So which is best. BHP's or torques....?

[warren_cox]

So which is best, BHP or torques?

As you'd expect, there is only one way to find out

Stupidity aside, the point I want to raise / question is this.

In the average car, BHP has always been one of the key headline 'Top Trump' figures alongside 0-60mph times, top speed, and more lately (god forbid) MPG. Only people with Tefal shaped heads or car manufacturer logo'd anoraks hide would even dare to bring the word torques into a public conversation for fear of alienation or loss of lifelong friends.

Hoooo-ever, one thing that has become apparent to me as I've crashed through the 300bhp barrier is that a bit more bhp seems to make VERY little difference in the real world. You need 40-50bhp increases to make a noticable difference now. And gone are the days where I'd quote BHP figures down to an exact figure (eg. 296bhp); now I tend to use figures rounded to the nearest 10bhp (eg. 350bhp for anything between 346 and 354).

The Dyno lottery has pretty much eradicated much in the way of outright credibility for BHP claims, providing purely a rough estimate (if the operator can select the right gear). With Haldex cars come ever more RR issues when using bhp as a measure as Dyno's don't like the Haldex system much giving slightly odd power results at times.

So back to torques. We've seen in diesel cars of late that astronomic torque figures mean you can set the world rolling in an opposing direction, and accelerate quickly in almost any gear / any time. High compressions help, but diesel's petrol supping cousins have been trying hard to play catch up since newer injection/turbo systems and head technology have been been developed. Honda, the masters of high bhp, and diddy torques show V-Tec lumps can deliver staggering performance from a small number of torques, as long as you have revs. So is there a magical equation which optimises the balance between torques and BHP's, or are they both purely arbitrary figures that shift in the sand as you optimise a remaps parameters? I appreciate the higher both figures the better, but do you ever have to compensate one for the other, and what are the pro's and cons?

So the big question I have is this:

1) When a remapping agent remaps, what determines how much torque / bhp they build into the 'maps' parameters,

and

2) at what point does one (BHP or torques) become more valuable than the other in outright performance terms? - is it about optimizing performance for ancillaries like clutch / turbo etc., or around managing issues like heat soak / timing?

3) Which would be the better overall map, one majoring on BHP or one majoring on torque?

I want to be absolutely clear here, I'm not quitting work and setting up a remapping service next week offering bedroom conceived remaps from a 286 desktop computer I bought from a car boot sale. I'm just fascinated to learn more about the science of how engines work. I don't get out much so humour me ;-)

Any knowledge greatly appreciated.

 

[DPJ]

Area under the curve.

 

[ibizacupra]

usable torque and spread of torque across the rpm range.. aka what dave says

bhp=(engine rpm * torque lbft)/5252

sustained torque up the rpms is what gets higher power.

 

[warren_cox]

My 16v Golf had more power than my 8v in the right rev band, but the torque produced around town for point and squirt in the 8v was far more usable. The head configuration / cam profile of the 8v seemed far more torquey than the valver.

Is this why VW went back to using 16valves in the EA888 2.0TFSi/Golf 5 engines from 20Valves in the 1.8T lump predecessors, to increase torques?

When I fitted a larger bore exhaust on the 8v I lost no end of midrange torque although the top end performance seemed to increase. I appreciate you suffer this less in a turbo car, but it seems quite a delicate balance as to what you can do to keep things operating at maximum potential.

 

[air121005]

Good questions Warren
interested to hear some responses from mappers

your right about a cars BHP being the 'benchmark' of performance for many years.
Top Gear have only started refering to "how many 'torques' it has" in the last couple of series.

i think with regards to TDi's, the torque output of a remap (stg.1) is restricted by the standard clutch, so tuners have that limit to work within to achieve reliability, then i assume they get what bhp is available

 

[s1l3nc3r]

I done some reserch on this a while ago after descusions about who's car would be quicker, mine or my mates fiesta st which is running 200bhp the same as mine, but not nearly as much torque...

to say its been talked about before in detail is a huge understatement Just type in bhp vs torque in google and see.

