horsepower vs. liters

[Kristi]

Okay, guys, I was raised in the age of horsepower. I know the diff between a 302 and a 305, and I know what size engine my truck had. I've never made the leap to liters. Too many people have already asked "what size of engine does it have?" My most intelligent answer is "a V8", which really isn't an answer. I can't say "a 3.9" because I don't know what that means.

Can someone out there explain to a reasonably intelligent Girl what size engine my T-bird has? And, is there a way to convert liters to horsepower?
Please, no serious gearhead explanation because I'll zone out on you. Plus, whatever the explanation, I have to be able to intelligently say it to my dad, who knows cars from waaaay back.

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[RTBRD_aka_jodrod]

There really is no conversion from engine size to HP, all depends on what is in/on the engine. The 3.9L engine is 241 cubic inches.

It has 4 valves per cylinder (4V) and is a double overhead cam (DOHC) design.

You will see it described as such: 3.9L DOHC 4V or 32V (4 valve x 8 cylinders).



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[TbirdSandie]

Kristi,
Obviously I am not a guy, but when people ask what size engine your bird has tell them it's a 32 valve double overhead cam V-8 with 252 horsepower @ 6100 rpm.

Sandie

 

[Kristi]

Jeez, Sandie, you've said a mouth-full! I can always count on you to put it into terms I understand.
RTBird, why did they switch from horsepower? Thanks for explaining the 32V. I really couldn't figure that out.
I think I'm adequatly armed to venture out this morning!

 

[RTBRD_aka_jodrod]

Kristi,

The didn't switch from HP, the 3.9 makes 252 of'em.

There are all kinds of things you can do to an engine to produce more or less horse power.

You have probably read in some posts about a supercharger being added. Now, the engine size does not change, it is still 241ci/3.9L but what the superchager does is pump more air and fuel into the cylinders and you produce more power (bigger explosion in the cylinder). So as you can see, there is no direct relationship between size and power, almost.

A larger engine has more volume in the cylinder and therefore you can get more air and gas into it and as stated above and produce more power, from this you get the old addage "there is no substitute for cubic inches".

Hope this helps clarify things.

 

[LON O'CONNELL]

Kristi a Litre is approximately 60.5 cubic inches. That figure is not exact but it gets you in the ballpark. Also the Litre reading the manufactures gives is not exactly right as they round the number up or down.
Example: 60.5 cubic inches x 3.9 Litres = 238.95 cubic inches. Close but not exact. Could be that the engine is really 3.95 Litres or there abouts and they round it off to 3.9L Take a 5.0L Mustang engine x 60.5 cubic inches and it comes out to 302.5 which is really close as the 5.0L is a 302. As the others have said Litres or Cubic Inches have nothing to do with horsepower, just a measurement of the size of the engine.

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Yellow/Yellow Prem. 02 Bird w/full accent
1999 F150 Super Cab 4x4 Off Road
1998 Taurus SE Sport 24V

 

[tr cruiser]

Horsepower is a measurement of energy per unit of time. The scientific definition reads:

Horsepower is the imperial (British) unit of power, now replaced by the watt - the new SI unit. One horsepower is the work done at the rate of 550 foot-pounds per second and it is equivalent to 745.7 watts. Horsepower was first used by James Watt, who employed it to compare the power of steam engines with that of horses.

There's an interesting story behind the historical origin of horsepower in case you're interested. There really isn't any reason to convert from the common unit when referring to an engine. I find it more intuitive to think of horses lifting a load, but then I never liked converting from miles to kilometers in countries where the cities and highways were originally laid out in English units and metric doesn't map to city blocks very well. Just my bias.

 

[BornAgain]

Kristi,

You are not all by yourself. Today I've learned a lot from these people in the know.

 

[txktom]

Kristi,
What LON O'CONNELL said. Plus, don't think about it--just push your foot down and go. Despite what its very few detractors might think, this car moves really well.

 

[LON O'CONNELL]

Also Kristi if you want to convert cc's to Litres, that is very easy. There are 1000 cc's in a litre. If a vehicle is reported to have a 2375 cc engine it would be rounded up to be called a 2.4L engine.

