ESE's works engine tuner

[F5 Dave]

He did.

[TZ350]

Page 410 collection of interesting stuff from the last 10 pages, there are other interesting collections on each decade page, helps making finding the good tec stuff easier.

I also found this with the dimensions of a lot of inlet manifolds etc
http://www.allensperformance.co.uk/p...manifolds.html

Inlet manifold data Gold.

EngMod2T

Grumph sent me some ideas about fitting a resonator after the carb, with his permision I have posted them.

"If I was you I'd try a proper heimoltz resonator....About 2 X cylinder volume and with a 24mm inlet.

with the big open end you're not getting the best from it.

the original use for them was F3 car motors - 1300cc if I have it right - but they were restricted to a 30mm ID inlet - the FIA wanted a 30mm carb obviously. What the builders did was short inlets into a log manifold - the resonator - with a 30mm inlet trumpet stuck on one end. With port injection they got better power than individual runner injection.

NASCAR V8's have used this setup with the restrictor carbs - one resonator per bank. Grumph"

You have to be careful when using the sim as a predictor of actual power.
You see even using the scavenging model of a RS125 isnt strictly accurate, as the GP has a huge A port and small B,C.
The axial up angles may be the same but I doubt the scavenging and or trapping efficiency are equal.
If you reduce the combustion efficiency a few % then you will get alot closer to reality.

The other issue is that to do what you are trying to do properly, you seriously need to plot egt against rpm on the dyno..
If you get such a huge difference in power by changing the main, then it was well wrong in the first place.
And yes, an electronic powerjet will add at leat 800 rpm of free power to that graph, if switched correctly with the right jet ratios - blowing Speedpro of the planet, unless of course he does what I told him.

I have become very interested in how to use a rolling road dyno properly and the inherant errors in inertia dynos used for measuring RWHP.

Food for thought on dyno errors and dyno technique.

http://www.sdsefi.com/techdyno.htm
http://www.stahlheaders.com/Lit_Dyno info.htm
http://www.modified.com/editors/tech...ble/index.html
http://www.pumaracing.co.uk/POWER3.htm
http://www.pumaracing.co.uk/coastdwn.htm

Re the dyno vs crank conversion.Many people have done this check on many setups, and the general consensus is that when using an inertia dyno on the sprocket
the difference is around 5 - 8% , and when using the rear wheel the difference is 12 to 16%.
These are the losses in the transmission/chain/tyre etc and seem to very similar % wise for a 125GP or a 1000 Superbike.
The BSL made 55 Hp per cylinder on the single with a crank driven dyno, at the same stage the triple in the bike read 142 at the rear wheel on a Dynojet - you do the math.

Really who gives a shit about the actual raw numbers generated, as long as the power curve shape and peak rpm point coincide between reality and the sim,then both the dyno and the sim can highlight if a change is better or worse.
The sims nowdays are a very good prediction tool, and way quicker/cheaper than the time spent cutting/shutting and dynoing for hours - unless of course you are being paid to do it..

Chassis dynos are great tuning aids but they only give a approximation of power output as some of the important variables are not accurately controlled. Tire pressure and wheel alignment can have very significant effects on losses at the rollers. Tire pressures should be set the same between each test.

Nothing is stopping you...

another factor not taken into account or different inertial weight of different tyres and wheels, after all its an inertia dyno and changing the overall inertial weight that has to be spun up changes the HP reading.

Which makes an inertial dyno the perfect instrument for the development of competition engines. Because that is reality: a bike with lighter wheels will accelerate a bit faster.
Use a gearing on the dyno that gives you an acceleration time, equal to the time between gear shifts at the track. Then you will measure the engine the way it has to perform in real life. And the biggest advantage will be that the exhaust pipe will then heat up and cool down on the dyno just like it does on the track.

a lot has been said about measuring the losses between dyno and crankshaft. Forget about that; it's bullshit.

Losses caused by friction between gears are load-dependent. You cannot establish those by way of a coast-down measurement, because once the engine power is gone, the load is gone (or at least decimated).

The old chestnut about heavy wheels and even worse the shitbox Harleys that have heavy flywheels "causing them "to make less power than a wee kart engine
on the rollers is a huge crock of shit.
The reality of the situation seems to escape some very clever people, alot of whom post on the net and sell dyno's as well - funny that.
At the end of the day the reason we put the kart - engine, bike, jetski, on the dyno is to achieve a "better " state of tune.
Once that is done, then taking the FZR and fitting light wheels will make it produce more "power " and it will be faster on the track because of this.
Changing from cast iron wheels, to carbon composite wheels is a "tuning" aid , just as much as a Wobbly pipe might be.
The rolling road will show this - the engine dyno wont.
Again as I keep saying - who gives a shit - if it makes more power on any dyno, no matter what the number is, it will be faster.

