ESE's works engine tuner

[crbbt]

Hello Brains trust,

I am wondering if anyone can advise me on removing the powerjet tube that protrudes into carb bore?

specifically on a keihin spj.

The issue I have is that the tube's outlet/discharge is facing away from the carb slide and need to be rotated 180.

I am assuming they are a press fit but do not want to destroy the tubes or the carbs

Thank you!

[Peljhan]

That is what I was referring to earlier that I am almost certain that most dyno softwares are adding some level of "correction" that is not user adjustable.

Where I am, dynojet is the most popular commercial dyno around. There are two local to me that I have had bikes on and the outputs are similar. When I set up our Dtec dyno, the power numbers were very low, so I did the same as you and adjusted the MOI to get them as close as I could to the dynojet figures so that, whilst not perfect, there was some level of comparability.

I think Wobbly stated that DynoJet overcorrects for 15%
Do you know how much did you adjust the MOI from what it actually is?

Darren from Dtec said, their software is made on known basic equations and no additional factors are used.
Dynomec had some correction inside that was 1.30, exactly the difference with Dtec.

I also saw written on VHM page for their dyno tests:
- We measure on the rear wheel, but add a small correction factor (0.05PK/Kmh) for the crankshaft. So the graphs in the video's show the power on the crank.
What junk of correction is that? And definetly not small. For 50cc measured from 30-120km/h that is 1,5hp at bottom and 6hp at overrev. So for weak bikes it can double the power and for 1000cc bike is like nothing.

Thanks for suggestion Frits, but that was not the case as you can change from imperial to metric in the software. Downside is I can't choose HP/Nm/°C, only HP/lbsft/°F or kW/Nm/°C because we all speak in HP figures between friends.

[TZ350]

I am almost certain that most dyno softwares are adding some level of "correction" Where I am, dynojet is the most popular commercial dyno around.

It looks to me, that DynoJet's are a little bit optimistic but seem to give consistent results between individual units.

[F5 Dave]

At some point the horse(sorry) has bolted and something is so ingrained that we have to keep using it.
Dieters count in calories but really mean kilocalories and joules aren't in any conversation. Our wheels an TVs are inches. Although there was a Citroën that had metric wheels decades back apparently.
So I'm a wild hypocrite fervently defending the metric system and English language from being Americanised. But accepting some things like hp are probably best left fairly constant. It was bad enough with quoted hp being believed. Journalists are usually aware of this now, but still like waffling on about torque as if some mysterious motive force that is somehow produced independently and not mathematically constrained.
Anyway, rant for lunchtime.

[Frits Overmars]

It looks to me, that DynoJet's are a little bit optimistic but seem to give consistent results between individual units.

I once hooked my software onto the Dynojet of nearby Ten Kate (superbike world champ at the time), so each run on the Dynojet was simultaneously monitored by Dynojet software and FOS software. Clear outcome after a series of runs: when a bike delivers 100 hp on the dynojet drum, Dynojet claims it was 111 hp.

[F5 Dave]

Ok so let's play.
How would the 54hp of the RSA compare to either?

And is some of the conversion to bring it close to crank hp vs at the drum maybe?

[Sketchy_Racer]

It looks to me, that DynoJet's are a little bit optimistic but seem to give consistent results between individual units.

I once hooked my software onto the Dynojet of nearby Ten Kate (superbike world champ at the time), so each run on the Dynojet was simultaneously monitored by Dynojet software and FOS software. Clear outcome after a series of runs: when a bike delivers 100 hp on the dynojet drum, Dynojet claims it was 111 hp.

Yes, this is exactly my experience and conclusion.

We can all fool ourselves and enjoy seeing a larger 'measured' power output though....

[Frits Overmars]

Ok so let's play. How would the 54hp of the RSA compare to either?

It wouldn't. The RSA power is measured at the gearbox exit shaft. So no varying losses through a chain that loses its lubrication over time and above all no wildly varying losses through the distortion of a tire on a drum, which will heat up the tire, which will raise the tire pressure, which will influence the distortion.
Measuring rear wheel power may be convenient for various purposes, but not for engine development.

And is some of the conversion to bring it close to crank hp vs at the drum maybe?

If Dynojet would say so, I would be willing to accept that, even if their 11% exaggeration is neither a constant, because of the unpredictable tire losses, nor very realistic.
Total power losses between crankshaft and dyno drum will rather be in the order of 15%. But Dynojet just let you think that what you see on their software is the measured power.

[lohring]

By the way, one British horse power is 1.014 metric horse power. That's 33,000 ft pounds per minute vs 4500 kg meters per minute. Pounds and killograms are force, not mass for these definitions.

Lohring Miller