hey i have had a JDM SIR-II b16a2 (1994) in my eg hatch for over a year and its running great. I installed the ctr intake cam and did a compression test just to see how it was doing........dead on 250 psi across all four cylinders. I'm positive we did the test right.

does this seem a little high to anyone else for what i thought was a stock cr?

I bought the motor from a shop in Asia I think they said they did something to it, but i just assumed it was stock. Has anyone reached these numbers with stock cr, stock head gasket and ctr cam on a jdm b16?

 

Mine was @ 225 across like 2 weeks ago. Yours is pretty high

 

i have a jdm b16 sir2 form a 93. compression is dead on at 240 across. seems like we both have the same issues. My car pulls pretty effin hard for a b16 tho. my motor was an auto, was yours?(maybe the condition of it)


Modified by sheBangZ at 7:41 AM 4/10/2006

 

Carbon buildup on the pistons can cause an increase in compression (from a SCC article).

 

250 is pretty high but the cam isn't going to make your CR higher!

 

my motor has 20 k on it. I don't believe it would have that much carbon build up.

 

yeah im just tryin to think of possibilities, the test yielded dead on 250 psi all four, i just wondering if maybe the cr was bumped up or head gasket changed. I'm trying to find out because i want to jrsc it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EX-T &raquo;</TD></TR><TR><TD CLASS="quote">250 is pretty high but the cam isn't going to make your CR higher!</TD></TR></TABLE>

While it won't make his CR higher, couldn't it possibly make the compression read higher IF the cam was installed a tooth off?

 

the motor is set to stock timing andI know the cam def installed properly, does anyone know the compression numbers for a b16b type r, so i can compare them?

mine is a 5-speed


Modified by deckster333 at 7:22 PM 4/10/2006

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EX-T &raquo;</TD></TR><TR><TD CLASS="quote">250 is pretty high but the cam isn't going to make your CR higher!</TD></TR></TABLE>

In most cases, a lumpier cam will make it read lower...

Sounds fishy to me...Test done at WOT?

 

oil in cylinders maybe. most performance cams will lower the reading because of more overlap.

 

Weird. My B16A tested at 240 across but my head was milled .020

 

the compression tester i am using is made by "ACTRON"

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by deckster333 &raquo;</TD></TR><TR><TD CLASS="quote">the compression tester i am using is made by "ACTRON"</TD></TR></TABLE>

Yeah thats what I used to. The autozone one lol. I heard they could be off a little. By off I mean the numbers could be slightly lower/higher in actuality. But as long as the numbers are all the same, you should be sound as a pound.

 

i just got an email back from my guy at the shop i bought it from over in singapore, he said he thinks they put type r pistons in it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by deckster333 &raquo;</TD></TR><TR><TD CLASS="quote">i just got an email back from my guy at the shop i bought it from over in singapore, he said he thinks they put type r pistons in it.</TD></TR></TABLE>

I'd take that as a grain of salt

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by deckster333 &raquo;</TD></TR><TR><TD CLASS="quote">i just got an email back from my guy at the shop i bought it from over in singapore, he said he thinks they put type r pistons in it.</TD></TR></TABLE>

ITR pistons would lower the compression. But CTR then maybe.

 

just for reference ctr's in a b16a should raise the comp to near 11:1

 

could be leaking injectors or oil getting in there somehow....i had some bad injectors in the gsr and the compression was almost 300!!!!...so check for that stuff.

 

i redid the test and only cranked a few times instead of untill the needle stops and they all go right up 245 PSI. There is a really good chance there is ctr pistons in there and as stated that would make an 11:1 compression. hmmmm gotta think about the JRSC; which pulley and tuning.

 

if its 245 its probably closer to 10.7 :1

 

Anyone running ctr pistons with a b16a2 please post your compression results so I can compare. thanks

 

if you do have ctr pistons...DO NOT SUPERCHARGE IT.

 

run sea foam through it

 

I have heard bad things about sea foam drying everything out, i ran a gas additive engine cleaner (guarenteed to pass) recently. maybe ill run it again and do another test to see if its carbon build up. Someone also told me 245-250 PSI is normal for a b16, but seems too high to me.