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Discussion Starter #1
I don't know if anybody else is a little confused over the difference between torque and power....?

If one compares the impressive results achieved by MikeR33 of 515/356 at 1.15 bar and Keith of 483/434 at 1.45 bar, what aspect/s of the engine's set up actually determines if it is a high power or a high torque engine or somewhere in between? I believe that both Mike's and Keith's engines are standard capacity.
 

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power

Peter my car is std capacity

rod has been playing with the maps and it now has

506 BHP AT THE ENGINE AT ABOUT 6500 REVS

409 BHP AT THE WHEELS

453 LBS TORQUE AT ABOUT 4800 - 4900 REVS

WHAT I WANT IS GOOD BHP AND A TORQUE FIGURE THAT IS AS CLOSE TO THE BHP AS POSSIBLE.
THE MINES R33 DEMO CAR IN JAPAN HAS CLOSE FIGURES
AND I HAVE A VIDEO OF ALL THE TOP TUNERS DOING A RACE IN JAPAN
THE MINES CAR DOES NOT HAVE BIG BHP LIKE ALL THE OTHER TUNERS.IT STARTS FROM THE BACK AND JUST BLOWS THEM ALL AWAY.
OFF THE TOP OF MY HEAD IT HAS SOMETHING LIKE
640 PS AND 600 LBS TORQUE MOST OF THE OTHER CARS LIKE THE TOP SECRET CAR SAY THEY HAVE 1000 PLUS.
IT COULD BE DRIVER THAT HELPS THE MIES CAR WIN THE RACE BUT WHEN IT COMES OUT OF THE CORNERS IT JUST POWERS PAST THEM ALL.

ALSO THE DRAG ON THE DYNO CAN CHANGE BIG TIME BY THE WAY THAT THE CAR IS STRAPPED TO THE DYNO.

THE CAR IS AT ROD BELLS GETTING MORE MODS DONE TO IT NOW

HE MOVES INTO HIS NEW WORKSHOP THIS WEEK

THE ADDRESS IS ROD BELL MOTORSPORT
TOWN GATE WORKS
DARK LANE
MAWDESLEY
L40 2QU

TEL MOBILE 07803 616948

TEL L/LINE TO FOLLOW

EMAIL [email protected]

WELL WORTH A VISIT HE IS ONLY 5 MIN FROM J 27 ON THE M6

GIVE HIM A CALL YOU WONT BE DISAPPOINTED.

KEITH
 

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The Mines GTR has 580-600ps and 60kgm of torque. Mine's unlike most tuners tunes its cars for response and not for max bhp. This is perfect for a track car, and as Keith said it blows all of the other demo cars for dead.

http://www.mines-wave.com/Demo-Car/R34gtr/index.html

Keith...do you mean the race in the Best Motoring GTR DVD? Quite impressive result!! And their R34 has done exactly the same thing many other times:D
 

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power

yes DCD that is the video

Rod could get more bhp out of my engine
but as i said it is with him at the moment he is trying to get more power from it
by playing with the maps in the power fc.
i will maybe try a set of 600cc injectors next with 1.6 bar boost
then may try a step 2 head set up later in the year.

what we are trying to do is get more torque than trying to gain big bhp.

i dont think there are many cars with 453 lbs torque at 4900 revs
we are trying to get more torque low down not just a big bhp figure, there are cars with big torque out there but what use is it at 7000 revs plus.

point to point this is a very fast car.

keith
 

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Discussion Starter #7
Thanks all but....

What I'd like to try to understand is *why* certain mods are more effective in increasing torque than power and vice versa.

Having read a little about dynos in Julian Edgar's excellent book, 21st Century Performance, power is actually calculated from the torque measured by the dyno (bhp = (torque x revs) / 5252). Power itself is not measured, only torque and speed. It therefore stands to reason that by making an engine rev higher, as long as torque doesn't fall off dramatically, you will achieve a higher power figure. So to get a high bhp figure, one needs to be able to maintain a high level of torque to the engine's red line. This does not therefore necessarily make the car accelerate quicker, only a better torque line will do that which bears out what Keith said about the Mine's car and his own, come to that.

Obviously the engine's (or turbo's) ability to maintain boost all the way will greatly influence this along with cams, cam timing, intake and exhaust or in a word, breathing. There are also the characteristics of the torque line to be considered, larger turbos, later torque, smaller turbos, earlier torque but perhaps running out of puff earlier than larger turbos so producing a lower overall power output.

Would a better measure of an engine's output be torque rather than power?

As I've been told many times, this tuning lark is a question of compromises, you can't have everything..... :)

Peter.
 

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Peter,

Torque is in my opinion the most important goal for any vehicle.

I tried to help tuners to focus in on this with the Dyno results comparing torque at 4000 RPM at http://www.sol.co.uk/h/hugh/Dyno Runs/ also found in the technical section of the GT-R site.

The only skyline to show significant maximum torque at an RPM close to Keith's is a set-up Guy had on his R33 that gave 358ft lbs. at 4450 RPM. A significant factor was Guy's standard turbos with steel turbine wheel in this application.