What I would do: assume a 5 % power loss for every set of gears, for the chain, and for the deformation of the tire on the drum.So what you would measure, is 0.95 (primary drive) * 0.95 (gearbox) * 0.95 (chain) * 0.95 (tire) * crankshaft HP = 0.8145 * crankshaft HP. Or, the other way around: crankshaft HP = drum HP / 0.8145.
Granted, this is not exact, but it's an honest approximation. In any case it is way better than calculating with coast-down losses that you know are not representative of the real losses.
hopefully you noted I spoke of drum HP. That is not the same as rear wheel HP. About 5% of rear wheel HP is lost between tire and drum and what really accelerates the drum, is drum HP. And something which you may not know: Dynojet-readings are already compensated for this loss, and then some. We once did a comparative test at Ten Kate's (umpteen times Supersport world champion, just around the corner from my house). It turned out that the Dynojet is 11% optimistic.

Thanks Frits I had been reading about them the other day on Burgerman he is a bit scathing of them as well.
http://www.dynamometer-info.co.uk/po...ywheel-BHP.htm
Plus another i was on today said just what you said. I note the Bosche Inertia Dynos has two drums and the main drum is twice the weight of the dyno jet.

… here is some mathematical Prozac for you: drum HP = Dynojet HP / 1.11 and crankshaft HP = drum HP / 0.8145. So crankshaft HP = 1.106 * Dynojet HP. And don't bother about those decimals; after all it is an approximation. So it would be safe to say that crankshaft HP = 1.1 * Dynojet HP.

Sleeving cylinders for F4 100 water cooled class.

The site is interesting in which the repairs are carried out i was wondering why i couldn't strip then tig up the whole cylinder and then machine it and re-coat it rather than a sleeve anyway.

Re coating i am not suggesting to send stuff oversea when we have a place in NZ.
Plus yes it would be easier to sleeve a cylinder.

http://www.poetonaptec.co.uk/default.htm
http://www.gkn.com/Pages/default.aspx

Pressing in a sleeve is a no-no to begin with. Shrinking it in is better, but not good enough. Because no matter how tight you make that interference fit, during use oil will creep between cylinder and liner, starting at the exhaust port.
If you remove an old liner, you can see the charred remains of that oil all around the exhaust zone. So do not worry about the limited thermal conductivity of an iron liner; charred oil conducts heat infinitely worse.
Been there, done that. If there's anything that makes me experienced in the two-stroke field, it's the fact that I have personally committed every imaginable error. Racing an air-cooled 500 cc two-stroke single with a liner made me the fastest man in Holland - in drawing a clutch. Not even Lucky Luke could draw quicker .

The ignition timing does not have to be changed when you use an electronic power jet. But both the ignition timing and the powerjet timing are means of influencing the exhaust gas temperature. A late ignition and/or a lean mixture both cause a higher EGT, so you can match the exhaust resonance frequency to a rising engine rpm.
And if you have that power jet available, the ignition does not have to do it all by itself anymore, so you can search for a timing that gives a better overall result.

To give you an idea of the main jet / power jet ratio: typical RSA-values are main 220, power 120. That means the flow area of the power jet is about (120/220)^2 = 0.3 times the flow area of the main jet. And don't shut the power jet until well past the rpm of maximum power or you will risk a maximum seizure.

The Fiat Uno unit was not a solenoid; it was a stepper motor; a rotating device. And stepper motors only function when pulsed.

It's like this I imagine..
Lots can be found under the name 'idle control valve' (not necessarily fiat).

… I found the YZ/KX250 Keihin 38 carb, which is about 1cm shorter than conventional PWK, has a TPS sensor and an electronic PJ! Actually, this carb is more similar to their PWM design, I don't know why they named it PWK. Perhaps "k" brand is more established in the community... It's powerjet solenoid says "Shindengen".

all these talks of solenoids and power jets perhaps a simple EFI system would be better?

http://www.mbe-motorsports.com/catal...roducts_id/337

http://www.ecotrons.com/2_Stroke_Sma...e_EFI_kit.html

There is a current discussion on ekartingnews about EFI 2T http://ekartingnews.com/viewtopic.ph...r=asc&start=75
They have a pic of a CR500. Some guys are creating their own using known fuel distribution curve and neediel/tube graphs as a guide for fuel flow.

thats a great thread, loving some of the info the HGT guys give out.

here another one with the ecotrons:
http://www.scootforum.com/viewtopic....a6cba9c463c4a0
and another with MS:
http://www.125ccsportsbikes.com/foru...pic=63480&st=0

This is a big post on control circuits and worth a look.