I found this if you want a read...http://www.pumaracing.co.uk/POWER1.htm

 

[warren_cox]

There are many things in the car world which remain dark sciences to me. This is one area, as is the optimum set up of high performance suspension systems for fast road use.

There are so many opinions cum fact / urban myth, I was fascinated to get some debate on the table and start to get some solid understanding of the input contributors.

By collating some learning / information into the public domain only helps us to better appreciate what we are doing rather than having loads of dark arts surrounded by one liners like 'oh you should buy a Milltek' or 'youve gotta buy coilies'.

Plus, occasionally its makes for slightly more interesting conversation than some of the more regularly surfacing threads which do the daily rounds.

 

[warren_cox]

to say its been talked about before in detail is a huge understatement Just type in bhp vs torque in google and see.

I found this if you want a read...http://www.pumaracing.co.uk/POWER1.htm

That tells me about the science of the numbers, but nothing to do with how the science is applied to a car itself to generate maximum benefit or a balance. I want to know at what power levels bhp makes less of a difference than torques, and beyond the remaps what mods make a significant difference to both / either / or. More about application than the science.

Thanks for the link though, always useful to refresh.

 

[ibizacupra]

do you think a 400lbft diesel would be quicker round a circuit than my similar torque ibiza 20v..
I'll answer it for you - nope.

do you think the diesel would be a better b road car where low end torque is handy?
yes

horses for courses.
both compromised in the wrong discipline

 

[ibizacupra]

the 8v seemed far more torquey than the valver.

possibly because the 8v motors torque fell away at a high rate as the revs climbed unlike the valver.. i have seen torque plots on 16v and 8v and the 8v is no higher, but the 16v keeps going longer

 

[m0rk]

I think you just need ample of both

 

[DPJ]

I think it's easier to get your head round if you forget about bhp (since bhp is just a product of torque - and directly related).

Just think of torque at whatever level of rpm. (ie the torque plot on a dyno).

 

[air121005]

do you think a 400lbft diesel would be quicker round a circuit than my similar torque ibiza 20v..
I'll answer it for you - nope.

agreed, as on a 400 ft/lb deisel you would only have ~270 bhp and a heavier car

 

[s1l3nc3r]

That tells me about the science of the numbers, but nothing to do with how the science is applied to a car itself to generate maximum benefit or a balance. I want to know at what power levels bhp makes less of a difference than torques, and beyond the remaps what mods make a significant difference to both / either / or. More about application than the science.

Thanks for the link though, always useful to refresh.

Yea i agree that wasnt the best example i just done a quick search and pulled on off...

The way i understand it is that torque is how much of somthing the car can do and bhp is how fast it does it.

There so much to put into it though with what power levels do and dont make a difference with gearing, weight, and where the power and torque cure are relative to rpm which also comes down to compression ratios, valves etc etc...

 

[air121005]

The way i understand it is that torque is how much of somthing the car can do and bhp is how fast it does it.

that's how i understand bhp & torque

 

[alx_chung]

Hmm another interesting thread. I wouldn't mind learning about this as well, is BHP (the main talking point with cars down at the pub)
Again a good combination of both is prob the best solution.
Alex

 

[Keith@APR]

As they say in NASCAR:

"HP sells cars, torque wins races."

Our pro drivers will tell you they want short shifting torque monsters as opposed to high revving dyno queens any day of the week.

 

[Keith@APR]

Hmm another interesting thread. I wouldn't mind learning about this as well, is BHP (the main talking point with cars down at the pub)
Again a good combination of both is prob the best solution.
Alex

As I learned from Mr. Jim Cotton:

"Pub talk is, well...., pub talk."

in the States we call it b.s.!

 

[ibizacupra]

and there's so much of it in the US of A in respect of power claims when you read good ole vortex

 

[ryan_s3]

All the yanks do now is run everything on e85 or meth injection and put them on dynojets/dynapack to get over inflated figures.

I've not bothered too read all the posts ,but seeing as holding torque high in the revs means more power it's a pointless question!