The Mines R34 that is also revered for it's useful torque gives 60 kg/m ( approx. 433 ft lbs ) @ 5400 RPM on HKS 2530.

Keith has not as far as I have seen disclosed details of the turbos he is using, but the fact that all the items work together to give such massive torque at low RPM means they are likely to be smaller than HKS 2530
 

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Discussion Starter #9
I think you're correct about torque Hugh which is why I'm interested to learn *why* certain mods are more effective at producing a good torque curve than others. I am more interested in having a car with a good wide torque curve than one which produces zillions of bhp at zillions of revs.
 

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Re torque....the Nismo Z-tune prototype 2 has 66kgm at 5800 rpm. I think this has to be the highest I have seen for a track oriented tuned GTR.
 

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torque

guys R33 did have 358 lbs torque at 4450 revs

my car has 453 lbs torque at 4800 revs
that is only 350 revs more than guys car had at 4450 revs and about 100 lbs torque more.

last week it made 453 lbs torque at 4900 revs but we did not save the
dyno sheet last week when rod had it on the dyno.


keith
 

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Discussion Starter #12
Hi Keith,

You must be over the moon with the results so far! Out of interest, do I remember you saying that you went for some hybrid turbos? If so, what size are they, i.e. 2510 or 2530 size? Which cams did you use, Tomei?

Have you posted a copy of your first dyno sheet? If not, could you post a copy here please.

Thanks.

Peter.
 

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dyno sheet

Peter here is the very first dyno run before rod played with the
cam timing and the power fc maps all the other dyno sheets are
at Rods did not take them home.
the cams are tomei 260 dur 9.15mm lift i dont know how Rod has timed them so dont ask. but every tuner has there own way of timing cams but i think the way they are set is spot on.

peter the turbos were ones that i got made up for the job with 360 bearings but one of them failed so they are away getting new
roller bearing cores fitted and will be back to rods for friday cant wait to see if there is more gains to be found with them

the company that done them told me they are the same as HKS 2530s
the wheel sizes are as big as i can get into the housings
thats all i know

keith
 

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right

i think tourqe is the engines abillity to accelerate (pulling power)
and bhp is the engine ability to stay at there (at the speed you desire)

cams make a big differance on tourqe
mapping is the other
turbos well i ve not read bout them yet! but the earlier they kick in the more the touque moves down the rpm scale (i think )

turbos,intercooler,injecters/fuel derlivery sys,cams,some good mapping with programable ecu to use it all properly
and the thing will do what you what !

well thats what i think
coz i dont know how the rb buillt i cant say much
but one day...
:)
 

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dyno sheet

sorry guys but that is as clear as i can get the dyno sheet
to look also max size that i can put up on this site.


keith
 

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Good torque is important but the spread of good torque is just as important. It's no good having shed loads of torque if it all runs out at 4000rpm - that would force you to be in a higher gear than you want to, thus undoing much of the benefit of all that torque.

Look at diesels - loads of torque but not much power because it's all at low revs.

At the end of the day, top end power is going to govern how fast a car is in 'balls out' mode but as others have mentioned, a good fat spread of torque in the mid range helps to make the car fast out of corners where you're probably starting from lower rpm.

It's not the peak figures that's important, it's as much the area under the graph.
 

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Forgive my ignorance, but my understanding was that torque was heavily dependant on displacement as much as anything else?
 
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Car 1 is making nearly 600bhp but just over 400lb/ft of torque. It is running lower boost but has a larger turbo. etc.

Car 2 is making just over 500bhp but nearly 500lb/ft of torque. This car is running higher boost but a smaller turbo and has been set up for more midrange torque.

Compare these cars on a drag strip and Car 2 should get an early lead, but because of the rpm's they are using, Car 1 should start catching up Car 2. There is almost 100bhp difference between these cars but they could finish side by side.

The graph is just an example btw.
 

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I await to be re-educated by techies or torquies but...

I am not convinced that torque is the way to go. Most people seem to look at the torque figures that are generated at low rpm. However when you are pushing your car (as a road user) you will be moving in and out of 3rd and 4th gear within rpm ranges that will optimise your bhp. Lets face it if you are looking at performance you can forget the "up to 3500 rpm" stats on a dynochart because you are only in these ranges pulling out of the car park.

From my very rough calculations on the gear ratios on a standard 33GTR if you are doing just 6000rpm in any gear above first you next upshift will take you into a minimum 4000rpm level. Say hello to your turbos and bhp. I know my car starts to move when I feel those turbos kick in and I assume that this is bhp not torque.

I have often read the words "I know which car I would prefer to drive" when we see cars with high torque. For driveability yes they are nice but in terms of pure performance surely you need high bhp maintained throughout your high rev range? :p

oh go on then..if you must :p

North
 

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Graham... a simple but almost faultless explanation of the pricipal of the torque vs bhp arguement... although in the 1/4 time it would the higher BHP car that would take the honours [all other parameters being equal] but on a track with a few serious turns and long turns the Torque orientated car would win...

Bang on mate!
 
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