Thread: Will be 10:1 High compression engine?

Hi, guys, I would like to know if this engine, that a saw in a junk yard is really true a JDM High compression 10:1. Ok here is that i know is JDM, dont have a EGR, has tubular exhaust, dont have JDM ribs and on the head have the code stamped 53J 5L.

Here some pic that i took that day. Any would be great, thanks for every thing.

Looks like mine JDM SR20DE from an HP10 10:1 cr.
Dont take me for granted but i really think thats a jdm 10:1 de.

What is your head code? the same one 53J 5L? if you can take a picture, i appreciate that very much!

Ok here is the Big Question for the SR20 gurus, if a JDM engine has stainless steel tubular exhaust is always high compression, thats mean 10:1? or any body saw or know about 9:5 compression wiht tubular exhaust?

From what i know ,not sure, jdms are all 10:1cr as also the eudms they both share tubular headers.I have both of them (jdm currently rebuilding eudm on car running) and they both are 10:1cr with tubular exhausts.

Pic i ll post tomorrow.

thanks man i wil waiting the your pics

Jdm de's are not all 10:1 most are 9.5:1. You for sure have a jdm motor the intake mani looks to be different from the uk one. I have a uk 10:1 and the only way to know for sure is to pull the spark plugs, shine a light into the cylinders, and see if the pistons are flat top, dished, or have valve receses. If they are flat top is it 10:1. You can also check the engine codes.

I wont desagree with SneakyOwner but from my experience from my 2 moters they both are 10:1 with the same tubular exhaust and same intake manifold.The only difference were the injectors and fyelrail the jdm had sidefeed and the eudm had topfeed.

Pics from the jdm head.






If tou cant see the code well it is 53J4R

Pics from the jdm 10:1 pistons




Pics from the uk one


The red injectors on the uk one are the sidefeed jdm ones as it originally had topfeed bosch ones (if i recall correctly).

thanks for you pics, i can see that you have a black channel on your silver valve cover? is black channel or just shadows.

Ok, i read a post from andreas miko, that he said most JDM engines that i have seen with tubular exhaust are high compression, 50% wiht regular exhaust are 9:5 and 10:1. http://www.sr20-forum.com/general-sr20/11407-how-indentify-10-1-vs-9-5-sr20-motor-oil-drain-tube.html

that is possible, check the piston with a flash light? and see if a flat piston.?

On the Jdm silver (more like champagne the colour) head yes there is a black channel in the middle where the plugs go.
The red ukdm one it is for sure 10:1 with flat pistons as we changed its head gasket for precaution.

Yup its a 10:1 congrats have fun. My boosted 10:1 pulls like a bat outta hell, but I don't think you will be boosting yours.