[LotusElise]

prayoonto 3 291PS
After several attempts on the dyno
the gap closed.
low same power,mid toda better and High 7-9rpm pr3 better 6-7 ps to close the gap pick to 3ps

Hi HP, thanks for sharing :up:.

The result is interessting as those cams has a very different character, despite sharing a similar duration@0.05". The Prayoonto 3 must have a more steep slope of the cam profile...more aggressive .

I still wonder why the 89x90.7 engine (~240 Nm/287 hp) produces at similar CR (12.5:1 vs 12.9:1) and same setup (I, H, IM?) a lower torque everywhere compared to the 87x90.7 engine (255 Nm/297.5 hp) with the same camshafts (TODA A3). This is a VE loss of about 10 % or about 1.2 bar IMEP at peak torque...sadly .

Did I understand something wrong of the setup? Do you have an idea for the difference in engine performance (SAE correction, injector duty same or more, I-H-IM did change too, and so on).

I just want to understand why it is like it is and am I am affraid to see that engine...something holds it back from breathing.

Markus

 

[K20actr.J]

K22 had:
13.3-13.4 static compression
4-2-1 header.
This is the answer of your question lotus

I am sure if i go with my old header and make more cr than 12.6-12.7
the results will be more powerfull.


These two things are the next step.

My only concern is Compression with 100 octane ron gas and 13.4:1 SCR

About knocks prayoonto 3 are more agressives with longer duration than toda a3.
Then will break more the dynamic CR and theoritically thats good about knocks...

 

[LotusElise]

Maybe I am too cockamamie to understand

K22 had:
13.3-13.4 static compression
4-2-1 header.
This is the answer of your question lotus

If you mean so?!

I just did some rough calculations:

• 87x90.7 engine: IMEP = 16.7 bar@8.72 krpm, VE about 1.2@8.72 krpm
• 89x90.7 engine: IMEP of 16.7 bar and VE of 1.2@8.72 krpm will yield to 311 hp, at the moment IMEP is 15.5 bar@9 krpm, a loss of about ΔVE = 0.1

Of course, the intake path (CAI, I, IM and head port) will limit at lower engine speed, so peak VE should be lowered at same everything despite displacement, but just roughly missing 20 hp at the top end.

I am really interested in the difference of injector duty. Would you mind to post it? It would help to analyze the root cause of the lost ponies...if it is on intake or exhaust.

Higher CR of 13.4:1
Yes, dynamic compression will be reduced by a longer duration cam. You may win 4 Nm at top end, but you will loose down low due to need to retard ignition timing for prevention of knock.

4-2-1 header
I am really curious about that. Is it your Joe adviced header? I am not sure if the header itself could add 22 Nm, which are missed, in the midrange when we assume the engine will gain same VE there as the 87x90.7 engine...even when we compensate the higher flow flux demand of the 89x90.7 engine, there are still about 10-15 Nm missed everywhere of engine speed range...

From status quo analysis it looks like brake is in and cut's ponies everywhere...even if combustion takes 2 °ca longer (bigger bore) you can't loose 10-15 Nm everywhere...it's like something systematically braking/cutting/consuming engine ponies .

Or just a simple coherence of the above:
More displacement = more torque
Less torque with more displacement = double lost of engine efficiency
Causes could be: less VE (header, intake or and exhaust port, stepped conjunctions?), mad combustion (2 mm more bore, wrong squish design?), mad scavenging (header, centerline exhaust cam?), tribology isn't retracted (blowby losses -> leakage test?), gearbox (efficiency loss?), dyno (wrong calibration, wrong drivetrain efficiency measurement?), and so on...

...easiest test would be injector duty comparison, it answers the efficiency, VE and possible scavenging loss in one value .

But maybe just CR and header

 

[K20actr.J]

Your hypothesis fell correctly.
Just diagnosed problem, the second cylinder.
It sounded idling one sound like knocks.
The fuel injector of second cylinder not sprayed correctly
The result was damage to piston.
Now i have to wait 1.5 month + the custom piston. fuck
I had wideband but it take readings from 4 cylinders (collector)

gearbox (efficiency loss?), dyno (wrong calibration, wrong drivetrain efficiency measurement?)
on this dyno k22 with 4.389 f/d made 298ps.
I didn't change enything just f/d 4.764 from 4.389 and made 290.
Now k23 with 5.062 f/d made the same power


Maby we see the same Number when fixed the issue of injector and piston.
And maby we see the same Number with 4-2-1 header and more cr.
That mean 89 piston to this setup didnt gave something espesially

 

[LotusElise]

Your hypothesis fell correctly.
Just diagnosed problem, the second cylinder.
...The fuel injector of second cylinder not sprayed correctly
The result was damage to piston.

