An Engine's Power Output

I've long grown out of high reving engines, they're ok when you're a boy racer, but as a "mature" (read old fart) driver, you just can't be bothered with all that, in fact I'm even finding autoboxes quite attractive. Nothing more hilarious than the modern Audi driver risking life and limb to gain 10ft in a traffic queue.

There is absolutely no point in a performance car on todays roads, you could easily keep up with modern traffic in an old 1ltr fiesta, such is the state of our roads. What I need these days is comfort and economy. ... and somewhere to put my pipe and slippers :LOL: I'm serious considering LPG on my 820 for that very reason.

I also don't agree that the mpg figures are unrealistic, I can easily match the quoted figures in my cars.
 
chrisyork said:
Must say, there's merit in your preferences there IATR. But, personally, I've always gone for a torque monster over a wailing banshee. The latter are just too much like hard work to row along in the real world. A delight for the two days a year when you're both up for it and have a road without traffic to play on, but for the eveyday scenario when you suddenly spot a gap and there's no time to change down four gears, Ill take the torque monster!

Actually, the bit of kit that has most attracted me in recent years is the combined supercharger and turbo as practised by Benz. Basically a turbo that uses a belt off the engine to keep it spinning at low revs. Allows you to fill in the turbo lag inherent in a high pressure turbo to give you the best of all worlds. Not sure how it fares in the ultimate economy stakes though.

Chris
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Daihatsu made a similar turbo'd and supercharged 3 cyl petrol engine which they married to a Diahatsu Sirion as a concept car, it achieved 3 litres per 100 KM's and had very respectable KW's to boot
 
Yes used to own a GTti, one of the most fun cars I ever drove 100 plus HP in a light bodied car, it may have looked like a 3 door charade but they did a lot of upgrading of all the steering and suspension and drive componants, used to get about 36 MPG when driven around the city in a civilised mode (very rare) but when thrashed about (standard mode) I got about 32 !!! fantastic car that loved to be booted, quite regularly had the speedo wound fully past the 180 KMH and had it pinned on the backstop, never felt fast and was as stable on the road as any much higher priced speced sedan. sure miss that car.

Graeme
 
so at 32 mpg when being booted that says turbos do make for efficient engines even 'on boost'

Rich
 
Yes thought in the case of the GTti the body weight and the small displacent were always going to be a good match. The turbo from memory kicked in at quite low RPM about 2500 2600 and really kicked you in the seat from about 3300 on all the way up, the car came complete from the factory with an adjustable rev limiter, though it was hidden where prying eyes could not see it under the passangers dash area. But for the performance and the MPG it was hard to beat.

Graeme
 
Think the trick with the turbo engine and economy is not going for massive power, these small turbo'd engines aren't going for big power like we're used to in stuff like the quattro / evo / imprezza etc.. These modern engines look more like replacements for larger naturally aspirated lumps, so this 1.4 turbo insignia engine is an alternative for the 1.8vvt engine, which I guess was itself a replacement for something like the old 2ltr ecotek.

It all comes down to how much of the power/torque you use, we've all seen the huge difference in mpg figures that we can get from the P6 V8 just be driving style, same applies to any car, if you've got 250bhp available, and you use it, it's going to cost you, regardless how that power is made. But it looks like 140bhp from a little 1.4turbo is a lot more efficient than 140bhp from a nasp 2ltr.
 
rockdemon said:
so at 32 mpg when being booted that says turbos do make for efficient engines even 'on boost'

Rich
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What? Those Daihatsus weigh half of nothing and have a mere 100hp from a very small engine. 36mpg max is NOT that impressive. If it had a naturally-aspirated 1.6 instead of a turbo 1.0 it would have been easily the other side of 40mpg.
 
IAmTheResurrection said:
rockdemon said:
so at 32 mpg when being booted that says turbos do make for efficient engines even 'on boost'

Rich
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What? Those Daihatsus weigh half of nothing and have a mere 100hp from a very small engine. 36mpg max is NOT that impressive. If it had a naturally-aspirated 1.6 instead of a turbo 1.0 it would have been easily the other side of 40mpg.
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On first glance you could get that opinion, however this is all start stop city driving with the pedal flat, country or motor way driving would be hugly better. In there day they were a real hot hatch and I managed to leave many RX Subaru and other "HOT" cars in the dust.

