|
Welcome Guest ( Log In | Register )
|
|
|
 |
Lowering Compression Rate |
|
|
|
| EvilChief
|
| The Evil One |
 |
| Group: ATFC Moderator |
| Posts: 223 |
| Member No.: 146 |
Car Profile: Available
|
| Status: Offline |
|
|
|
|
 |
|
| Posted:May 14 2003, 03:01 AM |
|
|
1tina:
Mick: I have been told that to lower your compression rate, you can get the head shaved, or replace pistons with flat-tops out of a 3.3Lt motor, they fit straight in. you may have to verify this with some-one, as I am not 100% sure.
Just a couple of more ideas for you.
SikXC:
Thanks Tina for that. MIght hafta look into it some more.
1tina:
no probs, thught I'd put it in here just in case I forgot to tell ya
another thing u may want to look into is getting the head shved a few hundreths of a mil, it will make the compression higher (or so I have been told), which will give your motor more power.
V8 Wagon:
you need to be a bit careful when increasing the compression of your motor, standard fuels are not high enough octane for a seriously high compression motor. I was running about 215psi and LRP and ULP would ping like crazy under load, premium unleaded and some of the other higher octane fuels were less of a problem but the only way to get it running properly was to run about 10% racing fuel to lift the octane rating up.
1tina:
would the same problems occure when lowering the compression? or is just when raising it?
V8 Wagon:
what your talking about (flat tops, shaving the head, etc.) is actually raising the compression from the factory standard 185psi to say 200psi, if you wanted to lower the compression ( if you were turbo charging your engine for example) you would have to make a up a spacer, or use two head gaskets (dodgy)
Ferryman:
the other ways of lowering your compression are, using dished instead of flat or poptop pistons. ala XE/FX EFI motors.
Or reworking the squish area of the head to open it up.
Some heads don't have enough meat in the squish area to make appreciable difference. But its always fun to find out.
Fun Cost money, how hard do ya wanna laugh?
EvilChief:
Shaving head | flat top pistons = raising comp ratio, which is good for NA performance figures (as V8 said make sure you use fuel with enough bang to avoid pinging)
Dropping comp ratio you do when u intend to run some serious boost (Turbo or SC). besides the mentioned spacer i have heard of custom conrods, but they tend to be $$$
--------------------
WHOHOO ... got my opens today ... as much as it would matter to me anyway
... and 96 in the ash tray! |
|
|
| Posted:May 25 2003, 12:55 PM |
|
|
 |
|
| 0 User(s) are reading this topic (0 Guests and 0 Anonymous Users) |
| 0 Members: |
| 3 replies since May 14 2003, 03:01 AM |
|
|
|
|
