ESE's works engine tuner

[husaberg]

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Attachment 250360

That explains what we found (and suspected). We tried header and mid section extensions, neither on their own or in combination moved the power spread lower in the rpm range. The longer the extension the less top end power and a pronounced double hump. But no significant low end improvement.

And I suspect slippery pipes will behave much the same but water may work because I think it would change all the sections of the pipe proportionaly.

Attachment 250364

The power came back as the pipe was progressively shortened to its proper tuned length.

You have to stay within certain length percentage limits for all elements of the exhaust system; you cannot make one part a lot longer or shorter in relation to the others without losing power somewhere.
It is best to concentrate on getting all dimensions correct for maximum power. In the high gears you don't ride low revs and in the low gears you'll have enough low-down power left to pull a wheelie or spin out the rear wheel (I'm not talking about buckets though, so you might want to reconsider your case).
If you have a decent setup for angle*areas, pipe, carburation and ignition, the necessary overrev potential will come naturally; no need to sacrifice maximum power in order to make it rev a little higher.

Thanks for the info Frits and TZ

What i was thinking was to have the proper tuned length with the resultant mid range and the ability to control the carb. But as well have te ability to shorten the tuned length a little for the very top end. As the icing on the cake as it were.
Would not shortening the header a little say 15mm give the potential for a little more over rev and possibly more power? in broad sense. i realise as usual i am making a broad generalisation here.

[Brian d marge]

In my cylinders it was mainly the complicated cooling ducting that forced me to find a way around casting limitations. For an air-cooled cylinder like you want, there is no need to resort to selective laser melting.
Rob Metkemeijer's MB40 prototype engines are cast using the lost-wax method. Below you see a mold with exhaust and transfer cores, a wax cylinder and the end product. A mold like this for an air-cooled cylinder is relatively easy to make.

While lost wax in this case is still one of the cheapest ways. I use rapid prototyping and almost day bt day the cost is comming down alowing one to really explore !

CFD the ports the literally cut paste into the printer! ( well there are more steps , but this is so exciting ( for me anyway !)

There has been some very creative work here fellas , world class , keep it up

Stephen

[TZ350]

Team ESE's new EngMod2T software.

I am still at the garbage in garbage out stage, finding out how the modules connect together. But my first impression of using EngMod2T is that it’s a very fragile application, prone to falling over at the slightest data entry mistake. Like a field might display a zero as a default entry and if you backspace to clear it before entering the value you want the program suffers a fatal error and falls over, this happens a lot, well has happened a lot to me anyway.

This sort of untidy logic error is not a problem with the MOTA software I have been using previously. MOTA seems a lot more refined from a user point of view but the EngMod2T approach has some user features I very much like. Like displaying the power potential of the various ports as you develop them. I think this is very handy, saves say, over cooking the exhaust port and then being limited for what can be done with the transfers. This feature alone puts its usefullness ahead of MOTA for me.

Because of the history of the author and the time over which EngMod2T has been developed I expect the underling simulation algorithms are pretty good and in spite of its user interface problems I am looking forward to modelling my engine and seeing what improvements can be made.

After learning how to use the modules and going about inputting the data I will model my motor as is and compare it to a recent dyno graph. If it’s a good match then we can be pretty confident that any changes in the model will reflect what I can expect to see on the dyno.

EngMod2T is already suggesting a 30+ rwhp air cooled engine is possible, now that alone won't make me a GP winner but it sure will be fun to ride.

[NordieBoy]

What do you 4-stroke guys use to model your engines?

[Buckets4Me]

What do you 4-stroke guys use to model your engines?

a spade. no wait thats changing tyres.

[wobbly]

There is EngMod4T that is used by many of the V8 Supercar teams, but probably the best program I have seen is what I use to develop
4T headers.
The pipes I did with it were then modelled and used with Fluent at Ch Ch Uni, to finally come up with the best pipes ever dynoed for FF1600.
It has a huge amount of additional info about the flow data etc needed to support the power that you are looking for.
Its called PipeMax Pro Version by MaxRace Software.

[dmcca]

Team ESE's new EngMod2T software.

I am still at the garbage in garbage out stage, finding out how the modules connect together. But my first impression of using EngMod2T is that it’s a very fragile application, prone to falling over at the slightest data entry mistake. Like a field might display a zero as a default entry and if you backspace to clear it before entering the value you want the program suffers a fatal error and falls over, this happens a lot, well has happened a lot to me anyway

interesting... I haven't experienced any stability issues at all... Seems quite stable to me.

[NordieBoy]

There is EngMod4T that is used by many of the V8 Supercar teams, but probably the best program I have seen is what I use to develop
4T headers.
The pipes I did with it were then modelled and used with Fluent at Ch Ch Uni, to finally come up with the best pipes ever dynoed for FF1600.
It has a huge amount of additional info about the flow data etc needed to support the power that you are looking for.
Its called PipeMax Pro Version by MaxRace Software.

I had a play a while ago trying to model my '79 XR250 engine on Lotus's free engine package but couldn't get it above 12hp
Knowing nothing about engines probably had something to do with it but it kept me off the streets.

