ESE's works engine tuner

[Frits Overmars]

I had a conversation with pipe-minded friend. We discussed how did you decide between two different power curves before a race, given specific gear ratios, weather conditions, and track characteristics. We were thinking how you did this when working at Aprilia team.
When designing something for a motor—perhaps in a simulator—you often have to decide what to build. Or when testing on a dyno and comparing 30 different power curves that look quite similar to the eye (one with peak power, another with better range), how did you choose between them?

I am familiar with your power range-concept. Instead of that, my friend suggested pipe design based on gear ratios and least missed area under ideal acceleration curve (what would be if motor is always at peak power). However, this approach doesn’t account for human factors, such as the need for mid-range and over-rev. While it’s possible to include these considerations, the result becomes a bit of a hocus-pocus calculation.

When simulating, I once started writing code to simulate a driver’s path around a track. I made drag racing version of it. I stopped working on track version because factors like varying pipe temperatures after corners and use of over-rev would have made the motor simulation inaccurate. This does seem to be only option, if it would be possible to make both track and motor simulation accurate enough.

Another possible shortcut is to optimize the engine using log data. For example, if the engine spends 4% of its time at 12,000–12,200 rpm and 5% at 12,600–12,800 rpm, these rpm ranges can be weighted accordingly to guide improvements. For me, this is most promising one, according to what is possible in normal tuner's resources. But, then there is problem that even when when we have two equal designs in this concept's, and power in different places in curve, pipes are not equally fast on track.

Hello Antti, designing a pipe based on gear ratios is a guaranteed recipe for a bad relationship with the person who has to ride it. In racing conditions you will need quite some overlap between the gears and a well-developed engine can provide this; it should not need fiddling on the track. This hard-learned experience is one of the reasons I developed the Range concept.
For track conditions you adapt the gear box ratios and the final transmission ratio, not the power curve. Throttle response is important but this is not something you can develop on a common dyno. Overrev is also important but this comes with the engine; it is not something that you should work on at the track, apart from getting the carburation right.

[aljaxon]

if my rev range is 9500 to 11500 do i want to be aiming for a pipe designed to produce peak power at 11500? or just below that to allow the tiny bit of overrev to chip in? or bang in the middle of my rev range so i'm nearer to where the clutch bite point is?

[Frits Overmars]

if my rev range is 9500 to 11500 do i want to be aiming for a pipe designed to produce peak power at 11500? or just below that to allow the tiny bit of overrev to chip in? or bang in the middle of my rev range so i'm nearer to where the clutch bite point is?

Design the pipe for the rpm that the blowdown angle.area and the transfer angle.area allow. That goes for any engine, direct-drive, shifted or CVT.
And make the clutch bite at the rpm of max.torque.

[wobbly]

Wos , the reverse cone scenario uses the idea that shallow rear cones help front side and overev capabiliity.
When using the reverse angle idea on the same tuned length , it looses a small amount of front side ,but the peak and overev is enhanced.
This is , I believe from observing the rear cone wave forms , due to a very early strong reflection that as usual would pump up the peak, but then the shallower
cone allows the engine to rev on alot better than it would were there a single steepish cone.
You can get the front side back with a longer TL , thus keeping the peak increase , but reducing the power in the overev.
No free lunch as usual.

[Betaversio]

Hello Antti, designing a pipe based on gear ratios is a guaranteed recipe for a bad relationship with the person who has to ride it. In racing conditions you will need quite some overlap between the gears and a well-developed engine can provide this; it should not need fiddling on the track. This hard-learned experience is one of the reasons I developed the Range concept.
For track conditions you adapt the gear box ratios and the final transmission ratio, not the power curve. Throttle response is important but this is not something you can develop on a common dyno. Overrev is also important but this comes with the engine; it is not something that you should work on at the track, apart from getting the carburation right.

Thank you for reply,

If I understood it right, at some point you did try to design motor based on gear ratios, but then it did not work out well. After that you went to this simple power range-model. Then you just somehow find this 1.4 range to be good enough, without any complicated math's. And there was no any hard-calculation-model determining what is good power curve and what is not.

Antti

[Wos]

Hello Antti, designing a pipe based on gear ratios is a guaranteed recipe for a bad relationship with the person who has to ride it. In racing conditions you will need quite some overlap between the gears and a well-developed engine can provide this; it should not need fiddling on the track. This hard-learned experience is one of the reasons I developed the Range concept.
For track conditions you adapt the gear box ratios and the final transmission ratio, not the power curve. Throttle response is important but this is not something you can develop on a common dyno. Overrev is also important but this comes with the engine; it is not something that you should work on at the track, apart from getting the carburation right.

No rider is a machine...no human is...so give us the chance/strengt in live/ race to get out of our mistakes
Thats best you could do ...

