bhp v torque

[Dustydog]

272 bhp 252 ilb/ft lexus rh 400 45o

138 bhp 253ilb/ft kia sorento 2005

Will the hybrid Lexus tug my ta wyoming. Mtplm 1697kg as well as the soento?
I'm finding it hard to differentiate bhp from torque converted to realistic tuggig.
Anyone using the lexus?
Lutz. Can you please tell me how good the lexus is please?

 

[WoodlandsCamper]

DD - from the figures you quoted the Lexus should be twice as good as the Sorento in maintaining speed. The power (measured in Brake Horse Power) is what is needed to maintain your speed, particularly going up an incline, without having to change down a gear. The torque is the same for both and is the ability to accelerate from a standing start, or just accelerate. So the Lexus should be better on paper, but await a reply from a Lexus owner.

 

[Sproket]

Have a read of this ..... and this from honest John ..... max tow 2000kg with 295BHP ..... Wow ...

 

[otherclive]

The Lexus 0-62 time is half that of the Sorento but without knowing the respective torque curves its not easy to advise. However I would think that the Lexus would hold its torque to higher revs than the Sorento so its acceleration under load should be better as the cars speed increases. So for overtakes on m ways I would expect the Lexus to have better 40-60 acceleration times and allow smoother driving.

 

[Dustydog]

Thanks Sproket just what I was after

Have a read of this ..... and this from honest John ..... max tow 2000kg with 295BHP ..... Wow ...

 

[Lutz]

I'm happy towing a 1800kg caravan with my Lexus and I've been doing it for almost 5 years now. Bhp is what determines whether the outfit makes it up the hill or not. Bhp is basically torque times revs. A car with lots of low end torque won't need as many revs and is therefore more relaxing to drive, but with an automatic it's less of an issue because the engine and powertrain will adjust the revs to suit.

The only issue that I would criticise about the Lexus is that the steering is very torque sensitive, especially when towing a heavy caravan. When accelerating under load from traffic lights, for example, the car pulls quite strongly to the left and one has to steer against it. But otherwise it's a lovely car.

 

[JonnyG]

DD - from the figures you quoted the Lexus should be twice as good as the Sorento in maintaining speed. The power (measured in Brake Horse Power) is what is needed to maintain your speed, particularly going up an incline, without having to change down a gear. The torque is the same for both and is the ability to accelerate from a standing start, or just accelerate. So the Lexus should be better on paper, but await a reply from a Lexus owner.

???? torque is what is needed to maintain speed without having to change gear and not BHP...and its far more complex than that silly old argument of torque V bhp given the modern turbo diesel for staters which fundementally by developing massive lowdown torque also develop far more of there total bhp lower down too...making MAX bhp figures quite complex to use for judgement calls when one cars need x 1000 more rpm to develop its max... even practical caravan has finally come around and i believe 80 Ft/lb of torque was being quoted as min per tonne now rather than solely using BHP as they did for ions based on petrol no turbo industry..as for the example given ? and the topic heading torque V bhp? i dont see a torque v bhp question merely a bhp one unless the lexus needs 10000 rpm to develop its max bhp and therefore 7500 rpm to develops it max torque that is,so it should be an excellent towcar..

 

[WoodlandsCamper]

Looks like we don't need bhp at all then !! Everything is down to torque.

 

[otherclive]

Looks like we don't need bhp at all then !! Everything is down to torque.

I think I will start looking out for a one owner stream traction engine. Lots of torque, low bhp and kerbweight to die for !!

 

[Lutz]

As the Lexus is a hybrid with both a petrol engine and electric drive, the torque vs. bhp argument takes on a completely different perspective. The electric motors develop maximum torque at virtually zero revs, so acceleration from standstill will always be good regardless of the performance characteristics of the internal combustion (in this case, petrol) engine, as the car always moves off in the electric mode.

 

[JonnyG]

Looks like we don't need bhp at all then !! Everything is down to torque.

leave the pedantics to me, your earlier statement was wrong with regards" hills and not needing to change gear" being down to bhp! , and indeed you are right about "everything is down to torque" afterall where does your BHP come from? thin air!!!.....but actually i didnt say you dont need bhp i said it was far more complicated than merely looking at bhp figures unless that is you drive at max rpm everywhere

 

[JonnyG]

Looks like we don't need bhp at all then !! Everything is down to torque.

I think I will start looking out for a one owner stream traction engine. Lots of torque, low bhp and kerbweight to die for !!

but you already own a Volvo? famed for being the swedish version of a traction engine..

 

[otherclive]

Looks like we don't need bhp at all then !! Everything is down to torque.

I think I will start looking out for a one owner stream traction engine. Lots of torque, low bhp and kerbweight to die for !!

but you already own a Volvo? famed for being the swedish version of a traction engine..

But I also own a Nissan Note and Pajero. What does that say about me! By the way the XC70 is a cracking car and has wonderful torque from its twin turbos and power to spare from its abilty to rev freely.

 

[JonnyG]

Looks like we don't need bhp at all then !! Everything is down to torque.

