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Luke, use the torque....

5K views 28 replies 9 participants last post by  Dan TM 
#1 · (Edited)
So many people talking about making an ETA rev higher, and putting in lower gears trying to make more "power", the fact is no body seems to know how to use what they have, to make what they have work better for them, and why torque is more important than HP.

ETA motors put out great torque, so USE IT. Putting in a lower gear differential doesn't help an ETA build power, it's an old school method that works by turning RPMs into torque. That is what the transmission and differential does, it turns the motors low torque and high RPMs into putting more torque at a lower RPM into the wheels. Loosely translated it means if you have lots of lower gearing you are going nowhere fast with tons of torque. Think of riding a mountain bike, starting off in first gear, you'll peddle like crazy (building loads of torque at the wheel) but you are not going fast or covering any real distance. However you needed less leg torque, just RPMs. Put the bike into a higher number gear and you need loads of leg torque to start off but now you can go faster. You need to find the gearing that makes the most of the available power (leg torque) and trading that to obtain most distance traveled with the most wheel torque.

This same principle applies to cars too. Since lower gears will up the torque it will also drop the useable torque RPM range. (staying in each gear less and shifting more) You must gear your car correctly for the rpm range to make the most of the torque your motor is building with the greatest amount of distance with out going out of your torque's RPM window.


What to do?

Now you should be thinking "So putting lower gears into an ETA (or any high torque, low rpm motor) is shooting myself in the foot, ok, so how do I build more low end torque? A large turbo?" No, a smaller turbo, another misconception. Turbos are, simply put, a torque multiplier. Larger turbos require great amounts of exhaust (aka RPMs) to spool up. Something the ETA doesn’t do well and is out of the ETA's useable torque range. (what good is it adding torque in the higher RPM range when there is no torque to add to?) The answer: Install a smaller quicker spooling turbo to increase the low end torque you already have.

With the quicker spooling turbo you "boosted" your torque in the motors torque rpm window (power band) Now lets jump back to the bike metaphor, this means with the turbo you have pumped up your legs (more "leg torque") and now you can use the upper gears to start off moving faster using "leg torque" getting the most out of gearing and still putting that power to the ground. Now since you have more power in the lower RPM range you also spread out your power band because you are moving faster at a lower leg RPM. In the car it means you can use that higher geared differential to turn your motor's higher torque into more wheel torque at lower RPMs, aka: More power and speed.

This principle is why that screaming 10,000 rpm, huge turbo powered honda seems to have so much "power" In reality it doesn't, the turbo is dumping torque into the upper RPMs just so it can trade it off for lots of wheel torque. It's also why you see so many dead hondas (and other high RPM cars) too... They are asking the motor to spin faster which is very violent and detrimental to a engine with so many moving parts. The wankel rotary motor is perfect for high RPMs (less moving parts) but that is another story....

Now I hope some of you get this and understand why torque is more important than HP. And also explain why a 180hp 460 ft/lbs of torque huge diesel powered truck can actually move very fast. Also why lower gears makes cruising on the highway going 60 mph @ 3500 RPMs very stupid because your motor is just spinning it's legs and going "nowhere fast".
 
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#3 ·
HP == fake number to please the public invented by marketing people.

Torque == the true driving force of a vehicle.

For those who want an even further lesson, whom may not understand...

HP = Trq x RPM / 5252

Some people / texts say 5250.. but thats hardly going to change the outcome..

So, thusly, if you have a given motor, making 150 ft/lbs torque at 5400 rpm, and you would be generating:

150 x 5400 / 5252 = HP

You'd be "making" 154.23HP @ that RPM.

So, hondas which appear to have 600hp at 10,000 rpm, are only making 315 trq.

VS a bmw that makes 600hp @ 6,500 rpm is making 484 trq at less rpm.

Trq is the actual work twisting your wheels around, so to make more, at lower rpms... and for more overall rpms.. means to go faster.

So, all the 900hp supras, bah.

I'd take a 500hp m5 any day.
 
#4 · (Edited)
Great Writeup!! i couldnt agree more, and yet i think joe is the confused one.

