308 QV Dyno results

Dave,
A couple questions for you.

Do you know what brand dyno it was?

Do you know what rear wheel to crank correction factor was being use?

Why did they stop the pull at what looks like 6500 rpm? Your hp peak should have been at 6800, not 6100....it look like they just let off the throttle.

Is this a euro or US version? I ask that because your torque peak is at 4600, it should be around 5000 for euro or around 5500 for US.

 

Same Dyno yesterday only a mondial 3.2

Engine power 244.4 HP at 6135RPM
Torque 227.9 at 4560
Accelerartion time 16.4 secinds
extrenal temp 6.8
Atmospheric pressure 1002 mbar

they didnt rev it to the maximum - maybe just being a bit cautious since we werent customers but just a group of local ferrari owners. Interesting non the less.
will be able to post readout tomorrow when i use the scanner at work

Sorry dave, didnt take ony piccys of your 308
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Hi there,
The dyno is a Dimtech Dyno from Dimensionne Sport, who do much work for Ferrari and based in Trino, Torino, Itali in Alexadria Province.

The rwhp (EURO) was 186hp, we tailed the dyno run as soon as power started to tail and because Dave informed us there was no rev limit on the car.

Room temps were 17 degrees so of course this would give the very highest results as it is the closest to Din9020 spec as possible being 17.2 degrees.

Its quite common to see higher than quoted torque on a Ferrari although VERY unlikely too see factory power figures, ive dyno`d many dozens of Ferrari over the years and always seem 5-10% lower than quoted figures but having said that, the room we use is temperature controlled and due to this will (should anyway) give the best chance of a true figure as possible on a bench dynometer.

On another note, we ran a few cars at open temp which varied from 22 degrees too 26 degrees room temps and the difference in power was -20hp ota so again, another proving factor of how the temps dramatically effect a power run on these cars.
We were finding the room going from 17 degrees too 24 degrees within 40 seconds when running these cars without refrigerant running (again, just a test to check temp control for our own personal use)

Hope this helps.

 

what percentage of loss are you using? If its 186 at the wheels, quoting 241hp at the flywheel is out to lunch. Please explain, thats a 30% loss..

 

This machine doesnt use a stock calculous, example, 18%fwd, 24%rwd, 28%4wd etc.

We do a run-down on the dyno to calculate power, this is prior too the power run and only for measurement etc etc, the software then dictates the losses, power etc.

We have done over 5000 cars on this bench and also do a lot of work for Jaguar, BMW, VW, Audi dealers etc and the results are almost always consistent.

We have used the standard figures before but in truth the results are not comparative due to the varying differences between cars, especially older ones.

The book would say the following applies.

Front wheel drive 18% losses
Rear wheel drive 24% losses
4 wheel drive 28% losses

The problem is, this would mean that a 308 (axample used because of the section we are on) would have the same lossed wether it was a mint condition car with superb suspension as a dog of a car thats close the the scrapyard.
This cant be the case, its easy to understand that a car with very tight suspention will give a lower figure to that of a one thats worn.

HP is ONLY a calculation, torque is the only true factor.

On a lighter note, we ran a 360 F1 Spyder yesterday that had a 60g wheel ballance issue and that made a difference of 30hp !!!!!!!

Any judder, worn bushes, mis-shaped tyres, buckled alloys etc will alter the hp figures.

p.s) daves figure was a typo, it was meant to be 196hp.

 

That was a big ps:

 

Any idea of what 1002 MBar translates to in "general" altitude? I'm assuming its near sea-level. I know Atmospheric pressure is not just a factor of altitude, but here in Denver Colorado, we are literally a "mile high" in the air, so we loose a substanial amount of HP to less oxygen / less pressure.

I think we loose around 15% of power based on the higher altitude.

James in Denver

 

James: This is a factor not many people understand and yes, you are 100% correct, the air is thinner the higher you are so of course power drops.
Our pressure is 1000ish as the dyno is placed at sea level and with a cold room the power should be very accurate.

 

Well, there is a bit of source of error there - those do not take into account that it is a mid engine rear wheel drive car -- RATHER, the more accurate number would be the front wheel drive 18% as it also is an assumed engine/transaxle combo. This also matches what we see here with about 17% being a good estimate on the transversal mid engine ferraris (246, 308, 328, Mondials).
I'd look at your numbers and refigure at 17 - 18% loss.

best
rt

 

29.92" InHg or 1013mb
15°C

This is the Sea level temp and presure for Standard Day used in aviation and NAAO calculations.

 

I dont understand your point ?
Im saying I do NOT use these figures because of the possibility of changes between types etc.
This is the VERY reason we run a callibration check on every car prior to doing a run so that we can take out as much chance as possible to get the figure as close as we can using a roller dyno.

 

A dyno pull should be simple to understand. What was the RWHP on the QV? 196HP? If we use 18% as a loss that the ferrari owners here like to use, we arrive at 231HP at the flywheel. If you go more realistic IMO at 15% then the tears will flow im sure.

 

cool.
we misunderstood each other.
sounds good.