I am sorry for that...those are no good news. I hope the head and the liners of the rest are ok?

Maby we see the same Number when fixed the issue of injector and piston.
And maby we see the same Number with 4-2-1 header and more cr.
That mean 89 piston to this setup didnt gave something espesially

I am in good spirits the engine will show something around 310 hp and about roughly 265 Nm...

Good luck with the reassembly :up:

Markus

 

[LotusElise]

Cam comparison seems to need some more attention

...the Prayoonto stage 3 has 245 °ca@1.27 mm (s. their hompage) and the TODA A3 has 257 °ca@1.00 mm, a typical stage 3 cam has an gradient of 4°, twice of it gives you 8 °ca from 1.00 to 1.27 mm lift, so we get an assumption TODA A3 has roughly 249 °ca@1.27 mm.

I have possible to correct my posting above...

 

[K20actr.J]

Prayoonto 3 camshafts -8620 billet core
Engine : k series

ADV duration 314/310 degrees
Duration @50 244/230 degrees
Lift .530''/.518'' 13.46/13.15

pr3 are more agressive than toda
more lift and more duration.

Can easily be understood by trying both that:
the lobes of pr3 are agressive.
When gives for example 28vtc goes in fact 30-31.
we installed vtc limiter pin 35degree when gave 35.
that was the max. recommended vtc from manufacturer (33-35)


toda A3 lobes are more frendly at idle and smoother to valvetraine.
i run them a few years.
vtc goes always exactly where you want

7-9500rpm pr3 are the king of power.
the sound of engine awesome!!!
those cams for small engines k21,k22,k23 needs 13.4 + cr.

 

[LotusElise]

Wow, that's a big difference

Norris from Prayoonto did replay "0 lash". This means:

• Prayoonto stage 3: in 245 °ca@1.27 mm, ex 240 °ca@1.27 mm
• TODA A3: in 257 °ca@1.23 mm, ex 252 °ca@1.26 mm

According to your observation HP and the dyno result I would aggree with you, the Prayoonto has a significant steeper opening ramp (s. below) and of course the 0.4 mm higher lift.

Source: www.grumpysperformance.com

...When gives for example 28vtc goes in fact 30-31...

Ok, torque demand on cam gear seems to be a indicator as VTC difference indicates an torque demand of the right rotational direction (counter clockwise, crankshaft is clockwise) :up:

7-9500rpm pr3 are the king of power.
the sound of engine awesome!!!
those cams for small engines k21,k22,k23 needs 13.4 + cr.

Yes the video sound made me smiling from left to right ear . Would you run them instead of the TODA A3 in a DD? What's about their idle character?

 

[K20actr.J]

Here is the damage of piston and darton cylinder
Piston melted more to skirt and no so much top.
Tomorow will give the injector for test.
I dont know why that hapened.
lean a/f/r ? issue on injector? i dont know

NEW pistons

and after from only 1.800milles antifriction coating has disappeared

There are good and bad coatings???
If YES Which is the best anti-friction coating??
It is something which concerns me.
I wanted to give less wear because low rod stroke ratio 1.5 but i think finally coating of skirts is waste of Money :Ookay:

 

[LotusElise]

Wow, that's a big piston seizure

Thanks HP, interesting pictures of the engine!

Piston melted more to skirt and no so much top.

Do you still have some oil of the engine? I would analyze the fuel content in it

...lean a/f/r ? issue on injector?

Heat source is combustion, would it were to lean (is that the right perfect subjunctive? Sounds awful...) the enlongated combustion and therefore higher mean temperature of the chamber (gas and parts) would show also some meltings/scratches or similar.

Those scratches in the liner surface and the loosen anti friction layer/couting of the piston skirt come definitively from friction. There are options:

• heated piston -> tighter piston-liner-clearance -> scratch
• oil squirt inefficiency -> to thin oil film at liner wall
• hone structure not adequat -> to less oil volume storage in the liner wall, leading to greater friction (s. above). BTW, I see no hone structure in that scratched liner, even not at 90° to the pressure or counter pressure side of the piston/liner. Could you check if there is any hone structure at pivot point at TDC and BDC?
• ...and some others like e.g. to thin oil due to overfueling or inefficient fuel droplet size and distribution, leading to fuel adhesion at liner without enough time to evaporize...