JoeMadoo said:
I agree. Tell that to krautman.
thats right tell me what i already know and agree to??.....yess....thats it :rolleyes: what was the point of this comment joe?
 
#5 ·
nukeduster said:
HP == fake number to please the public invented by marketing people.

Torque == the true driving force of a vehicle.

For those who want an even further lesson, whom may not understand...

HP = Trq x RPM / 5252

Some people / texts say 5250.. but thats hardly going to change the outcome..

So, thusly, if you have a given motor, making 150 ft/lbs torque at 5400 rpm, and you would be generating:

150 x 5400 / 5252 = HP

You'd be "making" 154.23HP @ that RPM.

So, hondas which appear to have 600hp at 10,000 rpm, are only making 315 trq.

VS a bmw that makes 600hp @ 6,500 rpm is making 484 trq at less rpm.

Trq is the actual work twisting your wheels around, so to make more, at lower rpms... and for more overall rpms.. means to go faster.

So, all the 900hp supras, bah.

I'd take a 500hp m5 any day.

WRONG!

The advantage of a higher revving engine (that can keep peak torque up at higher RPM) is that you get the same torque, same engine load (i.e. same gear) but more speed out of the gear and more time spent in peak torque at the lower engine load, where the engine can accellerate more easily. That's why it's better to have a midrange peak that pulls hard to the top. You can get very insane accelleration out of an 8000rpm Supra engine. Believe me. 900hp Supra will stomp 600hp M5 like it was standing still.

EDIT: Video evidence: 811whp 8000rpm Supra (black)vs 620whp with higher torque than the other (camera)
YouTube - Brad D's 800rwhp Supra vs Dan's 620rwhp Supra.
 
#6 ·
triggrhaapi said:
WRONG!

The advantage of a higher revving engine (that can keep peak torque up at higher RPM) is that you get the same torque, same engine load (i.e. same gear) but more speed out of the gear and more time spent in peak torque at the lower engine load, where the engine can accellerate more easily. That's why it's better to have a midrange peak that pulls hard to the top. You can get very insane accelleration out of an 8000rpm Supra engine. Believe me. 900hp Supra will stomp 600hp M5 like it was standing still.
exactly, see this is the point where i lost joe the other night and i think thats what he is reffering to with his little quip... :p
 
#7 ·
triggrhaapi said:
WRONG!

The advantage of a higher revving engine (that can keep peak torque up at higher RPM) is that you get the same torque, same engine load (i.e. same gear) but more speed out of the gear and more time spent in peak torque at the lower engine load, where the engine can accellerate more easily. That's why it's better to have a midrange peak that pulls hard to the top. You can get very insane accelleration out of an 8000rpm Supra engine. Believe me. 900hp Supra will stomp 600hp M5 like it was standing still.

EDIT: Video evidence: 811whp 8000rpm Supra (black)vs 620whp with higher torque than the other (camera)
YouTube - Brad D's 800rwhp Supra vs Dan's 620rwhp Supra.
Different turbo setups from the same motor.. i said same peak hp.. thats 200whp difference, the trq curves are still going to be vastly different(and possibly inefficient)

The 2005 vs the 2006 caddy CTS-V for example, has identical trq and hp numbers, but it has more torque, more of its powerband by swapping into a LS-2 motor from the LS-6.

Its more drivable power to torque down-low..

more hp @ the top = higher top speed/ability to pull better at higher speeds..
BECAUSE its in its efficiency range @ said rpm @ said speed.

Quarter mile times should probably be pretty close between those two vehicles, given equal drivers and conditions.

You also didnt read completely what i said.. more torque downlow, that stays consitent thru the whole rev range WILL be faster..

Look no further then the Audi le mans r10 diesel.. it has waves of torque the other gasoline engines didnt, and because of proper tuning, maintained the torque thruout its rev range, keeping it the absolute dominant racecar on the track. by LEAPs and bounds.

If you want race track top speed power, peak up high.. if you want 1/4 mile power and real life power, torque as low as you can, for as long as you can.
 
#8 ·
Brake Mean Effective Pressure (BMEP) is another very effective yardstick for comparing the performance of one engine to another, and for evaluating the reasonableness of performance claims or requirements.

