low toque down low?

[Not_An_Abba_Fan]

A set of extractors makes a big difference too. I did an SV6 2 1/4" twin into a 3" single a while ago and it gained mid and top end, then did extractors and hi flow cats and gained a huge kick in the lower range. This car is currently pushing around 220rwhp. I haven't seen the read out so I'm not sure where the torque curve is. He has had a tune too, but I'm not overly impressed with what he paid compared to the result.

 

[monaro327]

VZ sv6 makes max torque at 3100rpm VE makes it at 2600rpm. from my understanding only the tunes are different so obviously getting your vz dyno tuned will move the torque curxe lower in the rev range and will help alot.

 

[Escape-The-Fate]

had a look under my bonnet today, just being curious as to wats involved to replace the cai box and insualtors wen i decide to buy them off mace...and noticed that my plastic engine covers are loose.

not shure if this is normal and they are meant to be loose fitting but i had a look at all the clips and from wat i could see they are all intact and not broken, top of the manifold has a little ware mark from wat it looks like the engine cover has rubbed on over time..nothing major but just interesting to know?

 

[torana355]

VZ sv6 makes max torque at 3100rpm VE makes it at 2600rpm. from my understanding only the tunes are different so obviously getting your vz dyno tuned will move the torque curxe lower in the rev range and will help alot.

That's true but my car has the VCM tune and it still don't feel like and ecotec off idle (My uncle has a VX wagon). I think the Electronic throttle may have alot to do with it also, with the torque management taken out even Dale said VCM is fairly limited in what it can do regarding getting rid of all the crap Holden have put in there.

 

[torana355]

I'd probably trust your judgement moreso Torana, however fro my experience having owned a VS S2 ute and now a VZ SV6 as the comparo of eco vs alloy, you're right about the Eco's hitting torque earlier, but with my SV6, seems to hit torque about 2700rpm.

Yeah i have a mate that was working at holden in homebush suttons when the VZ was first released and the first thing i asked him was "How is the new alloytec" his exact words were its good but its a pig off the line compared to the ecotecs. Though i still think it could be the way the SV6 delivers its torque which is why its still quicker off the line then a ecotec yet feels slower. The Ecotec feels like it has 80% of its torque by 2k where the alloytec has a more linear curve.

 

[pk2k78]

While on the topic of torque... My dyno readout says that Motive Force = 5495.9N @ 40KPH. Does anyone know how to convert to NM?

 

[danja]

While on the topic of torque... My dyno readout says that Motive Force = 5495.9N @ 40KPH. Does anyone know how to convert to NM?

That will be Nm already, but that's at the wheel, which means it's being multiplied by the gearbox and diff (this is why people don't really talked about rwNm, because it totally depends on the gear and final drive ratio).

You can estimate the engine torque, by calculating 5495.9 / (gear ratio * final drive ratio).

 

[Not_An_Abba_Fan]

When comparing dyno readouts using different dyno's it is better to use the motive force as it is calculated using the roller diameter of the dyno. Dyno's with different roller diameters will show different torque readings although the power readings will be similar.

Using different gears can affect the Torque, true, but what evens things (the power figure) out is, if you are in lower gear on a dyno, yes you will produce more Torque, BUT, the roller will be rotating at a slower speed according to the different gear being used, so the same Power figure will be achieved at a given Engine RPM.

 

[danja]

When comparing dyno readouts using different dyno's it is better to use the motive force as it is calculated using the roller diameter of the dyno. Dyno's with different roller diameters will show different torque readings although the power readings will be similar.

Not 100% sure what you're saying here? The dyno measures torque, it can't measure power directly, then power is calculated based on torque and RPM. The power reading will only be as accurate as the torque and RPM measurements, if one is inaccurate, they're all inaccurate.

My understanding of why some dyno's are "happier" than others is that post-test "corrections" can be added to account for air temperature and other variables, and this is sometimes abused to inflate dyno readings.

Using different gears can affect the Torque, true, but what evens things (the power figure) out is, if you are in lower gear on a dyno, yes you will produce more Torque, BUT, the roller will be rotating at a slower speed according to the different gear being used, so the same Power figure will be achieved at a given Engine RPM.

Yes, that's why people don't normally compare dyno torque readings, they compare power readings, because the power curve will be the same regardless of which gear the test was done in, whereas the torque reading will be completely different depending on the gearing.

 

[Not_An_Abba_Fan]

Not 100% sure what you're saying here? The dyno measures torque, it can't measure power directly, then power is calculated based on torque and RPM. The power reading will only be as accurate as the torque and RPM measurements, if one is inaccurate, they're all inaccurate.

That's why chassis dyno's are only suggestive.

Motive force will be the same on different dyno's because it is calculated off engine RPM and uses the roller diameter, where as torque is measured by the load arm.