# Re: FINALLY, I NATURALLY ASPIRED AMERICAN CAR WITH 100HP/L!!!!!

Discussion in '2002 Cadillac Cien Concept' started by SHK, Aug 9, 2002.

1. #26
yes.
you see.
the figures you get for the S2000 have the engine running @ like 7200+rpms..
and the thing is it's already fine tuned.

The 3800series on the other hand is not fine tuned for max performance on it's own, and the 240hp comes at bout what? 5400rpms?
and the troque figures are way above the S2000.
I quite often see GTPs and S2Ks dragging, and scary how the GTP actually wins quite often.

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2. #27
Allright, here's your elaboration: power production (or "horse power," 1 horse power being defined the amount of force it takes to lift 550 lbs 1 foot in 1 second) works on an exponential scale. To create 2 horse power takes 4 times as much effort. In other words, to lift 1100 lbs 1 foot in 1 second would take four times as much output. To lift 1100 lbs 1 foot in 2 seconds would only take twice as much effort, but that's not horsepower.

"Volumetric Efficiency" is the amount of air/gas mixture an engine can dispose of (or "combust") compared to the amount it consumes every minute. Tipically, this goes up with compression (requiring higher octane gasoline). It has NOTHING to so with engine volume, and here's the proof:

To figure out carburetor (or throttle body) size, this formula is used by engine mechanics: Required Size (measured in CFMs) = VE x Cubic Inches x Maximum RPMs / 3456.

Now typical Volumetric Efficiency of a street engine is around 75-80%. Raise the performance, it goes up to 80-95%. It has nothing to do with volume of the cylinders (measured with each piston at Bottom Dead Center, not top, as was stated earlier in this forum). A dyno can tell you Volumetric Efficiency. HP/Liter can tell you exactly squat.

3. #28
I am Sorry to break it to you rice burners but olds yes the same car your mother drives broke the 100 hp per liter with the Quad 4 motor OVER TEN YEARS ago hate to break your hearts. it was also in its racing form had the record closed cource world speed record of all time. it did 270 standing mile and 260MPH CLOSED COURSE all this in 1987 yes that is right almost 15 years ago look it up it is the oldsmobile AEROTECH. driven by A.J. Foyt. good luck next time guys but keep trying.

4. #29
Yeah, I had a '90 Olds Calais Quad-4 International for a while. It was a badass car - 14.95 1/4 mile stock. Kept burning clutches, though. But didn't we just get done saying that HP/L doesn't mean anything?

By the way, the '91 Dodge Spirit R/T on this site has over 100 HP/L, also.

5. #30
Well said Brown i wouldn't start on the addition of Coef of Drag and its effect cube3 on need for HP as speed increases or hp losses through drivetrain, tires, etc. but it would take a large book.

6. #31
wasnt the Spirit a turbo?

7. #32
and as for the hondas challanging the F body's only when you move the engine and trans to the back of the car <IMG SRC="http://www.supercars.net/servlets/cMsg/html/emoticons/smile.gif"> if you wanna race you gotta have RWD period. dont debate it you wont win this

8. #33
Sure..put a NSX agaist the F-Bodies =P

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9. #34
"Sure..put a NSX agaist the F-Bodies =P"

Sure would an SS hell drag a 68' yenko camaro and youd see tail lights if you want to go dollar for dollar then i'd take a stock chev ZR-1 on pump premium straight drag, top speed, cornering, and road coarse. give it to lingenfelter to make up for the extra money you spent on the NSX and the Corvette will more than just dominate.

10. #35
An NSX will still lose, just be a little closer... but atleast the driving wheels are in the right place.

11. #36
1st of all, the dodge spirit r/t was turbocharged, just look at the torque figure of 217 lbft @ 2800rpm, sure sign of an artificially aspirated motor. As for the Oldsmobile Aerotech, u cant really use that either since it was a 1 (mayb 2) off and did it even run on normal gasoline?

2nd of all, indycars use 2.65-litre turbo V8s, not 2.5-litre V10s

3rdly, ur little explanation of HP is certainly correct, although i know it as P = Fd/t. This means that power is DIRECTLY proportional to torque, but INVERSELY proportional to rpm, so as torque rises, power rises with it on a linear scale, but if u raise rpm, power rises exponentially

SO, in my suggestion earlier, i was only changing torque by adding cylinders, not changing rpm, so the work being done by the system would remain constant throughout

12. #37
Americans like to make big engines, with high torque at low RPM's, the low-end type of engine, 'cos in the 70's, when the pony car race happened, most of the races were decided in a quarter mile straight drag-strip, so the architeture of the V-8s were made for it (and confort o the highway too...), most of america's supercar's including the Viper, have old engines under their hood just with a makeover, to agree with emission of poluents and that kinda stuff (Ford 302 "Cleveland" still lives, as Chevrolet 351, and the engine of the Viper is based on a truck engine).
This Cien engine is a new engine, based on state-of-art technologies, (built the European High-end supercars way)

13. #38

first the spirit was a ? not a statement second the Aerotech was an addition to the fact that olds had the quad 4 2.3 four cyl that nat aspirated had 230hp just letting the rice burners know they are 10 years late and i was not comparing the Aerotech to indy or any form of racing, concept, or production vehicles. Third i should have been more clear with my abbreviations so people would understand. I was speaking of coeficient of drag and its effect on need for hp to sustain a givin mph your as speed increases drag doubles and hp needed cubes now i oversimplify greatly i am talking about cars and have not even touched on advanced aerodynamics and don't have space to start. Fourth adding RPM adds power GREATLY oversimplifys and i think misleads you know anything in motion tends to stay in motion etc. mass and inertia but hp is not an accurate measure of power only torque! i am not teaching to students right know just in a discussion group.

