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567chevys
07-15-2011, 11:59 AM
The two most misunderstood measures of an engines power. So let's just clear it up.Torque is your engines actual power,horsepower is how fast you get it. Make any sense? Torque is the twisting force or energy placed on the crankshaft and horsepower places a time factor on how fast it makes that power.Most people read up on horsepower that a particular performance engine produces and they in turn want that kind of power.Now remember,torque is what you feel when you put the hammer down when the traffic light goes green.Making modifications that help produce low end torque is what you want for the street.Face it,if you've got and sense at all(and we KNOW you do) your engine is not going to ever see 6000 rpm on the street.



There are a number of things you can do to increase your engines low end torque and still maintain drivability.All of us (yes,even the guys that don't think they want it!) want more power when we hit the gas. Let's keep in mind that a 500 horse engine is not going to idle very well in traffic and will rarely see 18 mpg! 100,000 miles between tune ups are a thing of the past when you consider anything more than trying to gain the free horsepower that your engine already has.

Lets think about headers,cat-back exhaust systems and cold air intake systems for a minute.Headers help to balance compression,scavenge exhaust gasses and the engine breathe better.All a plus when thinking about performance and efficiency.Cat-back systems are just that,exhaust systems that are bolted or welded on after the catalytic converter.Almost all cat-back systems reduce back pressure by seriously reducing those tight wrinkle bends in your restrictive factory system helping your engine breathe better.headers and a decent cat-back system can help you gain very noticeable power.More so if there are other performance mods already in place.



Now cold air intakes are something relatively new to the bolt on performance scene.The performance gain comes from the engine getting a smoother,straighter flow of air into the intake manifold. Now when you introduce fresh "cold" air into the equation then the performance value comes in.The colder the air you have coming into the manifold,the denser the air/fuel charge and the more air/fuel you are going to get into your engine.The air intake system will basically give you better efficiency due to the straighter,smoother air coming in but,chances are it will be a colder denser charge that adds to performance so you may not see much of a fuel economy increase but,you may see a power increase or you could get both,I've seen and heard of both.

There are various other mods you could do like chip up grades,having your car or trucks computer parameters re-vamped or power programmers.It depends on your budget.If your Canadian like me,then a lot of us either get performance parts and upgrades to our vehicles or presents for the kids at christmas. With the products and parts that are available today,you could actually save yourself a little cash at the pump with some modifications because they increase your engines efficiency,that of course would depend on how you drive.



Now,one could argue that is these things are modifications work so well ,why doesn't the vehicle come out of the factory like that? Well simple,from my point of view cars and trucks are built on an assembly line and it's easier and cheaper for the factory to do what they do. They also do it the way the do to keep things quiet,now for anyone that loves and respects that throaty rumble it's not what we are looking for. However,the factory does builder your engine with durability and efficiency in mind. And the majority of consumer want their vehicle to be quiet and smooth.

chevynut
11-09-2011, 07:06 PM
Torque is NOT power. Torque is a twisting force, as you say. More technically, it is called "moment" which is force multiplied by the distance that force acts. It's units are ft-lbs or sometimes lb-ft.

Horsepower is torque multiplied by RPM. At 5250 RPM horsepower and torque are the same. In other words, if your engine is making 400 ft-lbs of torque at 5250, it's putting out 400 HP. Horsepower is torque divided by time, or how fast that torque is put to use...as in ft-lb/second. One horsepower is 550 ft-lb/second or around 750 watts. Watts is also power.

There is no reason an engine can't deliver 500 HP peak and still get 18 mpg. It probably can't be done with a traditional small displacement SBC, but a fuel-injected LS or BBC doesn't have a hard time making that much power, and an overdrive transmission can get MPG up there. Your engine only needs to use enough fuel to make enough horsepower to roll the car down the highway, no matter what engine is used. Larger engines are a bit less efficient than smaller ones at low RPMs, but they have more torque which enables use of the lower RPM range which saves fuel.

But youre right, torque is what you feel...that's why I have a Ramjet 502 in my Nomad. It puts out over 500 ft-lb from just above idle to redline...567 ft-lb peak stock out of the crate. I think mine is higher. ;-)

Run-em
03-27-2012, 07:56 PM
There is no reason an engine can't deliver 500 HP peak and still get 18 mpg. It probably can't be done with a traditional small displacement SBC, but a fuel-injected LS or BBC doesn't have a hard time making that much power, and an overdrive transmission can get MPG up there. Your engine only needs to use enough fuel to make enough horsepower to roll the car down the highway, no matter what engine is used. Larger engines are a bit less efficient than smaller ones at low RPMs, but they have more torque which enables use of the lower RPM range which saves fuel.

