Dyno Dynamics Shootout Mode – Fact Or Fiction.

[cuspub]

Interested in hearing a little story about dyno figures? If so, read on, if not (because you are inclined to believe the hype surrounding chassis dyno marketing), don’t bother reading any further!

The following is fact, having taken place literally minutes prior to me penning this ditty. And for the record, all dyno sheets are available for reference if proof is required.

Scenario; We take a turbocharged six cylinder vehicle and place it on an unnamed dyno (this info comes later), a dyno whereby the software makes it impossible for the operator to in any way fudge the figures, with the only variation being temperature correction (via an inbuilt weather station that automatically corrects in relation to the ambient), which is of course to SAE standards, and once again can’t be played with.

1. Said Test Vehicle produces 282.1 rear wheel kilowatts @ 14 psi boost.

2. Said vehicle is then driven approximately 300 metres to another workshop where it is placed on a current model Dyno Dynamics chassis dynamometer equipped with the latest Dyno Dynamics Shootout Mode software. Software designed, we’re told, to ensure an absolute level playing field between every Dyno Dynamics dyno in the country (when fitted with the Shootout Mode software).

3. Once said vehicle is strapped onto the dyno and the software is set to the ‘Shoot6’ Mode (for six cylinder powered cars), a power run is performed for a relatively consistent result of 288.5kW @ 14 psi.

4. Said vehicle is now run with the ‘Shoot8’ Mode (designed for V8 powered cars), with the power run resulting in 304.9kw @ 13 psi.

5. Said vehicle is finally run on ‘Shoot81’ Mode (designed for turbocharged/supercharged or nitrous facilitated V8 powered cars) with the power run resulting in 317.8kw @ 12.5 psi.

Okay, so we have the very same car producing more power with each run but with a lower boost output. Interesting huh! The bottom line is that the bigger the engine (4 versus 6 versus 8 versus forced induction , the faster the ramp rate, hence the potential for a turbo to achieve maximum boost is lessened. In other words, the run is so fast it’s hard for the turbo to come on boost.

So the question is this: Why should a V8 benefit from a faster ramp rate (hence vastly improved power output)? Could it be that the more the power, the more potential there is with a Dyno Dynamics dyno for the car to spin the tyres if a ‘real’ ramp rate was allowed?

Another thing to consider with these fast ramp rates is that they are far from ‘real world’. A ramp rate that sees an engine achieve maximum power and rpm in say five seconds is simply ridiculous. A concern here is that the slow ramp rate allows a tuner to go with greater boost, greater ignition advance et cetera because during a five second run this may not be a problem. In the real world it is.

The bottom line is that using the same car on the same dyno, and run after run it produced almost an additional 40 rear wheel kilowatts by simply changing the Shootout Mode.

Harking back to the third paragraph (scenario), the dyno used for the initial run was a DynoLogic.

Assuming the moderator allows this post to go up, a post that I believe offers a genuine summation of a real world situation, I would love to hear your comments.

[Cobra]

why wouldn't we allow this post to go up?

I'm wondering why you are trying to compare the different shootout modes (software based) ???

I have seen 30rwkw lost and gained by the way a car was strapped to the rollers ...

the key variables (that haven't been mentioned yet ) are temperature, barometric pressure and tyre pressure

if the dyno has a full weather station ... atmospheric variables are automatically fed in and should only act to standardise the results .... some dynos however only have a "local" weather station which requires the variables to be read and then fed into the dyno ... there is scope for variation there

cuspub ... please re-iterate exactly what your point is

oh ... I don't want any tuner to have my car beyond a 5 sec run ... engines no likey

[ducatijb]

I still think the only true dyno is a 400m dragstrip

[Macktheknife]

Crikey.

I'm with the Duke man.

The whole thing is so variable and subjective that only "Like" gear is really comparable.

However. Where straight comparisons have some sustainability, is where say, a vehicle is run on a known dyno at a certain criteria, modified, then run again.

Any increase at the wheels should then just be calculated as a percentage increase. From there you can really only then apply that increase to the manufactures quoted engine output.

failing that, it's only an engine dyno or as Duke man says, on the strip.

[Falchoon]

Wouldn't an engine dyno have the same variables?

[ktford]

An engine dyno should be more accurate, however with computer this n that there's still software & that's where the variences lie.

Scotty

[Macktheknife]

Also with an engine dyno, there are no variables to be taken into account like:

Tyres, Tyre pressures, Transmissions, Gears used, etc.

[bcl]

Having owned 8 turbo cars, all except 1 modified (wife’s car), I’m always wary of dyno results, and what is published.

Different dyno operators don’t use consistent variables, yet they always claim their method is correct. We even had a situation at the C&V dyno day, when comparing results, found some people had been dyno’d with CK:8 & some with CK:6 … oops..so much for consistency… they were meant to be identical.

