Been on rolling road.

[miller]

was just about to say the same thing, the car detailing pics look like they are taken from a half decent camera. I took pics of the graphs and printouts from when mine went on the rollers, in all honesty the quality is probably better than a scanner


Mike


edit, justn noticed my 1000th post jeeeeez!

[pitslayer]

my phone but it keeps loosing pics all the time trying to get one up now, but its just killed the phone

[pitslayer]

alot of messing about

[Kieran]

Just got that one graph Kyle? No AFR or Boost graph?

[pitslayer]

yeh, i only wanted to see what bhp it was putting out

[d i c k i e s]

any figures on the bottom piece of the paper?

[pitslayer]

bottom reads
corrected power- 290bhp at 5752 rpm
power atw- 158bhp
transmission losses 132bhp
max torque at flywheel, 344fltlbs at 870 rpm, but 280 constant
ambient temp- 20c
ambient pressure 1010mb
then the boost which i know is at 6 psi

[Kenneth]

um, that transmission loss looks to be a bit on the high side... 45.5%

you driving with the brakes on?

[psbarham]

um, that transmission loss looks to be a bit on the high side... 45.5%

you driving with the brakes on?

i was just about to say that, according to that dyno you need a 1.8gdi lump just to run the gearbox, i don't think so

[Wodjno]

according to that dyno you need a 1.8gdi lump just to run the gearbox

It's got "THAT MUCH POWER"

[Eurospec]

You reckon Ben? I'd say that's a bit low... Most of the standard ones we've tested in the past were between 170 - 185bhp give or take.

Yeah thats not that unusual. Different Dynos and different days, but its not that far off for an early auto. The machine i use is a DD, and ultimately you can only compare before and after, but it seems pretty repeatable.

Cheers,

Ben.

[pitslayer]

so any idea on what should be done?
86k miles on the clock,
do i take the turbos off and send them of to be rebuilt, or should a look for another problem?

the only thing i saw and remember on the exhaust gas screen was a co2 of 12,6 and the bottom one, was 1.00

[White Lightning]

I would suggest that we really need to see a graph showing boost to decide whether there is any problem with the turbos.

Have you got a boost gauge? I can't remember ...

[Throbbe]

so any idea on what should be done?

Do nothing is always an option. As Ben is saying, it's not an unreasonable result. If you don't have the boost/AFR data another run (maybe somewhere different?) is going to be a lot cheaper than shelling out on the turbos for little or no benefit.

If you do want to do something, then do the cheap/free stuff first*. Boost leaks would be my first port of call.





* While I rarely stick to it, this should be one of the golden rules for life.

[pitslayer]

ive got a boost gauge, mine reads 6psi, his read 6 psi.
i cant find any boost leaks or hear any, but the rear turbo sounds how to put it, grainy? i can hear the rear turbo, sounds like when my rear turbo hose blew apart. but its lower down this time and the turbo sounds coarse, not sure how to explain it.
i think we can agree though that my car is down on power against most, if everyone is 175 atw and up, and im like 30bhp down, that tis alot of bhp,

[WildCards]

Get it on another dyno, if that also gives low readings you know it's consistent, if not you know one of the dyno's is wrong.

[phosty]

Last year I did an experiment and took my Auto VR4 to two different rolling roads within 2 days of each other - no mods done in between:

17/09/07 @ Wallace Performance (Dastek): 202.2 bhp ATW / 239.6 bhp ATF (i.e. 15.6% losses)

19/09/07 @ Japerformance (Dyno Dynamics): 182.6 bhp ATW / 260.4 bhp ATW (29.9% losses)

Just looking at the ATW figures that was about 10% difference (air temps and pressures were about equal both days) with the same car.

When you look at the differences between the ATF numbers I began to appreciate why those in the know tend to disregard them.

The Dastek RR apparently uses coast down to estimate the true transmission losses - and worked them out to be much lower than the fixed value that the Dyno Dynamics road uses - 24% for AWD and 7% for the Autobox (0.76 x 0.93). However when I contacted Dastek directly to explain how their system worked it needs the operator to select neutral quickly on coast down to accurately measure the losses on autos. I don't know if he did this correctly or not.

Graphs below - note the silly torque figure (330 ftlb) like yours on the Japerformance graphs in the first two gears:



ATF figures. AFRs off the scale (<10)



And ATW.



Nice 8-10 psi boost being maintained. Silly torque at first.



Unfortunately no boost / AFR figure from Wallace Performance (didn't realise that was an extra £10!)

As you can see, due to the fact is was an auto box both RR's gave me graphs against speed. Using excel I overlaid the two curves but the Wallace one seemed to be out. However, I noticed the curve shape was similar but shifted to the left (I think their speed reading was out). Correcting for that I was able to overlay the two curves (ATF). Using the gearbox ratios I was then able to extract the rpm vs power to give an estimated typical rpm vs power curve (the rough black line through the scattered points).





Once I corrected for the Wallace speed difference the points all seem to agree approximately.

After reading around a bit (especially here http://www.pumaracing.co.uk/trans.htm ) I tend to ignore the ATF figure. As to if my car is putting out 202 or 183 bhp ATW - who knows????

[Nutter_John]

I recon your putting out 192 bhp atw ( but only at the time i wrote this )

[miller]

best test is the 1/4 mile kyle

[Eurospec]

True dat!

Cheers,

Ben.