HP vs Nm

[natett]

hi guys,

Ive been doing a litte research in my quest for more response.

Im trying to establish what is a better compromise.

I want enough power to enable a high 10 second 400m run eg 410-450rwkws but i also want a powerband a torque curve similar to a hipo v8.

Enzo Ferrari once said that power gets sales and torque wins races.

What I'm trying to establish is where torque is more important than power? for example and thanks to etuner for posting up these dyno sheets.

the below dyno run shows a small sized turbo producing over 1000nm of torque at a relatively moderate power level.


here is another with different EMS and cams (above is vvti below is not) making less power but even more torque.


should i be looking to reduce power levels for the increased low down torque or will loosing 50rwkws reduce any chances of reaching a 10 second pass (obviously my inabilty to drive will also affect that time slip)

Turbos im looking at are:
gtx3582r with t4 1.06 hot side
comp turbo billet TBB CT43-6765 T4 0.96 hot side
comp turbo billet TBB CT4-6465 T4 0.96 hot side
or GCG have recommended "T04Z with our up-grade billit 70mm extended tip tech compressor wheel fitted"

any help would be greatly appreciated.

Im also looking to use E85 for higher boost settings.

Engine is a stock 2jzgte, fuel system modifications and clucth have already been installed with the current 2000rpm power band gt42r set-up orginaly installed for a quick rebuild however as things change the engine build has become a long lost dream.

cheers

[beerhead]

The only way to pick up more bottom end torque on a boosted car is quality porting, higher compression or a smaller rear turbo housing. If you mod the manifold to take 2 large wastegates you can run quite a small rear housing and not run out of puff at top end, as the extra flow runs through the waste gate, rather than trying to force its way through the rear turbo housing. I only say this because a mate had a bit to do with a 600hp Ford sierra track car that ran 10:1 comp, a very small rear housing and 2 massive wastegates. Apparently it would make full boost by 3000rpm and rev to 9000rpm.

BTW what gearbox are you running?

[natett]

sorry its running a v160 manual six speed.

i realise torque is greatly affected by gearing so im more interested in weather something like the above diagrams is more benificial to something where teh torque and power lines eg 800hp wtih 650nm torque etc

[Indelible]

power in a basic explanation is power=torqueXrpm/5252
so more power = higher rpm where engine makes torque
so can have way more torque but still make less power as its lower in rpm

best way for big power and low down torque is a compound turbo setup but thats a bit expensive and complicated

http://www.youtube.com/watch?v=y-Me6yWApzY

http://www.youtube.com/watch?v=8zM71zgUK60

http://www.boostlogic.com/xcart/prod...?productid=160

[dnegative]

Torque and power are related, making a fuckload of torque with no power (ie kW's) is super super gay (go drive a landcruiser, sure they can pull a boat up a hill but they make fuck all power and dont rev). You can make up for a lack of torque with gearing and a willingness to spin fast but there is nothing you can do to make up for a lack of power. Ideally you would have a high revving engine making maximum torque as high as possible so you can take advantage of gearing but thats not exactly a excellent daily.

[Phoenix01]

To put a more positive spin on the same story...

You just need a lot more torque at low rpm to make the same power. Ideally if you could build an engine that makes 4 times the torque at 2000rpm as a sporty engine makes at 8000rpm, and the torque curves when scaled and overlayed (4:1 one axis and 1:4 on the other) are the same shape, then with the right gearing both should feel the same.

Theoretically to achieve that you'd need 4x the engine capacity (mostly a longer stroke), or 4x the boost (or a combination of both). But either way you'd end up with an engine that's not exactly compact, or simple.

[beerhead]

Fairly linear graph though, would a smooth engine to drive the way it is. But I take you want a flat linear curve like a NA car!

Not sure what you've done so far, but first up Cam gears, you should be able to get a bit more torque where you want it. Cleaning up the ports, but not going too far will get you a bit better spool time too. I'd purpose design a tuned intake manifold with trumpets if you're really serious, mates GT42 1.06 rear was on song at 3200 on a good custom intake. If you want it to scream down low get custom high lift billets done that are only a touch above standard duration, will need shimless buckets, but will make piles of extra torque down low and sacrifice nothing up top.

[JustenGT8]

Any of the turbos you have listed will do the job i think. Add to the list one of the Borg Warner EFRs and it's a matter of what will swap over with the least hassle. Results for all these (and more) are plastered over the web so spend some time trolling what results people have found.....i spent a few hours and came up with the GT3582R for my needs and with the tight 0.63 a/r turbine. That'll be too small for you but a larger a/r should see you right.

BTW ignore dyno sheet torque...that's usually tractive effort which is a different beast entirely.

[STATUS]

remember those types of dynos cant give real torque figures... they are TRACTIVE EFFORT figures and are not comparable to the run of the mill manufacturers torque readings etc. You will need an engine dyno or hub dyno to get accurate torque readings.

To give you an idea a W16 8 litre bugatti veyron @ 1001hp only makes 1250nm (which is shitloads really considering its @ 2200rpm ) of torque.... so graphs like the above are useless apart from comparing results done on the same dyno.

As for you goals the t04Z on e85 on a std bottom ended 2jzgte (cams and springs rec.) will get you your 10sec 1/4 no dramas power wise, chassis and so forth is then the remaining decider for et . 450-530ish rwkw and approx 650-730nm torque, well that what we generally see anyway.

no replacement for displacement though when it comes to torque.

[natett]

cheers guys.

I wanted to make sure i wasnt going in the complete wrong direction.

Im also looking at the precision billet 6765. its a similar size to the T04z but will yield more power (rated a little higher hp wise) but also more responsive with the lighter billet wheels.

My goal will be to bolt it all on with mild modifications to exsiting fittings and the dump pipe before a retune. deal with the pump fuel tune for long enough to sort out the e85 fuel system. I would love to swap the vipec v88 plug and play for a proEFI plug n play with flex fuel intergration but that may need to wait awhile!

[Supra967]

Is that Power=torque x rpm/5252 for american units? It doesn't work for metric units.

[beerhead]

Make sure you compare it to a borg EFR,had a bit of a read and they have a lot of titanium moving parts in them, they're meant to be the bomb.

[Phoenix01]

Is that Power=torque x rpm/5252 for american units? It doesn't work for metric units.

Yeah.
Use Power=torque x rpm/9543 for metric units.

[STATUS]

cheers guys.

I wanted to make sure i wasnt going in the complete wrong direction.

Im also looking at the precision billet 6765. its a similar size to the T04z but will yield more power (rated a little higher hp wise) but also more responsive with the lighter billet wheels.

My goal will be to bolt it all on with mild modifications to exsiting fittings and the dump pipe before a retune. deal with the pump fuel tune for long enough to sort out the e85 fuel system. I would love to swap the vipec v88 plug and play for a proEFI plug n play with flex fuel intergration but that may need to wait awhile!

why in hell would you do that? the link can do it easy.... in fact i have done it:

http://www.skylinesaustralia.com/for...quered-tuning/

The pro efi stuff is also rebranded euro gear, just like the vipec is an aussie re-brand of the NZ link... one of the best ecu's around atm.