For completeness, the definition of BMEP is: the average (mean) pressure which, if imposed on the pistons uniformly from the top to the bottom of each power stroke, would produce the measured (brake) power output.

Note that BMEP is purely theoretical and has little to do with actual cylinder pressures. It is simply an effective comparison tool.

If you work through the arithmetic, you find that BMEP is simply a multiple of the torque per cubic inch of displacement. A torque output of 1.0 lb-ft per cubic inch of displacement equals a BMEP of 150.8 psi. So a very practical way to calculate BMEP is:

BMEP = 150.8 x TORQUE (lb-ft) / DISPLACEMENT (ci)
(equation 8)

This tool is extremely handy to evaluate the performance which is claimed for any particular engine. For example, the 200 HP IO-360 and 300 HP IO-540 Lycomings operate at a BMEP of about 163 psi. (1.08 lb-ft of torque per cubic inch) at peak power and slightly more at peak torque. That is a respectable figure.

For contemporary naturally-aspirated, gasoline-fueled, two-valve-per-cylinder, pushrod engine technology, a BMEP over 200 PSI is quite difficult to achieve and requires a serious development program and very specialized components.

The upper end of the normally-aspirated BMEP spectrum is shown by these two race engines.

One was a 358 cubic inch circle track motor (gasoline-fueled, 2-valve, pushrod V8) which made 531 lb-ft. of torque at 6400 RPM (647 HP) and 503 lb-ft of torque at 7600 RPM (729 HP). Those data points represent BMEP figures of 223.5 at peak torque and 211.4 at peak power. Those numbers are truly excellent, and require very-highly developed components.

The best by far that we have seen was a 268 cubic inch drag-race motor (gasoline-fueled, 2-valve, pushrod V8) which made 413 lb-ft of torque at 7800 RPM (613 HP) and 372 lb-ft of torque at 9200 RPM (652 HP) for BMEP figures of 232.7 at peak torque and 209.6 at peak power. The 232.7 number is astonishing at any RPM. The 209.6 figure at 9200 RPM is nothing short of phenomenal for a two-valve pushrod engine.

To appreciate the value of this tool, suppose someone offers to sell you a 2.8 liter (171 cubic inch) Ford V6 which allegedly makes 230 HP at 5000 RPM, and is equipped with the standard iron heads and an aftermarket intake manifold and camshaft. You could evaluate the reasonableness of this claim by calculating that 230 HP at 5000 RPM requires 242 lb-ft of torque (230 x 5252 ÷ 5000), and that 242 lb-ft. of torque from 171 cubic inches requires a BMEP of 213 PSI (150.8 x 242 ÷ 171).

You would then dismiss the claim as preposterous because you know that if a guy could do the magic required to make that kind of performance with the stock heads and intake design, he would be renowned as one of the preeminent engine gurus in the world. (You would later discover that the engine rating of "230" is actually "Blantonpower", not Horsepower.)
 
#9 ·
nukeduster said:
Different turbo setups from the same motor.. i said same peak hp.. thats 200whp difference, the trq curves are still going to be vastly different(and possibly inefficient)
Do you want to see what that supra did to a Venom Viper? Or a S/C Vette Z06? It's brutal.

I was simply going for a torque comparison. The 620whp supra made like 20lb/ft more torque than Brad's car, but it wasn't as useful because the engine didn't rev high. Same case with the Venom Viper (except more along the lines of 100lbs/ft more tq) and the same results (actually the 620whp supra whupped the Venom Viper too)

Torque is also not always your friend, keep in mind. Peaking later in your rev band makes launching easier, and makes boost come in more controllably during upshifts. Fact O' life my friend. Torque is the mortal enemy of traction.
 
#10 · (Edited)
There are too many other factors to take into account to give an accurate account of how power is used and transferred: Power to weight ratio, transmission gearing, the balance of weight from front to rear, suspension, and tires. If you want to be fare in an example of better use of power use, then you must compare two cars of identical makes and models to see the benefits of any modification. To use torque, you must gear in order to make use of it and not waste it.
 
