ESE's works engine tuner

[wobbly]

Thats crank, should translate into around 34 rear wheel.
Same deal as getting 30 Hp was considered as impossible, for how many years - if everything is done properly there is no reason at all why the numbers cant be achieved.
Used to be that " the dyno dont lie", well now the same thing can be said of the Simulator.

[bucketracer]

38.45? ......

Whatt!!! we are still sniffing around 28 rwhp ourselves. I guess we will sooner or later find the upper limit of a 24mm carb, we have been to 30 but are not sure what the upper limit of a 24mm pumper kart carb is and may have to start looking at the plenum again.

[F5 Dave]

then if you can just re-engineer those annoying corners out of your track

[bucketracer]

then if you can just re-engineer those annoying corners out of your track

Yep ..... ..... working on it.

[husaberg]

Whatt!!! we are still sniffing around 28 rwhp ourselves. I guess we will sooner or later find the upper limit of a 24mm carb, we have been to 30 but are not sure what the upper limit of a 24mm pumper kart carb is and may have to start looking at the plenum again.

Id like to the the carb where you have it in the Photo replaced with an air filter and then the carb placed in the std position with probably with a spacer plate to fit it in under the cover. That's my 3 cents.

Below is the crude rendering of what I was saying. Sorry about the carb being back to front don't try that at home.

[bucketracer]

Id like .... the carb placed in the std position with probably with a spacer plate to fit it in under the cover. That's my 3 cents.

Av's is setup that way, works well but she is happy with limited hp.

Attachment 248309

That is a 34mm inlet tract inside the plenum, the simulation package says we need 34-36 or so for big hp.

The idea of the plenum is that the engine gets to suck fresh mixture from the plenum through a 34mm (or bigger) inlet tract while the plenum is refilled by the 24mm carb. This works at WOT because the 24 gets to flow all the time and the engine, because of inlet timing only gets to suck for half the time allowing the carb double extra time to keep the plenum full.

When TeeZee first thought of this idea, like most people he believed that it was the 24mm carb class rule that was the limiting factor keeping F4 125's running about 20rwhp.

As he pushed the power up past 20 on the way to 30, with each significant step, the plenum was tried and it made about the same as the conventional carb. We concluded from this that the conventionally mounted 24mm carb was not the real problem. It became apparent that the plenum was a clever solution to a problem that we didn't have yet.

The plenum with its extra complication may eventually have a place when we find the real limit of a conventional 24mm carb.

[husaberg]

Av's is setup that way, works well but she is happy with limited hp.

Attachment 248309

That is a 34mm inlet tract inside the plenum, the simulation package says we need 34-36 or so for big hp.

The plenum with its extra complication may eventually have a place when we find the real limit of a conventional 24mm carb.

30 hp is big HP, Isn't it.
I understand the Idea behind it (the Plenum) But have you tried the set up AV has along with tz's engine spec.
As I guess the rest of AV's engine could be the limiting factor. Just a thought.


I also believe there could by a case to be made for not having all the air flowing through the carb.
To do this by way of a supplementary air intake and the mixture flowed through the 24mm carb richened say by a electric controlled power jet to compensate or fuel injector.
kind of like how some modded turbo cars used to bypass the restrictive airflow meter if you catch my drift. Easy for me to say. No doubt harder to do I suppose.

Here is the old CanAm way of tucking in a carb on a old Disk valve Rotax engine. A bit long for high revs probably.

PS the Rotax was 6 speed in 125 form and is not legal I checked.The road legal version was still listed as a Enduro model.

Or just chuck on a big ol Harley flat filter. I hear the chicks dig harleys. Most of them are nearly 30
IQ/Stone for the chicks HP for the Harley's

[bucketracer]

Attachment 248325

Here is the old CanAm way of tucking in a carb on a old Disk valve Rotax engine. A bit long for high revs probably.

Attachment 248326

In trying to get the carb tucked in, it has realy upset the curve.

Attachment 248324

Red line is the sticking out the side carb arrangement, Blue line is the tucked out of the way arrangement.

