noriceoz

what compression do we run

HobieKopek

iTrader: (8)

9.0:1. Next time please search.

EDIT: Moving btw since this has nothing to do with forced induction.

TypeIII

Well it kinda does... High compression + Forced induction = Boom

Boeturbolancer

iTrader: (26)

9.5:1 would be the stock lancer and ralliart compression

Hobie... where did you get 9.0:1?

Spiderman

Hey boeturbolancer I was wondering if you got the thicker headgasket yet? I remember you saying you were going to do it but I wasnt sure if you went ahead and did it. If so, how much did it lower compression and how much did you raise boost?

Boeturbolancer

iTrader: (26)

I never did it... decided to start playing with my mustang instead. The gasket i had planned was the 1.10mm which should have dropped me to about 9.1-9.2:1 and i was going to run 12-13psi on pump gas... 15 on race gas.

rhyzin

iTrader: (1)

does dropping compression mean you can run more boost on stock rods?

Boeturbolancer

iTrader: (26)

not exactly... the rods are still a factor as to strength. (if they can't take the power then lowering compression won't help since you are actually adding power that way)Lowering the compression ratio in the cylinder drops the temps down at max compression. Thus you are able to add some boost and in some cases add some timing back in. This gives you more power and tends to be safer. Remember for every 2 psi of boost you go up one point of compression. When your compression ratio gets up to around 15:1 you start getting preignition and detonation. This can be detered by higher octane fuels but running race gas for daily drivers isn't feasible for most. By dropping the compression down you can boost more before acheiving this volitile point in the combustion cycle.

lookslikeanevo

iTrader: (23)

is there a gain to higher a compresion(if possible) in an n/s app?

Boeturbolancer

iTrader: (26)

do you mean in NA applications? If so then yes there are great advantages in higher compression ratios for NA cars. A lot of higher hp/tq NA cars get there by running 11:1 or even 12:1 compression ratios. In the 2.0L setup we have, a jump to 11:1 could net you 30hp. However you'll need to have this setup tuned as the stock ecu will not adjust the fuel/timing properly for that high of compression.

Some drag applications run 13:1 compression ratios or higher. There is a limit though as the heat generated at those ratios is just as intense as in a boosted application. It is more controllable though since there is less to it but it still requires professional tuning.

lookslikeanevo

iTrader: (23)

ya i meant n/a...what do you mean by having it tuned?...ems? ..and how do you actually raise the compresion?

Boeturbolancer

iTrader: (26)

Also keep in mind that lowering the compression ratios usually creates a drop in torque levels... raising them creates an increase. With proper tuning these drops/increases are negligeable due to the higher hp levels achieved but they are relevent.

rhyzin

iTrader: (1)

hey boe, do you happen to know of any good books whether on NA or turbo?

Spiderman

Hey boe do you still have the gasket?

Boeturbolancer

iTrader: (26)

No i don't... check with RRM. I left it there and i'm sure they still have it. Talk with Rob. If he still has it i'm sure he'll sell it to you.

As far as tuning for higher compression you could just use a piggyback like the emanage for it. You can raise compression by changing the piston top/height, decking the head down, increasing the bore size, etc. All these require motor work though.

As far as books go i don't know of any off hand. You can just go into any library though and research both Forced induction, Naturally asperated, and Nitrious applications.