Its a big one sorry all this talk of piggy back circuits.
These curcuits can also be used in numerous ways partically like a couple of them.
use a microcontroller to generate the required PWM signals, the 555 PWM circuit explained here will give the novice robot builder an easy to construct circuit, and good understanding of pulse width modulation. It is also useful in a variety of other applications where the PWM setting need only be changed occasionally.

The 555 timer in the PWM circuit is configured as an astable oscillator. This means that once power is applied, the 555 will oscillate without any external trigger. Before the technical explanation of the circuit, let's look at the 555 timer IC itself. http://www.dprg.org/tutorials/2005-11a/index.html

Right i had a wee search on the net.
The genuine kit is a little expensive, I couldn't find the Keihin but here is the Mikuni, as you know i had already posted this.$303nz.
Maybe the Keihin kit is less expensive.

I haven't had the chance to look through Sudco yet.
Had a wee look at Sudco it seems the soilniod is not listed as a separate part bugger.

Here is one from the UK Mikuni person no prices.
http://www.allensperformance.co.uk/products-power jet kits.html

I also found this with the dimensions of a lot of inlet manifolds etc
http://www.allensperformance.co.uk/p...manifolds.html

TZ's keihin copy carbs i believe have a Powerjet the obvious way to me for a budget conscious bucket racer would be to modify this for electric use with a car solenoid.

PWM control of the powerjet is a very sexy use of technology,slowly ramping off the fuel flow against rpm, but in reality using a simple rpm controlled switched solenoid work perfectly fine.
Yamaha and Honda have used the switched powerjet since forever, its reliable and does the job.
Only issue you need to address is the jet size and switch point ( along with TPS value ).
Running Avgas as we are still allowed to do, means that the tuning is based around getting high egt numbers to create good power, with lots of com and advance - unleaded is the opposite..
Thus experience has shown that as leaded fuel works best with a lean condition at peak power, we only need to switch a small jet just past peak - to increase the pipe temp and
thus give better overev.
In the Keihin numbering this is in mm dia and switching off a .35 is perfect.
When running unleaded, as the GP bikes have for years, the fuel likes to be rich at peak to create the best power, thus we need to switch off alot of fuel flow to increase the pipe heat quickly enough.
In this case a .65 is needed to do the job.
On the dyno or on the track it is easy to tell if the switch point is a little too low, as it feels exactly like the bike has changed into another gear past 6th.
It jumps forward when the solenoid kicks in - making the fuel curve lean, too early.Do this enough - and bang.
Its critical to 100rpm, and is working perfectly when you dont feel it happen - the power just keeps going.
To do it on the dyno you have to run the bike in 6th to simulate the acceleration rate as seen in that gear on the track, and is easy to do running back to back run ups.
Changing the rpm number 100 at a time, lower in the Ignitech, reprogram on the fly and run again.
If the rpm is too high - nothing happens, as there isnt time for the heat to affect the pipe wave speed.

thats a great thread, loving some of the info the HGT guys give out.

here another one with the ecotrons:
http://www.scootforum.com/viewtopic....a6cba9c463c4a0
and another with MS:
http://www.125ccsportsbikes.com/foru...pic=63480&st=0

It just occurred to me TeeZee that you guys need to feed a free copy of Gadwin printscreen into the dyno computer.
You can save to a file or a printer very easy.

That's the general idea, TerraRoot; the 24/7-valve and the exhaust powervalve can be synchronized.



But you do not need a fancy reed cage. As long as the engine is running below the powerband, it is not making power anyway, so the reed does not have to be sophisticated; a simple single reed petal will suffice. Remember, it is there only to start the engine. And instead of a finger to hold the reed open, you can mount the reed on a shaft; that makes swinging it out of the way much easier.
Here is that original picture once more for those of you who haven't seen it yet: over-engineered like I said. One shaft with one petal (and of course no gears) will suffice.

[TZ350]

There is something going on with my carb that I don't understand.

I can see the fuel drawn up the line to the PJ as the rev's build up, and this is what I would expect to see. Then when the rev's are getting to around 10-12K the fuel drops back, something I didn't expect to see. I have seen this on other carbs and it can't be a good thing.