#11 ·
You guys are all correct in one aspect or another. The real trick with todays technology is achieving a movable torque band! Having low end grunt when it's needed and high end HP when it comes time! All you Vanos haterz out there need to wake up a smell the possiblities that come along with that kind of tech. Combine VVT type of tech. with Direct injection and variable vane turbos and you can have it all. Not to mention the new incredible CVT or DSG type trannies out there that will allow infinitely variable ratios and or lightning fast gear changes to keep your little electronic bad ass right in the sweet spot, right when you need it! The days of choosing one way or the other torque monster VS. high revving race motor are all but gone and in the near future, as much as it may pain me to say it, we will all be talking about how inefficient the internal combustion engine always was compared with the electric motors that will be replacing them. I hate to see em go, but I think that we can still have just as much fun with electric motors, if we have to.
 
#13 ·
DIRTE30 said:
You guys are all correct in one aspect or another. The real trick with todays technology is achieving a movable torque band! Having low end grunt when it's needed and high end HP when it comes time! All you Vanos haterz out there need to wake up a smell the possiblities that come along with that kind of tech. Combine VVT type of tech. with Direct injection and variable vane turbos and you can have it all. Not to mention the new incredible CVT or DSG type trannies out there that will allow infinitely variable ratios and or lightning fast gear changes to keep your little electronic bad ass right in the sweet spot, right when you need it! The days of choosing one way or the other torque monster VS. high revving race motor are all but gone and in the near future, as much as it may pain me to say it, we will all be talking about how inefficient the internal combustion engine always was compared with the electric motors that will be replacing them. I hate to see em go, but I think that we can still have just as much fun with electric motors, if we have to.
1. Low end grunt is not always a good thing, and in fact is usually counterproductive to such things as launching the car.
2. You're out of your mind if you think that VVT can make a car that has low end torque and can also string out to high revs. Closest motor I know of is the Z06 motor, and that doesn't actually rev very high at all, and doesn't use any fancy technology to achieve what it does, just good old brute force.
3. Electric motors fucking suck. They suck because they are terribly inefficient in terms of power consumption and power storage. Batteries lose energy as they sit. Fuel does not lose it's potential energy by sitting.

Starmavin said:
There are too many other factors to take into account to give an accurate account of how power is used and transferred: Power to weight ratio, transmission gearing, the balance of weight from front to rear, suspension, and tires. If you want to be fare in an example of better use of power use, then you must compare two cars of identical makes and models to see the benefits of any modification. To use torque, you must gear in order to make use of it and not waste it.
I will give you this, alot of those factors come into play, but the fact of the matter is that every single supercar out there has a midrange torque peak and is designed to pull hard to a high RPM at the top. Koenigsegg, Ford GT, Saleen S7, McLaren F1, Pagani Zonda, Radical SR8, Ferrari Enzo, Ferrari F50, Ferrari F40, all of these have engines that are designed to spend as much time in the lowest engine load possible and get the highest speed out of each gear. Some cars are designed to be more torquey in their delivery and have a lower revving engine, such as the Koenigsegg, Saleen and GT. Other cars have a more balanced torque/hp delivery, such as the Pagani Zonda and the Mclaren F1, others still have a higher revving, peakier engine, such as the Ferraris, and the Radical SR8. Regardless of how it goes, all of these engines hit peak around the middle of their rev range, which is the point I was originally making. Torque is all fine and good but delivering it in the most efficient way possible is the end goal.

The Eta motor, the original subject of this thread is a great example of a motor that was not meant for sport. It peaks it's torque down low and provides a vast area under the torque curve, which makes for elegant and efficient travel, yes, but does not do you much good when you want to go fast. The i motor, by comparison, is high revving (and only by comparison, believe me) but is actually a more middle of the road kind of engine. It produces nearly identical horsepower and torque figures, and much like a scaled down S50, peaks at around 4200 rpm and pulls hard to around 7 or so when chipped. This is by no means "peaky," when compared to a high strung motor like, say, an S2000 motor, which peaks at more like 6500rpm and goes to 9k.

The Supra is a good example of a middle of the road boosted engine. Despite it's higher revving, it makes it's peak power in the middle of it's rev range, even when boosting on a giganto mondo turbo. Alot of people talk shit on them, but until you've driven one, you have NO idea what they are capable of. People just think they're slow because of the stupid people that drive them. Get a good driver in a good Supra and you'll never see them again.
 
