StephenDone

Hi Nom,
Power in each gear will be different, but will depend on each car. All the following factors (and others I haven't thought of!) have an effect: ECU mapping, spec of turbo & drivetrain losses. Differences are more marked between 2nd and 3rd gear. I haven't tried a 4th gear run, since I couldn't do it even close to legally.

Hi T-UK,
Well, he's broken his gearbox. Your guess is as good as mine as to whether he'll do another one before the engine ! Stunning figures. I can't wait to get hold of the DDF file.

Regarding the jagged nature of the power graph & smoothin; I'd like to compare this graph with the peaks and troughs of the active ignition curve. We may find that they at least partially correspond. Some of this roughness may actually be there, but is not picked up by rolling roads. Writing all this stuff, I actually get less time to try out stuff _in_ the car than I used to, so please anyone do some experiments and see what you find.

Hi Phill,
You have to put in the total weight of everything being accelerated by the engine, so that includes the car, you, the fuel the Mrs and the stinking great ICE in the boot. If in doubt, get it weighed.

Hope to see some of you at the PE RR day on Saturday.

Cheers

Steve

P.S. If you do see me there, you aren't allowed to take the **** out of my exhaust. I decided to lag it for noise reduction, and people think it now looks like a giant pink lipstick. No, not the tailpipes

Paul_M

is this ever likely to come out for MY98 scooby (with the OBD-II port)?

StephenDone

Unlikely from EcuTek. We are flat out working on new cars as they come out and 98 would be going backwards for us.

mutant_matt

Stephen,

I haven't used the DDyno yet but I plan to on the way to PE tomorrow and some on Sunday. When you record a run, does it do a "normal" DetaDash trace as well?

The other thing, you have mentioned a couple of times getting your car weighed but where can you do this?

Cya tomorrow,

Matt

StephenDone

It only logs engine RPM, but very quickly. No other signals are recorded. You can get your car weighed at a weighing bridge, scrap yard, or on corner weight scales at some tuners. Not PE though - I've checked. Maybe you can find someone coming to the RR day that can bring some scales along.

Cheers

Steve

StephenDone

You nutter !

Andy.F

RESULT John Are you up for the 60 bhp upgrade from the TD06 hybrid next

john banks

YES Need a gearbox and engine though to do it safely. This already feels like I am pushing everything possible to 11 on a dial that only goes up to 10

Andy W

How much is the delta dash in total?

D Power

Further information on DeltaDash and the new Road Dyno feature is available on www.ecutek.com

Price is £215 + Vat including postage in the UK, £225 rest of world.

EMS

Forget rolling roads!

Mark.

StephenDone

Hi John,

Interesting stuff. One way or another, I think everyone is in agreement - you have a bl00dy fast car !

To assist you in working out why the figures differ, I thought I'd mention what goes on inside DeltaDash Road Dyno:

Air intake temperature and atmospheric pressure are NOT used to compensate any of the calculations made by DDRD.

Some might argue that I should use atmospheric pressure to correctly compensate for drag - the thinner the air, the less drag. I was about to add this today, but then noticed how many cars are reporting dodgy atmospheric pressure. This is probably due to the presence of boost signal clamp devices. And, as I've said before, if you test in 3rd gear (as you have) then errors in drag power calcs will only cause a 2-3 BHP error, which is minute compared with the differences that you are seeing.

Some might also argue that I should use IAT to compensate power figures, but this makes things even worse. The IAT is the temperature of the intake air. We don't really know the charge temps or the temps of the cooling air flowing across the intercooling. Better to leave well alone I feel.

There are absolutely no fudge factors in DDRD. Pure physics calculations - scale RPM based on gear ratio, final drive and tyre to get vehicle speed. Differentiate to get acceleration. Integrate to get distance. Work out the drag force based on Cd, frontal area & vehicle speed. Force Required = Mass x Acc'n + Drag. Power = Force x Speed. Bob's yer uncle.

I.e. with DDRD, assuming you have the setup correct, what you see is what you got. Note that wheelspin would cause overestimations of power and torque, as would clutch slip - the reverse of chassis dynos. Maybe a partial 4th gear run could confirm that DDRD is not the one at fault here.

