ESE's works engine tuner

[Muhr]

If I ever finish my own cases, Im trying shafts in "Uddeholm Vancron SuperClean", should negate the need of coatings.
Shafts are finished, but still a long way to go before I have running engines.

Hope to see more of that project !!

If the ultimate power of a two stroke is limited by port areas,as I think it is, we can rate these 36.47hp from a 85ccm with 52 from a RA125.

52*(85/125)**,6666=39.25 to be compared with Katinas 36.47.
Considering that the 85ccm has relative higher thermal losses it is awfull impressive for a private run project..

It's BMEP at 16.36 bar, right?
Hats off

[flyincat]

Part of this is also due to the fact that to fit the CR250 block in place meant that the petal exits were off bore center by 6mm - the CR125 is 6mm narrower , so it can be put back on center with an adapter plate
then a stuffer plate fitted down one side.

So one lesson I learned is that asymetric intake regimes loose power - be it an offset block or even worse sideways angled manifolds.

If reed engines are clearly sensitive to asymmetric intake flow, how does the rotary intake work so good coming in straight sideways?? Does it have to do with not using all of the reed area, with most of the flow biased to one side of the reed assy, and not so much to do with where the flow goes inside the crankcase? Thanks in advance!

[katinas]

Muhr, Niels one notice, this result was without air filter and torque was 22.28 Nm at 11542 rpm. With an air filter, max power range dropped between 35 and 36 hp. Stock 2020 85cc on our dyno shows 11.8 hp at 7000rpm until 27-27.7 hp at 11335 rpm. torque 18.22 at 9989 rpm.

Frits, yes its about the floors of the transfer ducts where they enter the cylinder. On SX 65 this add 0,7hp on several engines, but on 85 we never test this alone, just together with other modified things.
Probably this would reduce the power of the engine, where the piston sides cutouts is low, and transfers is masked when piston is at TDC, like on Aprilia rotary valve engine.

Looks like, from all KTM/Husky 50, 65, 85, 125 cc engines, 85 is most successful Austrian engine. And engine modification could be done without any additional kit parts, only modified stock.
I am still wondering how good is 85 std exhaust pipe. The only modification on it, was a smaller tail pipe insert, from stock 19.5mm to 17 mm. We reduce it step by step until mid range started to drop with 16.5 mm. But max power still rises.

[wobbly]

So this is where we run into trouble with the numbers , that simply cant lie. IF the TC85 has 36.46 WHp @ 11,756 then
with the usuall 12.5% losses to the crank we get 41.05 CHp.
At 11756 rpm ( a ridiculously low 19M/s piston speed ) this equates to 18.39 Bar.
Sorry - simply not possible on petrol ( and for sure never been done , as its way better than Mr Thiel even dreamed of ).

Now , if you rev the thing to 15500 as it should be ( 24M/s ) then the BMEP is 13.94 Bar - easily achieved by many a clever Dutchman or a Kiwi in a shed for that matter.
Not to put a finer point on it - someones dyno is telling porky pies , unless the numbers have been misquoted somehow.

[dutchpower]

I think Katinas you have around 30 hp now and that is pretty good ( stock TC 85 lays around 22 hp )

[wobbly]

Flyincat , I think that the angled manifold is the worst offender . I did days of flowbench testing of the SKUSA CR125 intake when using the straight RS125 rubber was effectively stopped , by
banning the use of the riubber stuffers if opting to use that manifold.
The flow exiting the petals on the inner short turn radius was so bad it was hard to measure using a velocity probe.
After cutting a heap of petals and using asymetric backups I managed to get something like 60/40% and power went up 1.5Hp.
The new petal setup biased flow upward under the piston as well as pulling it around to the LH side.