#14 ·
triggrhaapi said:
1. Low end grunt is not always a good thing, and in fact is usually counterproductive to such things as launching the car.
2. You're out of your mind if you think that VVT can make a car that has low end torque and can also string out to high revs. Closest motor I know of is the Z06 motor, and that doesn't actually rev very high at all, and doesn't use any fancy technology to achieve what it does, just good old brute force.
3. Electric motors fucking suck. They suck because they are terribly inefficient in terms of power consumption and power storage. Batteries lose energy as they sit. Fuel does not lose it's potential energy by sitting.
1: launch technique.
2: porsche variocam
3: they produce no pollution, have fewer moving parts, require no external lubrication, and doesnt suffer from reaching the maximum moment of inertia that piston driven motors do before pistons disintegrate. which means, it really has no realistic rpm limit.

3.2: actually, fuel does break down sitting.. at actually a faster rate of decay then li/ion, li/manganese dioxide which have a shelf life of over 10 years with ~2-5% decay / year, with no /little voltage drop occuring over time. true, old lead cathode batteries exhibit this, but technologies are changing, very very quickly.

Ethanol mixed fuel, has a shelf life of appx 60-90 days if not stored in an air tight metal container as it is very hygrophobic.
 
#16 ·
nukeduster said:
1: launch technique.
2: porsche variocam
3: they produce no pollution, have fewer moving parts, require no external lubrication, and doesnt suffer from reaching the maximum moment of inertia that piston driven motors do before pistons disintegrate. which means, it really has no realistic rpm limit.

3.2: actually, fuel does break down sitting.. at actually a faster rate of decay then li/ion, li/manganese dioxide which have a shelf life of over 10 years with ~2-5% decay / year, with no /little voltage drop occuring over time. true, old lead cathode batteries exhibit this, but technologies are changing, very very quickly.

Ethanol mixed fuel, has a shelf life of appx 60-90 days if not stored in an air tight metal container as it is very hygrophobic.

1. Launch technique won't save you from wheelspin if you have too much torque down low for the tires to handle. Why do you think the Stig couldn't launch the Z06 without a slow start? Keep in mind he's the Stig...
2. Porsche's Variocam is actually a knock off of BMW's second gen Dual Vanos, and you're wrong, it doesn't do shit for the N/A motors' low end torque when compared to how the Z06 is naturally. EDIT: If you're going to use Porsche's Variocam as your example, you might as well stop arguing with me. The Porsche engines have a midrange peak, not a low down grunt.
3.1 Nobody uses ethanol mixed fuels, we use MMT, a variant of Toluene, which has a longer storage life because it doesn't break down the fuel like ethanol does, so it takes longer to "go bad." Anyway, ethanol is destructive to pretty much anything that is remotely petroleum based.
3.2 I'm sorry, but you're never going to ever sell me on the whole electric car bit. It's just stupid. Where does the electricity come from? Magic? God? Space? Did aliens bring it here? No. We burn coal and gasoline, we use fusion reactions and destroy the earth just like we do with cars, but the part that's really stupid is that despite the massive loss of energy in the transmission of the power from it's source to the car (caused by the resistance of power lines and the transmission decay over long distances) and the inefficiency of your storage method (I'm sorry but anybody who says a battery stores energy more efficiently than a fuel is one chemistry class short of a GED) proponents of electric cars still think they are 1. good for the environment and 2. the wave of the future.

I'm sorry, but GM proved that the electric car has nowhere to go but, well nowhere.
 
#17 ·
Actually, the electrical vehicles of the 90's were VERY sucessful. For reasons officially not publicized, they were claimed to be failures.. but look it up.. prior leasee's loved the vehicles and many tried to buy them out when the lease was over and were not allowed, regardless as to the price.

Anyhow, yes, actually go look at the gas pump next time you go fuel up.. from XX month til XX month the fuel is ethanol mixed, and the rest of the year its MTBE mixed.