Definitely worth getting your car weighed accurately. You could even chalk your tyres and work out the true rolling circumference if you wanted, but this will be pretty close anyway. Alternatively, you could use a GPS to calibrate RPM against vehicle speed - e.g. 4th gear 3000 RPM, measure speed and adjust tyre spec accordingly. Don't worry about the drag values too much, unless you weld on truck mirrors

We need a few more people to compare rolling road wheel figures with chassis dynos. So that nobody is in any doubt, I'll clarify something: DDRD was not designed to create power figures that match PE's rollers. 227 ATW on PE's rollers, 222/233 ATW in 2nd/3rd gear on the road. However, I must admit to not being too upset that they are so close

But don't be hard on Star just yet - there are plenty of factors at play that could affect figures:
# How quickly do Star do the dyno run ? If they run the car quicker than PE, then your big turbo will have less time to spool up. Next time I'm at PE, I'll time a run, but I think it's in the order of 10-15 seconds. If they run it slower than PE, then it should produce more power, unless heat build up causes the power to drop off, bringing us onto cooling...
# What power rating are Star's cooling fans ? If they are bigger than PE's then you would expect better figures. Smaller, then you would expect worse figures. From memory, PE's fans are 3kW three phase centrifugal, and they'd probably run two on your car.
# What gear was the run done in ? 4th I think. Could you possibly have been slipping on the rollers, and not transferring all the generated power to the rollers for measurement ? I don't think so though - I just checked what 6750 RPM in 4th gear would be, Star say 124 mph, and DDRD says 125.9, so not much slip going on there.
# If the figures you have quoted have been normalised to a certain air temperature and atmospheric pressure, then what are the values ? If their benchmark is based on say 25°C ambient and the ambient was only 11 (as here), then that could explain some of the variance. Having said that, it appears that the normalised figure is only 1.5 BHP down on the measured figure, according to the chart.

I get the feeling that this is going to kick off a bit of a rolling road debate. But if it does, let's all stick to facts (not you John - you always do) rather than giving anyone a slating. We know how slanging matches are being treated by the moderators at the moment, and I don't want this thread getting locked ! Too much good stuff getting discussed. I want to see how much power your car is producing in _another_ week !

Cheers

Steve

Andy.F

JB's AP22 figures which tie up rather nicely with delta dash

Start Speed 40.0mph
mph s g ft hp
50.0 1.27 0.42 83 196
60.0 2.21 0.49 158 274
70.0 3.15 0.46 248 309
80.0 4.20 0.41 364 320

Pk Power: 80.1mph 4.22s 367ft 323hp
Peak G: 59.9mph 2.20s 158ft 0.50g


Start Speed 40.0mph
mph s g ft hp
50.0 1.52 0.35 99 169
60.0 2.65 0.42 190 243
70.0 3.74 0.41 294 279
80.0 4.93 0.37 426 300

Pk Power: 84.6mph 5.54s 499ft 306hp
Peak G: 67.1mph 3.42s 262ft 0.42g


Start Speed 40.0mph
mph s g ft hp
50.0 1.47 0.37 96 177
60.0 2.52 0.44 180 251
70.0 3.56 0.42 280 287
80.0 4.69 0.38 404 310

Pk Power: 79.7mph 4.65s 400ft 315hp
Peak G: 67.1mph 8.53s 864ft 0.51g

john banks

Thanks Andy, interesting that the best AP22 60-80 time is 2.0 rather than 1.8 seconds, but this was with you in the car also. It is a bit tricky always finding a bit of guaranteed flat road that you won't irritate people on, but there were some back to back both directions AP22 runs which settle around to the 315 BHP figure.

Spanpody.

John/Andy

The standard blue EVO 6 that ran on Star's rollers yesterday gave a figure of 280BHP and 274Ibs/ft which are bang on for a stock EVO 6.

just my 2ps worth

Pavlo

Looks like it's surging badly (on the rollers) as it hits peak boost, could this be screwing up the airflow readings to such an extent that the ECU never really recovers during the run?

Might be work watching the run on Delta ECU to ensure the map coverage is as you expect it?

Other than that, the dyno curse strikes again, looks to me like you need to get a VF24 and go back to the top mount

Paul

Re-Bitten Hero

[Off topic - does anyone want to sell me an AC22 or AP22 that they don't need any more? ]

Excellent thread guys, extremely interesting. Yet another lengthy thread with the inimitable Mr Banks involved

Just for the record, my MY00 with about 20kgs ICE, half tank of petrol, floor mats, and lardy German bloke doing the MOT test (I guess about 90kgs) came out at 1360kgs. Hope that's useful!

Cheers
Richard

john banks

It wasn't surging on the rollers Paul (and even if it was I have some very surgey road dyno runs where it still makes excellent power and torque from 4000 RPM, just flutters the MAF signal and the torque whilst it is surging and then quickly recovers), it was just that the boost comes in in three distinct stages to stop it surging hence the graph, because the run up time is longer on the rollers than the road it shows steps because it reaches each target more quickly and then holds it before going onto the next one. On the road it is still climbing smoothly even in higher gears as the next boost zone is hit hence the smooth curve (there are only 8 boost zones, I used three for the boost coming in progressively). If the run up time on the rollers was more realistic...

Hear what you are saying on the Evo making standard figures, guess I just need to take it to some other rollers and see what I get. Whose are right?

