[dxb335d]

I know it's been done to Death, and some are believers some are not. Here is some results from a 5-6 year old 5th gear test

renault Clio



golf GTi




Seberio imprezzo





6 runs done with each fuel and ECU re-set.

[creepy coupe]

Is that at the crank?

Which GTi was that?

[mowflow]

From this test we can conclude that you should buy a Clio as it's the most consistent performer.

[dxb335d]

Originally Posted by creepy coupe

Is that at the crank?

Which GTi was that?

Actually it was a Hub dyno that was used mate, figures are flywheel.

[creepy coupe]

Originally Posted by dxb335d

Actually it was a Hub dyno that was used mate, figures are flywheel.

Crank/flywheels figures are the same, still like to know what GTi that was.

I'm assuming a MK5 which pushes 200 BHP ish, so 177 bhp is only 12% parasitic loss.

[KadeSdad]

surely a 'proper comparison' can only be done under clinical conditions i.e barometric pressure being the same, temperatures, weight etc.

Guess this shows an average increase / decrease, but we all know Shell usually out performs most.

[The_Bear_Yid]

I remember this. It's one of the reasons that V-Power was the first fuel i put in my E92.

[dxb335d]

Originally Posted by creepy coupe

Crank/flywheels figures are the same, still like to know what GTi that was.

I'm assuming a MK5 which pushes 200 BHP ish, so 177 bhp is only 12% parasitic loss.

I know they are. Crank/ fly are the same. Yanks use crank. That's why I don't!

[creepy coupe]

Originally Posted by dxb335d

I know they are. Crank/ fly are the same. Yanks use crank. That's why I don't!

But the experiment you posted, were Crank according to you.

[dxb335d]

Measured at the hubs mate. Converted to flywheel. A little like rollers but then converted to flywheel.

[creepy coupe]

Originally Posted by dxb335d

Measured at the hubs mate. Converted to flywheel. A little like rollers but then converted to flywheel.

I know how it works, but my original point was regarding the conversion reduction of only 12% from hub to crank.

[LexS]

Your only seeing a 12% loss because there are no tyre friction losses to account for with this type of dyno. Gearbox and diff loss at 12% isn't unreasonable

[creepy coupe]

Originally Posted by LexS

Your only seeing a 12% loss because there are no tyre friction losses to account for with this type of dyno. Gearbox and diff loss at 12% isn't unreasonable

Thanks, that was my question. I understood there were no Tyres or rollers, but as we couldn't see how the test was compiled, wondered how the results were arrived at.

[doughboy]

Super juice -

Defo on a turbo / high revving performance car

Not really on a 'regular' car

Never on a soot chucker. Old chip fat will do.

[The_Bear_Yid]

Ha ha ha.

[m1bjr]

I put my 335i on the hub dyno at TDI South in bluewater when I got it.

The hub measures actual torque as it has a load cell inside.
Unlike others that are notoriously 'guess work' - inertia rollers for example.
If you know RPM and torque you can then ACCURATELY calculate bhp.
The load cells are calibration checked with a weight on a long arm, very simple and idiot proof.
IIRC Mine made 275BHP at the hubs, and with the 11% loss typical for an efficient RWD BMW drivetrain thats an estimted 305bhp at the engine

Back OT...
Anything that is sensitive to octane and additives will produce more output.
A bigger turbo car like the 335i, especially with a tune, is always worth higher octane/better additive packs.

[DavS1]

Originally Posted by mowflow

From this test we can conclude that you should buy a Clio as it's the most consistent performer.

you could say that..........but the other 2 cars are turbocharged so therefore things like octane/air temp are going to effect them more.

I work with a rolling road on a daily basis, shell V power IME is a significant bit better than BP ultimate. Tesco 99 seems to be just as good as V power. going by ignition figures and det limits.....
If a car is detonating, you have to retard the ignition, or put in a higher octane fuel. You can then advance the ignition and the car therefore makes more power.

I also know that after 6 runs, the same car will make a few (3-6ish) bhp more as things like gear oil heat up/thin out.

[m1bjr]

Originally Posted by TrackRat

chassis or even hub based dyno data isn't worth the paper it's printed on due to all the fudge factors, guestimates, uncontrolled conditions, etc.


If you want accurate dyno data you need a properly functioning engine dyno and an experienced operator who can conduct the test in accordance with SAE or DIN engine test procedures and standards.

And what do you think a hub dyno is exactly?

Yup, an engine dyno modified to fit wheels instead of flywheels.

As for accuracy it doesnt matter at all if you are doing a COMPARISON test as per the OP.
What matters then is repeatability. And all the 'fudge factors' you mention can stay the same and so are negated.

If you doubt what I say do your own research and confirm what I have posted is correct.

[creepy coupe]

I understand what Track Rat is saying. the less variables you have, the more accurate the result and the better the repeatability. That’s why all GOOD engine builder use Dynos which couple off the crank

[m1bjr]

You are missing the point.

The original post is about a fuel comparison test not yanking out an engine to bench test it.

No more from me. I just test and calibrate stuff for a living so clearly know feck all.
I'll leave it to the net experts.