Yes important info,I forgot that,throttle body 70mm both test.
You are right pr low lobe make more power with bigger Duration and lift
has smooth idle without up & down rpms and quite cylinderheade.On that helps probably risky ti retainers..
Always "lifter" cams makes more power low but midrange lost importan power before and after vtec.My tuner spend few time to make midrange.
Of course those cams made for k24 engine but not bad!!

 

Yes important info,I forgot that,throttle body 70mm both test.

Thanks man.

has smooth idle...On that helps probably risky ti retainers..

Thermodynamically the centerline position of both, the cam overlap, lobe profile design and duration are the main drivers of idle speed level and quality at cylinder head. Did you ever seen broken Titan retainers on your engine?

"lifter" cams

Maybe an abbreviation you use for high lift cams at your place?

Weird that only 33vtc on high cam.

I was asking it before, but seems to be an arcanum . I had also the impression of an constant VTC in that tune...did suggest to start advanced, e.g. like you suggested at 40° of VTC, and retard as the engine like it. I asked for the calibration to check it out, but didn't get it...the tuner kept it like a precious .

When you tested bigger cai did you try different vtc?

Simulation shows it too, especially in the high and low end there are minor differences in VE, so differences in VTC accordingly.

How long intakes you used? Rrc like short intakes.

For what support? Low end, midrange or high end?

I change my header too and help high

:up:

On 40vtc don't believe is able to make more power.

I am not sure if we talk about the same situation. Zof484 is talking about using 40° VTC only in the area directly beyond VTEC for high speed cam and than retard it as the engine like it.

To explain it:
It is a physically fact, that the arriving pressure wave, which was send out by the opening intake valve shock and suction process, has always speed of sound. This leads to the fact, to match the highest pressure of that arriving pressure wave just at closing of intake valve, a continous retard of the intake cam is necessary...just keep in mind the valve opening time reduces with increasing engine speed while the pressure wave movement duration is constant! So the valve closing need to adapte that to have a retarded intake cam actuation.

If you just keep VTC constant for every engine speed of e.g. the high speed cam, there are definitly engine speed points (just think of driving with your eye along the torque line) which are not tuned for maximum VE or maximum torque as every pair of engine speed and load has it's own single optimum.

I am not sure if this already was done in your tune by your tuner. This was always the cause I wanted to check out the calibration for you K20actr.j.

Just as an example, here a stock near engine setup:

Source: K20a.org

On the left is high speed cam, I guess stock ITR cam, CAI, H, E nothing more and on the right a tyical tune for low speed cam with aboves setup. You can see, the high speed VTC is almost continously retarded over engine speed. Forget the kind of load tuning with row constant VTC, this is more or less tuning philosophie, but look at the high load VTC's (columns 8, 9 and 10). I don't like the kind of low speed VTC tuning for full load (= BS!) and row solution at VTEC, but full load VTEC is around 3700-4000 rpm.

So to read the engine acceleration on full load like following: engine increases engine speed from 500 rpm on at full load (no one should do that for real LOL ) with 30° VTC, just shortly before VTEC (at 3500 rpm) intake cam gets advanced to match the best VTC for high speed cam...while the intake cam is continously advancing VTEC locks in and high speed cam get's activated. At this moment, when high speed cam is active for first time, VTC has likely 40°-43° (depending on gear it could be even less!) and still need to finish the advance process to 45° setpoint at 4500...I don't believe VTC will reach 50° in the first three gears while acceleration if you start in gear 1 or 2 or 3 that acceleration process, the engine speed increase is faster than VTC mechanism can rotate...now, with further increasing engine speed the same speed running peak pressure wave of the IM runner arrvies more and more late (relatively to valve closing time), so the engine will like to get a retarded intake cam. Therefore the high speed VTC is continously retarded, here for that bolts on setup, from 50°@4000 rpm to 10°@8500 rpm

Pressure wave moving video from Jaskirat Singh to understand the above better:

Markus

 

What vtc did it liked at low cam?

Weird that only 33vtc on high cam.

With all my testings on k22, k24 and k25 those engines liked
40vtc after vtec (skunk2 ultra, dc4 and k600v cams) and with that
the dip was gone.
You might need to change your header setup.

When you tested bigger cai did you try different vtc?
In my tests different intakes liked different vtcs. (+-3)

How long intakes you used? Rrc like short intakes.