Having fiddled with a lot of Scoobies in various states of tune, it is difficult to imagine how a MY99/00 with a VF24 flung on it with standard fuel system and intercooler makes more at Well Lane than I made at Star. Putting the two side by side would be comedy I guarantee it.

Would love to run my car at PE, Well Lane, Star etc with the same spec. I think someone said they would do this? We have already heard of Bob getting 58 BHP more at PE than Well Lane, yet there were some silly high figures at Well Lane, like a decat P1 making 330 BHP or something.

I nominate AP22 or Road Dyno as the most objective basis for comparisons between cars that we can make since the rollers across the country read so different. It is not a dick measuring competition to want to be able to compare figures, it is so we can all see what works and what doesn't and learn from each other how to get decent power out of modifying these cars.

[Edited by john banks - 2/10/2003 4:17:10 PM]

David_Wallis

yeah that confused me as im sure my car would be entertaining against it..

Theres not many cars that have worried mine yet.

Dick Measuring

Think the only way might be engine dyno then straight to a rolling road..

David

Razor2001

Hi Stephen,

I think you asked earlier what other features you would like to see from the DeltaDash. Here is my suggestion (although I don't know if it is possible as the actual Subaru ECU may be the bottle neck):

Can the deltadash be made to read more than 18.4 psi relative manifold boost ? It would be great to see the actual boost the car is running above 18.4 and not just the 18.4 readout.

Cheers,
Ray

StephenDone

Just read Manifold absolute pressure in bar and then subtract one. You can then read up to around 23 PSI.

Cheers

Steve

P.S. The earlier request for configurable graph colour has now been done.

Razor2001

oh, cool beans

Cheers,
Ray

john banks

And if you want to read more than 23 PSI you are insane

Steve do you know what the ECU does if it sees FF (25 PSI) on the MAP signal - does it fuel cut or ignore it? I had it holding 24.2 PSI with no issues, but there was no peak either.

Razor2001

Will the manifold absolute pressure read above 33.10 psi or 18.4 psi equivalent in relative pressure, or so you have to set it to 'bar' vs. 'psi' ?

Cheers,
Ray

StephenDone

Hi John,

Not sure. But I'm sure you'll find out !

Ray,

You can use bar or PSI. I just find it a little easier to subtract 1 than 14.5 from everything. Just try it and you'll see.

Cheers

Steve

Razor2001

Hi Stephen,

I was looking at some of my logs and I noticed that the correlation between relative and absolute can differ. Sometimes there is a 15 psi diff sometimes 14.3 diff ?

Is there anychance when running 200ms that the DeltaDash can miss the actual true 'peak' boost as it is too fast for the ecu and delta dash to pick it up. I just want to be sure as my manual GReddy boost gauge I have seen read 1.4 peak for a second but when I look at the log the highest bar reading I get is 1.3 ?

Any thoughts ?

Cheers,
Ray

john banks

Interesting to plot the power curves of the road against rollers. The graph from the rollers was a second run and the car had been bounced off the rev limiter several times in the previous run.

Wondering if the prolonged run time is creating internal losses. Some previous Scooby runs at Star even on smaller turbos have much less power and torque until 4500 RPM and then the curve is almost vertical as though the load has been turned on. This would result in 4500-6000 RPM under major load rather than 3000-4500 RPM, which could seriously cause some heat buildup. I think putting the load on at 3000 RPM or lower is better, but needs to have something like a third of the run length so like on the road, much kinder to the cars, and they should produce more realistic power?

StephenDone

Hi Ray,

The difference between relative and absolute pressure is atmospheric pressure, which varies from day to day.

Hi John,

Maybe next time you are there on the rollers, log just RPM at max rate with DeltaDash. Then we can plot revs against time and see how the roller speed is changing over time.

Cheers

Steve

mutant_matt

Ray,Yes, it is possible though I don't know if 200ms is fast enough to catch everything. I normally use 100ms on the road when logging several parameters and 50ms when logging less on the dyno. On the dyno at the weekend, my Ecu was getting really busy around 4000rpm and missed a spike (according to Merv and some guy from Prodrive ) so Merv gave me a new interface (the ODB connector). I haven't had a chance to test it yet so I'll let you know how I get on.

One other thing, the later versions of DD show the log points and if they are a long way apart, especially around the 4000rpm boost peak point, it may be missing it....

Just a though,

Matt

Razor2001

Hi Stephen,

Fair enough, problem is it was on the same log right next to each other.

I.E.

4000 ms absolute: 30 psi relative: 15 psi diff: 15 psi

4200 ms absolute: 28 psi relative: 13.8 psi diff: 14.2 psi


The two readings were only 200 milliseconds apart ?

Cheers,
Ray