Ford Muscle Cars Tech Forum banner
1 - 20 of 23 Posts

·
Registered
Joined
·
904 Posts
Discussion Starter · #1 ·
Hey everyone I have a few questions that have been bugging me. When I look at the stock numbers, my 68 mustang produces more torque than the 360 Modena with only about half of the horses. How is this possible with only a 2bbl carb? if i change to a rpm air gap manifold, a holley 650 double pumper, roller cam, aluminum gt40 heads, and a msd ignition kit, how close to these numbers do you think i can get????? Can someone explain what the horsepower and torque at the different rpm range will do for you? I see these numbers but dont get what they mean at thoes rpms. last question, what limits top speed???? I want to keep the car totally streetable.
thanks alot,

2002 Ferrari 360 Modena
90° V8
Bore & stroke 3.34x3.11in.
Displacement 219 CID
Maximum power 400 Bhp @ 8,500 rpm
Maximum torque 275.6 lbs/ft @ 4,750 rpm
Listed Top Speed 190

1968 289 Mustang
90° V8, OHV
Bore & Stroke 4.005 x 2.87
Displacement 289 CID
Maximum Horsepower 195 Bhp @ 4,600rpm (196

Maximum Torque 288 lbs/ft @ 2,600rpm (196

Listed Top Speed 120

2002 Z06 Corvette
Overhead-Valve (OHV)
Displacement 350 CID
Maximum Horsepower 405 @ 6000
Maximum Torque 400 lb/ft @ 4800
Listed Top Speed 176
 

·
Registered
Joined
·
237 Posts
Those cars are built and fully tuned, not just the motor, everything is made to work together perfectly from the motor to the suspension to vehicle weight, etc etc. also, the horsepower figures you have for the 68 are gross horse power rating that they used in the past. im not sure exactly when, but i figure it was in the early 80s or so that they switched to net horsepower rating. net horsepower is what the motor actually makes as it sits in the car with all the accessories and smog equipment attached. the gross ratings are without all the accessories or exhaust system. In reality, your 2bbl 289 makes about 150hp. the old GT mustangs made more like 175hp not 225 as rated. the newer mustang GTs make an actual 225 as rated.
 

·
Registered
Joined
·
904 Posts
Discussion Starter · #3 ·
Ive read at fomoco that when Bhp follows the horsepower rating that it means gross horsepower with no accessories/chassis mass, just engine, so I wonder what the Ferrari 360 Modena is really putting out with its 400 Bhp rating?
 

·
Registered
Joined
·
7,501 Posts
Torque is the twisting force a crank can exert.

This force can be multiplied with gearing. A 2.78 first gear requires the engine to turn over 2.78 times in order to spin the tranny once... and in doing so, multiplies the torque by a factor of 2.78.

This would take the 400ft-lb of torque the engine makes, and turn it into (400 x 2.7
1112ft-lb. THEN, routing it to a 4.30 rear gear would produce (1112 x 4.30) 4782ft-lb of torque to the rear axles!

The engine's torque output does not change with gearing, but the torque transferred to the rear wheels DOES.

Tractors don't have very powerful engines at all, but they are geared so low, they can drag about anything around... just not that fast.

Next, a few words about POWER

Now, as far as dragging something around... FAST.

It takes a certain amount of work to drag something from point A to B. Let's say a car from the starting line to the end of the quarter mile. A 2700lb Yugo and a equal weight dragster can both get the job done... and in doing so, do the same amount of work. The ONLY difference is, the dragster does it a lot faster!

Power is how FAST work is done. The dragster had to produce more POWER to get to the finish line first.

When relating Torque to Horsepower... Torque is the ability to to work, and horsepower is how fast it gets done.

Take two engines... One produces a LOT of torque at low rpm, and the other produces less torque, but at a high engine speed. Both engines can produce the SAME maximum horsepower. One effectively uses a BIG shovel to to load the wagon, but works slowly, while the smaller engine uses a smaller shovel, but works at a fever pitch... They both end up loading dirt at the same rate!

In theory, the smaller engine can be geared to have the exact same output to the rear wheels as the larger one.

Get it?


Good Luck!
 

·
Registered
Joined
·
567 Posts
And to why that Fords engines have so much torque- Ford loves torque! 99% of Ford's engines have wayy more torque than horsepower. I prefer torque over horsepower anyway, it seems to be more fun, and applicable too.
 

·
Registered
Joined
·
4,154 Posts
I always describe torque as that all powerful force that makes my passengers heads hit the back glass in my truck when that thumpin 460 grabs 2nd and takes off like Batman after the Catwoman. Horsepower is a number for the honda guys to describe how many NOS shots they have...
 