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Yellow/Yellow Prem. 02 Bird w/full accent
1999 F150 Super Cab 4x4 Off Road
1998 Taurus SE Sport 24V

 

[RTBRD_aka_jodrod]

Lon,

I believe the venerable 302 (5.0L) is actually 4947cc, I guess that 5.0 sounded better than 4.9.

 

[LON O'CONNELL]

Boy Rtbrd you are right. It won't even roll off your tongue right if you try to say "Saleen Mustang 4.9L" LOL

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Yellow/Yellow Prem. 02 Bird w/full accent
1999 F150 Super Cab 4x4 Off Road
1998 Taurus SE Sport 24V

 

[mikedmeyer]

The exact conversion is as follows: One inch = 2.54 centimeters (by definition). One cubic inch = 2.54cm * 2.54cm * 2.54cm = 16.387064cc (not rounded off). One liter = 1000cc/16.387064cc = 61.024ci (rounded off).

302ci * 16.387064 = 4948.89cc = 4.94889l (doesn't really round off to 5.0l, as previously stated)

305ci * 16.387064 = 4998.05cc = 4.99805l (does round off to 5.0l)

3.9l * 61.024 = 238ci.



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[Gobird]

OK guys, I think we lost Kristi somewhere along the way. She ask for a simple explanation and things got out of hand. Although infromative they may be behond her experties.

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02 T-Bird 9293
69 Vette
73 MGB
97 F-150 4x4
2-Seadoo Jet Skies
a dog a cat and a couple hundred fish in my pond

 

[RTBRD_aka_jodrod]

Gobird,

Typical male reaction, get a couple of guys hanging around the shop and this is what you get.

 

[Kristi]

Gearheads!
I'd say we've got some "experties" on this board....
So much for my attempt to impress my dad, all he wanted to do was climb ALL OVER the car! (He said he'd wait for a sunny day to drive it.)
Thanks for the in-depth discussion about horsepower. oops, litres. uh, cc's. no, ci's. I'm still not sure why they gave up on it in favor of litres, but I think it's akin to the invention of the Miracle Bra. You know. Boost.
Anyway it's amazing the number of women who want to talk about the 'bird, comparing it to the '55-'57. The guys have been decent, impressed that I can knowledgably talk (even if I can't spell) about the car. One guy today tried to tell me that it was front-wheel drive. duh, right.
Thanks guys, and Sandie. Hubby says now I need to get the litre info on a new Corvette engine to reasonably compare what I have.

Okay, to the next question. Did anyone else read the owner's manual? Something about an intelligent transmission, learns as it goes? The first 300 miles I put on the car were hiway miles, not much around town. I noticed the last couple of days it's been slow off the line in town. Tonight - big diff! I 'bout left my teeth at the light! So is the car now learning my in-town driving habits?
What do you ex-purts say?

 

[DavidA]

As THE resident expert I say ... YEP!

 

[KYbluebird]

Mine has learned a strange trick. Sometimes when I mash the throttle about half way, it downshifts before it revs the engine. Gives me whiplash, throwing my head forward then back, very annoying.

 

[niteflight]

This thread and this last entry seem like a good place to chime in with a question: Not that I would ever thrash my new T-Bird mind you - heaven forbid - but....... anybody able to burn rubber? I can't, even in low, with the traction control off. The '63 Galaxie I drove as a teenager would burn rubber all day until you lifted your foot off the throttle, or until it ran out of gas. I remember you could see the gauge drop right before your eyes. Of course it did have about 50 extra HP, a lower torque peak (and higher peak torque), more weight to get moving, and skinnier tires to do the job. It'd be nice to know that it could be done in the T-Bird, even if I am now far too responsible and mature to indulge in that sort of thing.

 

[RTBRD_aka_jodrod]

niteflight,

Not that I have ever done this but if you power brake (left foot on the brake, right foot to the floor) you'll leave about 10 - 15 feet of expesive tires on the road. The engine management computer will detect that you are not moving and limit the revs to about 2500 but it is enough to lite up the tires. Of course the traction control needs to be off.

On the '63 you had more inertia to overcome and the skinnier and far less sticky tires allowed them to break loose easily. The new tire coumpunds are extremely grippy and the tires have a bigger contact patch.

I have also noticed that the computer does seem to somewhat limit the amount of power initially delivered. The engine does not want to wind as fast when first accelerating in low gear.



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