 

Yes of course played with different vtc,advance both dia cai make the same power (short long cai 3-3.5")

I change my header too and help high.
Don't forget that crank only 90.7mm,not 92mm and not "clean"2.2 (2.157cc)after 33 vtc power dropped..vtec-revlimiter.
On 40vtc don't believe is able to make more power.
Norris told me that too (benefits are max 33-35 vtc)

 

Smaller k20 engines like even more midrange vtc than k24->.

Cai testings showd difference in high range.
Low and midrange is usually same.

 

I do not remember if we could go over 35 degrees vtc, iirc with 40vtc p2v was 1.4 or 1.8mm
I don't know if that is enough safe?if has project benefits why not to measure again and try 40? :up:
Norris informed never go over 35, never recommends that exactly wrote.
But from my experience:
This dip is expected by camshaft like this which like high speed power

Sure high 6500-9300 i am contented and I think it has caught the limits of power that can produce these cubic..
Sure 99mm crank could make midrange..
But can't have in all range rise with 2157cc and those big cams.
245Nm on dip for 800rpm is not issue for 1080kg chassis.
Ti retainers markus aren't for ever.As wrote in correct thread ti broke.After 25.000km here one quy broked his k20. The other retainers was in bad condition.
Racing teams can't see that when rebuilt every short periods engines.
I replace ti every 17-20.000km.



Zof before 3 months engine produced max torque before vtec.
best power was 288hp.
I raplace primaries and secondaries in 3 different headers.
Placed the header which produce lean gas (and gone from 12.5 to 13.3 afr) and of course could gave hp(+16 hp).
This header is aprox.Joe M.

 

...with 40vtc p2v was 1.4 or 1.8mm...I don't know if that is enough safe?

Depends on engine speed, as the higher the engine speed the more the elongation due to the centrifugal force. In this calculation has to be covered:

• valve stem length and material
• engine size (stroke, rod length, piston height, ...)
• coolant and oil temperature
• weight and material of rod and piston
• head gasket height
• cold PTV clearance
• engine speed
• application for safety factor choose (ash layer thickness, ...)
• grade, torque and material of rod bolts...

Larry from Endyn reported once over his B20 engine's squish height of 1.5 mm, which touched the head at around 9000 rpm. This is something I see also in my calculation of that situation for a B20 engine. The minimum (safety factor of 1.5, not lower!) PTV clearance height should be 1.8 mm at your VTEC point of around 6000 rpm, for my perspective of it. But be aware, that minimum height is a function of engine speed and increases with increasing engine speed.

If PTV clearance is 1.8 mm@40° cold, I would give it a trial to set VTC to 40 from 6000 rpm or VTEC start till 7000 rpm and then retard it according your actual map. With my actual engine a 5° VTC advance means 5-7 Nm at the lower edge of the high speed cam.

Markus

 

Tested my ep3 with forged f22 s2k fully build.290hp s2k but break in.only 2000km


https://youtu.be/4q__vgkFv_s

https://youtu.be/GVRjiB5tZ-g


It need to replace the clutch.when shift flat don't engage next gear and hit the limiter.

 

Tested my ep3 with forged f22 s2k fully build.290hp s2k but break in.only 2000km

You need to place the camera in the backside, to see your competitors longer .

The S2000 chassis is more heavier and the F22C engine misses the cam phasing mechanism (VTC) and of course the S2000 always need more power at the flywheel as a FWD engine for same wheel power.

It need to replace the clutch.when shift flat don't engage next gear and hit the limiter.

Does your ECU support flat shift via ignition stop? It would reduce the lower traction of the clutch...or your feet get slower on the left side

 

Pre face lift honda gave ep3 ctr 1196-1204kg.
Face lift 1232-1240kg.
Europe s2k chassis 1250-1270kg.

I believe non vtc too and losses hp from differential (RWD)

Does your ECU support flat shift via ignition stop? It would reduce the lower traction of the clutch...or your feet get slower on the left side

Never had a problem with foot throttle shift. my aging pressure plate has lost the hardness and not able to work anymore

 

...ep3 ctr 1196-1204kg...s2k chassis 1250-1270kg.

Every kilogram counts

...I believe non vtc too and losses hp from differential (RWD)

These are the main factors for sure.

