[Technique] Réalisations de Maarten JANSSENS

as you says , it's not a matter of look   

the stock Mahle piston have an very short clearance 0.02 / 0.04 mm , CP piston run more clearance , up to 0.1 mm

be very carefull   


at the end there's nothing better than Mahle   

Je suis impressionné par tout ce post, ce loustic (et son entourage surement) est incroyable Wahouuuuuuuuu, certains choix m'échappent mais c'est super classe, magnifique.


Kcnarf.

fd-racing a écrit:

as you says , it's not a matter of look   

the stock Mahle piston have an very short clearance  0.02 / 0.04  mm , CP piston run  more clearance , up to 0.1 mm

be very carefull    


at the end there's nothing better than Mahle   

that is why this piston is oversized to 102.03 mm instead of 102 mm and the cylinder needs to be honed in order to get it in with the correct clearance!  

panerai a écrit:

Je suis impressionné par tout ce post, ce loustic (et son entourage surement) est incroyable Wahouuuuuuuuu, certains choix m'échappe mais c'est super classe, magnifique.


Kcnarf.

thank you!

Put here on the dyno today. shocked in a bad way!

75 Nm (ok!) but only 55 wheel horsepower  (weird because that is 8 hp lower than stock but doesn't feel like that at all...)

Good thing is that I apparently managed to use them pretty good on the red bull ring against the others that have +- 85-90 hp so now I have to find out how to get my horsepower back and if I have them back I can go to the race on Assen 17/18 may and should be able to get a better result than on the red bull ring.

wish me luck to find my lost horsepower!?!?

I have seen one of them, explaining me that he has made the right choice. Sorry Maarten...

[Vous devez être inscrit et connecté pour voir cette image]

C1 canasson ?


Kcnarf dans le ciel azuré.

MJ-Works a écrit:

Put here on the dyno today. shocked in a bad way!

75 Nm (ok!) but only 55 wheel horsepower  (weird because that is 8 hp lower than stock but doesn't feel like that at all...)

Good thing is that I apparently managed to use them pretty good on the red bull ring against the others that have +- 85-90 hp so now I have to find out how to get my horsepower back and if I have them back I can go to the race on Assen 17/18 may and should be able to get a better result than on the red bull ring.

wish me luck to find my lost horsepower!?!?

it's not a matter of luck !!!!

your feeling is from the torque , but on raceway you need rev's and so the power curve that climb all the way


first of all your exhaust pipe is way too long , for that engine 1.5 m ( overal lenght , from valve to air ) is the max , your final silencer is too big , stay at 50 mm( max ) inside , and you should reduce the end diameter , 36 / 38 mm is correct

control your cam timing , the rally cam has to be centered  perfectly  , because of the small overlap

comp ratio at 12.5/1 , and an bloody open airbox !!!

be care with the ignition advance , that engine love it til 7500 rpm , over not more than 32 °

get back to the dyno ( having the correct AF of course !!)  and enjoy  

that's what you should have at the rear Wheel  with your setup   

the torque should stay Under 72 Nm , this graph has been made with 1.45 m exhaust pipe lenght  ,47 mm inside silencer diameter , 38 mm end silencer diameter  , 50 mm throttle body ..

[Vous devez être inscrit et connecté pour voir cette image]

Very generous information sharing :)

Maarten, I think I expresed doubts about your airbox already... it certainly sounds like you have  breathing problem. If it makes only 55hp with 75Nm, the torque must drop like a stone after 6000rpm!

My mad scientist personality would love to know which is the biggest problem... so maybe just re-run with the airbox open first and see how much that improves things?

Do you have a dyno curve for the "too loud" version of the pipe?

thank you for this information!

Had a test-day at Croix today (with the bad engine setup) and did a 1.02 min laptime (pleased with that) but it lackes top power on the straight.

Also had a shifting problem (internaly!) and need to extend the seat so I can tuck in more behind the screen.

I'll post the 55 hp dyno run today or tomorrow.

I tested it without the final silencer and it didn't really make a lot of difference...

I didn't test it without the airbox but do you think that I could have lost HP because I closed the hole at the side and replaced it with the extra inlet at the front?

I'm going to make a new front exhaust-pipe! calculations say 68.5 cm to the first silencer. if you ad the 33 cm from the first silencer that comes down to 1 m at the back of the first silencer.

here you have the curves:

[Vous devez être inscrit et connecté pour voir cette image]

...they never got my name right   

MJ


Hope that I find some time fast so I can test it again!

Thanks again for the info/tips!

MJ-Works a écrit:

I didn't test it without the airbox but do you think that I could have lost HP because I closed the hole at the side and replaced it with the extra inlet at the front?

It's just a feeling, but a single takes air in big gulps, so having to pull air from a distance is going to hurt...
it would be ideal to have at least 10 litres sitting right above the intake trumpet... or just leaving it open with a filter like this

[Vous devez être inscrit et connecté pour voir cette image]

The carbon plate mounts the temp and pressure sensors, but is mainly to stop the disgusting airfilter oil from dropping on the engine!

GrahamB a écrit:

MJ-Works a écrit:

I didn't test it without the airbox but do you think that I could have lost HP because I closed the hole at the side and replaced it with the extra inlet at the front?

