Dish Valves VS Flat Valves

Aussie

Zoom-Zoom
Ok nice copy and paste :roll:

1. Compression ratio comes down to clyinder pressure.
2. More cylinder pressure equals more power
3. Lower compression equals less cylinder pressure, so more room for boost
4. Higher compression equals more cylinder pressure so less room for boost

High compression boosted engines aren't really worth it, you can make more power, safer, on a lower compression motor.

Dynamic compression plays a big role in your motors performance also and is the bigger factor when it comes to compression ratios. This type of compression takes into account your cams, valves, head, etc.

Here is a real write up if you want to learn something, not just a bunch of big words:lol:
http://www.clubintegra.com/board/showthread.php?p=317467#post317467
 

Cheesenip

I <3 2.4l's
Spody02 said:
ok well what should i run 9.0:1 or 9.8:1
with dished?
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If you plan on boost, go 9.0:1...or lower.

the SRT is stock with 8.1:1..and my na 2.4 is 9:5.1. you can boost the 9.8:1 but you wont be able to run as much boost.
 


patrick4588

Integra God
im on 9.7:1 pistons and i feel thats a good number for boosted cars. look at most drag racers, they run at least 10:1 compression. they run on race gas and 40+psi. higher compression motors make the same hp as a lower compression motor with less boost; and they spool faster. the only drawback to higher compression is detonation. if you have a good tuner, you should have no problems having 10.5:1 or lower turbo car. you will be able to make about 450-470whp on pump gas and not worry about anything. srt's come with such low compression because those cars do not get tuned individually. every car gets the same ecu, but some cars are at different altitudes and every motor responds a tad bit different. the lower compression is only a buffer since the dealer has to warranty the car. there is nothing wrong with a high compression (meaning 10.5:1 or lower) turbo motor.
 

dc2GS-R

Super Moderator
patrick4588 said:
im on 9.7:1 pistons and i feel thats a good number for boosted cars. look at most drag racers, they run at least 10:1 compression. they run on race gas and 40+psi.
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But that is a strictly drag race car that gets rebuilt every 6 months, not a street car
 


dc2GS-R

Super Moderator
I'm just saying I wouldn't purposely go build something like a 10.5:1engine for a turbo street car
 

Cheesenip

I <3 2.4l's
i agree 10.5:1 is kinda high for a boosted street car. id go as low as you can then boost the living shit out of it
 

Aussie

Zoom-Zoom
I'm running 9.5:1 in the MS3 and that's really nothing considering it has direct injection.

Honestly in b series I would run around 9.5:1, that will still give driveability and response and be low enough that you'll be able to boost the shit out of it without any problems.

Though Patrick is right, like my previous post, it all boils down to cylinder pressure and that's what makes torque which makes horsepower. The more compression the smaller the turbo and less boost you will need to run to make the same horsepower. But it is a lot harder to tune and I wouldn't recommend it because of the fact that your really pushing the limit. On a daily driver it's just not necessary, there's too many more safety factors that come into play when dong the higher compression + boost combo and it's safer and just as easy to obtain the same power by doing the latter.
 
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patrick4588

Integra God
on another note, lower compression will make the turbo spool slower and lower the response. on a daily driven car you want some kind of response and torque in the lower rpms
 

Cheesenip

I <3 2.4l's
patrick4588 said:
on another note, lower compression will make the turbo spool slower and lower the response. on a daily driven car you want some kind of response and torque in the lower rpms
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nuh uh, the srt4 is 8.1:1 and its at full spool before 3k..blows off at idle :oops:
 

Aussie

Zoom-Zoom
patrick4588 said:
on another note, lower compression will make the turbo spool slower and lower the response. on a daily driven car you want some kind of response and torque in the lower rpms
Click to expand...
That's not really true, turbo sizing, piping diameter, etc, there's a bunch of other things that factor into spool and response time.
 
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