ESE's works engine tuner

[RMS eng]

How exactly does getting it to the track backup/prove the dyno data, dyno data is dyno data. Better that someone drages a Derbi or Aprilia over and does a back to back on the dyno with my GP and we post the results.

The track is more a measure of riding skill I would have thought, as there is plenty of evidence at Mt Welly of good riders doing well on bikes with inferior engines, Mark for one.

Having said that, it would be interesting to have someone who can ride well, try it out and give us their opinion.

rob i don't think any of the top guys have inferior engines ,they may not make a lot of top end power,but make the right type of power to get around a small kart track fast,Derbi 80s make 20-23hp when dave gets back i will see if he has a dyno sheet i can post,Johns dyno is the one he used.

[TZ350]

.....they may not make a lot of top end power,but make the right type of power to get around a small kart track fast

Totaly agree, do Derbies have a 4.5K rpm power spread?

Derbi 80s make 20-23hp when dave gets back i will see if he has a dyno sheet i can post,Johns dyno is the one he used.

Johns dyno does a good job but only displays hp against road speed and when we were there it was not able to give a print out.

As Jasons comment was "Prove the Dyno Data" if you want that, best someone brings a Derbi over and we run Back to Back comparisons.

This thread was about posting what we and others were doing, and making a few friends.

I hadn't wanted this to be a "" my engine is better than your engine"" thing, and I have nothing against Derbies, it's just not what we have........

But you have made good use of the thread to compaire Derbies in a faverable light at the expense of our efforts with the GP's making it a hijack if your not posting anything interesting at all about your own work.

And if you think the Derbies you put together are that great, lets run em up on the ESE dyno in a back to back test, you can supervise or even do the tests yourself and then we can post the results and people can make up their own minds which they would rather ride.

[Buckets4Me]

That is the best graph I have seen from you yet.
Now get it to the track to back up and or prove your data!

I know I'll use Daves bike and he can ride TZ350's and we will see weather his one can beat TZ's

I bet i can be lapped faster than he can

[bucketracer]

Now get it to the track to back up and or prove your data!

I know I'll use Daves bike and he can ride TZ350's

Yesss sir that's the answer, Buckets4me rides the RMS Eng prepared Derbi of Dave D's and Dave rides TeeZee's FZR/GP125.

No doubt the Derbies superiority assures Buckets victory..........

[RMS eng]

Yesss sir that's the answer, Buckets4me rides the RMS Eng prepared Derbi of Dave D's and Dave rides TeeZee's FZR/GP125.

The Derbies superiority assures Buckets victory..........

Dave D has done most of the work on his DERBI motors,RMS only did a little machining and fitted the motors in the frame,Dave does all his own set up work.as i have said before the little Derbi motors may not be the best motor out there but are new,light and make enough power to be in the hunt.

[TZ350]

Page 260

Recent Interesting technical comments gathered together here so they are easier to find, other link lists can be found on the decade pages starting with Page 80.

There are over 1,200 images on this thread, to find the interesting ones use “Thread Tools”, then “View Images” near the top of this page. You can view the images 70 at a time from the beginning. It’s a quick way to find some of the interesting posts too.

A handy (and cheep $16 USD) Porting Calculator from:- http://www.porting-programs.com/ is based on Blairs and Jennings work. And gives blowdown areas required for a selected power output.

Kel gave me this link to a very interesting book. www.prme.nl/download/engine-1.pdf

A good reference to sharpening or re-shaping drills:-
http://users.bart.nl/users/summer/16...Sharpening.htm

If you have any issues with the Mallory coming loose ( hope you dont) you can Tig weld them in place.
In the stroker Banshee/RZ/LC cranks I build, they are 0.08mm press fitted, then Tig tacked each side.

Just one thing to add here re the screamer 100 engines we are looking at building. To make the sort of power we are looking for, we have to use around 200* of Exhaust timing. This works with a TL of around 800mm to give power up to the 14000 mark. But this timing and pipe length is a resonance mismatch. For it to work, and rev that high, we HAVE to use a solenoid powerjet, to get heat into the pipe ( along with pulling out timing to near TDC ). This combination will not run above the power peak on a normal carb. To get power and revs with a "normal" carb requires a timing of around 83* ATDC and a tuned length of around 830, but this seriously limits the blowdown STA and thus the power that can be achieved. And I use a 182MC right angle head ,available from C C Speciality in the States, for porting the transfers - but I hate it with a passion.

The only reason that the clutch slips in the taller gears is because its a crap clutch pack and needs more plates or more spring to take the applied torque.

….. high rpm coughs between gear changes? sometimes they appear on bikes with tame, well, not radical inlet durations (piston port & rotary).