[aljaxon]

Design the pipe for the rpm that the blowdown angle.area and the transfer angle.area allow. That goes for any engine, direct-drive, shifted or CVT.
And make the clutch bite at the rpm of max.torque.

cheers frits, i used janbros excel and all seemed good

. ......... ,,,,,, ...... . STA ....... . Target ...... , % ....... ' Out of breath RPM


BLOWDOWN ....... 5.79 ....... 4.11 ....... 40.8 ....... 11265

TRANSFER ....... 50.13 ........ 40.04 ....... 25.2 ....... 10017

that took some time to format correctly hence the punctuation

...

thats if i aim for a realistic 8 bmep which could give 11.7bhp. its saying my torque will be maxed at 8000.

and im guessing from those numbers my max power revs is in between the 11265 and 10017.

if i wanted to make a FOS pipe but with a narrower powerband to suit the the cvt can you recommend which angles to change? or lengths to adjust?

[Frits Overmars]

if i wanted to make a FOS pipe but with a narrower powerband to suit the the cvt can you recommend which angles to change? or lengths to adjust?

Yes I can: stick to the FOS pipe dimensions. Trying to make the power band narrower will reduce power instead of enhancing it.
For example, you could make the rear cone steeper which would yield a shorter, fiercer return pulse. But such a fierce pulse would develop into a shock wave before it reaches the exhaust port, and shock waves are not very good at shoving mixture back into the cylinder.
I know you are sceptical: try it for yourself and let us know what you found .

[aljaxon]

so you are saying even a 1 degree change in angle to the fos pipe wont make a sharper powerband?
its like you are saying your fos pipe is a one size fits all which surely cant be right, if it was the perfect pipe then everyone would be using it. btw ive made 2 fos pipes and ive got one fitted to the bike at the minute.


its looking more and more like im going to have to fork out for engmod 2t
ive been chatting with a pal who has it and he's been making adjustments to pipes and seeing the changes

[Frits Overmars]

so you are saying even a 1 degree change in angle to the fos pipe wont make a sharper powerband?

That is not wat I was saying. You can make the power band a whole lot narrower if you wish, but it won't improve power; it will cost power, as I already told you. You don't have to take my word for it, but then you'd better stop asking and start building.
The other day you wrote: "i havent got enough time left on this planet....im an old git".
Well, I'm an old git too; do you think I fancy wasting my time over this?

[Condyn]

I feel comfortable in being Frits muscle on this one. He has never once stated it is the holy grail, final tuned pipe you will ever need. His concept literally says it is for getting beginner tuners on their way. I have made a few FOS pipes and they taught me a lot. To believe any of us can give you a perfect scenario pipe design is foolish. There are too many variables. Engmod still needs good inputs, and it is a design tool, not the sorcerers stone. You will be disappointed with engmod if you do not real world test along side of it, until you know you are feeding the correct information.

While on the topic, my personal belief with the simulation pipe challenge is that more than the top pipe design should to be dyno tested in conjunction with the sim results. Showing everyone how accurate reality replicates the sim on multiple designs would be beneficial to all parties. I would be happy to laser cut and build some of the pipes, but I would not be happy to ship them to NZ lol.

[koba]

I have proposed on the FB group EngMod 2T Users , the we conduct a shootout to design the best pipe for a specific application.
This will help users understand how to most effectively use the sim , as well as see others attempts at pipe construction.
It was decided to do something " different " , not the usual 125/250 cc things that have large tech history to draw from.

I have bought a KR150RR bare engine that is used exclusively in Thailand scooter drag racing.
Im having trouble finding out what the rules actually are , but know they run VP Q16 fuel.
Once I have the rules nailed down , I will construct a sim , and people can give it there best shot at designing a pipe to suit.

When we have a " winner " I will build the engine to the complete sim and dyno it.
Anyone here who has info on these engines or wants to get in on the shootout , join the FB group ( Im an Admin ) or PM me on here.

This is a great Idea!

[wobbly]

The initial proposal is to dyno test the " best " pipe with all the other variables of the sim replicated in hard parts. This will show the veracity of the simulation , but I believe even more will be learned from what is not right.
It all depends upon " the money " , of course - its going to cost plenty to even collect all the parts needed , then a huge amount of work to actually build the thing.
Several people have offered to build pipes , but even in this scenario , there are hours of CAD work to generate the .dxf files for laser cutting the segments.
In the mean time I am testing Neels code update before distribution and the first technical description of a page of the proposed sim has been posted on the FB EngMod site.
Go have a look.

[Condyn]

Yes yes, easier said than done. It will be interesting to see how it all pans out. I will take a look on farcebook.

[JanBros]

cheers frits, i used janbros excel and all seemed good

. ......... ,,,,,, ...... . STA ....... . Target ...... , % ....... ' Out of breath RPM


BLOWDOWN ....... 5.79 ....... 4.11 ....... 40.8 ....... 11265

TRANSFER ....... 50.13 ........ 40.04 ....... 25.2 ....... 10017

that took some time to format correctly hence the punctuation

...

thats if i aim for a realistic 8 bmep which could give 11.7bhp. its saying my torque will be maxed at 8000.

and im guessing from those numbers my max power revs is in between the 11265 and 10017.

who or what is "it" ?

"out of breath rpm" = rpm after which your max torque will not rise anymore. so the predicted rpm of max torque.
your STA's say 10000 for the transfer's and 11200 for the Bd , not 8000. so your engine has too much A.area if you are shooting for 8BMEP (to protect the engine) ? or raise the BMEP ? or other things are not correct/entered right.