Honda / Acura K20a K24a Engine Forum banner
1 - 20 of 31 Posts

· Registered
Joined
·
21 Posts
Discussion Starter · #1 ·
Hi,
Recently, I was finally able to dyno my engine with low dyno results I wanted to share. My build;
88x99 K24, stock crank
14.5 compression
4P 163 Head (k20Z1)
S2 Ultra 3 cams
4P cam gears
4P ported ultra manifold/90mm tb
4P assembly & cam degree
Myers under car header/3" exhaust
Sunoco E85-R fuel

The tuner said its' probably a mixture of the cam profiles and no vtc. His suggestion was use a different cam and add vtc back to mix.
 

Attachments

· Premium Member
Joined
·
6,801 Posts
i wouldnt say its low... but its low for the effort you put in it.

1. this forum historically doesnt use S2 anything...
2. did you build it yourself? adjustable cam gears, aftermarket cams, high compression... did the motor get clayed to set the advance on the cams?
3. what does 4piston say? since they degreed the cams and all
 
  • Like
Reactions: neomegasupreme

· Registered
Joined
·
21 Posts
Discussion Starter · #3 ·
4Piston assembled the long block and degreed the cam gears. I emailed them for advice but haven't heard back. I'd like to send the long block back to them, and have them install their RR4 cams, and degree the engine with VTC. I don't know how to degree cams.
 

· Arouse the DAMPFHAMMER!
Joined
·
10,383 Posts
The S2 U3 cams are really huge (277°/275°@1 mm lift of in and ex cam).

The tuner said its' probably a mixture of the cam profiles and no vtc. His suggestion was use a different cam and add vtc back to mix.
What centerline or fixed cam angle did the tuner set the cams? I don't think the cams alone are the root cause of this flat torque line, they are indeed huge, but when I look at the lambda curve I would say there is much left, indicate tuning is not finished and has further potential. The VE seems to be insensitive to engine speed, which happens either if the cam is too big and quite retarded. Would be great to see the calibration and WOT log, if you don't mind to share. Especially the clay and cam center setup.

4Piston assembled the long block and degreed the cam gears. I emailed them for advice but haven't heard back. I'd like to send the long block back to them, and have them install their RR4 cams, and degree the engine with VTC. I don't know how to degree cams.
I don't think that heals the full story. I assumption is the ex-camshaft has to less overlap or too less lift at TDC. What was the claying result? For me this looks a bit too much wrongly setup'd. I wouldn't give up so fast, the engine is still not finished in tune, the cams where clayed by 4Piston. I would be really interested which cam angles on ex and intake were run and tuned.

In Stuttgart we would say "des hot a Gschmäckle!", in the US you may would say this is highly suspicious.
 

· Arouse the DAMPFHAMMER!
Joined
·
10,383 Posts
...this forum historically doesnt use S2 anything...
That's right with the S2 Tuner series cams, which are really nothing for a K-series quality level. Big but, the Ultra series is a different dimension and gave us better results in terms of reliability as the RR-series of 4Piston.
 

· Arouse the DAMPFHAMMER!
Joined
·
10,383 Posts
Does this help?
At a quality level yes, but not on a quantity level, therefore I would need the picture with their degreeing card. The exhaust cam is quite advanced, and the intake cam is quite retarded, which aligns with my above mentioned assumption. Do you have the clay results on these cam phase angles available?
 

· Arouse the DAMPFHAMMER!
Joined
·
10,383 Posts
I will ask 4P if they have the build data. I think they provided it to me but it was about 3 years ago this was built and I believe I lost it along the way. If I can figure out how to get the tune data out of Hondata, I will send it.
These are good news. Both would help a lot to find out why the heck the torque is so insensitive to all the resonances of the header. Could you provide also further data like the valve sizes and exact header model?
 

· Registered
Joined
·
21 Posts
Discussion Starter · #13 · (Edited)
50 degree 37MM valves
https://myerscompetition.bigcartel.com/product/k-series-under-car-race-header , 3 step header, not the pro series. I bought it new from them so I had to give them the engine build specs.
Yeah, we are confused on the torque as well. On the dyno, we were fighting it breaking up bad at 6K+. We traced it back to poor crank trigger connection and too big of a spark plug gap. We settled on .020 gap I believe at the end to make full pulls without break up. The dyno operator said to wire the crank trigger sensor direct to the ecu next time in lieu of the rywire harness. Also, to go back and dremel all the grounds to bare metal between the engine and the chassis just to be safe.
 

· Registered
Joined
·
1,034 Posts
Not for nothing but i’ve seen “tuners” undegree engines because they didnt understand what they had to do with the setup. Not making any assumptions but your combo is pretty common, at the very least i would go back go a VTC gear on the intake, i’ve seen better results in top tier all motor cars going back to vtc instead of solid degree gears.
 

