My Dyno Result

[Sambo33]

I got my Power FC tuned dyno today & Bosch 040 fuel pump installed, the skyline runs great now & im very happy with the result

btw - boost was set @ 10psi & is goes up to 12psi just as the power reaches its peak.

[pkblade]

Making some nice power there Sam, although torque figure looks rather low. I'd assume it should be more like around 400+Nm.

So whats next on ya list - injectors & bigger turbs ? U know ya want to :lol:.

What sort of boost controller you got btw?

[Sambo33]

Cheers mate

ive just got a bleed valve as the boost controller, its a turbosmart one i think. I think ill upgrade the turbo/injectors/coils at some point, i just gotta save some more $$$, i plan on doing some handling upgrades soon too

[writeoff]

I saw "Sam R33" in Shaun's appointment book for today and wondered if it was you Sambo.

I ran the white GTR there yesterday and pulled 185rwkW at just over 9psi, and 249.8 rwkW at 17psi.

[Sambo33]

yep, that was me nice work on your dyno runs there

[Cubes]

Making some nice power there Sam, although torque figure looks rather low. I'd assume it should be more like around 400+Nm.

So whats next on ya list - injectors & bigger turbs ? U know ya want to :lol:.

What sort of boost controller you got btw?

<{POST_SNAPBACK}>

Torque figures are fine.

Power = Torque x rpm / 5252

Drop it back to third and torque will be up around 400Nm.

I'll be throwing mine on the dyno with the vg30det turbo (smaller comp wheel but larger turbine housing), it shall be interestering to compare figures. How close the vct gets a 2.5ltr to a nonvct 3ltr.

Edited October 3, 2005 by Cubes

[gtrGhosTDoGG11]

Nice dyno graph there Sam!

Nice figure for 12psi.

I run 0.8 bar which I think is 12 psi too.

Look forward to seeing you at the dyno day.

[Sambo33]

Torque figures are fine.

Power = Torque x rpm / 5252

Drop it back to third and torque will be up around 400Nm.

I'll be throwing mine on the dyno with the vg30det turbo (smaller comp wheel but larger turbine housing), it shall be interestering to compare figures. How close the vct gets a 2.5ltr to a nonvct 3ltr.

<{POST_SNAPBACK}>

thats a releif, i was wondering why the torque figure seemed a bit low compared to similar dyno-graphs.

whats vct? variable cam timing?

[Sambo33]

Nice dyno graph there Sam!

Nice figure for 12psi.

I run 0.8 bar which I think is 12 psi too.

Look forward to seeing you at the dyno day.

<{POST_SNAPBACK}>

cheers will. whats with the avatar there?

[Cubes]

VCT is variable cam timing. Its not completely variable, it switches on around 5000rpm and increases cam overlap.

VCT turning on is the lump (increase) in torque you see between 120 and 140km/h.

Without VCT you try to find the happy medium.

I've left my cam timing the N/A standard which is 8degree's overlap. The rb20 turbo cams run zero degree overlap through the whole rev range, rb25dets run 0 degree overlap on idle then something like 4degree's over 5000rpm.

Apparently if you disconnect VCT so that its always on the car cams over quite a bit.

I think thats how it is. Feel free to correct me on the minor details.

EDIT: Just out of your possible curiosity, Bl4ck32's RB30DET making 200rwkw made 380Nm of torque and made peak power by 5000rpm or ~132km/h. The biggest difference is 55rwkw at 100km/h. Bl4ck32's was making 170rwkw, yours ~115rwkw. Exactly why you need more torque to make power at lower rpms.

Edited October 4, 2005 by Cubes

[Deluxe]

Yeh my 25 has 189Kw and 490Nm I love having the tourqe, makes the hills alot more fun!!!!

[Cubes]

Its only good comparing cars on the same dyno.

i.e mine, Bl4ck32's and Sambo33's.

Care to post your dyno sheet Deluxe?

Chances are yours was run in 3rd to achieve a torque reading as such.

OR shootout mode played funny buggers with it.

Edited October 4, 2005 by Cubes

[Deluxe]

Here's mine from a few months ago(most recent) that was done by Graham West and was definatly not done in dyno shoot out mode un like some out there, this shows the peak NM and Avg NM

[Cubes]

That explains the high/different torque.

Throw it on a DD Dyno and it will read lower.

Good to see all the peaks are in the same place though.

Are you coming to the dyno day?

