After today's rolling road that Ben organised, I'm none the wiser after the car doing two runs while on the rollers!
With Stage 1 the car had been rolling roaded on two separate occasions at Track 'n Road in Rayleigh. Both times the figures were in the expected range, the latest ones being slightly higher due to, I think, the car having had a new boost pressure sensor to sort out a little glitch that was going on.
So, with the new Stage 3, and based on BSR's figures (which have always been conservative) and the figures from Stage 1, I was expecting to have around 240/245bhp and 280/290lb.ft (flywheel figures).
So I was second onto the rollers. I asked them to put the boost pressure measuring device on to record what was happening with the boost. Disappointingly they had no facility to measure the AFR (air to fuel ratio) to see how the car is fuelling - which can tell you a lot and also show if the fuelling is the reason for any unexpected figures etc.
So, onto the first run. For some reason they do their runs in 3rd/4th, as opposed to 4th/5th which is what I've always seen in the past. I did ask why and it just seemed to be the way they do it. So the first run was done in 3rd gear - result was 224bhp (188.5 at wheels) and 238lbft (wheels) - so taking a conservative 15% for transmission loss that's around 273lb.ft Slightly surprising result for the bhp given that with Stage 1 it was 217bhp. At 273lb.ft the torque figure matched BSR's figure, although I was expecting a bit more as my engine seems to produce more than standard.
Here's the graph for that run......
As I said, the flat torque graph isn't odd/alarming given that the BSR one is like this........
EDIT: (after something pointed out by Hideous in alter post) - On my first graph the torque drops to 200lb.ft at around 4500rpm. Converting the 200lb.ft wheel figure to Nm and then adding the 15% estimate to get a fly reading has it at around 310Nm. On the BSR graph it drops to that at around 5500rpm, so 1000rpm different!!
So, onto the second run which they did in fourth this time. Results were 209.8bhp (flywheel) and 287.3 lb.ft (wheels). Using the conservative figure of 15% transmission loss that equates to around 330lb.ft at the fly!!! Now given that BSR quote 273lb.ft for a Stage 3, that's a massive 60lb.ft over that figure!! There's no way on earth that my car is running at 60lb.ft over BSR's figures. The bhp at 209.8 is less that I was getting with Stage 1 and only 4bhp more then BSR's conservative figures for Stage 1. Something very wrong there indeed!!!
The graph of this run....
Curves look nice enough, although it hasn't got the flat torque curve like BSR's - and the figures simply don't add up. Barely more bhp than BSR's Stage 1 figures and 60lb.ft more than BSR's Stage 3 figures!!
EDIT: What I've also noticed, and it hadn't really clicked before, is that on the 3rd gear graph it has the power peaking at 3350rpm!! - on a petrol turbo?, I don't think so! Complete twoddle.
The 4th gear graph has it peaking at 4200rpm - again complete twoddle. The BSR graph has the power peaking at around 5300rpm - exactly where you'd expect it on a petrol turbo with the rev range that the 2.0T has. [/EDIT]
What was also interesting was that on the only other petrol turbo there today (Soulman's 2.0T with BSR Stage 1) there were inconsistent figures. I can't recall both torque readings, but his first run was 173bhp (which is what the car is bog standard) and then the second run was 198bhp. Helluva difference between two runs done minutes apart.
I'm not moaning/complaining, just somewhat puzzled. I'm not going to get into any theories or 'accusations' etc. - simply no point. Although I was a bit puzzled by a couple of things I saw today which I'd never seen done elsewhere.
Before today's RR I always said I was going to go back to Track 'n' Road to get a run there, given that the figures tallied with what was expected, and also to keep consistency by using the same RR. They also do an AFR (air to fuel ratio) reading as well, so that will add more data to the results.
I'm simply going to scratch today's results and leave it there and go to Track 'n' Road. If those results show that overall things aren't looking right/are significantly down on expectations then it'll be time to contact BSR and have a chat. Given how the car is performing on the road though, I've got no reason to think anything is amiss. A couple of folks had a drive of my car today and I have a feeling they would be thinking the same.
So, that was my RR day today! Long way to go to end up with something that simply doesn't make sense! lol Hey ho - C'est la vie!