I've driven a new viper, supercharged CTS-V's, couple other exotics .. torque beasts galore, and its ALL about launch technique. That, and wrinkle wall tires... most the luxo car's main downfall with high low end torque is the fact they run on low pro tires which are not good at holding torque down low at all.

When we used to run our supercharged cts-v for promos on friday nights we could run mid 12's with 18" wheels but could barely touch low 13's with 20"'s bling wheels which we often ran on - just because thats what the crowd wanted to see it running on.

READ: low end torque works, with the right setup. With big stock 18, 19, 20+ inch wheels, the tires just slip on the concrete as if it were covered in ice.. but the right sized wheel, and right kind of tire, and low end torque destroys.. all.

Again, read, audi R10 le mans car.
 
#18 ·
As a side note also, I'd prefer the 750h bmw made over any other technology. Its absolutely refreshing they took a completely different route, one that I vastly prefer over many of the others available..

Filling with DI, using a roof made up of solar panels, burning hydrogen in a piston driven motor.. still fun.

Will it happen? Probably not.

Will electric cars take over? Probably.

Every car manufacturer either makes an electric hybrid or is considering it... its not a big leap of faith to assume they'll go full electric eventually.
 
#19 ·
triggrhaapi said:
2. Porsche's Variocam is actually a knock off of BMW's second gen Dual Vanos, and you're wrong, it doesn't do shit for the N/A motors' low end torque when compared to how the Z06 is naturally. EDIT: If you're going to use Porsche's Variocam as your example, you might as well stop arguing with me. The Porsche engines have a midrange peak, not a low down grunt.
I'm not knocking you or anything, but how many porsches have you driven? They have plenty of torque considering the size of their motors as compared to larger CI motors.

Yes they are somewhat peaky, but they have alot of torque down low thanks to more agressive cams and variocam working in conjunction.


Also, variocam came out in 1991.. vanos came out in 1993 and the dual vanos didn't come out until 1999 model years....

Who copied who? :p

The purpose of variocam and vanos was to give as much as feasible as low as possible while still giving as much as possible, for as long as possible.. why else would car review's (european car, motortrend, automobile) always praise high end cars like bugattis, etc for having peak torque as low as 1500rpm, etc etc.
 
#20 ·
nukeduster said:
Actually, the electrical vehicles of the 90's were VERY sucessful. For reasons officially not publicized, they were claimed to be failures.. but look it up.. prior leasee's loved the vehicles and many tried to buy them out when the lease was over and were not allowed, regardless as to the price.

Anyhow, yes, actually go look at the gas pump next time you go fuel up.. from XX month til XX month the fuel is ethanol mixed, and the rest of the year its MTBE mixed.

I've driven a new viper, supercharged CTS-V's, couple other exotics .. torque beasts galore, and its ALL about launch technique. That, and wrinkle wall tires... most the luxo car's main downfall with high low end torque is the fact they run on low pro tires which are not good at holding torque down low at all.

When we used to run our supercharged cts-v for promos on friday nights we could run mid 12's with 18" wheels but could barely touch low 13's with 20"'s bling wheels which we often ran on - just because thats what the crowd wanted to see it running on.

READ: low end torque works, with the right setup. With big stock 18, 19, 20+ inch wheels, the tires just slip on the concrete as if it were covered in ice.. but the right sized wheel, and right kind of tire, and low end torque destroys.. all.

Again, read, audi R10 le mans car.
Read: Highest revving diesel in history...
 
#21 ·
nukeduster said:
I'm not knocking you or anything, but how many porsches have you driven? They have plenty of torque considering the size of their motors as compared to larger CI motors.

Yes they are somewhat peaky, but they have alot of torque down low thanks to more agressive cams and variocam working in conjunction.


Also, variocam came out in 1991.. vanos came out in 1993 and the dual vanos didn't come out until 1999 model years....