Check out the APS graphs at their site, even though you see shootout mode you still see various differing parameters … CK:2, CK:9 CK:8.

Published graphs are used for marketing purposes, and don’t necessarily reflect what you’ll get after you pay your money.

These days I always ask for 3 printouts 1.power/torque 2. power/afr and 3. power/boost.

If 2 cars get the same or similar power levels, they can drive very differently. One may be very laggy, then hit you with a sudden surge of power (almost undriveable), the next car may come on boost far earlier with far more consistency, and still achieve a similar level of power. People need to carefully look at the power/torque curve. Real world driving is what counts.

The power/torque between 2500 and 4000 revs is more important for driveability than peak torque, unless you are into drag racing or trying to impress other people with big numbers.

Some dyno operators have shown me impressive power graphs, then qualified it by saying that a bit of octane booster was added to get that result!

In terms of turbo spool up I think I know what you mean. A lot of people would be surprised to learn that in a lot of turbo cars running higher boost levels you won’t hit max boost in first gear, as there is not enough time to fully spool up. Depending on how a dyno operator does the run in/into 4th gear may determine how quickly the turbo spools up, causing variations to the graph, and possibly maximum power.

At low boost levels (5-6lb) there may not be a lot of difference between say CK:6 & CK:8, but at higher boost levels it may be significant, as your tests today indicate.

If 2 cars are being compared an independent operator should test them. Often in the past after I have my car tuned with piggyback/replacement ecus I take it to another dyno for an independent check.

Brian

[cuspub]

BLKXRT.

You make valid points, and I agree wholeheartedly.

1. However the point is that when running back to back runs on a dyno, they should remain consistent. In this instance, the vehicle was strapped the same for each as they were literally one after the other.

The point I am making is that I am suggesting PEOPLE TAKE CARE WITH PAYING GOOD MONEY FOR MODIFICATIONS, after having received a 'before' dyno readout, then an after. Make sure the parameters are exactly the same. EG: If the original is run in Shoot6, then the final is Shoot8, this is not a fair comparison because the ramp speed is different (shorter) and the power will be greater as a consequence.

I simply want people to be careful when they pay money for performance modifications.

2. Comparing software modes - why? Because Freddy from Ripsville does exactly what I have just stated, and to justify the money spent with him, he changes the shoot mode or the Extra Correction Factor to provide a greater figure than is actually true.

3. "the key variables (that haven't been mentioned yet ) are temperature, barometric pressure and tyre pressure"

I was under the impression I mentioned a weather station. In any case, the SAE standard should be adhered to, and this takes care of the correction. Tyre pressures typically only come into play on dynos incapable of handling big power unless a vehicle is heavily strapped down. This is not the case with the DynoLogic. Strapping down is important from a safety point of view, as is - for example - running the tyres at 30psi. However the effect these have on the different dynos (Dyno Dynamics v DynoLogic) is massive.

4. Not wanting your engine to run more than 5 sec... interesting. Consider this. A tuner modifies the ecu timing/fuel et cetera, running it extremely close to detonation - but not quite there with a 5 second ramp. That's fine on the dyno for 5 seconds. Take the car out on to the road under constant acceleration for 15 seconds and what do you get? The potential for detonation and disaster. I am not going to cast any aspersions on any tuners, suffice it to say that a credible tuner will - when tuning the likes of a MoTeC, spend quite an amount of time at full throttle under full load, mapping each point. Once this is complete, he would then run it on an appropriate ramp rate (say a 20 second run), to ensure absolutely no detonation - which we all know is the biggest engine killer around.

ducatijb. I agree 100%!

Macktheknife. Agreed once again. However if you want consistency, the DynoLogic dyno can't be frigged with, it provides accuracy run after run, and provides optimum traction (the driven roller is literally twice the size of a DD). You are also right about percentages, thing is, if the original figure is way off the mark, the percentages will also be out.

[hypnodoc]

ducatijb. I totally agree with you. I lost 30 - 40kW and 2 nights sleep and changed a $600 centre muffler until a clown who shall remain nameless rang me three days after a dyno run to tell me that their dyno computer had been playing up. That same night I read a multi-dyno test done in WA on a Commodore (sorry to swear) ute, in Perth Street Machine.

10 different dynos = 10 different readings up to 100 kW difference, and guess what my EX TUNER had the lowest readings of them all.

IN MY OPINION DYNOS ARE CRAP :ermm: . The most powerful car is the one who makes it to the end of the line first. No more $50 for such hard revving misinformation for this little duck. Although one thing all of this did was make me find a tuner in the west who is actually interested and even knows what ther'yre doing. :banghead: :banghead: