Well, Erling: here I am!
Finally, I’ve carried out the dyno test with my GS…
First, the setup:
- UNIFILTER foam air filter;
- NGK Iridium spark plugs;
- SAS unplugged (long since, so, possible ECU self adj already over);
- Quat-D headers (Torque-type, referred to competitors);
- Akrapovic silencer with open OEM Db-killer (that one without “parachute”);
- Reflashed OEM ECU – actually my third release by a friend, so far only with dyno-butt feedback;
- Rear tire: slick-worn Tourance, lended me from the dealer dump to not have knobby one.
First, I’d like to point out the target of my general setup and remapping in detail – or the wish to make a stronger torque delivery, eliminate all the flat spots, and smooth the odd throttle reply; stock peak power is already not that handy in combat mode, off or in tight roads... no sense to take care of.
The test was in 4th gear, with wideband λ installed directly into the headers seat, temporary removing the original – therefore no sniffers, with obvious advantages.
Moreover, the SAS was plied in order to be very sure about possible gate-valve leakage.
We’ve done three launches each % of throttle opening (linear leverage: verified) – so, respectively 40, 70 and 100%.
Now, the WOT power & torque graph.
Since I haven’t any previous test, I’ve asked to the dealer about a comparison…. He shown me several test reports, included a MY2013 performed for an Italian magazine – and all of them are almost equal in quality and quantity, with about 77,… HP & a bit less than 55 lbs.
I wouldn’t put him in an uncomfortable position, asking for one of them, so I digged into the net to find a test with the same bench (Dynojet), believable as per average stock curve, as below.
BMW declare 83,7 HP (85 CV) @ 7500 rpm
Stock = 77,61 HP @ 8200 rpm
Mine = 80,17 HP @ 7800 rpm, or +3,3% @ 400 rpm lower
BMW declare 61 ft-lbs (83 Nm) @ 5750 rpm
From BMW 11/2007 Media Info Bulletin, with the same numbers of “Unstoppable” brochure, where the curves (with an infinite smoothing to fill holes) are the same of 650 GS!
Pity the curve is applicable only onto 800 GS, so double-bulls§it! …moreover, they haven’t confirmed the mistake about 800 torque value numbers, to be always able to demonstrate their good faith into mistakes.
Stop to fuel the argument, Gaspare….
Anyway, tested stock = 54,65 ft-lbs @ 5600 rpm
Mine = 59,58 ft-lbs @ 5650 rpm (+9%, about same rpm)
The 85% of torque is available since 3000 rpm, as per stock curve – but with more 3-5 lbs on the whole range.
Notice the torque curve is dropping before the stock when revving, that’s ‘cause of “torque” headers - with less HP than possible with others.
Then, the MY 2013 is weaker in torque matters… ;-)
The best is anyway the trend, with no holes compared to stock, as shown below Vs the taken reference (same smoothing algorithm).
Erling, hope You won’t mind if I compare your graph with my equivalent, too.
I’m not able to explain your knobby tire-slip and late rev limiter intervention, compared to mine.
Possible the very-worn-tire diameter effect is more than your slip?
Could be, but in this case there’s anyway no proportion with power readings IMHO.
Notice it’s the only graph with speed; others with rpm.
Then, to complete, the over-rich mixture obtained with my carburetor-tuned dyno-butt driven to an average +14% more fuel consumption… obviously, I’m going to correct the shot, reporting the 40-70 (the only passable one) - OWT launches Vs respective AFR, as shown below.
That’s all; on Friday the last true-trip of the year… Seafood in Genova, with a proper mountain crossing.