ESE's works engine tuner

[ken seeber]

For the DCI engine, which seems to work, the next thing is to find out if it offers anything in terms of increased power. So, need a dyno. Decided to make one that fits directly onto a kart, swinging off the LHS of the rear axle. So, with a couple of Ø40 bearings and a Commodore front disc and caliper and some bits in between, the thing is now sort of in place. The torque reaction will be measured by a 50 kg strain gauge, which with a readout, was kicking around from another ongoing project.
Once working, the plan is to fit a standard ARC piston ported inlet cylinder to the engine and then do a baseline power run. After that run the DCI engine, firstly with the pissy little snipper carbs we have been using and then fit some larger Tillotson ones….this will be the real test.
Being a friction brake, I hope we can control the thing, manually, such that we can hold it at constant speed points, enough to optimise the mixture (which could be anywhere at present) and get a torque reading. If we used an inertia dyno it’d take years to get a decent clean carburation operation over the rpm range.
Also, I can use it to test the unfinished slider engine project, which fits straight onto the kart.

[TZ350]

For the DCI engine, which seems to work, the next thing is to find out if it offers anything in terms of increased power. So, need a dyno. Decided to make one that fits directly onto a kart, swinging off the LHS of the rear axle.

Great work. I am totally looking forward to the comparative dyno results.

[jonny quest]

Beef up your torque arm. That will flex way too much for consistent readings

[Muhr]

I am thinking 15-20 kgf which is gradually applied with a caliper, should it handle or? or is it something I do not understand?

[F5 Dave]

Another Commodore out of commission. I applaud your efforts even before we know if the engine is a grunter.


Can you take out a few Fiord Rangers too?

[ken seeber]

Dyno brake disc thoughts:

In my case, am considering an engine of say 15 kW @ 10k rpm. Doing the mathS, this equated to a torque of 14.4 Nm. With a chain reduction ratio of 8:1, this means the axle is seeing 116 Nm.
With the current setup as in the pics, the strain gauge is aligned to be tangential to the axle at 300 mm. So the force it will be seeing is 116/0.3 = 386 N. The strain gauge is rated at 50 Kg = 491 N.
Compare the forces for the brake arrangement in a car. 1500 kg, 0.5 g de-acceleration and a wheel rolling radius of 330 mm. Force to slow the car is 1500 *9.81/2 = 7358 N. Say if all 4 wheels share the braking, then each wheel sees a tangential force at the ground of 1839 N. The torque at each wheel is 1839 * 0.33 = 607 Nm. Well safe.

Weight. Weighed all the major individual bits, totalling at 19.2 kg. Thought it’d be more when my dainty, but aging body had to lift them up and down all the time when making them. Thus the load on the axle is low when compared to a kart weight of 160 kg with a 60:40 distribution = 48 kg per rear wheel.

Will it shake due to flex? Dunno. The arm is certainly strong enough rotational inertia of the disc will act as a juicy flywheel, so I think the thing will be relatively smooth.

It is what it is.

Dave, everyone loves a grunter….

[Muhr]

Dyno brake disc thoughts:

In my case, am considering an engine of say 15 kW @ 10k rpm. Doing the mathS, this equated to a torque of 14.4 Nm. With a chain reduction ratio of 8:1, this means the axle is seeing 116 Nm.

I built my assumption closer to 4: 1 eg 11-44.
Just want to say that I did not try to be a dick regarding the potential success of the project!

[ken seeber]

I built my assumption closer to 4: 1 eg 11-44.
Just want to say that I did not try to be a dick regarding the potential success of the project!

Muhr,

You are a contributor and absolutely NOT a dick. Keep on keeping on.

[TZ350]

I just love the sound of this ........

[wobbly]

I really hate it when U Tubers do dyno runs like this and dont simply turn the camera around and show the graph on the screen.
Suter must have done 20 videos showing the thing screaming thru the gears - not one dyno graph I can find anywhere.
Rant over.

[philou]

Sorry, vidéo in french.

he uses a sheet of paper to visualize the scavenge

[husaberg]

cool idea, i give up, why is the frenchmans septums so sharp?

Is it as fast as a F104

[JanBros]

cool idea i give up, why is the frenchmans septums so sharp?

he says he didn't touch the original concept of the engine, he just wanted to optimise/even out the flow of the original concept. not a bad result.

[Hoebra]

If you like triple or twincylinder sound, here`s a clip of a twin project a friend of mine and me build last saeson, just for dyno competition where 88cc was the limit:

https://youtu.be/A6qjmcgAO1Q

The frame is a dutch replica of an privat eastgerman selfmade chassis of the late 70`s, the engine in base is from a Simson S51, in serial condition 50cc, 38/44 bore/stroke, aircooled, pistonported 3,7CHP.
We changed it to 180° twin, shortened te stroke to 37,8mm, added reedvalves (rotary disc was forbidden), turned the cylinders 180°. Still with iron sleeve inside, no nicasil or other ceramic coating. Carbs are 28mm Keihin clones.
So its 42,9ccm per cylinder, 85,7cc in common.

We createt a header with variable length to enlarge the powerband. Unlfortunatly the servo was to weak to manage the planed way of 90mm, so we had to reduce it to 30mm 2 days before Competition. While Tuning a bord of a inner bearing ring broke and damaged 1 piston/cylinder/crank. In legg of oversize piston we coated an new piston an honed the cylinder +0,1mm. it "worked", but the coated cylinder gave constantly 2 PS less over the whole powerband than before, so in best condition it should be round about +2PS (and about 1000rpm earlyer starting power band if the servo woud work the whole way).

The dyno curves have some dimples, because the dyno we used for tuning has much less inertia then ne one which was used in Competition, so time for acceleration and heating changed a lot. Hope you like the sound.

edit: pictures now visible on next page.

[andreas]

Sorry, vidéo in french.

he uses a sheet of paper to visualize the scavenge

Seems like such an unscientific method, and it's up 5-6 Nm over a wide range. Is just bogus?