable
7. Street Useable Low RPM Power
you have to turn a small block engine hard to make it really perform. Unless you only use your car at the racetrack an engine that puts out max power from 6 to 8 thousand RPMs is almost a waste. You just don't have many opportunities to get your engine turning that high on the street. To win on the street you need an engine to have max power under 5000 RPMs
low RPM power = street useable power. You don't have to peg the tack out to get the cad engine to produce max power it starts putting massive amounts of torque on the ground the minute you hit the gas petal. The same thing holds true for hauling and towing applications. Pulling a heavy load you need power right off the bat and up to highway speed. You certainly don't want to have to turn your engine that high when your in an off road 4x4. A bored over cad can produce more than 400 hp around the 4500 RMP range. Over 500 ft pounds of torque in the 3000 rpm range. That's neck breaking street useable power!
8. Better Gas Mileage
better gas mileage from a 500-cid engine? If you using your engine for towing you bet! A cad will produce more power at lower rpm than any other towing engine. That means more power with less gas petal. This will equal better gas mileage!
9. Durable Blocks
today when you think luxury you think Mercadies Lexus or BMW. When Cadillac was making these engines they were installed in the most luxurious cars of the time The American Made Cadillac. The Cadillac Engine blocks are extremely durable. This is because they have a high Nickel content. I have seen these engines run 90 thousand miles with very little cylinder wall ware! They last so long in fact that the bearing often go out before much cylinder wall wear in noted. DrChop just built a cad 500 that had 70 thousand miles on it. The cylinder walls were so good that he just had them honed, added new rings and used the same pistons.
Even now years after it went out of production you can still buy 472/500 engine for next to nothing. It can be built to produce 500 hp on pump gas at a reasonable cost. For 600 hp or less it can be built cheaper than any "other" brand of engine.
another strong point for at least for now, is availability. Go to your local salvage yard and ask for a Chevy big block. Good luck. If you find one they will want a fortune for it! I have a 454 out in my shed that has spent a main bearing. It needs to be center or line bored! Any day of the week. I could still get 400 dollars for the core. I keep it around so I can say I have one. I didn't use it because for the money will not perform on the street as well as a cad 500.
Now go to a large salvage yard and ask for a Cadillac with a 472 or 500 in it. Chances are there will be several in the yard. Complete with the boat anchor still under the hood. Try and buy the whole car you can usually get the whole car for under 400 dollars. You'll be able to sale the car back after you have removed the engine and other needed parts. This should get you a 100 dollars or so of your money back.
12. More off road power
there is no better engine for a truck, sports utility, blazer or a 4x4! The torquey cad 500 can be built to grunt hard! It has plenty of power to turn one, two, three or all four wheels and it dos it at a low RPM. That's just what you would want in a performance off road rig.
13. It can take the juice
Take A stock low compression plain Jane with a cam Cad 500. Something simple with an honest 350 hp. "A cake walk for a cad" Combined it with a 200-hp Nitrous kit. Imagine the possibilities! A fresh stock Cadillac engine with stock rods, pistons, crank, etc. Can take a 200 Hp shot of nitrous with out damaging the engine! A full quitter mile shot! No problem! 20 times? 50 times? 100 times? Not a problem! Of course I don't advise you juice you old 80, thousand-mile engine. You also need to know how to properly use your NOS system. With These factors in line A fresh stock cad engine can take it. If you were to build one with a few forged parts it could probably take hundreds of nitrous shots. These engines are incredible durable.
15. The Sleeper Effect
looks big but no chrome, cams not hitting all that hard. No headers a little 750. It can't be much! A plain Jane stock cad engine makes for a great sleeper. Even if you build it all the way. I think Al Betker said it best in his common Caddy question article.
"Last but by no means least is the sneak factor. Never mind you're packing up to 600 hp or close to 700-ft lb. of torque in your 540-cid stroker Cad motor. It's still a Cadillac and everyone knows they're boat anchors. You will get no respect. Because of that you will get to spank a lot of people hard. YOU WILL go home with their money after the race. You just won't be a popular guy with a popular engine under his hood"
Well that about covers the long answer to why I would want to build a Cadillac engine. Keep in mind that I'm not an expert or a processional. I'm just a fan of the Cadillac engine! Hopefully this will inspire you to become one as well. I hope you have found this page useful. If you have some helpful tips that I have over looked " and or corrections" please email them to me. This is an on going effort I'm constantly looking to improve it.
Copyright Caddy Shack 1999 All rights reserved.