ap2002

iTrader: (8)

I would like to know what the compression will be with this set-up?

LQ4 + 5.3 Patriot Heads milled .050 (sponsor >) + stock gasket =?

with a comp cam 224/224 .581/.581 112lsa, I dont understand alot about heads, from what I read, I just know something about piston/valve clearance? or something like that?

this is not for me, a friend is building a motor and, he collected all this as a budget build, the main thing that concerns me is the .050 milled?

if the gasket is a problem, what gasket do yall recommend to use..?

TurboBerserker

iTrader: (1)

Need to know a bit more...

Stock LQ4 slugs and rods? What is the CC of the head chamber?

I believe he will need to clay a cylinder to check for p/v clearence with that much milling. Check with someone like Richard @ WCCH to be sure though (or just clay 'em to be safe)>

ap2002

iTrader: (8)

yes the lq4 is completely stock, other than cam, motor came with 317 heads and he just pulled them off cause he was just going to mill them but these patritot heads popped up and he got those instead

Tootall

iTrader: (79)

skeet is running a similar setup on his, but he's got a LQ9, with less clearance. He's running the TR cam with no issues.

TXsilverado

iTrader: (19)

he is looking for the dcr and if he can install the heads without flycutting. anselmo if i knew how to figure it out i would do it for you. try the internal section at tech. let them know its a stock lq9 with your cam and lobes. they should spit you out a number and what combo will work best. 5.3Ljimmy was a huge help to me

Yogi Bear

Here's a link to a static compression ratio calculator. I've seen the one for DCR but I don't have the link. I think that you will also need the cam duration @ .006 to calculate DCR.

joshua022

iTrader: (12)

https://ls1tech.com/forums/showthread.php?t=630637

I used these when calculating my new set-up

ap2002

iTrader: (8)

thanks stew, I go over on tech and see what they come up with. FYI.. this is not for me, its for a my friend with an LQ4... i already know with what Im going with..

thanks to everyone else for the info...

TurboBerserker

iTrader: (1)

Need to know this before we can do the static CR.


Two formulas:

Formula 1:

CR =

[{(B/2)^2 * S*Pi}+Vcc+Vp+{(B/2)^2*Pi*(DH+TG)}]
[{(B/2)^2*Pi*(DH+TG)}+Vcc+Vp]

Where:

CR= Compression Ratio
B = Cylinder bore
S = Stroke
Vcc= Combustion Chamber Volume
Vp= Piston Volume
DH = Deck Height
TG = Head Gasket Crush Thickness
Pi = 3.1415


Formula 2: (I prefer this one)

Compression Ratio = (GV+DV+HV-VV+PV) / (GV+DV+HV-VV)


GV (Head Gasket Volume) = Bore(in) X Bore(in) X 12.87 X (Head Gasket Thickness in Inches)

DV (Below Deck Volume) = Bore(in) X Bore(in) X 12.87 X (Inches Below the Deck)

HV (Head Volume) = CC's

VV (Dish, Valve Pocket, Dome Volume) = CC's
(Minus for dish or valve pockets, Plus for dome)

PV (Volume displaced by Piston) = Bore X Bore X Stroke X 12.87


----------------

deck height is -0.008 (yep pistons stick up over the deck)
compressed gasket thickness for MLS = 0.052
LQ4 pistons have a slight dish (which I don't remember)

tarinitup

iTrader: (11)

static compression calc
http://www.diamondracing.net/cocalc.htm

dynamic calc
http://www.bid2race.com/DynamicCompr...Calculator.php