Going Bigger Turbo....Any Suggestions?
06-22-2010, 06:13 PM
#106
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when i dremel the heads, i start with a carbide bit, then sanding barrel, then fine sanding, then light polish. It is actually smoother than the casting marks left in the rest of the head's combustion chamber. I questioned it myself, but 3 different tuners have told me that they didnt see any type of knock issue while adding timing.
have any before and after pics?
i'd love to see that
06-22-2010, 06:21 PM
#107
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factory EJ255 head
2.0 head after a little dremel work, not completed
bad angle on the 2nd picture, but trust me....it's almost the same
2.0 head after a little dremel work, not completed
bad angle on the 2nd picture, but trust me....it's almost the same
06-22-2010, 06:35 PM
#110
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it isnt cleaned or polished yet in that picture,but you can see the general idea...looks 95% the same as the professional CNC job. the curve just isnt as perfectly smooth.
06-22-2010, 06:36 PM
#111
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Yeah there really is no comparison.
the pics speak for themselves.
EQ tuning heads:
VS:
yeah, the prices arent the same, but in this case i guess you get what you pay for.
the pics speak for themselves.
EQ tuning heads:
VS:
yeah, the prices arent the same, but in this case i guess you get what you pay for.
06-22-2010, 06:52 PM
#112
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It doesnt look as pretty, but as far as performance, is it really worth all that money for the probable and likely 5hp gain over a dremel job?
If money is not an issue, sure go for the CNC job. It is better no doubt.
Dremel work it isnt a job for the artistically challenged, but if you can draw or sculpt it's kinda the same idea. It is just recreating what you see or invision.
If money is not an issue, sure go for the CNC job. It is better no doubt.
Dremel work it isnt a job for the artistically challenged, but if you can draw or sculpt it's kinda the same idea. It is just recreating what you see or invision.
Last edited by spinplay01; 06-22-2010 at 07:00 PM.
06-22-2010, 06:59 PM
#113
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i think the peace of mind knowing you have consistent compression ratios across the board speaks volumes for the CNC job. not to mention the proper quench, and combustion volumes. oh and having even pressures on the headgasket in each cylinder is nice too. so yeah.
taking a dremmel to your heads is about as redneck / ghetto as you can get.
taking a dremmel to your heads is about as redneck / ghetto as you can get.
06-22-2010, 07:12 PM
#114
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i think the peace of mind knowing you have consistent compression ratios across the board speaks volumes for the CNC job. not to mention the proper quench, and combustion volumes. oh and having even pressures on the headgasket in each cylinder is nice too. so yeah.
taking a dremmel to your heads is about as redneck / ghetto as you can get.
taking a dremmel to your heads is about as redneck / ghetto as you can get.
haha. i am redneck/ghetto.
but i bet there is less than .25cc variation between all the cylinders. Changing one of your spark plugs to one 3mm longer will make a bigger difference.
I have personally assembled over 100 engines, no, i wouldnt eyeball it and guess on bearing clerances, head bolt torque, or gear lash. but this is one area that it really makes a very minor difference.
the subaru ecu is very intuitive and addaptive, I doubt it minds the .25cc difference.
for example, if you blow a headgasket and machine just one head like .012 inch. it will learn it and run just fine.
06-22-2010, 08:22 PM
#117
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what he said ^
i'd avoid 2.5 NA heads Lorenzo.
just pick up a set of 2.0 heads, have them properly machined, throw in some STi cams and call it a day
i'd avoid 2.5 NA heads Lorenzo.
just pick up a set of 2.0 heads, have them properly machined, throw in some STi cams and call it a day
06-22-2010, 08:24 PM
#118
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i would imagine that they have a large quinch area and possibly smaller chamber.
that would be great if you re running low boost and want quick spool. but if you are going for more top end power, not so much.
I have read that those heads flow better than the usdm wrx heads though.
but i dont think that your intake/ tgv bodies will bolt up to those heads.
ask if they are phase 1 or 2.
or at least get some more pics from multiple angles
06-22-2010, 08:40 PM
#119
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the difference is realiabilty. how long will the stock block last? no matter who your tuner is they can help make it religable but not bullet proof! if any tuner was ever to tell you that they can make you car so it dont blow up is BS and you would be a fool to listen to them...... thats why building is the better way to go. its "less likely" to have things go wrong under extreme conditions.
This is it. Besides, drop in pistons don't increase power. They increase reliability. With the difference in turbo size, it's understandable. Also, the dyno at RADS doesn't load very well. I've noticed that spool especially isn't correct most of the time. His setup is spooling near 3500, mine spools at 4200. an extra 1k rpm of power is worth it. Like he said, my turbo is roughly 2lb/min larger compressor. Also, TD05 exhaust housing vs 7cm^2. I still thought it would make 340, but like he said, Chris tunes conservatively.