It's just a feeling, but a single takes air in big gulps, so having to pull air from a distance is going to hurt...
it would be ideal to have at least 10 litres sitting right above the intake trumpet... or just leaving it open with a filter like this

[Vous devez être inscrit et connecté pour voir cette image]

The carbon plate mounts the temp and pressure sensors, but is mainly to stop the disgusting airfilter oil from dropping on the engine!

Nicely made! Should I just forget about the ram-air effect and open the airbox up again then? I probably should right...?

P.S. I posted the graph on the previous page

MJ-Works a écrit:

Worked on the bike again today:

[Vous devez être inscrit et connecté pour voir cette image]

Maarten

I didn't noticed, but your airbox seems/is small for a big mono. Even if it has some liters, shape is not very good, not enough volume around the inlet trumpet..

Ram-air effect is only effective at high speed.
Front inlet entry is good for fresh air.

all your dyno's run  were made in perfect atmospheric situation , 15 ° , low humidity , high pressure , if it was here ( in south france ) it's 2/3 ps   less  !!

open that air box , and make an good exhaust pipe / silencer  , and you'll see what !!!!

The maximum density gain you can get at 220km/h from ram-air is about 1.6%... but if the air is 10° cooler, you get twice that, so drawing
in front of the radiator is good. But air has momentum, so to make it move towards the inlet when the valve opens implies a pressure drop.

If you imagine as a gross simplification that the airbox has in some sense an "effective" volume of 7 litres (the 10x volume rule of thumb)
that is not replenished during the inlet phase, then the end of phase pressure drop will be 10% (or about 7% density drop under adiabatic conditions),
which is much bigger than the ram air effect! That 10:1 ratio is really for multi-cylinder engines, so it's more like 40:1 for each cylinder...

fd-racing a écrit:

all your dyno's run  were made in perfect atmospheric situation , 15 ° , low humidity , high pressure , if it was here ( in south france ) it's 2/3 ps   less  !!

open that air box , and make an good exhaust pipe / silencer  , and you'll see what !!!!

I'm going to do just that! thanks!

Started work on the new exhaust today!

Did everything with a hand saw because I didn't have a machine to my disposal today.


this is the sharpest turn.
[Vous devez être inscrit et connecté pour voir cette image]

45 to 50 mm
[Vous devez être inscrit et connecté pour voir cette image]

the new pipe is 77 cm shorter and now it goes from 45 to 50 mm after 20 cm, before it went from 45 to 50 after 50 cm

New dimensions:

valve to first silencer = 60 cm

first silencer = 32.5 cm

exhaust after first silencer = 28 cm

second silencer = 27 cm

Total = 1.47 m

OLD total was 2.24 m

I know the régulations are thigh in terms of noise , but be carefull of the first silencer , it may help for the noise but  not for the end result , the gases  should be as warm as possible  , and  silencers  does right the opposite , if it's possible for you try with an simple tube instead , the lenght is very important but the exhaust temterature also and may be more , next dyno run will tell you what  

and be care of the very last diameter ( when the gases get to the air )  , it will set the all thing  , it's a matter of millimeters   

nice job anyway  

[Vous devez être inscrit et connecté pour voir cette image]

ready for testing :)

How many hours to make this?

I do admire the craftmanship, Maarten, but is it really necessary? Can't you use commercial 90° bends like most car exhaust manufacturers do? That would mean a lot less work and smoother internals.

Marc a écrit:

How many hours to make this?

I worked 4 hours on sawing and filing the tube with a hand saw (would go faster if I had the tools I normally have)

Welding takes a lot of time if the fitment is bad as it was here. Normally i'd say that if you know your lay-out in advance`
you'd be looking at 6 to 8 hours total for this part...

Frits Overmars a écrit:

I do admire the craftmanship, Maarten, but is it really necessary? Can't you use commercial 90° bends like most car exhaust manufacturers do? That would mean a lot less work and smoother internals.

But not in titanium....

btw, I also do it for the work that I love doing!

And you are right.

MJ-Works a écrit:

Frits Overmars a écrit:

I do admire the craftmanship, Maarten, but is it really necessary? Can't you use commercial 90° bends like most car exhaust manufacturers do? That would mean a lot less work and smoother internals.

But not in titanium.... btw, I also do it for the work that I love doing!

Maybe not in titanium, but certainly in Inconel and that is even better suited for exhausts.
But doing it for pleasure is as good a reason as any .

PS: if you ever consider building a bike around a two-stroke engine, let me know!

Frits Overmars a écrit:

MJ-Works a écrit:

Frits Overmars a écrit:

I do admire the craftmanship, Maarten, but is it really necessary? Can't you use commercial 90° bends like most car exhaust manufacturers do? That would mean a lot less work and smoother internals.

But not in titanium.... btw, I also do it for the work that I love doing!

Maybe not in titanium, but certainly in Inconel and that is even better suited for exhausts.
But doing it for pleasure is as good a reason as any .

PS: if you ever consider building a bike around a two-stroke engine, let me know!

I've built my first one round a two stroke:

[Vous devez être inscrit et connecté pour voir cette image]

And you might not remember but you actually helped me with it!....

Frits @ 20/05/11:

"Hallo Maarten,

Toen ik je mail ontving, dacht ik eerst: "O nee, niet wéér iemand die me tot diep in de nacht uit mijn bed houdt". Maar na het zien van de fotoreportage van je project was ik van mening veranderd. Je enthousiasme werkt aanstekelijk ;-) ........"

enzovoort!

Toujours du beau boulot et de belles pieces !