14. #39
Basically everything affects everything is the general idea here =P

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15. #40
Ford never made a 203 "Cleveland," it was a 351 Cleveland. The Boss 302 was a regular 302 with Cleveland heads. And Chevrolet never made a 351, just their infamous 350.

That Spirit is not Turbocharged, and who cares if it was? What does that have to do with our dicussion, ch1? I just don't get what you're trying to point out. But it was a 2.4L NA engine. And Sepicific Output doesn't matter anyway.

The "Pony Cars" were not made for drag racing at all - they were mainly for competition in the Trans-Am and Rally circuits. When you make a light car with a large, powerful engine, people are going to take it drag racing, that's all there is to it.

The '67-'69 Z/28 Camaro - 302 CID engine, a destroked version of the 327, specificly for competition against Mustangs and Cudas in the Trans-Am circuit. Redline was in the 7's, made power well above 5 grand. Hell, NASCAR uses mostly Chevy/Olds 350's, and they make power up around 9800 rpm.

Ford 427-Cube side oiler - made power above 7 grand, banned from NASCAR after Ford took 1st-6th, 1967.

16. #41
Hehehe..the 427 is a big mutha....
larger than the competition..Hell..if they didn't ban it, GM would surely bring in like a damned Turbine engine =P

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17. #42
i can just repeat, Newtonmeters * RPM / 7127 = BHP
or
lb-ft * RPM / 5152 = BHP

And please see the difference between turbo engines and naturally asp. ones. Cart Racers go on 2.65 V8 (V10 today???) Twin Turbo
around 12.000rpm, loads of torque because of the turbos

but FORMULA ONE CARS are naturally aspired, they do their power just by revving. 18.000rpm, 800BHP from a 3 litre V10. I calculated that they only have 350Nm/approx 280lb-ft of torque at their power peak.

So you can either have power from turbos (which we arent talking about as even the topic says) or from revving or from a big engine. High RPM engines will get damaged and worn out very fast, and americans never wanted that, thats why their low BHP/liter

But this concept is quite impresive anyway <IMG SRC="http://www.supercars.net/servlets/cMsg/html/emoticons/smile.gif"><!-- Signature -->

18. #43
tru dat<!-- Signature -->

19. #44
Like already mentioned in another topic, i vote for a club-forum <!-- Signature -->

20. #45
I prefer lower revs.
smoother engine..less vibration and a nice sound =)

DA PUN<!-- Signature -->

21. #46
ok BrownDoggie, the spirit r/t comment was a sidenote

but u havent got around to explaining y a 4-litre V8 is working harder than a 2-litre 4cyl to make 100hp/litre, forget about how irrelevant the figure is, its still worth discussing as a physical property. Tell me y my previous posts on the topic r wrong

and SuperDan, fluid mechanics is my speciality, but that has got nothing at all 2 do with this discussion, my post wasnt aimed at u i dont think, sorry to confuse

by the way my username is supposed to read 'chicane', as in the things that break up the Mulsanne

22. #47
there is more to it than i will explain now but this is the most relevant reason an 8 cyl 4 liter "works" less than a 2 liter producing the same power first if we are talking about piston accell you have a piston that goes from a stop (top dead center) to max accell 90 deg to a dead stop agian (bottom dead center)if you have less accell lower rpm or shorter stroke you have less accell decell and will have less cyl sidewall loading not to mention givin the same valvetrain you have the same story. have you ever seen a valve spring on a hard dyno pull for say 3 to 4 minutes valve springs without proper oiling can glow like a light bulb (yes valve springs need oiling to keep them cool just bend a coathanger back and forth and see what i mean)there are many others including higher loading to bearing requiring higher oil pressure that means more hp load from oil pump they are the largest hp sucker on the whole motor.etc. etc. etc. etc.

23. #48
Well, no, not really, but you're hitting on some good points. Let me start with turbos.

Turbocharging is merely a way to force-feed air into your engine (just like centrifugal superchargers and roots style blowers). Nitrous works similarly, it's heavier than air and forces the gas mixture to fall faster. When you increase the pressure in your cylinders (as with Turbocharging), you increase the force with which the pistons are fired by, increasing high-end torque. You sacrifice compression (ratio) in order to accomplish this, however, so everything is relative. My engine produces 50 more torque than HP and is naturally aspirated, go figure; maybe it's the 10.3:1 compression. Once again, the HP/Torque conversion has nothing to do with this.

24. #49

Cars are not better than one another all cars are created for a reason to go fast to be good on gas or for comfort

I am a test driver for Motor Trend TV I drive my car because it is what I like to drive and that it was is important.

Cars are great people say my car is better than your well so be it mabey to you but even if that guy is driving a 1986 Tempo it his car and he love it because it is his/or hers.

So don't trash anyones ride or any car for that matter !

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1990 Linclon Towncar HO 5.0

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25. #50
Shut up, I'm not done.

Chicane, I thought your user name was some funky combination of Carbon, Hydrogen and Nitrogen. Go figure.

Anyway, an engine with twice the volume is not twice as large, per say, but merely compresses twice as much air/gas mixture per stroke (or 4 strokes, really). Engines are susceptable to the exponential effects of power production, that's why HP/Liter figure is irrelevent.

I was responding to your comment about an engine with twice the number of cylinders with the same volume/cylinder being twice the motor - it doesn't work that way do to the complex nature of engine dynamics. A good example: a V-twin motor historically produces more torque than an inline-4. It all has to do with balance and engine design. To further explain:

A longer stroke typically enables an engine to rev higher, whereas larger bore usually produces greater low-end torque. Bore and Stroke are more important than Volume. But a 400-cubic inch engine with a very large bore and small stroke will not perform, same with a long stroke / small bore engine.