Bite your tongue. Speaking ill of the SBC!!

mokicruz
10-14-2013, 11:24 AM
Next-Gen LT1 6.2-Liter V-8 for 2014 Corvette Revealed with 450 HP, New Tech
Zero-to-60 mph performance for the new base Corvette (http://wot.motortrend.com/caught-again-2014-chevrolet-corvette-cockpit-looks-more-driver-oriented-277443.html) is expected to be under 4 seconds. Efficiency is increased, making this one of the most fuel efficient 450-hp vehicles available. That’s right, an estimated 450 horsepower at 6000 rpm and 450 lb-ft of torque at 4000 rpm.

This is the engine we've all been waiting for Program in as much HP/Toque as you can afford.

chevynut
10-14-2013, 01:18 PM
This is the engine we've all been waiting for Program in as much HP/Toque as you can afford.

I don't think it's quite that simple. :)

Rick_L
10-14-2013, 02:13 PM
Torque is your engines actual power,horsepower is how fast you get it. Make any sense?

Off to a bad start in the first line. Torque is not power. It is rotational force. Power (horsepower is just the units) is the rate of applying torque.

Bihili
10-16-2013, 08:46 AM
I remember Rick_L and Chevynut debating Torque and Horsepower eight years ago on another forum.

chevynut
10-16-2013, 09:53 AM
Bihili, I doubt it. I think Rick and I have a pretty good understanding of torque and horsepower. Torque is the "twisting" force that en engine puts out (force x lever arm), and Horsepower is the rate at which that twisting force or torque is applied. HP = T x RPM. This is pretty simple in concept and with both of is being mechanical engineers I can't imagine that we debated this, but if there was a debate it may have been centered on something else, or a misunderstanding which has often happened. :)

Rick_L
10-16-2013, 02:55 PM
Maybe we were in a debate. Over this point, not with each other. Maybe us against someone else, or over a different point.

If you want torque at the wheels with a SBC, just put a 5.38 gear in the car. :)

chevynut
10-16-2013, 03:29 PM
Yeah, you may be right. I thought Bihili said we were debating each other, but just noticed that's not what he said.

It's like the ongoing debate about putting a restrictor in your radiator hose to supposedly slow down the coolant to help your radiator work better and keep your engine cooler. LOL! I remember some guy saying he didn't believe the laws of physics anyhow, and laws are made to be broken. I laughed my ass off. And O shut down the thread because it got a little too confrontational for his blood. LMAO! :)

mokicruz
10-16-2013, 04:17 PM
Direct injection and high compression made it more tunable than any gas engines, other than BMW F1's, have ever been. It's like tuning diesels. I had an article about it making over 800 HP without any adders. They claim the block is 1500 + HP reliable should they decide to dual turbo Crank , Rods, Pistons and valve train would be all you need. One of the last Boyd Coddington roadsters had a 1,200 HP big block with two pro chargers and it was a street driven car. My 67 Firebird I built in 72 had 721 HP on the dyno and retimed with street jetting was 668 hp. It was sort of streetable but a big pain to drive with overheating, fan belts flying off and loading up in 5 blocks of slow driving. It amazes me how streetable big HP is now.

Rick_L
10-16-2013, 04:40 PM
Well maybe so. Let's see, you have to add those Prochargers and turbos to get there. How about posting some links to those packages? I don't think they exist yet.

Were you smoking that weed all the way back in 72? And still do it? Even beer distorts your memory.

chevynut
10-16-2013, 05:11 PM
Direct injection and high compression made it more tunable than any gas engines, other than BMW F1's, have ever been. It's like tuning diesels.

No, it's not like tuning a diesel. A diesel doesn't depend on a stoichiometric fuel/air mixture. It has no throttle, and pulls as much air as it can on each stroke, even at idle. The more fuel you add, the more heat and power you get. It's a completely different thermodynamic cycle than a gas engine (diesel cycle vs otto cycle). And the new LT-1 Corvette engine is only 11.5:1 compression ratio...high, but nowhere near as high as a diesel. My Porsche Boxster S has 11:1 compression and the new ones are 12.5:1.

A normally aspirated gasoline engine, has a limit on how much air it can pull into it's cylinders. And then you have to add the right amount of fuel to get the correct mixture. Any more fuel and it doesn't produce any more power...it just wastes it. The only way you can make more power is to get more air into the engine, and add more fuel, keeping the mixture correct. That requires superchargers. There's no way with a 6.2L engine that you can just "Program in as much HP/Toque as you can afford".



I had an article about it making over 800 HP without any adders.

I don't buy it. You can't get that much power with a stock new LT-1 6.2 liter normally-aspirated C7 Corvette engine. If they could, they would. Please post the article.