The carb made good power when stuck on the side conventionally but lost power when tucked out of the way, I expect the result would have been the same for the CanAm

[husaberg]

The carb made good power when stuck on the side conventionally but lost power when tucked out of the way, I expect the result would have been the same for the CanAm

Yes and No

The Cam am was the class leader for its time for both spread of power and for outright HP. This was achieved I believe in spite of its layout, rather than because of it. It certainly wasn't a revver around 8000rpm Whoops (9000 rpm actually EX spread though it was a bit of a revver) I think? (will check and Edit later) Later Well revs better than I thought. Don't get to excited by the HP as it is the 250 but it was the best they had ever ran a 250mx bike in 73 and had the best spread of power too. (Only a 32mm carb as well which would be the EQ of a 20mm carb on a 125)

But we digress
I put a pic in to show the lay out only hence the tag with it. What about the other bit. A workable solution or what.(assuming I don't have to do the work that is)

30 hp is big HP, Isn't it.
I understand the Idea behind it (the Plenum) But have you tried the set up AV has along with tz's engine spec.
As I guess the rest of AV's engine could be the limiting factor. Just a thought.


I also believe there could by a case to be made for not having all the air flowing through the carb.
To do this by way of a supplementary air intake and the mixture flowed through the 24mm carb richened say by a electric controlled power jet to compensate or fuel injector.
kind of like how some modded turbo cars used to bypass the restrictive airflow meter if you catch my drift. Easy for me to say. No doubt harder to do I suppose.

[Frits Overmars]

..........

[Frits Overmars]

...The idea of the plenum is that the engine gets to suck fresh mixture from the plenum through a 34mm (or bigger) inlet tract while the plenum is refilled by the 24mm carb. This works at WOT because the 24 gets to flow all the time and the engine, because of inlet timing only gets to suck for half the time allowing the carb double extra time to keep the plenum full.

Way to go, Bucketracer. But there's one thing to consider: unless the tract from plenum to engine starts at the deepest point of the plenum, a puddle of fuel will form in the plenum which will make setting the carburation a nightmare. I've been there....

...I guess we will sooner or later find the upper limit of a 24mm carb, we have been to 30 but are not sure what the upper limit of a 24mm pumper kart carb is and may have to start looking at the plenum again.

If you manage to get a really continuous flow through that 24 mm hole, the limit should be about 60 HP, give or take. No, I'm dead serious.
(I'm just talking about the carb though; not about its combination with a bucket engine).

[Buckets4Me]

Way to go, Bucketracer. But there's one thing to consider: unless the tract from plenum to engine starts at the deepest point of the plenum, a puddle of fuel will form in the plenum which will make setting the carburation a nightmare. I've been there....

snap. TZ did get it to run around the track but it did have problems with rear wheel grip (wet track and running the oval on slicks)

[wobbly]

WooHoo, we have the esteemed Mr Overmars poking around in here, better be very careful in what I say, he has hawkeyes for the slightest mound of bullshit.

As I have said before the 24mm carb is a long way from being the final restriction in the bucket engine - we have regularly seen 46 Hp from a Maxter 125 kart engine with a 30mm carb on the front, its the ports and pipe that need serious attention.
The poxy old RS125 pipe hanging off that 28Hp engine is miles away from being optimum.

[Frits Overmars]

WooHoo, we have the esteemed Mr Overmars poking around in here, better be very careful in what I say, he has hawkeyes for the slightest mound of bullshit.

It's a bit late to start being careful now, Wob . I am a fairly regular reader here; I just refrained from writing, for lack of time; you know how it is with forums.
But Bucketracers remark about continuous flow via a plenum was too good not to react.

Now what could be the next step? Moving the plenum volume to the other side of the inlet disk?
An enlarged crankcase volume would lower the resonance frequency of the inlet system and you would need to correct this, for instance by drastically lengthening the inlet timing.
See where this is going? You tell them, Wob; while you guys are having breakfast, it's time for me to get some sleep.

[richban]

WooHoo, we have the esteemed Mr Overmars poking around in here, better be very careful in what I say, he has hawkeyes for the slightest mound of bullshit.

Not Fare. I'm emailing Prof Blair. We may now need to rename bucket racing to F1.