...my aging pressure plate has lost the hardness and not able to work anymore

Mmmhhh...it is designed as an spring. If it would loose spring rate during life time (around 100,000 km at least) it would be ok, but didn't you write it has around 2,000 km? That steel would have loosen too fast his properties with too few load changes. Would mean it has a too low quality. But it also would mean the torque, where the clutch begans to splip will be lowered. Did you observe such clutch slip e.g. during down shifts. You would see it in the KManager (gear vs. engine speed).

Is the clutch support cylinder still ok? Did you test it also?

Markus

 

All parts are in good condition include cylinder..
This clutch has ~ 22.000km.
Don't sliping.

The only issue are the comps of pressure plate.
After from 2-3 pulls acceleration on road racing comps takes a heat and can't work p.p fine.

I took act clutch organic
AR1-HDSS. (Heavy duty pr.pl)

I hope to work fine.
Capacity ~350Nm.

If i can do my work with organic disk,there no a reason to go again to 6 puck

 

Don't sliping...comps takes a heat and can't work p.p fine.

Where do they get heated if not from relative velocity of flywheel and clutch?

 

Hi K20actr.J, anything new? Whish you a happy new year man !

Markus

 

Hi Markus all fine.
Happy new year too

About news,on Monday go to
-replace clutch
-replace bearings preventive
-measure p2v clearance with 40vtc.If is enough will tray to take a benefits midrange

 

That's great, I am fine too, thanks man !

...measure p2v clearance with 40vtc.If is enough will tray to take a benefits midrange

Your engine need it ! Good luck with it!

Markus

 

There is approximately 2 years I followed your project and I also wanted to make the motor approximately square 89x90.7 I am still being edited because not much temp for 2 years but I hope to arrive at a good result In any case pretty work that you have to perform and also research
i change just one work for cranckshaft f22 with pulley distribution k20a
I attach the pictures

 

Hi Lumbergx
Hope to finish you project and smile every day & every night when kick your stroker monster!
Difficult work gone as i saw from nice pictures!!
What about cr,coats of pistons?

 

Time for maintenance:
Check oem bearing.
Used on my first k22,k23 and now k22
32.000km 9300-9500rpm r/s ratio 1.50 and condition like new.



22.000km clutch kit.
Disk from from fx400 and pressure plate from work shop here because clutch masters fx400 pressure plate had issue..



Plased ACT AR1-HDSS organic.


J's racing FCR discs 100.000km.
Very happy with those!
Team that wins does not change.
Will buy new fcr.



Check Ti retainers and check valve to piston with more vtc.. on low and hight lobes...
For the time are in good condition.





I see on sof484 thread on k22 stroker...the same dip with my own project too.(4000-5700rpm)
Rrc vs ultra vs 9.0 whp

After from check PtV easily can go with more vtc on low lobe and will try to
decrease the dip midrange
On high lobe as I wrote on this thread tryied more vtc than 33 and lost power..

 

Time for maintenance

Preparing for next season? Did you check the timing chain and TCT too?

I see on sof484 thread on k22 stroker...Rrc vs ultra vs 9.0 whp

The green line looks like the 9.0 IM of Joe McCarthy...the picture size is a challenge to recognize details ...he was looking for peak power in his designs to be competitive with ITB's .

After from check PtV easily can go with more vtc on low lobe and will try to decrease the dip midrange...On high lobe as I wrote on this thread tryied more vtc than 33 and lost power..

The header design, which is near to that of McCarthy, you are using is mainly designed for peak power and has a lower midrange VE support than other 4-2-1 systems. The Prayoontos have a bigger low to high speed torque curve distance, therefore the dip deleting would be a great success. I have my doubts on that...a small dip will at least remain.

Markus

 

We will see if my doubts are correct . I am looking forward to your results, may you can falsify my doubts .

Markus

 

Of course there will have dip always with these stage cams
The goal is to reduce that dip as much as can.

Even so stay the substantial goal (maximum power 6500-9500) has achieved !!

Just always I have perfectionism

 

https://youtu.be/SpO1DsmIIiA

 

A few days ago the car
visited scale
1090kg

Power to weight = 3.5
With me = 3.9

 

...1090kg...Power to weight = 3.5

That's pretty awesome K20actr.J! Around 180 kg less than stock...you did give it a diet? Would be interesting to see the power to weight curve from 6500 to 9500 rpm, there where you bite the SC'd cars on street, like in the previous vid's you showed me :up:.

