[CPH]

Originally Posted by Speed-Freak

Hi GTO,

Quiet some interesting figures, tells me a lot about what is the real power on the wheels rather than feeling nice about the engine power as specified by the manufacturer.

I plan to do a dyno run on my stock Getz Crdi, i intend to remap my ECU and upgrade the filters, so as suggested in this thread, i would like to have a stock report and then do a 2nd run post the upgrade. This way i can really understand what is the %age difference in my ride after the remap.

Let me know if you guys intend to go there, i would love to join with my ride for the maiden dyno run.

Mapping a turbo Diesel and a normally aspirated petrol will show totally different results. The gains on your Diesel will be much more dramatic. A correctly designed air intake revision on a turbo Diesel will widen the window for mapping even further.

Originally Posted by Rehaan

After looking at these graphs, and looking at peoples examining them i realised that the scale of things was a bit confusing.

The fact that each run is squeezed or stretched to fit the full width of the graph, and that the HP curve is compressed down to fit in the same box as well.

So i put them all together onto one graph! This more clearly shows how each car is different from the other when producing power...

Note : The length of line along the RPM range is different for every car, since some runs did not cover as much of the RPM range as others. Also i've cut off the inaccurate data that was trailing off on the original graphs.




Observations :

• The v6's huge power in comparison to the other cars is much clearer now
• Notice the jump in HP at ~5300 for the v6 -- i'm assuming this is when the vtec kicks in. Wait till you see the torque!
• The Jetta (diesel)'s low redline shows. However, note that the power produced all the way from 3k up is roughly more than the ford 1.6 makes till redline. Taller gearing makes this more usable.
• Why does the Fusion HP dip like that between 5k-7k rpm?
• Is it possible to see the Linea's slipping clutch post 6k? We'll compare once its re-dyno'd - as the clutch has been changed.

... what else?

Torque coming up next.

cya
R

Rehaan, you have got too much time on your hands.

The Linea graph does not look much different on the graphs I have form the 1.4 16v engines. I very much doubt that the clutch was slipping as it would not show up at peak power but rather at the pek torque area. The torque curve looks also ver close to the graphs I have of the 1.4 16v engines.


Note from the Team-BHP Support Team : Please use "Multi Quote" option for quoting Multiple posts, instead of creating another back-to-back post.

[issigonis]

Originally Posted by Rehaan

After looking at these graphs, and looking at peoples examining them i realised that the scale of things was a bit confusing.

The fact that each run is squeezed or stretched to fit the full width of the graph, and that the HP curve is compressed down to fit in the same box as well.

So i put them all together onto one graph! This more clearly shows how each car is different from the other when producing power...


Torque coming up next.

cya
R

>>>

Rehaan,

Terrific work-clarifies immensely.
Look forward to the 'real' graph, of the torque.

Originally Posted by Rehaan

After looking at these graphs,

Observations :[list][*] The v6's huge power in comparison to the other cars is much clearer now[*] Notice the jump in HP at ~5300 for the v6 -- i'm assuming this is when the vtec kicks in.
...
R

>>>

The two Hondas have a steep slope- is this characteristic of Honda's VTECs even prior to the mods?
The Accord rules, not only in power but also by its spread over a wide rev range.

Originally Posted by Rehaan

After looking at these graphs,
[*] The Jetta (diesel)'s low redline shows. However, note that the power produced all the way from 3k up is roughly more than the ford 1.6 makes till redline. Taller gearing makes this more usable.


cya
R

>>>

Is it the norm for diesel engines to have a smaller band of revs? Or is it specific to VW's oil burners? This is an 1896 cc pump duse.
The (peak) power is spread over almost the whole range of revs, which helps usability. I imagine a taller gearing implies the engine is in the meatier band of torque, quicker.

Regards, awaiting the torque curves

[oxyzen]

Originally Posted by Rehaan

It starts past ~2500 on most of the graphs.
Also, its not a typo. Just that the dyno is less and less accurate at lower RPMs and therefore it has been set to start reading after it can assure a certain level of accuracy.

Thanks..
But I am not quite convinced about the way the testing is done.

Well I am gonna tell you how exactly it is done in OEM's. They dont actually do this on Chassis Dyno but on Engine dyno except when the need arises (To check power at wheels).
A few points to clarify before I start.
- Gear has nothing to do with power. It is so chosen that the max RPM of the dyno does not exceed its limit.
- Dyno is able to measure/control just 2 parameters Speed (RPM of dyno) & Torque. Power=Speed*Torque*Constant(For proper unit)

Select lets say 3rd gear. And press the throttle fully.
Set dyno RPM to XXX so that engine RPM is 1000.
Dyno achieves this RPM by applying specific load (torque) at the wheels.
Now torque at wheels = Torque applied by Dyno. (Since there is no acceleration)
Power at wheels = Speed*Torque*C = Power at Engine - Losses
Now this will give you power at 1000 RPM.
Do it for other RPMs and you get the graph.

I believe what is done here is a free acceleration test with a specific road load. Am I right?
Though it might not give accurate results but one can have a pretty good relative idea.
Also any dyno is capable of doing tests like mentioned above. But you need some time for that.

[opendro]

@oxygen, you stir up my mind. I don't know how dynamometer works. But I always assumed that it should be able to do the job pretty close to the engine flywheel outputs. Anyways, I will learn more about it before commenting further.