See this all the time in kart racing - reeds as well, usually its the needle/tube combo going lean as you pass thru 3/4 throttle, when backing off for the change.
Get an Ignitech on there and do full throttle shifts - easy.

Also happens when an engine is reved too far past peak power before a gear change. The airflow drops in the overev, the carb goes lean and it will backfire as the change is made ( even using a speedshifter). RS125 engines in karts do it with steep baffles, as soon as you rev them too hard.

Jan Thiel
When rpm raises still more there is no more transfer flow and the engine stops completely. So transfer flow depends completely from what is 'allowed' by the exhaust (blowdown) flow!

The dyno load ( gear ratio) should be selected to simulate the end use.
ie do you want the thru the gears performance as seen at Mt Welly or pulling 6th gear for several seconds at Taupo, where you have a huge wind drag factor to push against. Around a sprint track you can use way more timing and not see deto due to the short "power on" period. But either way the heat soak in the pipe and case should be similar to what would be seen on the track.

Re the rotary valve timing.The problem here is that every engine is different, with the case vol interacting with the timing and the carb length/size.
Basically when you exceed 140/88 you get finicky jetting and questionable power increases at the expense of drive down low.

Only way to define what is best is to leave the closing at say 88 and go from 135 up to 145 in 2* increments. Stop or go back if no useable power is seen.
Then see if top end is lost by going back to 86/84 on the closing.

The RSA does not have any taper at all at the top of the duct divider ( septum), the end of the divider just has a small radius on each side. This is to reduce the area ratio between the duct entry and the port exit.

If you look at the old Rotax pic it has a duct entry to port ratio of about 1.4. The base gasket dimensions are virtually identical to the late model cases. The RSA/RSW has a ratio close to 1.2, so its still tapered down to the port exit but no where near as much. If you look at the Delivery Ratio of a full on 2T engine, virtually all the volume that ends up in the cylinder, is actually sitting in the transfer ducts, NOT the case. The smaller this volume is, the quicker it can be accelerated through the duct into the cylinder.

Jan Thiel
…. flowing the transfers makes little sense! The important thing is more their direction and how they influence upon each other. At high rpm there is some reverse flow, the transfer ducts becoming black, and even the crankcase and carburettor bellmouth because of the entering burned gasses. This happens because with raising rpm. the pre-exhaust flow (blowdown) becomes insufficient. When rpm raises still more there is no more transfer flow and the engine stops completely. So transfer flow depends completely from what is 'allowed' by the exhaust flow!

Wobbly sent me an email (and permission to post it) re the shape of the RSA rotary valve disk.

Hi Rob Here is a pic I just got from Frits, I asked about the RV timing as I am building up a Sim of the RSA/RSW. He said that the opening wasn’t critical between 140 and 145, the closing between 85 and 88 depending upon the rider and track. He said they tried opening timings all the way to 155*, but 142 to 145 was the norm. The angle on the closing side is purely to help with wear on the case. Cheers Wob

My opinion of closing angle (the important number) is that the later RSA has a much narrower port width than the RSW, and thus these timings give a much increased STA, as the disc is covering the port for less time, with the same actual timings.

Thus maybe that engine can deliver better performance within an envelope of non "radical" port timing numbers. In the old Rotax tandem twin, going from 85* ( stock) to 88* is like night and day in overev performance, but carburation becomes finicky and alot of bottom end power is lost.

The rotary valve timing.The problem here is that every engine is different, with the case vol interacting with the timing and the carb length/size.
Basically when you exceed 140/88 you get finicky jetting and questionable power increases at the expense of drive down low.

Only way to define what is best is to leave the closing at say 88 and go from 135 up to 145 in 2* increments. Stop or go back if no useable power is seen. Then see if top end is lost by going back to 86/84 on the closing. Graphing power Vs rpm takes the load out of the equation,

Riley Will
The 125cc engine made 48 hp (sae) at the rear wheel. I believe I can make more with the reed valve engine by focusing development on the reedcage and inlet. However, it has been my experience that the mid range power of the disk valve engine is always superior. I have found over rev power of the reed valve engine to sometimes be easier to achieve. In the past I would also produce more peak hp with the reed valve engine but the mid range maybe 7% less than the disk valve. I have also made tests on a 125cc disk valve engine with fuel injection. This made 10% more power everywhere than carburated!!!

Yes, dead right the STA numbers havnt changed at all since the theoretical work was published out of Queens in Belfast by Blair etal. Aprilia completely changed the whole layout from previous 3 port geometry. Instead of the main port being right at the 72% limit, they reduced this to 68% and dropped the main transfers below the rest.This enabled the large secondary Ex ports to be added, plus gave room to pull all the transfers around and create more area with less timing.

What this lead the way with,is being shown all the time now in the sims I run, that the Ex STA means jack shit, Blow Down STA is Everything.

