Cylinder Head project !!!
Jul 2, 2007, 04:52 PM
#290
Alright, some more silly questions.
When RRM first offered the PnP IM, there were a few people opting to go for the DIY solution. Basically, in a nutshell people were suggesting that if you port and polish the IM, you only want to port, but not polish the head as the turbulence created in the runners caused more efficient airflow. Is that right? I assume that it is, and that is why you opted for the knife edging on the intake valve port division...?
When RRM first offered the PnP IM, there were a few people opting to go for the DIY solution. Basically, in a nutshell people were suggesting that if you port and polish the IM, you only want to port, but not polish the head as the turbulence created in the runners caused more efficient airflow. Is that right? I assume that it is, and that is why you opted for the knife edging on the intake valve port division...?
Jul 2, 2007, 05:25 PM
#292
good question. If I understand things correctly some have suggested that the "roughness" of the unpolished head allows for a bit of turbulence in the air which actually helps. I really have no idea if this is actually the case or not, hence why I ask.
The only thing I can find on it offhand is mentioned here, post #13:
https://www.evolutionm.net/forums/sh...+cylinder+head
IIRC, there have been other discussions on this that I simply cannot find. I realize #13 is in reference to the IM, but I swear I remember this conversation coming up before, and someone had suggested that the polish of both could mess things up. Again, I really have no idea so I'm just curious to see what you guys think.
Jul 2, 2007, 05:26 PM
#293
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Actually I didnlt polish anything , The port job was left near polished because turbulence helps the air mix with the fuel better ... that the main reason I didn't do it , I am very technical about my stuff and I dont see a real benefit in polishing it besides the extremely amount of job it requires.... Just port and semi polish
Jul 2, 2007, 07:19 PM
#294
Its a balancing act between maximizing flow and getting a good usable fuel mixture. it has to do with atomizing the fuel through the intake air supply. A mirror finish on the intake will cause the air to flow very smoothly. When the fuel is sprayed into the air stream, if the flow is very smooth, the fuel molecules tend to bunch up and form drops, which wont ignite well in the chamber. Adding a bit of turbulence to the airflow just before the injectors, while slightly detrimental to flow volume, does wonders for atomizing the fuel so that the fuel molecules spread out and form gas instead of a liquid and can ignite easier. Atomization is good for fuel efficiency and power output, so we need this.
So you don't want a mirror finsh on the bottom of your IM. On the top of the runs, its ok, but it wont matter too much since you only flow as much overall as your bottleneck, which is usually in the middle where you cant reach with a die grinder. Its usually good to polish the exhaust side of the head, though.
There have been some 'studies' that conclude that a slightly rough surface actually flows more CFM than a well polished surface. but there have been many more studies saying the opposite. Since the industry opts for super-smooth surfaces on critical parts, I think that theory is where i'd put my money.
Btw, while on the subject, miguel, have you taken a look at the cuts on the valve seat? Does it look like we would have any reason to consider angle cutting the seats, or did mitsu do a good job of this stock?
if anyone is confused by this, heres a good article /w links to start learning: http://www.team-integra.net/sections...?ArticleID=353
So you don't want a mirror finsh on the bottom of your IM. On the top of the runs, its ok, but it wont matter too much since you only flow as much overall as your bottleneck, which is usually in the middle where you cant reach with a die grinder. Its usually good to polish the exhaust side of the head, though.
There have been some 'studies' that conclude that a slightly rough surface actually flows more CFM than a well polished surface. but there have been many more studies saying the opposite. Since the industry opts for super-smooth surfaces on critical parts, I think that theory is where i'd put my money.
Btw, while on the subject, miguel, have you taken a look at the cuts on the valve seat? Does it look like we would have any reason to consider angle cutting the seats, or did mitsu do a good job of this stock?
if anyone is confused by this, heres a good article /w links to start learning: http://www.team-integra.net/sections...?ArticleID=353
Jul 3, 2007, 05:03 AM
#295
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+1 on blk-majik's reply. The fuel could tend to seperate and run down the walls of the intake..
However, we have a dry intake, so it shouldn't matter much... Unless you're running >4 injectors and your spraying into the intake system.
However, we have a dry intake, so it shouldn't matter much... Unless you're running >4 injectors and your spraying into the intake system.
Jul 3, 2007, 05:10 AM
#296
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I've read, not tested but read, that you polish everything except the intake manifold after the injectors. you would only port match this part of the manifold.
Jul 5, 2007, 08:02 AM
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It was 3 angle , and cryogenics was done but I did not posted pics because there is no dofference in the appearance of the cyl head nor the parts.... The only part that hasn't been send to CRYO is the cam which I will call today to know the status of it...