I think I will start looking out for a one owner stream traction engine. Lots of torque, low bhp and kerbweight to die for !!

but you already own a Volvo? famed for being the swedish version of a traction engine..

But I also own a Nissan Note and Pajero. What does that say about me! By the way the XC70 is a cracking car and has wonderful torque from its twin turbos and power to spare from its abilty to rev freely.

lol. no one is questioning the Volvo's multi tasking abilities. Always find it strange though that the rise of the turbo diesel engines indeed firstly abroad then here had it basis in the better drivabilty it was endowed with due to superior torque and nothing to do with, at the time still inferior bhp when compared to petrol engines.....strange how people still seem to look at bhp figures! like that really answers anything where real life on the road driving or indeed towing is concerned if you dont look at other thing firstly.ie torque.
no doubt some would say they bought diesels in the olden days because of mpg and fuel prices!

 

[Lutz]

It's still bhp that gets you up the hill, not torque, so can't get by one without the other.

 

[Dustydog]

Thankyou all very much for your comments. The Lexus seems a very suitable replacement for the Sorie. I notice the Lexus petrol engine is not a conventional 4 stroke otto cycle but an Atkinson cycle.
Anyone know in plain dog language what this is? I Google d it but still not clear.
Also how long are the Lexus batteries likely to last?

 

[JonnyG]

It's still bhp that gets you up the hill, not torque, so can't get by one without the other.

LOL really ? so what happens does the torque stay at home! Its the torque charectorists that decide if you need to change gear or not, and not the BHP... its this overlooked fact of life that still has soo many happily looking at Max BHP figures and not at how much and where Max torque is.. anyway it doesnt matter anymore even practical caravan has finally caught on to that often over looked fact...
nice easy formula.... adiquent BHP plus excellent low down torque equal decent towcar.. more than adiquent BHP plus inferior lowdown torque equals inferior towcar..........

 

[otherclive]

Dustydog,
Dont worry the pistons still go up and down. For the theory read Mayhew and Rogers Engineering Thermodynamics Work and Heat Transfer, but better still Wikipedia link below.

http://en.wikipedia.org/wiki/Atkinson_cycle

 

[Lutz]

Thankyou all very much for your comments. The Lexus seems a very suitable replacement for the Sorie. I notice the Lexus petrol engine is not a conventional 4 stroke otto cycle but an Atkinson cycle.
Anyone know in plain dog language what this is? I Google d it but still not clear.
Also how long are the Lexus batteries likely to last?

I presume your mean the batteries for the traction motors, not the starter battery. The traction batteries carry a 10 year warranty, which is more than can be said for the starter battery. It is woefully too small (because there's no space for anything bigger under the bonnet) and I was on my second one after 4 years. On the positive side, because it's small it is also cheap. It is identical to the one fitted to the Nissan Micra.

 

[xtrailman]

So is the car scrap after 10 years?
Who would buy a 10 year old car that may need new batteries at high cost, i stand to be corrected.
The other thing i've read with these hybrids is the relatively poor economy.
I would be interested in a full electric car once they can travel longer distances, and the batteries become cheaper.

 

[seth1]

Basically Dusty a conventional four stroke works on 760 degrees of crank rotation in other words two revolutions of the crank to complete the four stroke cycle.The Atkinson works on 360 degrees or one complete revolution of the crank.Im still asking myself why my 150hp sports bike doesnt enjoy pulling my caravan.I cant understand it because i always thought 150 horse was not to bad,it has only got 55lbsft of torque though.Would this matter?Lutz who are you kidding?

 

[otherclive]

While the above description of the Atkinson cycle is correct most modern cars that supposedly run on the Atkinson cycle are adaptions of the Otto cycle to better approximate the Atkinson cycle. This is achieved using valve timing changes some of which can be speed variable. The Wikipedia link in my post above gives a lot more detail and lists cars that run to the Atkinson cycle. Its quite a common feature across a number of marques.

 

[Dustydog]

Interesting Seth about your bike compared to my Sorie's 138 bhp 253llb/ft . I've got nearly 200lb ft more! I guess it's "horses for courses".
Thanks Lutz re the powertrain batteries.I was hoping to find a 3year old low mileage so at least I'd still have 7 years of Mr Lexus warranty left.
I may have misquoted the Lexus figures in my OP. I'm not sure if they factor in the power and torque from the electric motors??

 

[seth1]

After the Sorrie you maybe disappointed.The figures you quote would suit a sports car but not really a towing vehicle,not for me anyway.

 

[Lutz]

Basically Dusty a conventional four stroke works on 760 degrees of crank rotation in other words two revolutions of the crank to complete the four stroke cycle.The Atkinson works on 360 degrees or one complete revolution of the crank.Im still asking myself why my 150hp sports bike doesnt enjoy pulling my caravan.I cant understand it because i always thought 150 horse was not to bad,it has only got 55lbsft of torque though.Would this matter?Lutz who are you kidding?

It's all a matter of gearing. If the bike develops only 55ftlb of torque, it would probably need to rev at about 10000rpm at about 20mph in order to deliver the necessary bhp to tow the caravan.