Graeme
 
IAmTheResurrection said:
a mere 100hp from a very small engine.
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100hp from 1 litre is not 'mere'. As a (i think you said elsewhere) 20 yr old who doesn't drive
you are very blinded by horsepower. Webmaster is right when he says he grew out of high
revving screamers. I am the same nowadays i like something with a bit of low to mid range
torque when if I am going to overtake something I just want to squeeze the throttle and go
straight round them with a minimum of fuss, Very satisfying! Give me torque any day.

Colin
 
so blocks that can fit the original factory V8 mounts are available in 3.5, 3.9/4.0 and 4.6 flavours from Rovers and Range/Land Rovers.

What about TVR's, do their blocks fit "straight in" to the P6b mounts?

I've been looking around at larger displacement blocks and 3.9/4.0 and 4.6's with tophat liners seem to be the way to go, but has anyone ever looked at the TVR engines? (and yes I know they're screamers)
 
ewokracing wrote,...
I've been looking around at larger displacement blocks and 3.9/4.0 and 4.6's with tophat liners seem to be the way to go, but has anyone ever looked at the TVR engines? (and yes I know they're screamers)
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Hi Geoff,

They are just Rover V8 engines, the blocks are the same so they'll fit just the same. TVR do there own head mods and fit camshafts to suit the light cars that the engines run in.

Ron.
 
colnerov wrote,...
100hp from 1 litre is not 'mere'. As a (i think you said elsewhere) 20 yr old who doesn't drive
you are very blinded by horsepower. Webmaster is right when he says he grew out of high
revving screamers. I am the same nowadays i like something with a bit of low to mid range
torque when if I am going to overtake something I just want to squeeze the throttle and go
straight round them with a minimum of fuss, Very satisfying! Give me torque any day.
Click to expand...

Spot on Colin and I'll take torque over top end power any day too. When I want to overtake in my Rover thanks to the massive torque of the 4.6, I have never needed to use kickdown no matter how steep the road may be nor change down manually for that matter. Just open the throttle a little more and the car will just surge forward giving you that lovely push in the middle of the back when it does... :)

Ron.
 
Absolutly, Horse Power is a more a marketing figure, torque is where it is all at!
 
100 bhp in the late eighties early ninetys from a 1 litre turbo is very good. My first car was an MG metro 1275 which was iirc 72 bhp, and whilst not that powerful, i think it was pretty representative in terms of normal power levels.

Another early ninetys car like this was the fiat uno turbo. (120 bhp 1.4 which was a lot back then!)

These turbo'd cars have very flat torque curves, which means you have power all the way through the rev range providing they dont have too much lag, which new turbos dont seem to.

The turbo is providing enough air to combust the fuel properly, so if you want it to accelerate a fixed vehicle at a certain rate of acceleration then surely a turbo'd engine of the smaller capacity but similar power has to be better in terms of efficiency ( due to less wasted fuel).

Rich
 
colnerov said:
IAmTheResurrection said:
a mere 100hp from a very small engine.
Click to expand...

100hp from 1 litre is not 'mere'. As a (i think you said elsewhere) 20 yr old who doesn't drive
you are very blinded by horsepower. Webmaster is right when he says he grew out of high
revving screamers. I am the same nowadays i like something with a bit of low to mid range
torque when if I am going to overtake something I just want to squeeze the throttle and go
straight round them with a minimum of fuss, Very satisfying! Give me torque any day.

Colin
Click to expand...

Not blinded by horsepower, but 100hp/litre isn't remarkable when forced induction is used. Heck, Honda were getting 100hp/litre from their naturally-aspirated VTEC motor 10 years ago. I too would quite like a reasonable amount of torque, but I just lament the way that modern low-capacity high-torque engines are usurping much more characterful engines - some of which were hardly short of torque to start with - on an entirely false premise.