Having said that I'm itching to take a dyno test on my Linea with the Race Dynamics. I'm planning to do this when I get the XM500 installed. Whatever the gear, if I can take two tests - one without the box and one with the box, it should give fair idea of the gain of using the tuning box. I will update once the RD guys get the XM500 ready for me. BTW, I saw some of the most awesome cars in their Koramangala R&D office today, real treat for the eyes!

[Sutripta]

Originally Posted by oxyzen

Thanks..
Well I am gonna tell you how exactly it is done in OEM's.
....
Dyno achieves this RPM by applying specific load (torque) at the wheels.
Now torque at wheels = Torque applied by Dyno. (Since there is no acceleration)
Power at wheels = Speed*Torque*C = Power at Engine - Losses
Now this will give you power at 1000 RPM.
Do it for other RPMs and you get the graph.

I believe what is done here is a free acceleration test with a specific road load. Am I right?

Two different types of dynos, brake and inertial. Current thread is on an inertial.

Regards
Sutripta

[Ricky_63]

This whole thing is flying over my head....LOL I am waiting for when someone puts up a dyno here in Delhi / NCR. Should be happening soon, with the first F1 scheduled for October 2011.

No relevence, but certainly incentive I say



Cheers

[oxyzen]

Originally Posted by Sutripta

Two different types of dynos, brake and inertial. Current thread is on an inertial.

Regards
Sutripta

Ya you are right. Just thought I would share.

Anyway now coming to inertial dynos.....(to put an end to this confusion)
Inertial dynos are nothing but large spinning barrels of high mass. All you need to know is its moment of innertia.
It is very simple. The torque/power you produce is responsible for the acceleration of dyno. You get that data you can know power/torque.
Inexpensive, simple and reasonably accurate. If calibrated correctly produces results quite similar to Brake type.

[CPH]

Originally Posted by oxyzen

Ya you are right. Just thought I would share.

Anyway now coming to inertial dynos.....(to put an end to this confusion)
Inertial dynos are nothing but large spinning barrels of high mass. All you need to know is its moment of innertia.
It is very simple. The torque/power you produce is responsible for the acceleration of dyno. You get that data you can know power/torque.
Inexpensive, simple and reasonably accurate. If calibrated correctly produces results quite similar to Brake type.

All dynos build today are inertia dynos and many have the additional feature of the load cell and eddie current.

[GTO]

Originally Posted by Rehaan

Wider in the sense that they rev higher, sure. But otherwise i'd imagine the diesels generally have a flatter and higher torque curve, or in other words, higher torque per unit rpm.

Yeah. But ever had to forcefully upshift a diesel in the middle of a fast corner, or in a tight overtaking manouveur?

Originally Posted by kutlee

they will allow anyone to dyno. They have one dyno- hub dyno. Charges 3000 + tax for one hour. you can have as many pulls in one hour. Awesome dyno room.

Awesome! So, if 8 - 10 cars get together, the cost of each run will be dirt cheap.

Originally Posted by Speed-Freak

I plan to do a dyno run on my stock Getz Crdi, i intend to remap my ECU and upgrade the filters, so as suggested in this thread, i would like to have a stock report and then do a 2nd run post the upgrade. This way i can really understand what is the %age difference in my ride after the remap.

Let me know if you guys intend to go there, i would love to join with my ride for the maiden dyno run.

Drop me a PM with your Mumbai location . My K&N Typhoon is all ready to be dyno'ed

[pranavt]

Originally Posted by GTO

Awesome! So, if 8 - 10 cars get together, the cost of each run will be dirt cheap.

Don't think they would allow multiple cars lol. That pricing scheme is tailored for people who want to tune their cars on the dyno.

[kutlee]

Originally Posted by GTO

Awesome! So, if 8 - 10 cars get together, the cost of each run will be dirt cheap.

i think pulls allowed on one car in one hour.

[Rehaan]

...and here's the comparo of the torque curves of all 5 cars :



cya
R

@ issigonis - diesels typically have a longer stroke than petrols, and hence don't rev as high. Here's a related discussion :
http://www.team-bhp.com/forum/techni...ast-stone.html

[issigonis]

>>>

Rehaan,

Is the unit of torque in Nm?

Regards, drive safe

[CPH]

Originally Posted by Rehaan

...and here's the comparo of the torque curves of all 5 cars :


cya
R

@ issigonis - diesels typically have a longer stroke than petrols, and hence don't rev as high. Here's a related discussion :
http://www.team-bhp.com/forum/techni...ast-stone.html

Even if they are having the same stroke as petrols they rev slower. Example I am extremely familiar is the 2.4 5 cylinder TD Fiat engine, which is stroke and bore identical with the with the 2.4 5 cylinder petrol engine. The Diesel hit the rpm limit around 5k and the petrol about 6,7k.

The reason for the difference in the rpm limit is due to the much heavier piston etc as well as Diesel specific tolerances.

Originally Posted by issigonis

>>>

Rehaan,

Is the unit of torque in Nm?

Regards, drive safe

The torque would be Llb ft. You can see it because the crossover point between torque and bhp is at 5252rpm, which only is possible when it is a bhp/lb ft graph. Multiply lb ft x 1.35582 and you will get the result in Nm.

[Sutripta]

Originally Posted by CPH

The reason for the difference in the rpm limit is due to the much heavier piston etc as well as Diesel specific tolerances.

What is Diesel specific tolerances?
What effect would the differences in the nature of fuel delivery and of combustion have on rev limits?

Regards
Sutripta