·
Registered
Joined
·
46 Posts
the ferrari makes more horsepower because is is making its torque at a higher rpm. horsepower is calculated from, (torque * rpm)/ 5250 = hp
If you make your torque in higher rpm , you get more horsepower, but in a very high rpm. Your car makes its torque lower so its has less hp than the ferrari. If you want to build your 289 to have its powerband up around 8 grand, you will kill the ferrari in power, which doesnt seem so hot anymore.
 

·
Registered
Joined
·
567 Posts
On 2002-05-25 15:38, Luv70sFords wrote:
I always describe torque as that all powerful force that makes my passengers heads hit the back glass in my truck when that thumpin 460 grabs 2nd and takes off like Batman after the Catwoman. Horsepower is a number for the honda guys to describe how many NOS shots they have...
, I agree soooo much with that, torque is just wayyyy more fun! And you cant make torque with a rubberband.
 

·
Registered
Joined
·
904 Posts
Discussion Starter · #11 ·
On 2002-05-25 23:16, ant123 wrote:...If you want to build your 289 to have its powerband up around 8 grand, you will kill the ferrari in power, which doesnt seem so hot anymore.
how would i get it up to 8000? Would it still be streetable?
 

·
Registered
Joined
·
1,068 Posts
A big roller cam, edelbrock victor intake, a very good set of heads, and a 750 cfm carb would get you there, but I wouldn't personally put a motor that I built to reach 8,000 in my street car. The power band would be really high-and that brings hi-stall converters, big rear gears, etc....I have known plenty of guys that have done it though, its just not for me. Give me gobs of torque between 2500-4500 rpm for my street car.
 

·
Registered
Joined
·
904 Posts
Discussion Starter · #13 ·
So the Ferrari is not considered a daily "Street Car" since it produces peak power at 8500 rpm?
 

·
Registered
Joined
·
46 Posts
the ferarri is a street car, but thats why it costs so much. It can run that high rpm and be reliable. If you wanted to bring your powerband that high and use it all day with no reliablility problem you would need to have super strong, super expensive aftermarket parts. Get an aftermarket block, billet crank and rods. Roller cam and rockers. And every other high dollar part in the summit catalog and your engine will be able to rev past 8 grand with no problem, but youll be paying a lot more than 8 grand.
 

·
Registered
Joined
·
904 Posts
Discussion Starter · #15 ·
So I guess the Corvette achieves its power through displacement, what limits a cars top speed besides drag?
 

·
Registered
Joined
·
143 Posts
Actualy the horsepower figures changed in 1972 they were gross at the flywheel, then they went to SAE NET, that is at the back of the trans with all accesories running.
 

·
Registered
Joined
·
567 Posts
Top speed is limited by gearing and redline, and some power issues, 4.10's=Great acceleration, bad top end, 2.80's=Bad acceleration, high top end (Provided you can get there)

<font size=-1>[ This Message was edited by: BuiltFordTough on 5/28/02 3:08pm ]</font>
 

·
Registered
Joined
·
41 Posts
The power an engine makes is mostly all you need to know to estimate it's acceleration and top speed etc. The TQ numbers will tell you how big your engine is. In general the TQ an engine makes is directly prortional to its cylinder pressure at a particular RPM and it's size. The power is proportional to the amount of fuel and air the engine can burn in a given amount of time which also sets the upper limit on how much work it can do in the same unit time. Power figures tell you how much cylinder pressure an engine can maintain at any RPM at a certain engine size which is primarily dependent on the heads and intake system. Big engines can use taller gears while smaller engines need deeper gears to achieve the same rear wheel TQ which does influence acceleration.

The reason the Ferrarri has so much top speed and acceleration is simply good power to weight and aerodynamics. Even Ferrarri has some big torquey engines in it's cars. It's still easier to make power with larger engines than smaller ones because you don't have to turn as many RPM which has exponentially increasing inertial losses and higher frictional losses as well. for the same engine family. Always build big if you can!
 

·
Registered
Joined
·
904 Posts
Discussion Starter · #19 ·
my car currently has its original 3.25 traction lock rear end. Is this decent for a small block street car with a C4 in it?
 

·
Registered
Joined
·
67 Posts
The things that limit top speed is simple.
Aerodynamic drag is the biggest factor, but rolling drag from tires is also noticable. Aerodynamic drag increases with the square of the speed. Downforce will limit top speed. Lift will limit top speed as the car gets unpredictable to drive faster. Who wants to take off like a plane without the wings?
But to reach the highest speed possible for a given car with a given engine, then you have to optimize the gearing ratio for top speed driving.

Increasing engine output is of course the most used method to increase speed, but the most efficient would be to reduce drag.

Doc
 
1 - 20 of 23 Posts
Top