DYNO Experiment - Why power can be down on a dyno...

We did a little experiment today. A while back we took a bog standard 2001 V70 T5 manual, and remapped it with RICA software. Then the car was driven for a while for the adaption to adjust. Here is how the car runs on the road, after several days of driving -

3000 rpm - 1.0 bar
4000 rpm - 1.0 bar
4500 rpm - 1.1 bar
5000 rpm - 1.2 bar
5500 rpm - 1.25 bar
6000 rpm - 1.2 bar
6500 rpm - 1.2 bar
7000 rpm - 1.2 bar

Today we took the car to an independent dyno, and on the dyno it performed like this -

3000 rpm - 1.0 bar
4000 rpm - 1.0 bar
5000 rpm - 1.0 bar
6000 rpm - 1.0 bar
7000 rpm - 1.0 bar

Max power was 250 bhp @ wheels at 6000 rpm @ 1.0 bar. What is quite clear from todays testing is that under the adverse dyno conditions, the ECU refused to allow the boost to run above 1.0 bar.

When driven on the road straight after, the boost was back to 1.2 bar. The reason for this is simple - lack of proper air flow on the dyno due to the small fan, so the various sensor readings were telling the ECU to lower the boost. It's a good demonstration to show why a car can easily be down on power on the dyno if the air flow from the fan is inadequate.

Adam.

ps. This is not some post for making excuses for low power figures! It's a genuine attempt to let those who are interested see how dyno conditions will determine engine performance, compared with on-the-road conditions. More experiments to come...

Interesting reading. I look forward to the results of other tests.

Regards

Andy

[big h]

Thanks for the info Adam. I to look forward to your further test results.

[don kalmar union]

Some weeks ago Partsforvolvo hosted a rolling road session at Power Engineering for both Saab and Volvo owners.

Amongst the Volvos present were three which had Rica software installed. Each of these cars produced a peak bhp figure that was considerably below those claimed by that software supplier at the time that their owners made their purchases.

On that day there was one early 850 T5, unmodified, in first class order but with starship mileage that gave an output within 3bhp of that claimed by Volvo at the time of its manufacture.

It is reasonable to assume therefore that on that day PE's machine was fairly accurate, their fan able to provide the conditions for the aforementioned 850 to achieve its maker's claimed peak power when new.

There is an interesting thread on www.volvo-t5.co.uk on this very issue.

There have been several such sessions held at Power Engineering over the last few years where the outputs of similar cars with software offerings from a number of competing suppliers, including Rica, gave similar results.

I would be the first to accept the outcomes claimed at the head of this thread if they were supported by some verifiable documentation from an independant source.


Don.Norchi.

www.kalmar-union.com

TME engineered software UK distributor.

[don kalmar union]

And another thing.....













Power Engineering are fairly well up in the field....modern equipment, recently callibrated....experienced and able staff, owner of unquestioned veracity.



The unidentified facility quoted above......on top of their game........modern recently callibrated equipment(small fan?).......experienced and able staff......owner of unquestioned veracity.



Just what is it about the installation at Rica in Holland, their staff.... that enables them to attain these much vaunted real road cooling air conditions that we are being invited to believe they alone can?...what of the callibration of their equipment that allows for such claimed peak figures that no one else has yet been able to achieve and verify.....such figures in fact that no other competitor claims.


Don.Norchi.

www.kalmar-union.com

TME engineered software UK distributor.

[Peter Milnes]

Perhaps their rolling road is run with more than adequate cooling available from an oversized fan blowing directly into the cars radiator and engine bay simulating open road conditions. You cannot rely on the cars cooling fan when using a rolling road. Remember the series on Men & Motors with "The Reverend Bob". They always had a very powerful fan blowing at the car's front when doing power runs on the rolling road.

All the best, Peter.

Don,

What exactly is your problem? What have Power Engineering got to do with my experiment? Nothing. Other than providing the ECU software, what have RICA got to do with my experiment? Nothing!

The results of this experiment indicated one thing, and one thing only - that dyno conditions can easily deviate far enough from ideal road conditions in order that performance is adversely affected. In this particular case, it was the dyno fan that was the issue, and in fact it wasn't even capable of providing enough air flow for adequate engine cooling as the engine temp went above normal. I would imagine that driving the car in the Sahara desert in full heat, uphill, towing a caravan, would also give similar results for the same reasons.

More experiments will follow. Whether or not you accept the results, well frankly I don't care. I'm doing it for my own benefit and will post results for interested parties.

Adam.

Adam I think Volvo-t5.co.uk and volvot5.co.uk will be very interested in this thread.

x

[Traduk]

Don,

>>>On that day there was one early 850 T5, unmodified, in first class order but with starship mileage that gave an output within 3bhp of that claimed by Volvo at the time of its manufacture.

It is reasonable to assume therefore that on that day PE's machine was fairly accurate, their fan able to provide the conditions for the aforementioned 850 to achieve its maker's claimed peak power when new.<<<

I think that you are missing the point and compounding the error by using the 850 T5 as an example.

Adam has shown that in a test that the air supply on a rolling road caused the vehicle's electronics to limit boost to 1 Bar whereas open road tests allowed higher levels of boost. Simple deduction leads to the conclusion that the rolling road is a test with limitations and not typical of open road results.

A stock 850 T5 does not boost as high as 1 Bar (0.7 to 0.8 is the factory norm) therefore as it is well below the apparent air supply limitation it is hardly surprising that it is unaffected by the air supply limitation. As you have put it forward as some sort of proof of accuracy of a rolling road it in fact only proves that the limitations are not understood.

Traduk

[don kalmar union]

Liam,

That is a fair point.

On the day to which I refer there was a Saab running that got about 380bhp. The owner was happy with that. So I would think it fair to make the point that the equipment was adequate for all the lesser powered Volvos.

Regards

Don.Norchi.

www.kalmar-union.com

TME engineered software UK distributor.