This means that at higher rpm the pressure in the float bowl is less than inside the carb's bell mouth.

How can this happen?

[dinamik2t]

Perhaps pressure/drain through main jet is so high that no fuel makes it up the fuel line of the PJ. A loose fitting-air leak that lowers PJ's feed circuit pressure would probalby enhance this phenomenom - I think.

[teriks]

There is something going on with my carb that I don't understand.

I can see the fuel drawn up the line to the PJ as the rev's build up, and this is what I would expect to see. Then when the rev's are getting to around 10-12K the fuel drops back, something I didn't expect to see. I have seen this on other carbs and it can't be a good thing.

This means that at higher rpm the pressure in the float bowl is less than inside the carb's bell mouth.

How can this happen?

Well, that just tells me that the pressure in the float bowl is less that the pressure at the _PJ-entry_ into the carb.
Now, the pressure at the main jet entry must be less than that of the float bowl, otherwise the engine would die, right?

-Perhaps this is an effect of the PJ-entrys position in the shortened bellmouth? Could you show this (bellmout and pj-entry) somehow?

[F5 Dave]

Anyway; All hail the new HP arms race leader. Good work TZ

[dinamik2t]

Actually, low pressure is what draws air -and so fuel- from a higher pressure area. Both main and powerjet draw fuel from the same bowl. And that fuel is drown by the same sub-atmospheric pressure of the crankcases. Powerjet's fuel though has to rise up the line, in comparisson to the main jet which is just above the fuel bowl.
So, in theory, at PJ needle opening in the venturi, a larder sub pressure would be needed to accomodate for the extra travel of the fuel.

Since back-flow happens, I guess that either too large fuel amount is drawn and it chooses the shorter way or PJ circuit is bleeding somewhere causing pressure to rise near-er to the higher atmospheric, thus fuel is drawn back.

I 'm thinking of a logical solution and I will edit -unless somebody already knows how to fix it.

[F5 Dave]

I have no idea what you are seeing physically, but could it be there is inertia forcing too much fuel up & causing reflections of some of the gas back down the sides to make room as more is pumped up the middle of the tube, you see the outer flow returning perhaps?

[bucketracer]

TeeZee has asked me to help make a video of it, will see if we can do this tonight.

[jasonu]

I've had my bike on the dyno.

I got quite a surprise.

http://www.youtube.com/watch?v=54m2CD47BUs

What's wrong with it?

[koba]

What's wrong with it?

No obvious faults as such, it's in a real low state of tune.

The broad nature of the power delivery... Oh no, It doesn't have that either! It's only over a 1000rpm range and drops of greatly either side with a small spike much later on.

I suspect the porting is insufficient to allow it to get on the pipe. Furthermore, the Crank-case compression has been lowered significantly by the way I mounted the carb. There was a reason for me doing it this way but it probably won't manifest until I'm pushing the engine a lot more.

I have got plans and I suspect to see a good boost when I finally get the barrel raised and the exhaust port hogged out bigger than a prison bitches bumhole.

[F5 Dave]

don't forget the compression raised but std ign & no adjustment made.

But the plus side is it did make its stella performance at about 8000 rpm.

[koba]

don't forget the compression raised but std ign & no adjustment made.

But the plus side is it did make its stella performance at about 8000 rpm.

That too! Haha.

On the positive side I now know I'm not full of shit and making excuses when I say my bike is gutless.

[TZ350]

There is something going on with my carb that I don't understand.

I can see the fuel drawn up the line to the PJ as the rev's build up, and this is what I would expect to see. Then when the rev's are getting to around 10-12K the fuel drops back, something I didn't expect to see. I have seen this on other carbs and it can't be a good thing.

This means that at higher rpm the pressure in the float bowl is less than inside the carb's bell mouth.

How can this happen?

TeeZee has asked me to help make a video of it, will see if we can do this tonight.

Someone thought if I was looking for more horses they would help!!!! cheaky sods ......


Well we got all sorted to video this PJ problem and it had disapeared ... ...



The OKO main jet and lower half of the venturie is a removable piece and earlier in the day I had glued up all around the joint on my one to seal it.

It must have had an air leak because the problem has gone and we now get consistant runs on the dyno.

I have seen this PJ problem on other OKO carbs so its possibly something to look out for on any Keihin copy carb.

Its all good to go now ...

[Buckets4Me]

Someone thought if I was looking for more horses they would help!!!!

that isn't a help it's a ZEBRA it is riding an early E.S.E engined gp125