What about the cavity on pressure side of the liner at about half way of stroke in picture one? Photo issue or real cavity?

There are good and bad coatings???
If YES Which is the best anti-friction coating?

There are options, there are different coatings possible or something which isn't a extra layer, which is instead of incoperated in the piston skirt: http://www.dzt-power.com/lieferprogramm/micro-rollierstrahlen...it is a sort of micro rolling plast with micro granulate for a better oil cavity and lower friction...some racers gone that way. I never did test it...so no own experience.

 

[LotusElise]

Ahhh...forgot to ask. Could you please document which picture belongs to which cylinder # and which side of the piston (pressure or counter pressure side).

I also would appreciate detailed pictures of the good liners vs scratched liners to understand better the whole situation. Sorry for my questions, but there are many root cause for the same symptom...just curious .

Thanks

Markus

 

[K20actr.J]

As i wrote up damaged second cylinder piston.90%damage was from lean gas by injector.injectors didnt worked linit .max 75% sprayed.
When have news from testing shop will write again.

For sure k23 project has finished.
Back to oem 86x86
Some thinks our life needs luck

 

[LotusElise]

...injectors didnt worked linit .max 75% sprayed.
When have news from testing shop will write again.

Ok, that could be massively lean :scared:...anyway I am curious what news it will be.

For sure k23 project is finished.
Back to oem 86x86

I understand...that's a pitty. Would you say despite the actual damage, which seems to be a injector issue, the steel liners from Darton, their installation and the operation of the engine with them shows a good perspective for doing racing/DD mix?

I just ask as so many racers did recommend to me not to go oversized because of leakage issues when it comes to heated operation (lot of WOT content during racing) as those tiny dimensions between the liners of smallest 2.5 mm x 2 = 5 mm leading to overheat of gasket and than...

:whiner:

...but I could imagine this is just said as some few did bad results just by e.g. wrong installation process or wrong tolerances :devil:.

What would you say after that experience? I would appreciate your meaning. Thanks

 

[zof484]

What is condition of the coils and spark plugs?
Might be bad / no ignition and unburn fuel washing all the oil off
cylinder wall.
Make sure spark is good.

 

[K20actr.J]

Coils and spark plugs all fine.
second spark had oil.
Those symptoms i believe creating unstable idling.my idle was fine

 

[Stoney]

What injectors ? From where ?

 

[K20actr.J]

Today tested the injectors four bar pressure.
All worked fine.
Next step is that check
the connectors of injectors,cables, etc
I know several cases with bad connectors contacts.

What else

 

[LotusElise]

What else

Please check the following, to investigate the basis of above #108:

• oil squitter position and spray pattern
• a picture of the damaged piston and a healthy one: top, skirt, bottom and from ring land
• we need also picture from liners: good one and the 2nd one...I didn't see there a hone structure anymore
• do you have pictures of the hone before the installation?

Markus

 

[K20actr.J]

Please check the following, to investigate the basis of above #108:

• oil squitter position and spray pattern
• a picture of the damaged piston and a healthy one: top, skirt, bottom and from ring land
• we need also picture from liners: good one and the 2nd one...I didn't see there a hone structure anymore
• do you have pictures of the hone before the installation?

Markus

1) oil squirters are withdrawn.
Holes of course are closed.



2)healthy piston

Piston of 2nd cilyder

From picture cannot be perceived if not measured.
Easy and faulthy can believe someone that is ok.


3-4)

I havent other photo.
The other cyliders are in good condition for rod/stroke ratio 1.50:1
And skirts too.
Can see the honing from this photo.
Generally machine shop doing good job.
My old motor made here with no any issue.

Head gasket its fine.No burned etc.
I never had any issue with coolant and oil laek from headgasket.

Before I understand this problem that I noticed was the moderate consumption of oil. More than K22 project but not something tragic.
I assumed it was normal for forged and sleeved engine.

I am sure the problem was from lean a/f/r only 2nd cylinder
something didnt worked wright and has to be with lean gas

 

[AWOC]

What is the piston to cylinder clearance? Even your healthy piston looks horrible.