Its not scavenging that’s directly the issue, its lack of blowdown time, that effects scavenging efficiency and delivery ratio. Means the cylinder is full of exhaust residuals, as much of the mixture waiting in the ducts is reverse flowed back into the case.

Jan Thiel
At high rpm there is some reverse flow, the transfer ducts becoming black, and even the crankcase and carburettor bellmouth because of the entering burned gasses. This happens because with raising rpm. the pre-exhaust flow (blowdown) becomes insufficient. When rpm raises still more there is no more transfer flow and the engine stops completely. So transfer flow depends completely from what is 'allowed' by the exhaust flow!

[TZ350]

Electric Power Jet Carb.

The FPE superkart engine that won the NZ road title at Manfield a few weeks ago makes 92 RWHp on the Dynojet 168 I use.
Still not quite as good as the RS250 setup we did that won at Laguna Superkart Worlds a couple of years ago.

The powerjet carb is controlled by the Ignitech with a combination of throttle position and rpm in a "truth table".
In general the solenoid is activated with 12V ( no fuel flowing) below 4000 rpm and 75% throttle on the TPS.
Above 75% and around 12400 rpm it is activated again to lean off the fuel curve over the top of the pipe.
Looks like you will be able to reverse the fuel exit, blocking off the hole on the throttle bore side, and take off fuel from the outside bung, thru a needle jet and into the top of the venturi next to the slide.

And something that I scraped from the net.........

""The solenoid control on TZ type powerjets really just shuts off fuel flow to the powerjets right at the top of the rev range to lean the mixture off to increase the over-rev once you are past peak power.

I don't have the solenoids plugged in currently though as I find they work well enough for my current needs with the powerjets simply responding to venturi vacuum pressure in pretty much the same way as the oem 3MA powerjets work.""

And here is a picture of the carbs and what I can make out, a dyno graph without, and with the power jet solenoids shutting off (red line) and extending the over rev.

So it looks like you can use an electric power jet like a standard one and when the carburation is sorted, try switching it of by activating the solenoid at or just after peak power and see what happens with the over rev.

You have to be very carefull with the switch point and the run time on the dyno.
The switch point is dead critical to 100rpm,so i always set it too high initially and make sure that the dyno is loading the acceleration rate to be as close to that on track as you can.
This gives the pipe time to heat up and affect the power over the top, as it would in reality.
On a RS250 dropping the switch point from 12800 ( std) to 12400 gives easily another 800 rpm of virtually no power drop past peak.
On the track,if the rider can feel the switch point ( it feels like hooking another gear)the jet is too big,when its right it should be seamless and just keep reving out.
Leaded fuel is the opposite to unleaded, in that as leaded likes to run lean - you can only use a small powerjet and thus only switch off a small amount.
A leaded engine works best with around 35 to 38 PJ, the unleaded fuel can switch a 60, in Keihin numbering, as the crap fuel makes best power at peak when quite rich..

Mallory Metal Plugs

If you have any issues with the Mallory coming loose ( hope you dont) you can Tig weld them in place.
In the stroker Banshee/RZ/LC cranks I build, they are 0.08mm press fitted, then Tig tacked each side.

[TZ350]

Attachment 236972

This is where we started, can't say we haven't taken the traditional bucket racing route.

[wobbly]

Bastards, taking a perfectly exellent road bike and making it into a bucket - shouldnt be allowed.

[F5 Dave]

3 years on from now that bike on Trademe, once the H2s, T500s & Z1s have dried up, will probably be worth some serious coin & Team ESE members will be hunted like dogs in the same manner that builders of Vincent Chops were previously.

[jasonu]

How exactly does getting it to the track backup/prove the dyno data, dyno data is dyno data. Better that someone drages a Derbi or Aprilia over and does a back to back on the dyno with my GP and we post the results.

The track is more a measure of riding skill I would have thought, as there is plenty of evidence at Mt Welly of good riders doing well on bikes with inferior engines, Mark for one.

Having said that, it would be interesting to have someone who can ride well, try it out and give us their opinion.

Yes mate. What I was getting at was to get it on the track to see how it performs, carburates, revs etc. Your latest curve is really similar to mine up to 10k when mine has more or less peaked at 22.5hp and yours keeps going for 5 more HP. My bike is very tractable for a 2 stroke so if everything is as your dyno results look I think you will have a rocket.

By the way I wasn't having a go or anything like that, just really interested in seeing how these dyno results translate to track performance which (I think) is what it is all about.

[F5 Dave]

and to say go out & spank those coal burners!

[Henk]

and to say go out & spank those coal burners!

Diesels are the future

[F5 Dave]

So is a dusty waterless irradiated wasteland, but I try not to dwell on it too long.

[TZ350]

.....really interested in seeing how these dyno results translate to track performance......

Hopefully this weekend .........