[TZ350]

interesting... I haven't experienced any stability issues at all... Seems quite stable to me.

Thats good to hear as the crashes were driving me nuts while trying to find my way around a new application.

The sequence leading to a typical crash is.

In the Dat2T application.

Create a New Project.

On the Pipe Types screen.

In the Header Pipe Restriction field
Deleting the default “0” provokes a Visual Fortran Run Time Error.

In the Header Pipe Restriction field
Backspacing to remove the “0” provokes a Visual Fortran Run Time Error.

In the Header Pipe Restriction field
Entering any number without deleting the “0” first results in a Dat2T error message.

On the next page of the module backspacing to clear a field before entering a value invokes a Dat2T error.

I can’t try to enter a value here without either crashing the program or getting an error message that I have to work around. The data entry logic could do with some fine tuning.

As an easily confused newbe just starting out these data entry problems right at the beginning were a real frustration but now that I am getting more familiar with the program it’s not such an issue.

[teriks]

TZ350, I can repeat most of the problems you are describing.
Might be a good idea to send Neels a bug report.

[teriks]

In my cylinders it was mainly the complicated cooling ducting that forced me to find a way around casting limitations. For an air-cooled cylinder like you want, there is no need to resort to selective laser melting.
Rob Metkemeijer's MB40 prototype engines are cast using the lost-wax method. Below you see a mold with exhaust and transfer cores, a wax cylinder and the end product. A mold like this for an air-cooled cylinder is relatively easy to make.

I'm quite lost when it comes to casting, but I can see that once you have the mold done, changing cores for different configurations would be quite straight forward.
Thanks for the pictures, at least two of them are new to me.

Ill stick to the bottom end for now though, I want rear induction.

[wobbly]

TeeZee I have never had a runtime error using the program since it was first created by Neels???
What version of Windoze are you running?
When you have created the project, do you go thru and spec the pages in sequence.
ie the pipe program will need the Ex Port duct length created before the pipe, as its a prerequisite to calculate the complete tuned length.
Dont know but just maybe this is an issue???

Talking about TeeZees, the setup I did for Trevor Discombes TZ350 worked a treat today - he broke the Pre 82 lap record at Puke.
I got sunburnt to hell, dumb.

[TZ350]

The sequence leading to a typical crash is.

In the Dat2T application.

Create a New Project.

On the Pipe Types screen.

In the Header Pipe Restriction field
Deleting the default “0” provokes a Visual Fortran Run Time Error.

In the Header Pipe Restriction field
Backspacing to remove the “0” provokes a Visual Fortran Run Time Error.

In the Header Pipe Restriction field
Entering any number without deleting the “0” first results in a Dat2T error message.

On the next page of the module backspacing to clear a field before entering a value invokes a Dat2T error.

I can’t try to enter a value here without either crashing the program or getting an error message that I have to work around. The data entry logic could do with some fine tuning.

TZ350, I can repeat most of the problems you are describing.

TeeZee I have never had a runtime error using the program since it was first created by Neels??? What version of Windoze are you running?

Did you try the sequence described in my post?

Windows, XP pro ver 2002 service pack 3 and yes I work down the page in order when creating a new project.

I very much like the EngMod2T programe, lots of great features and after two days and a bit I can create a project, process it and display sensible graphs. Modelling the carb and inlet tract and accuratly measuring the theta angles of the transfers are a bit of a trick. I havn't been able to produce a graph that accuratly matches my existing motor yet, that might take a bit of time but I expect I will get there.

Wob, Great work on Trevors engine, its great to see someones bringing the old TZs into the modern age.

[pete 2]

Sorry guys a bit off topic,but this thread has some very knowageable people, could i just ask what they think about this?
at the entrance to the transfers the rsa aprilla has very wide dividers between each one while most tuners would narrow these down, i wonder what people like frits think about this or does it not matter.
great thread by the way

[wobbly]

The wide septums between the transfer ducts is there for two reasons.
One it reduces the duct entry area, and thus the ratio between the port and entry areas.
This drops the volume of the duct.A smaller volume sitting at the port has less inertia that the pressure ratio across the port has to accelerate into the cylinder.
Also consider that if you calculate the delivery ratio at full power and compare this to the cylinder swept volume of the cylinder, the air/fuel mixture sitting in the ducts
is more than enough to fill the cylinder - the is very little "flow" from the case, around the duct and into the cylinder in reality.

Secondly, the front and rear wall radial angles of the ducts are maintained all the way from the port, out to the duct entry.
As in 4T ports, trying to "bend" flow in two dimensions concurrently,lowers the bulk flow rate considerably.
Thus the ducts taper all the way from entry to exit, but only change direction in the one plane, around the short turn to give the correct axial entry angle.
The old bullshit you see of sharp divider edges is just that.
Only supersonic aircraft have sharp leading edges on the wings,and we certainly arent dealing with supersonic flow in transfer ducting.
Any flow loss due to the corners on the flat topped septums is way offset by the better directional control and reduced volume of the duct acting to fill the cylinder quicker.