Who copied who? :p

The purpose of variocam and vanos was to give as much as feasible as low as possible while still giving as much as possible, for as long as possible.. why else would car review's (european car, motortrend, automobile) always praise high end cars like bugattis, etc for having peak torque as low as 1500rpm, etc etc.
I would say that Porsche engines are around the same sort of torque and hp output as a BMW motor, just made slightly larger and in a different configuration. They still have a midrange torque peak, not a low down grunty pull like an american motor. They still don't wreck tires the way American muscle does. Again, that feeling you're feeling isn't torque exactly, it's a properly geared and balanced drivetrain that revs to it's torque band quickly. It doesn't make peak torque just off idle like American engines do, it still peaks around 4500rpm or so....

you are making the same argument I am, you just don't realize it. I'm not making a case for a strung out engine here, I'm making a case for torque vs. gearing.

Let's get back to the original topic of this thread, the Eta. That motor again, was made for torque, not power, so while it can be kind of quick, it just doesn't have the torque to make up for the higher engine load the taller gearing gives it and it just does not accellerate as fast as an i motor, which has less torque, but a lower engine load and higher amount of time in peak torque. /thread.
 
#22 ·
My point of this original thread was that too many times I've been asked "how do I get more RPMs out of an ETA" As if it was the magical cure to get more power out of an ETA, to that I wrote this thread so that those people can change their mind set so their aim would be to build more power within the ETAs power band and gear for it rather than trying to make it rev higher and gear the rear lower. It's just counter productive to an ETA.

The ETA is a rather durable motor if cared for, (nearly any motor is for that matter) and with better thinking you can get more out of the ETA than with unnecessary engineering. A few simple mods can make the ETA scoot until you can save up to do a swap for a newer motor. Or if you are a purist and your car must have an M20 then swap it out for and "I" motor and/or beef it up with stiffer springs, a well matched turbo, better exhaust, different head, etc. Or if you don't have a lot of cash to do either of the above, don't waste it on parts that just hurt your performance and lower your ETA's life. Lastly, no amount of money is going to make the ETA into a 800hp performance motor and even if you can do that, it won't last long plus its money that could have been better spent down another road...
 
#23 ·
Power and Torque.

Alright, I'm a little disturbed at the perception that BHP is a farcical figure. This is just not true. Torque (referred to in Nm in this post) and Power (in kW) each have their own particular function in the whole scheme of a car performing.

I'll give you an example.

One day at work, we took a few Xs on a road trip. Myself and another consultant decided to pit an X3 3.0D (me) against an X5 4.4i (him). One thing to keep in mind is that while this may seem one sided; diesel straight six Vs. a 4.5 litre V8, the M57 in the 3.0D boasts being 40Nm shy of the monstrous V10 in the M5/M6.

Here are the relevant figures:

X3 3.0D (Facelifted and new engine version)
Power: 160kW
Torque: 480Nm
0-100km/h: 7.9 seconds.
Weight: 1.81 Tonnes

X5 4.4i
Power: 235kW
Torque: 440Nm
0-100km/h: 7.0 seconds.
Weight: 2.12 Tonnes

On a long stretch of road, we lined the cars up, rolling them down to 20km/h. Disengaged traction control. Flicked on Sport mode. Then we lit them up. For some time, I was three car lengths ahead of the 4.4i - the torquey, responsive M57 getting power to the ground, quick as you like. However, as soon as I had hit about 92km/h, the Le Mans Blue X5 streaked past me, throaty V8 taunting me as it blared that sweet song. Game Over.

Now, as with any experiment, all the factors would need to have been examined - they werent. Lol. This was just a fun squirt on a highway early in the morning. But the results speak for themselves - 3.0D, significantly lighter with more torque lost to a heavy car, with considerably more power. Of course the N63 doesn't exactly lack for torque itself - maintaining a figure of 440Nm.

The point of all this? Each figure plays its part; delivery of both power and torque play crucial roles in propelling the cars forward. Period. From a standing start, of course torque is important, but so is roll-on acceleration, which is a direct result of broad, and consistent power delivery across the rev-range. Blanketing statements and generalisations are immature - be more specific.

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KMFDMR
 
#24 ·
I believe he meant that hp is fictional due to the fact that there is no realistic way to compare what 100 horses can do to what a motor can put out. Not it's formulated function. I mean that horse power means just that, how much a horse can move within a certain of time across a measured distance, which in fact is relative from horse to horse. I have the same problem when someone tries to classify the light out put by way of candlepower, again it's a rather inaccurate and implausible measurement.
 
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