We tested three different prototype specifications of the S290 (Spec ‘A’, Spec ‘B’ and Spec ‘C’) as well as running an S280 as a baseline comparison on the new engine. Here are the results:
||S290 Spec ‘C’
||Did not respond well to increased boost levels
||S290 Spec ‘A’
||Increased boost, mapping optimised for this spec
||S290 Spec ‘B’
||Same map as Spec ‘A’, much lower temperatures
||S290 Spec ‘B’
||Mapping refined at peak power only
Here is the resulting power and torque curves from test 4, and the peak figures from test 4a:
Test 4 highlighted that the performance from Spec ‘B’ was achieving very similar results to that of Spec ‘A’, however with lower temperatures it appeared that we could possibly extract a little more power, despite already having surpassed our target of 400bhp. Some fine tuning of the mapping gave us our highest figure of 437bhp (and still running safe), but frustratingly we didn’t have time to apply these changes to the rest of the map. However, we did note that the torque figure from this result (327lbft) is only slightly reduced from the peak figure of around 330lbft, so we think it may be possible to hold a virtually flat torque curve from 4000rpm through to 7000rpm. N.B. although this curve shows strong results below 4000rpm, we suspect that these will not be replicated on the road, as the vehicle will have accelerated through this point by the time the turbo spools.
A big thank you goes to SBD for giving us the opportunity to use their hardware and valuable expertise during our development, enabling us to demonstrate the capabilities of the turbo with these astonishing results.