I'm betting the high-end Corvette is going to have a supercharged LS-7 instead of the LS-9 (a supercharged LS-3). They need to get it higher than the current 638 HP of the ZR-1 to generate any excitement. I think the LS-7 would put it over 700HP.


They claim the block is 1500 + HP reliable should they decide to dual turbo Crank , Rods, Pistons and valve train would be all you need.

Yes, I believe the block is CAPABLE of that much horsepower. The LSX iron block is supposed to support up to 2000 HP. The only way to get that is with superchargers. Contrary to your statement, you can't just "tune it" to as high HP as you want.

mokicruz
10-16-2013, 08:46 PM
Boyd Coddingtons Roadster had two pro chargers. I had a 461 cubic inch stroked 400 with Ram air 722 heads angle milled .040 with offset dowels moving the heads up .060. I used dads haugs to shape the intake and exhaust Bowels then smoothed the ports without enlarging them and installed Aluminum Bronze guides Dads engines had pistons made by Bob Toros and Mushroom lifter cams made by Dempsey Wilson I used what he ordered for me from the same people. Flat top pistons made about 12 to 1 compression on the dry decked blocks but I ran copper so it was a little lower. my cam only had .628 intake lift and .638 exhaust. I think the duration at .050 was 326 not sure on that May manifold was edelbrock for a 1050 cfm Dominator. headers were 2 1/8" x 32" total length tubes into a 4 inch collectors that we bent and fabbed in our shop. Crank was turned to 4.25" stroke then built up then turned and radiused for aluminum M/T pontiac rods that came out of Dads engines after they had ran on a freshen engines. Nope dad wouldn't let me smoke weed how about ? Did you like it? As for Twin turbos when I worked for Evert Hatch we Installed them on Chamberlain's IMSA Vette.

mokicruz
10-16-2013, 09:01 PM
http://wot.motortrend.com/next-gen-lt1-62-liter-v8-for-2014-corvette-revealed-with-450-hp-new-tech-280365.html

This is motortends article on it. I'll go find the The one on Scuderia forum they were arguing about street vettes being inferior to the Ferrari and Dodge viper.

JT56
10-17-2013, 06:20 AM
I guess one of my questions is these motors with 11.5.1 compression and up take pump gas? Then if you do add boost how can they do that without running more octane? Do the computers adjust the timing and fuel? I know with ProChargers they recommend 9.1 and and for Roots style its 7.1.

mokicruz
10-17-2013, 08:17 AM
Direct injected Gas engines Like Diesel engines can't pre detonate. Huffing huge amounts of Oxygen creating enormous compression ratios then injecting a lot of Hydrogen is the goal. If compression ratio's are High enough any fuel injected will detonate without spark plugs provided heads seal.. http://usatoday30.usatoday.com/sports/motor/2009-02-18-3701603738_x.htm

monaliza23
08-03-2016, 03:13 AM
I don't think it's quite that simple http://www.scatzx.com/img/1469613638.jpg (http://www.scatzx.com/1469613638.html)

rockytopper R.I.P 5-13-2017
08-03-2016, 09:07 AM
Here is a fine example of torque vs HP. In this case the nova has both lol. I believe it is the 620 hp 650 torque at 4200 version 572 gmpp crate engine with a 5 speed behind it. The 400 hp ls3 Camaro and my 350 hp ls1 cutlass was no match out of the hole. I punch mine in this vid trying to keep up with filming although all you will here is the roar of that 572 as he walks off and leaves us both. It was surprising when we played around at speed above 85 or so my Ls1 would hang with the nova. And the only saving grace I had is my cutlass is built for corners the nova is nose heavy. When we hit the winding back roads on the tour I walked off an left the nova lol...... Although I will never run anything other than an LS or new LT I do miss the bottom end torque of a big block. Put 4 real men in my cutlass and it is a gutless dog ........

https://www.youtube.com/watch?v=mFzlYekoZDY

chevynut
08-03-2016, 09:45 AM
Horsepower is simply the mathematical product of torque and RPM. Torque is the mathematical product of a force and a lever arm.

All else equal, the car that has the engine with the most torque across the whole RPM range is going to outrun the car with less torque, at any speed. Notice I said ALL ELSE EQUAL.

You can give any anecdotal "evidence" you want, but physics still rules. ;)

Larger displacement engines generally produce more torque than smaller engines, as do supercharged engines. Torque is a function of piston area, pressure on top of the piston, and the length of the crank throw. Increase any of them and you increase torque. Larger displacement engines have larger diameter pistons and/or longer crank throws. Supercharged engines have better volumetric efficiency and therefore higher cylinder pressures at the same CR.

Torque is rotational force. If you increase torque, you increase the rate at which you can turn a driveshaft. That in turn increases the rate of acceleration of the car.