Are you going to review the gear ratio's again or do you want to keep them. BTW, with a Lotus it is easy to get there, as a K20 (CAI, H) + Elise = 3.3 kg/hp.

Markus

 

Stock ep3 its 1204kg.
About gear ratio that is big headache.

Today replaced 215-45-17 for some bigger diameter 205-50-17 to produce more km each gear.Not much..
1st gear= 66 to 68 km/h
2nd 102 to 104km/h
3d 142 to 146km/h
4th189 to 193km/h
5th 223 to 227km/h
9310 rpm revlimiter.
5.062 final drive
K20a2 stock 1,2,3,4 gears.
5th gear 0.972 jdm
6th tsx 0.659

Maybe stock 4.764 is better choice and replace in future


Every opinion is helpfull for 1090kg chassis and 305 engine hp

with stock 4.764 f/d and 215-45-17
1st 70km
2nd 108
3d 152
4th 201
5th 235

 

About gear ratio that is big headache.

I've build a software which calculate all drag forces (air, roll, acceleration, lift) for a car, that means the power demand for certain situations. With that it is easy to calculate the time for an acceleration time demand under various conditions like different gear ratio's with your engine's torque curve.

As an input I need at least the all rational combined gear ratio's you have on hand or want to test. The model get's more exact if I get the specific cW coefficient value, car weight, roll resistance coefficient, rotational inertia's of drivetrain...but I can do assumptions according spec data and my calibration measurements of the Lotus and K20 drivetrain.

The result here would be the best gear wheel combination for the shortest time for a reference task, e.g. 40-200 km/h time.

Or you can just test all of them and spend a bit more time and money for the same result LOL.

Markus

 

Any update to your engine K20actr.J?

 

Hi mark

No any update about engine.
Now give attention to reduce the weight of ep3 chassis

 

No any update about engine...Now give attention to reduce the weight of ep3 chassis

Thanks for your replay. No approaches on the gear ratio for better acceleration results in those vehicle speed ranges you race?

 

I expect the temperature to drop to take some times.
Finally plased 4.764 f/d

 

I expect the temperature to drop to take some times...

Cold and dry would be a good requirement for the engine to pull at best performance level...you know your stuff

...Finally plased 4.764 f/d

All about acceleration! Are the gear ratios like you stated before in one of your previous posts, K20actr.J?

 

Yes gears all same.
3.266
2.13
1.517
1.147
0.972 (jdm k20A)
0.659 (tsx)

Changed final drive 5.062 to 4.764 which it's longer 5.88%
That mean losted some acceleration but is not understanding to feeling.

For the time rolling 100-200km it is faster because it is no need to shift 5th gear,but maybe
60km to 200 lost..
Before a week ago had a battle with eg sedan k20 (260hp).
Eg was faster from 60km/h to 230 and 40 to 230 too

Power to weight ratio is same both cars but eg accelerated better because lower weight and shorter transmission.
Maybe 4.7 is wrong choice for road race

 

...Maybe 4.7 is wrong choice for road race

If I find the time, I will feed it into my dynamic chassis simulation to calculate several different roll scenarious next week for you with the given data: gear ratio, FD, weight, torque line over engine speed and some chassis relevant parameters like air drag and so on. What tire size and rims weight do you have on that car?

 

215-45-17

 

What does a single wheel rim (χείλος) weigh? I need it to calculate a first order approximation for the angular momentum of the drivetrain and the rest of the rotating parts... (Χρειάζεται να υπολογίσει μια προσέγγιση πρώτης τάξης για τη γωνιακή ορμή, if Google translator is correct :wink

 

oz alleggerita 7j( 7 width if you mean that) X 17 et 45
6.8kg wheel weight

 

oz alleggerita 7...X 17 et 45...6.8kg wheel weight

Thanks K20actr.J.

I saw your pictures all are lost in the Photobucket.com Nirvana. Could you please send me your last dyno curve to my email or just post it here?

 

Here with Pr4

 

And here with toda A3

 

And here with toda A3...

Thanks for the info :up:. I will find some time on Friday to let that model doing his snappy curves :wink:.

Markus