ESE's works engine tuner

[lodgernz]

I wonder: how did you arrive at 83,3? I think I've seen this value before, but I can't remember in what context.

Time for 1 rev = 60/RPM secs
Ex is open EDº = ED/360 of a rev
so Ex is open for ED/360 * 60/RPM = ED/(6*RPM) secs
in that time, sound wave must travel 2 * Lmax at V m/s
So Lmax = V * ED/(12 * RPM) * 1000 mm = V * ED * (1000/12)/RPM mm
and 1000/12 = 83.3

[mr bucketracer]

Time for 1 rev = 60/RPM secs
Ex is open EDº = ED/360 of a rev
so Ex is open for ED/360 * 60/RPM = ED/(6*RPM) secs
in that time, sound wave must travel 2 * Lmax at V m/s
So Lmax = V * ED/(12 * RPM) * 1000 mm = V * ED * (1000/12)/RPM mm
and 1000/12 = 83.3

can you make my 50 fast as you are blowing my mined

[lodgernz]

can you make my 50 fast as you are blowing my mined

Based on my performances so far.... no.
Ask me again in a coupla years.

[crbbt]

quick question (I guess for wob)

I have my non power jetted carb (Keihin PJ) 'sorted' I am happy with the performance through the rev range.

I recently acquired a SPJ carb. other than running a smaller main jet. would it be correct to run the same sized slide cutout and main needle?

[ken seeber]

This just shows old blokes are not necessarily stupid:

https://www.mxlarge.com/2017/10/28/d...ack-2-strokes/

[husaberg]

quick question (I guess for wob)

I have my non power jetted carb (Keihin PJ) 'sorted' I am happy with the performance through the rev range.

I recently acquired a SPJ carb. other than running a smaller main jet. would it be correct to run the same sized slide cutout and main needle?

wob mentioned ealier adding the Power Jet and MJ size together to arrive at the corect size in relation to a non Power Jet ML size.

[F5 Dave]

Thank you Frits, very good information, as always. My engine is an NSR50, so is limited in blowdown time.area with a single oval exhaust port. It's water cooled of course, and happily over-revs to 14000 for short periods without exceeding water temp of 65º during a race. However, as you suggest, because I'm using such a big restrictor, the gas temperature and pipe pressure will both be low and this is borne out by the pipe length Lmax being only 678mm for an ex duration of 192º.
Lots of work to be done.

One more question, if I may: Your formula for Lmax features the constant 88, whereas I would have expected 83.3.
Is your constant adjusted for the fact/likelihood that the mean reflection point from the baffle cone is not at the pointy end of it?

Build the pipe. I'll find the Dyno time for you.

[TZ350]

Bit of a production run of 28 rwhp Bucket racing Suzuki GP/NSR110cc engines.

Following on from Nath88's idea of using a Piezo element to sense a pressure pulse as a way to know if the motor has fired and Flettners idea of timing the sensing point to coincide with a selected period of crank angle.



I took a look at a Piezo switch and thought that I might be able to use the exhaust pulse instead of a finger press to activate it.



A NO circuit is fairly easy and to time it to a selected area of crank angle all I need to do is use a winding on a pole in the right place on the alternator to turn on another NO transistor switch.

Then if both NO switches wired in series are closed there will be a pulse that the EFI will see as an engine firing event.

[RomeuPT]

I know it was discussed before here, but can't find :/



in the pic this was done just because of offset ring position and should be grind symetrical or has something to do with performance? i can't be sure...

Cheers

[lohring]

That picture is from the paper below.

Lohring Miller

[RomeuPT]

That picture is from the paper below.

Lohring Miller

Thanks. I think I have this document in a hardrive somewhere, got to put all of this on google drive or something

[wobbly]

In the paper the two hook positions were part of the experiment matrix.
The two positions gave different results, but in some older RS125 cylinders the pin is offset,and grinding the boost port septum's symmetrical gives
more power when used with the later pistons that have the pin at 6 o'clock.

The PJ and SPJ jet quite differently due to the length difference,if you are running a race 125 then the stock Honda jets in the SPJ are a good start point.

[lodgernz]

Build the pipe. I'll find the Dyno time for you.

Thanks Dave. I'll call you

[Lbracing]

Wobbly I sent you a pm last week , got it ?

[trevor amos]

Frits,
If you are still wondering where you once saw the reference to 83.3 as Lodgernz calculated, it can also be seen in Gordon Blair`s books shown his pipe calculation formulas.