Analyse This... Torque curve needs improving

[superpursuit83]

I dont know how to put image on screen.

Any suggestions to improve my torque curve. (different extractors ??) have 4 into 1 pacy's and 3" cats into 2 1/2" system to rear

[jonbays]

This curve isn't bad but is is a typical slightly exagerated one for a 4V Boss engine the 4V is peaky like this. The 3V motor much better in a torque curve comparison if you don't mind losing a few peak rwkw.

I am pretty sure its a function of the long stroke small bore engine needing the velocity of the smaller ports in the 3v to produce torque and the better flowing 4V heads not really working well till 3500rpm.

Still its extreme something must be able to be done but I dont know what.

[BLKFPV]

doesn't look that bad .... remember the graph for torque is only tailing off from 480 to 430 after 4000rpm

that kink is often seen on the torque curve, the power curve is good with only slight variations in rate which result in large kinks on the torque curve if the output scaling of torque curve is high

[superpursuit83]

So I think what your saying is where you can see small falls in the rate at which KW is climbing, is egsagerated on Torque curve mainly due to scale.

Then If I were to attempt fine tuning the areas that kw rate drops, I would see a flatter torque curve ?
The ute had its tune at 7500km, now 15000km. Ya think it may be time to throw the 4.11's in and re-tune?

This is making more sense now I think

[parawolf]

So I think what your saying is where you can see small falls in the rate at which KW is climbing, is exaggerated on Torque curve mainly due to scale.

Spot on. The nervousness of the torque function is a direct result of the amplification of the scale, relative to that of the power function.

Remember Torque is the true force in action here. Power (kW) is a calculation of Force and Time. So as your rpm increases, if your torque is holding flat, you will be producing more power. Example is say you produce 200Nm at 1000rpm and 200Nm at 2000rpm, then the power at 2000rpm will be greater.

Throwing in 4.11's will improve your rear wheel torque. Torque, when applied through gears (easiest example to picture for me is a bicycle gearing) is increased or decreased depending on the ratio change of the gears. Increasing your ratio from say 3.45:1 to 4.11:1 means that your torque is 'stepped up' however to achieve the same road speed you will need to rev your engine harder, so all in all you are shifting your road speed higher in your torque curve.

There is something to be said for a high torque engine to have longer gears (once you get up and moving that is) to use torque to keep you moving rather than stirring the pot with more gears (concept of CVT gearboxes). However you still have to appeal to the masses with their understanding of more is better.

[Rollin]

Power (work) is a combination of twisting force (torque) and movement.

Fixed.

[BLKFPV]

Originally Posted by superpursuit83

So I think what your saying is where you can see small falls in the rate at which KW is climbing, is egsagerated on Torque curve mainly due to scale.

Then If I were to attempt fine tuning the areas that kw rate drops, I would see a flatter torque curve ?
The ute had its tune at 7500km, now 15000km. Ya think it may be time to throw the 4.11's in and re-tune?

This is making more sense now I think

you got it

with all the variables putting a car on a dyno ... to chase those relatively small variations will not be worth it IMHO and will only stress the car and you

the ute's donk will go hot after a few runs anyway and you'll watch the powers levels just drop