· Arouse the DAMPFHAMMER!
Joined
·
10,383 Posts
Yeah, we are confused on the torque as well. On the dyno, we were fighting it breaking up bad at 6K+. We traced it back to poor crank trigger connection and too big of a spark plug gap. We settled on .020 gap I believe at the end to make full pulls without break up. The dyno operator said to wire the crank trigger sensor direct to the ecu next time in lieu of the rywire harness. Also, to go back and dremel all the grounds to bare metal between the engine and the chassis just to be safe.
Oh, that means your tuner and you didn't do a check up of the engine upfront of the tuning: leakdown test, TDC-IGT timing confirmation test, oil level check, clay result discussion and cam angle variation bandwidth clarification and so on before starting idle tuning, correction table check or zeroing of it...?

If your engine need a gap of 0.020", then it may be the case the ground electrode touched the piston already. Maybe the spark plug gasket was missing or to flat already? Even CR 12.5:1 86x86 engines can run 0.030" on idle fine and smooth. Gapping them down means the misfire issue came from another root cause, not the spark plugs.

To clarify this around the ignition of an air fuel mixture:
  • the electrical energy of the ignition coil is concentrated into a very short duration of 100-400 ms and is therefore able to build a plasma, which has up to 6000 °C
  • tuning the ignition system:
    • the bigger the spark gap, the more energy will spark over and heat up the involved as long as the ignition coil can supply the energy to fill up the necessary electrical capacity and voltage level. Counter parameters are: a too high gas velocity through the gap at spark timing, blowing it out, insufficient fuel mixture and or or droplets at the electrodes, to low energy or a too low winding ratio of the ignition coil and so on. Gap size has to be tuned on that two counter fighters.
    • the higher the cylinder pressure the higher the voltage threshold needed to breakdown the gap with an electron driven plasma. That means, on boosted engines, where cylinder pressure is system immanently higher the gap need to be lowered to align the ignition coil capacity, if not adapted
  • on E85 the gap size would need to be bigger from an standpoint of a thermo-chemical demand, but as E85 has a much slower evaporation, just because of the higher not yet vaporized mass, entering the combustion chamber, the same gap can do the job also, just suffer more on low load misfire.
But in any way, once lowering the gap size helps to reduce WOT misfire there is something different going on, where the ground electrode is only showing the symptom, but not the root cause. I would measure the distance between gap and piston first. And maybe adjust the gasket height to correct the tip distance.

BTW, I would change the tuner too, there are too many unsolved questions at your engine and the tuning and that guy claims that only on the cams? I would expect different from an prof. tuner.
 

· Arouse the DAMPFHAMMER!
Joined
·
10,383 Posts
what's wrong with s2?
S2 underestimated quality process demands:
This is a short list of it. I am not aware of what was user and what is Skunk2 related, but there were built rumours of a bad quality. But remember these guys were one of the first in the market and always went big and were quite successful with their parts NHRA, NOPI and other stuff. They gone through hard times and are still on the market, some improvements on the quality side were done. The Ultra Series is a step forward in design and material quality. For me I made with all US aftermarket companies, I ever bought parts, not the best experiences.

I won't compare them, but it seems to me there are several points causing it: time to market, lack of competence or wrong partners, not finished design process and what almost always is the case, customer does not intentionally the endurance testing for them. We have to remember, this is an enthusiast driven scene, which is valid for the aftermarket companies too. They have all no time and may also not the budget to finalize the design process properly, but of course their approaches to get there and their level of reaching it is different. It doesn't matter were you buy, there is a risk, which I price up into products when I buy from the US aftermarket for revise design or quality issues. But finally, there are parts, which saves a lot of time and money.

Compared to that, I never had quality issues with parts from Japan. Why that? Their market and culture is different. For an Japanese company reliability and reputation is cultural immanently of an much higher value, also there market is more based on circuit racing then on 1/4 mile like in the US. There design approaches align much more the durability factor and therefore their designs are not as extreme as and of better quality. You won't find e.g. cams specs from Japanese companies which compare to that of the US companies. JUN, SPOON, TODA, all of them have no high speed valve lift higher then 13 mm. Why? It is not necessary for their market, but durability is a demand on it, which is not the case for the 1/4 mile driven US market. There seems to count 3 numbers: peak values for power, torque as well as the 1/4 mile time. The curve shape of the torque is almost not of interest. Which is, if you run around a circuit for hours and gears count is lower then 100 ;).

So I wouldn't point to any of these brands and companies, just to parts, which are known to have a lack in design or quality, e.g. like the S2 Tuner-series camshafts, which are too hard on the seating ramp. The S2 Ultra series is are an improvement over those.
 

· Registered
Joined
·
1,034 Posts
what's wrong with s2?
They had a past, comes with being the first on the scene, for what it’s worth, their cams are what’s law in the best and highest performing NA cars in the world now, can’t hang the BS of the past on them anymore
 
1 - 20 of 31 Posts
Top