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Discussion Starter #1
I have been researching for i while i have a relatively new 2011 si about 40 000 km. I wanted to play with the engine and some parts and let it rev up but i am not 100 % sure what the stock internal can handle. According to all post valves will start to float around 8600 rpm and the oil pump will become inefficient in that range . So the plan is to fix this problem with Toda valve springs and RRC oil pump. Now the big question is how much rpm the connecting rods and pistons can handle . I am aware that if i rebuild the engine with forged components i will have no problem revving up to 10 000 rpm. There are amazing products on the market titanium valves, beehive springs etc. This is all way off budget unfortunately for me. So if anybody has a good idea what can be done with the stock for please advice. I am willing to spend a few $ to get the car more fun . I am not expecting the to 2 L engine to become 5 L v8 this is not the point. I had very recently a big V8 Mercedes that i crashed and i never looked back. Fuel cost comparing to the Honda is unreal so i would like to stay NA 2L engine . I know that this topic has been discussed before i did spend reading a few post but it wasn't very clear because there was a lot of topic comments.
Thanks to all for your input .
Alex
 

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Discussion Starter #2
About type R pump

Since i did additional research on balance shafts i found that keeping them in is the way to go. I know people will start an argument but here is a link that explains in details way the balanced shafts are where they are now. Keep Your Balance Shafts – Jacks Transmissions
Also there is a link in wikipedia that link is easy to find.
One more thing i know i am answering my own question i am doing this only because i am sure other people wonder the same thing. Since there is so much disinformation the vibrations that does shafts are canceling out are relative to the rpm but in a square relations ship . This means that if the force they generate at 1000 rpm let assume is equal to 1 Newton at 8000 rpm this force is not going to be 1x8^2= 64 Newtons.
 

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It's very interesting that the JDM type R has no balancer shafts as standard. Some one should tell Honda they messed up lol.

I also swapped to the RRC oil pump(JDM Type R) in my K20Z4 engine with a lightened flywheel. The engine revs freely and doesn't bog down like it use to, makes the car much better to drive in traffic or enthusiastically.

I've ran my car with a rev limit of 8600 for years now with no issues. I know of some that run 8800 with the RRC oil pump, although I think that's bordering on the limits of the valve train.


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Discussion Starter #4 (Edited)
This is really interesting. I am not sure how the oil pump will affect your performance light weight flywheel will always help. From what i have learned up until now K series engines are internally balanced so the weight of the flywheel will not affect the engine balance. But if you use a litter flywheel the engine will speed up faster because it has less mass to accelerate . On the other hand the oil pump with no balance shafts will also help to speed up the engine . The problem with the balance shafts is that they are part of the engine internal balance and by removing them you are not balancing the secondary forces that act on the engine internals. How is that going to affect the engine only Honda knows but it is affecting the engine balance . In some cases people will install external detuner that will reduce the effect of secondary unbalance forces. It looks like a pulley with weights and soft compound that will dampen the vibrations. If i were you i will look in to it .
 

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This is really interesting. I am not sure how the oil pump will affect your performance light weight flywheel will always help. From what i have learned up until now K series engines are internally balanced so the weight of the flywheel will not affect the engine balance. But if you use a litter flywheel the engine will speed up faster because it has less mass to accelerate . On the other hand the oil pump with no balance shafts will also help to speed up the engine . The problem with the balance shafts is that they are part of the engine internal balance and by removing them you are not balancing the secondary forces that act on the engine internals. How is that going to affect the engine only Honda knows but it is affecting the engine balance . In some cases people will install external detuner that will reduce the effect of secondary unbalance forces. It looks like a pulley with weights and soft compound that will dampen the vibrations. If i were you i will look in to it .


Are you referring to a harmonic dampener? Also I cant see Honda individually balancing each and every engine... especially a mass produced engine like the K20....


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Discussion Starter #6 (Edited)
They are you will be surprised . Every engine manufacture balance every engine . Every part is weighted and inspected and it has to follow with a specific factory tolerances. Yes harmonic dampener is a different name for the same thing. The purpose of the flyweight in the oil pump is to act as a harmonic dampener . The engine will vibrate more without it and all this vibrations will be transferred to the rotational assembly. About the tolerances it is a fact that if you have your engine hand build you can reach better balance because the machinist can balance the rotational assembly to a higher tolerance let just say factory balance +- 2 grams custom engine build tolerance +- 0.2 grams.
I hope this helps.
 

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A little late but from what I've gathered the Stock Cast Pistons will take about 9200rpm of continuous extended abuse before you risk ripping the wrist pins right out of the pistons. If you don't have cams you won't gain much from going past 8600.
 
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