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Originally Posted by SilverSurfer
Just to put things straight,
There is nothing wrong with the results achieved for both Nige's and Worzels car on the rollers and no-one is at fault (mapper or RR operator).
For the boost they achieved at the top end of the rpm range, the power is about right.
My car was actually 0.1-0.2bar higher then their's hence I was marginally ahead on power.
Don't just look at the power figure plot, look at all the others that Charlies supplied, they all tell a story.....
Neither car made the boost on the rollers that they do on the road, regardless of gear.
If the car was hitting the top limit of the WGDC (Max Waste Gate Duty cycle) it wouldn't make much difference which gear it was in).
Normally a car will achieve slightly higher boost in the higher gears, hence more power. But the ECU in these cars has 2 WGDC maps to help maintain a more even boost per gear with a degree of self-learning. However, too much WGDC and you get boost spikes/oscillation in 5th/6th which can lead to lean mixture/detonation etc.....it's a fine balance.
Both cars hold 1.4bar out on the road so will be getting v.close to the expected figures of 340-350BHP for Worzel and 360-370BHP for Nige.
Retrospectivley looking a Nige's log we took when Road dyno'd he was hitting 35% WGDC for 1.45bar, Initial WGDC was 33, top limit was 38%.
On the rollers it may of been hitting 38% due to the different load effect of the rollers. It will not go beyond 38%, hence boost levels may not hit target.
All this is my take on the situation, and I am investigating further........
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Thanks Scott, that explains things beautifully.
I know the figures I got are not reflective of how the car feels. I know for a fact that the scoob feels so much more pokey than my completely unmolested M3, which should be 343BHP & 360nm. I drive the M3 every day and the scoob wets all over it. I know that the M3 is heavier, but even so the difference is massive. My scoob was beating M3's on the old map let alone this new one. (tore one to shreds last year on the East Peckham by pass, much to the other guys disgust
)
As said in a couple of posts in this thread, it's how it feels. The good old "Bum in seat" dyno doesn't usually get it wrong.
In fairness, anyone who saw Nige having a play with CJ on the M25 on the way to the meet, would say that there is never in a million years 80bhp difference between the two cars. Blast for blast (nothing silly for any watching fuzz
) was completely even.
I have no doubts about Chris's figures, his car was mapped on those rollers so it should be showing good returns on them. I just know that Niges and my own just don't seem right at all.
As AP said above, the debates will always happen. And will no doubt rumble on. But nothing takes away from the fact we had a great day out. We got to watch Rob donut around the car park, Martyn wore a pigs head and Chocks Chockington had his first tentative try at "formation Parking"! Happy days.
Group hug anyone?
