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Discussion Starter #1
Hey i've been kicking around the idea of rebuilding my motor and i thought about raising the compression to 9.5:1 ..... hold on i know what your thinking .... detnotation ... but i was thingking of keeping the boost at about 10psi ..... while im not conserned with making gobbs of horse power im really just looking to get the best response out of my motor and i thought this would be the best way ... i've heard of people chainging out their 8.8:1 pistons to 9:1 but how come on one has gone a little higher? just kicking around the idea and wanted to see what you guys thought and/or had expirence with. I know there are turbocharged versions of SR20's running in the NA SE-R's on 9.5:1 pistons ... anyway just some food for thought let me know what you guys think. Thanks
 

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With well designed pistons, a good combustion chamber, good fuel, and good fuel and spark maps, you'll be fine upwards of 10:1. 9.5:1 should be cake as long as you're careful.
 

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I haven't been down the road of 9.5:1 pistons before, but I'd have to agree with PseudoRealityX. My new shortblock is 9:1 and it's just fine so far (still breaking it in). I think it'd be nice to see some people experimenting with higher compression on the 3sgte. I would think as long as you keep your intake temps low with a good intercooler setup, have plenty of fuel available and adjust your timing maps accordingly you should be fine... but then again I'm no expert at this.
 

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If you want response and not a lot of power, couple your higher compression with a CT20b turbo. A lot of people will vouch for how much it likes to spool. :) Good luck with your rebuild.
 

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Discussion Starter #5
yea i was thinking along the lines of a CT27 because my stock one is due for a rebuild anyway.... Yea im gald there are people who areusing the idea of higher compression ... no one in my area understands the idea of having good response over high peak power ....

Baktasht .... what are you running for a turbo setup and what are you going to run for pressure? Yea i know about haveing a good intercooler lol my friend just blew up his talon lol anyway i was wondering about the setups for that too it was thinking trunk mount like jekyl's but i would have to do a lot of cutting another option was the berk technology side mount what do you guys think is the best for response and cool intake temps.
 

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Discussion Starter #6
Basically my goal is much like mazda's to make it seem like the turbo isnt even there .... have the car feel like a really good 2.5L as apposed to feeling like a 2L turbo.
Thanks for your responses they were very helpful so far ..... sometimes when i throw out a idea it needs a reality check but i think this one should be worth trying it.... i alos had a question about the oil pump.... as far as RPMs go how high can you rev on a stock oil pump and what do you upgrade too? Thanks again
 

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I normally run 14-16psi on my 9.2:1 DSM motor (and it was dyno'd at 18psi originally on pump gas, just starting to knock). Have been thinking about a 10:1 motor for autox in it. 4g63 is VERY similar to the 3S-GTE, so I don't see a problem with 9.5:1
 

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Discussion Starter #10
thanks i just need to resarch other things like cams .... i know its not nessary until you reach like 300hp but i figure if i want the revs to stay up with the horsepower i should change to different cams? im no expert but if i can change the cams or something else to make more liner power and more of a flat torque curve it would be amazing but this car still is my daily driver for now
 

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On my 4agze in my 89 I had a regular block with 9.5's was boosting just shy of 11 just fine because of my larger pulley. But this car was running pig rich above 3500 anyway so I wasn't worried about fuel.

Bottom line sure it can be done. But make sure you have your fuel and timing set up right or you WILL have problems.
 

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Discussion Starter #12
hmmm good to know i cant find any pistons for my block thats are 9.5:1 if i send a stock piston to a company like JE pistons will they costom make one or will it cost a arm and a leg
 

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high compression is no risk as long you keep enough fuel and timing...

never noticed the new VW Golf MKV GTI ? 2.0 turbo 200hp with a compression of 10.5 !!
 
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