In the CPI Cheetah cylinder the LH/RH bias from the reed tips would have had a direct result on the flow thru the big Boyesens and thus directly into the transfer tunnels.
And the whole reason Jan liked the idea of the rear mounted RV was to eliminate the asymetric flow regime of the side mounted version.
The RSA was a sucess , power wise , but had a down side in that the front exit pipe limited the positioning of the engine in the frame , so it never handled as well as the RSW.
Jans opinion now I believe is that a RV on each side would be the best route to ultimate performance.

[katinas]

Wob, Duchpower, yes its always difficult to say real power with different dyno, but latest stock 2020 SX/TC 85 dyno graphs from others, shows very similar 27hp and 18Nm and identical 11.8 hp at 7000 rpm results.
From 3.27 https://www.youtube.com/watch?v=_TvRVPJrrN4

[dutchpower]

Wob, Duchpower, yes its always difficult to say real power with different dyno, but latest stock 2020 SX/TC 85 dyno graphs from others, shows very similar 27hp and 18Nm and identical 11.8 hp at 7000 rpm results.
From 3.27 https://www.youtube.com/watch?v=_TvRVPJrrN4

That are crank hp Katinas

[katinas]

That are crank hp Katinas

Thank you, so its better sensitive to feel the difference from modification.

[Muhr]

Thank you, so its better sensitive to feel the difference from modification.

We use the same software and dynos that VHM uses and I would say the same thing as Duchpower, most likely to be able to compare data between them (or the the big brother of the one vhm uses)
I have worked on a few Tm mx85 in recent years and have not seen that we are left in the dust. we have quite strict regulations where we can make exhaust systems but not modify anything on the engine. We get out around 30 crank. (I ended up with a 17.5mm reduction)
I do not think this takes anything away from your performance increase

[wobbly]

Notice that the VHM dyno result has a weather station connected , but the correction factor is 1.00 - one simple way to make the dyno lie.
I did wonder why we could never get near the results they posted about how fabulous their KZ pistons were.
Sure , they are doing comparative tests , but now their actual numbers are not reality.
But anyway - its just not possible an 85cc @ 11756 rpm is making 41 CHp with a resultant bmep WAY better than an RSA125.

[andreas]

This 85 cc would be reed inducted, but it has a few advantages over the aprilia, lower rpm while being just over 2/3 the size. Also the rpm is so low it can probably use the second reflection exhaust pulse at peak power- enough for that astronomical bmep??

[wobbly]

"Astronomical bmep " is the key phrase here.
Being a reed engine is an absolute ,proven , guarantee that it will make around 10% less power than a equally developed RV , and as for making peak power at just 19M/s piston speed
further reinforces the determination that the facts are seriously in question.
Is anyone seriously agreeing that a reed 85cc on petrol has been so well developed that it makes completly off the planet comparable Hp to an RSA125 at a piston speed suited to a chainsaw.

[katinas]

Notice that the VHM dyno result has a weather station connected , but the correction factor is 1.00 - one simple way to make the dyno lie.
I did wonder why we could never get near the results they posted about how fabulous their KZ pistons were.
Sure , they are doing comparative tests , but now their actual numbers are not reality.
But anyway - its just not possible an 85cc @ 11756 rpm is making 41 CHp with a resultant bmep WAY better than an RSA125.

Wob, VHM dyno result, like Duchpower said, is crank hp. We have two TC 85 2020, one with still absolutely stock engine, other modified so it was easy to compare. If VHM power graph of stock 85 is correct, that shows 27 hp from crank, it is the same that we found on our dyno for std engine. So modified engine power shows crank 35-36 hp, but just measured from wheel.
And yes, absolutely agree that 41 Chp at this rpm from 85 cc impossible, just maybe with turbo charging that ended immediately with melting piston.

[dutchpower]

VHM TC 85 is 27 hp incl. exh/head/piston/that air thing

27 hp less vhm parts is 25 hp 25 hp to the wheel is 25 hp - 3.125 hp (12.5 % ) 21.875 hp


Did you test both stock bike's !!!!!

The higher you make exh. degree the beter stock pipe

Your upgrade is oke only not your numbers