As for me not driving? That's simply because I have had no luck getting a job, thus making the running of a car an unaffordable luxury.
 
rockdemon said:
The turbo is providing enough air to combust the fuel properly, so if you want it to accelerate a fixed vehicle at a certain rate of acceleration then surely a turbo'd engine of the smaller capacity but similar power has to be better in terms of efficiency ( due to less wasted fuel).

Rich
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Once again, great in theory, but, thanks to vastly increased exhaust back pressure, it ain't that simple.

Personally, what I think could be the future for forced induction petrol engines would be an electrically-driven supercharger using energy recouped by regenerative braking - or quite simply a direct electric motor torque/power boost as seen this year in Formula One, complementing the naturally-aspirated petrol engine.
 
IAmTheResurrection said:
Personally, what I think could be the future for forced induction petrol engines would be an electrically-driven supercharger using energy recouped by regenerative braking - or quite simply a direct electric motor torque/power boost as seen this year in Formula One, complementing the naturally-aspirated petrol engine.
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Electric superchargers are a good idea in concept, but there's too many changes in energy type to make them efficient, as well as probably being a damn sight heavier than a standard turbo setup. Using the braking to boost is a great idea, and I hope it makes it into road cars.

As far as driving habits go, having both a lunatic revmonster midget and the P6 it's great for when you're in either mood. Don't think I'll ever grow out of overtaking stuff in the midget, it's just so raw and mad and noisy and epic. Equally, overtaking in the P6 is a point and squirt affair, which is equally satisfying albeit in a different way. The midget is quicker though!

The K in the midget is probably at around 110bhp with 98lbft, which for a 1.4 designed in the 90's is pretty good, especially as that's over 1hp per kg. Other manufacturers are only just starting to catch up with that now (discounting the Vtec stuff, which is apparently rather torqueless at low rpm). K-midget also averages 50mpg.

I reckon what needs to be done is lightness, hard in this age of safety and comfort I know, but light, relatively low powered stuff is the way forwards IMO.
 
I reckon what needs to be done is lightness, hard in this age of safety and comfort I know, but light, relatively low powered stuff is the way forwards IMO.
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I totally agree, it's such a shame to see all this technology going into producing more and more efficient engines, only to end up with economy figures that haven't really improved in at least 20 years, by stradling them with cars that weigh sometimes twice as much as the equivalent older car. Not to mention they're all much bigger than they used to be, the photo posted the other day of the Octavia next to the P6 shows just how bloated cars have become.

We used to laugh at the yanks and their massive cars, I recon it won't be long before we meet in the middle, if we haven't already.
 
IAmTheResurrection said:
personally, such research as I have done leads me to think that the Roots-type supercharger (as made by Eaton and found, among other places, atop Jag V8s) can match turbos for efficiency
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I'm afraid you're way off the mark there Richard. I struggle to get much more than 22mpg out of my Jag, and that includes a fair amount of long journeys. If I use it solely around town and down the country lanes, that can easily drop below 20. The Eaton blower is pretty hopeless from an economy point of view, and also for outright power. The problem with it is it generates a huge amount of heat and the air doesn't get compressed as it passes through the supercharger. It also takes a large amount of BHP to drive. Manufacturers use them because they are reliable and cheap. A much better bet would be the Lysholm screw type supercharger. To achieve the same boost pressure and intake temperature as the Eaton requires a lot less BHP to drive the supercharger.

The supercharger does make the Jag a very nice car to drive though. The torque curve is pretty flat and the in-gear pickup from pretty much any speed is excellent, just don't watch the fuel gauge when you put your foot down :LOL: Peaky engines are great for the race track, but don't make for nice road cars. It's for this reason that I didn't find my P6 much slower than the 2l Focus I used to have. Book performance figures show a significant difference though. At normal driving speeds, the 2.2tc has a useful amount of torque, and pulls similarly if not better than the Focus. The extra performance of the Focus was all found further up the rev range, by which time the P6 is feeling rather harsh, but most of the time I'm not using the full rev range of the engine.
 
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