valencia100hp said:

I would agree the ECU mapping is different, especial in sport mode, the 100HP dose have lower gear ratios and better standard tyres so a little of each could be the reason.

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I don't think the mapping changes in sport mode, rather it is just the responsiveness of the throttle. Shorter gear ratios in the 100hp would certainly be enough to make the difference on acceleration as would grippier tyres to an extent help the car to get off the line better.

Does anyone have info on what the difference is in gear ratios?

I meant difference in mapping in sport mode between the 500 and the 100hp. The 500 sport mode is much less noticeable.

Gear ratios for the 500 are 23.4, 28.5 and 34.3 km/h per 1000 rpm for 4th, 5th and 6th respectively. I have lost my sheet with the 100hp equivalents but IIRC top gear was 32.7km/h and all the others gears were about 1 km/h lower which I guess means the box is the same but the final drive is lower.

It is interesting to see that for the 100HP I have read 4 reviews none of which agree if sixth is low or hi geared! I guess it depends if you come from an S MAX (all gears aboce third are Looooong or a Clio or Swift sport which have a ver low fifth)

The six gear ratios are certainly the same on the 500 and the 100HP. I'm fairly sure that the final drive ratio is also the same and that the difference in kmh/1000rpm comes from the slightly larger rolling circumference of the 500's standard tyres.

I've no idea about the differences with the 'sport' map, but this chart is from FIAT's original press release for the 500:

Regarding performance figures, is the 500 heavier? Although mechanically very similar and with same floor plan etc, it got a higher EuroNCAP rating than the Panda. To do this it must be stronger, and I'd guess stronger = heavier?

Herts Hillhopper said:

Regarding performance figures, is the 500 heavier? Although mechanically very similar and with same floor plan etc, it got a higher EuroNCAP rating than the Panda. To do this it must be stronger, and I'd guess stronger = heavier?

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According to Fiat which i'm not sure can be totally trusted the 500 is some 40kgs lighter than teh 100hp.

Problem with rolling roads is that if you visit 10 different ones they will give you 10 different readings as they all estimate transmission losses - mostly on the high side by all appearances - which gives higher flywheel bhp figures.

Scwenck, that Fiat graph I would guess is plotted from 6 or 7 data points rather than continuous figures like the magazine plot. Through the arse you can feel there are definite steps in the torque curve.

HP. said:

Problem with rolling roads is that if you visit 10 different ones they will give you 10 different readings as they all estimate transmission losses - mostly on the high side by all appearances - which gives higher flywheel bhp figures.

Scwenck, that Fiat graph I would guess is plotted from 6 or 7 data points rather than continuous figures like the magazine plot. Through the arse you can feel there are definite steps in the torque curve.

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Actually I tried this visiting 4 different rolling roads giving flywheel figures and they all seemed to be within 1bhp of each other. So there does seem to be a reasonable amount of consistency in that.

You must have either found 4 accurate or equally inaccurate dynos then, your experiences seem to differ from others on here.

I have a plot somewhere of an alleged 89bhp from a 1242 8v with chip, back box and home made induction kit - same rollers quoted an 85bhp Van Aaken turbo conversion at 99bhp.

HP. said:

You must have either found 4 accurate or equally inaccurate dynos then, your experiences seem to differ from others on here.

I have a plot somewhere of an alleged 89bhp from a 1242 8v with chip, back box and home made induction kit - same rollers quoted an 85bhp Van Aaken turbo conversion at 99bhp.

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#

They were just random around the country really. You have to take rolling roads with a pinch of salt really. Wheel horsepower for example can be affected by stuff like tyre pressures etc. If you are using a rolling road for its purpose Ie tuning then you can get comparable before and after results and that's what tells you what direction you are heading with it.

It very much depends on the ability and quality of the rolling road and operator. With good rolling roads and well definied techniques (tyre pressures, air, oil and coolant temperatures etc) I've found pretty accurate results but care is required. At the other extreme, pick a bad one or do it badly and the results can be terrible.

The only thing I wouldn't trust rolling road figures for are for forced induction cars, because it is near impossible to control, or even know, what the post cooler charge intake temperature is. Therefore the results can fluctuate massively and are impossible to repeat even with good methodology. All the corrections I've seen use intake temperatures, and therefore don't adjust for the variance.

here is an example of a good rolling road

http://www.enginetuning.net/Rolling_Road_.html

£300,000 well spent. Put a couple of my cars on it (not the 100hp yet) and got some very interesting results. Also they store you previous runs so you can compare your mods.

Anyone wanna do a dyno event?

Fiat_N_Fast said:

Anyone wanna do a dyno event?

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Can't see any point in doing it on a standard 100hp.

trackdayqueen said:

Can't see any point in doing it on a standard 100hp.

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I'm gonna do a run on the rollers with mine before I play with it. I just want a benchmark really??

I guess I'll need to put a couple of thousand miles on it first though.

trackdayqueen said:

Can't see any point in doing it on a standard 100hp.

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Couple of reasons, production cars have differring power outputs (even standard) they maybe slight but is interesting to know.

Also a standard should always attend a group dyno test so what ever modified cars can be set against the stock standard to prove increases in power from mods.

Just an idea.

Fiat_N_Fast said:

Also a standard should always attend a group dyno test so what ever modified cars can be set against the stock standard to prove increases in power from mods.

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Although if all standards put out differing powers, it's not much of a stock standard

The only real value of dyno days is doing before and after runs of your car without a mod and then with a mod to get a comparison. Not hugely accurate, but will give you a feel for the difference it makes.

Chris

trackdayqueen said:

Can't see any point in doing it on a standard 100hp.

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Come on, it's obvious! This way we will have genuine proof that the red ones are more powerful therefore faster

Fiat_N_Fast said:

Couple of reasons, production cars have differring power outputs (even standard) they maybe slight but is interesting to know.

Also a standard should always attend a group dyno test so what ever modified cars can be set against the stock standard to prove increases in power from mods.

Just an idea.

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Yes I know what you mean and I do appreciate that. On our one and only foray to an ITR meet we did put our stock Teg onto the rollers as the opportunity arose. I'd be prepared to do it if it was £20 or less and not a million miles away.

trackdayqueen said:

Can't see any point in doing it on a standard 100hp.

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Forgetting the obvious bit really, the social event

Also as mentioned, interesting to see the effects of other 100hp mods - most of us have a slightly different setup in some way.

HP. said:

Forgetting the obvious bit really, the social event

Also as mentioned, interesting to see the effects of other 100hp mods - most of us have a slightly different setup in some way.

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The social aspect is a given.

Well if someone fancies organising something it is do-able.

It would be very interesting to get some more dyno results for the Panda 100hp. Using the Italian road test figures, and assuming a kerb weight of 970kg, flywheel hp should be at least 110bhp, perhaps even slightly more. Working from the two rolling road curves I have, one for the Panda and one for the 500 1.4, they would tend to confirm this. Both sets of curves are from Peter at GSR, and I would think they are pretty reliable especially as they were done on the same dyno. When you look carefully at the standard curves you can see that all the difference in output between the two cars is between 5,000 and 6,500 rpm - below that they are identical within the limits of experimental error. Also interesting is that Peter's induction kit made much more difference to the 500 than to the Panda in terms of absolute power gain.

So the mystery remains - not so much that the power outputs are different - but that Fiat specify them as identical. Strange indeed.

John