Edited October 4, 2005 by Cubes

[Deluxe]

It's quite funny you say that Cubes, Cos i also have a dyno readout from Tilbrooks from 2001(previous owner) and it read 215kw and 510Nm. When i took it to GW, that readout were just to richen up the fuel map on the FC and lower the boost slightly. I still need to go back and get a full FC retune.

Yeh will prob be there, not too sure if i'll run it, Prob will!

[gtrGhosTDoGG11]

Whats with the avatar Sam?

Just frustration pissing down money down the petrol tank.

[Cubes]

Deluxe,

To compare torque figures the only way would be to run on Shauns dyno. Other than that the only other use for the torque figure is when tuning, dial a degree in and you can see that section of map increase torque.

You should throw it on $25 is bugger all.

[Oosh]

When my car was dyno'd at Graham West's a few months back, it was done in 3rd gear, as were all the other cars there (to the best of my knowledge).

[Sambo33]

whats the difference between normal & shootout mode? i remember the last dyno-chart my car did (willall racing) was done in shootout mode.

[chops]

Here's a great post a guy made about torque on a chassis dyno on another forum:

The Torque number on a Chassis Dyno can be difficult to understand for an operator, let alone the general public, so I'll try and explain in simple terms.

Most people are aware that Power(HP) = (Torque(ft/lbs) x RPM)/5252, and both an Engine Dyno and a Chassis Dyno use this formula to Calculate Power, the difference is though, an Engine Dyno uses actual RPM(Crank RPM) and Torque measured on a Load Arm attached somewhere to the Engine Dyno Cradle in it's calculation, whereas a Chassis Dyno uses Roller RPM and Torque measured on a Load Arm mounted on the Retarder that is coupled to the Knurled Drive Rollers.

Now the reason why typically you see higher "Torque" numbers on a Chassis Dyno is due to gear multiplication, (remembering that the torque is being measured down in the Dyno Bed),so any gear multiplication between the Engine and Rollers will increase Torque (less any losses).

A typical scenario is (using your LS1 example of 470nm), if we use a 1:1 ratio in the gearbox, we still have 470nm (we won't assume any losses in this example) out the back of the gearbox, the torque then goes thru a ratio of for example 3.46 in the diff, so now we have 1626nm at the AXLE.

The next step is the Tyre to Roller, but in this case it is a gear reduction due to the Tyre being larger that the roller diameter, so we would see a Torque reduction, a typical reduction using Sonny's dyno (and most other Dyno's used in Australia which have rollers in range of 217-218mm Diameter) would

be the Tyre Diameter divided by the Roller Diamter, so if we use a figure of 650mm for the tyre and 217mm for the dyno roller we end up with a figure of 1:2.995, so we divide 1626nm by 2.995 giving us 542nm measured at the roller, remember this example is assuming no driveline loss,so the measured Torque would be less than 542nm.

Some people have eluded to that using different gears effects the Torque, this is true, but what evens things (Power) 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 will be produced at a given Engine RPM.

Another difference that no-one realises is that a different Diameter Roller also changes the Torque reading, so a dyno with 217mm rollers that is showing 100RWHP at 100kph would be measuring 215ft/lbs and the ROLLER RPM would be 2443RPM, so those that want to do the maths can verify the 100RWHP.

On a Dyno that uses 270mm Rollers (such as Sam's and PowerTorques), if one of these dyno's was showing 100RWHP at 100kph, then it would be measuring 267.3ft/lbs and the ROLLER RPM would be 1964RPM.

Rather than looking at Torque on a Chassis Dyno, it is better to look at the Motive Force, which uses the Roller Diameter in it's calculation, so dyno's with different Roller Diameters will show the same Power and Motive Force.

Motive Force is also known as Tractive Effort.

Motive Force is the Linear Force at the Roller Diameter pushing the car forward.

A few things to remember when looking at Dyno Graphs:

1.The Torque Curve (shape) will be the same regardless of gear used or Roller Diameter.

2. The Torque Curve will be the same as the Motive Force (tractive effort), except it will be a higher number.

3. Look closely at the scale on which the Torque/Motive Force/Tractive Effort is displayed, it is very common to see a Tractive Effort plot of around 3000-4000newtons being plotted on a scale of 0-13000newtons, all this does is make the "Torque Curve" look flat, because itis being squashed down on a large scale.

4. If a vehicle has made more power at the same Road Speed with identical gearing after some mods, then it has to of made more Torque, so do we need to see Torque?

A better approach all round is look at the Average Power, or even better, the Integral of the Power, this is the all of the Power added together that is under the curve, and not be too concerned with Torque Numbers.

from THIS THREAD HERE if you'd like to read it all.