does anyone know how high the compression will be if i install standard bore ctr pistions or jdm integ pistons into my 1st gen JDM B16a?


MODS on my motor:

type R cams(both)
type R manifold
p30 ecu
gsr hydro tranny
type R axles
Planning on adding type R fuel injectors

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by methos713 &raquo;</TD></TR><TR><TD CLASS="quote">does anyone know how high the compression will be if i install standard bore ctr pistions or jdm integ pistons into my 1st gen JDM B16a?


MODS on my motor:

type R cams(both)
type R manifold
p30 ecu
gsr hydro tranny
type R axles
Planning on adding type R fuel injectors</TD></TR></TABLE>

10.8:1 would be the new compression ratio. Why would you run Type R axles? They are no different then other B seris axles. Same with the type R injectors. 240cc, just like all the other B series. If you want an injector upgrade then go with Prelude injectors. Don't think its going to help you much, if at all. But each to his own.

 

got the type r axles for under a 100, it was cheap, so i got it. As for injectors, thanks for letting me know.

 

Compression will be a little higher than 10.8:1. More along the lines of 11-11.1:1. Less deck height and rod length with the same piston will yeild more compression.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by WAFFLEStheDude &raquo;</TD></TR><TR><TD CLASS="quote">Compression will be a little higher than 10.8:1. More along the lines of 11-11.1:1. Less deck height and rod length with the same piston will yeild more compression.</TD></TR></TABLE>

I don't see how. With a B17, compression is 11.3:1 with CTR pistons. It has a longer stroke. How could the B16 be higher then this? I used the C speed compression calculator to get these numbers.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by methos713 &raquo;</TD></TR><TR><TD CLASS="quote">got the type r axles for under a 100, it was cheap, so i got it. As for injectors, thanks for letting me know.</TD></TR></TABLE>

That makes sense.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Na99Si &raquo;</TD></TR><TR><TD CLASS="quote">

I don't see how. With a B17, compression is 11.3:1 with CTR pistons. It has a longer stroke. How could the B16 be higher then this? I used the C speed compression calculator to get these numbers.</TD></TR></TABLE>

there's your problem. C speeds calculator is off by about .2. I don't really like it.
A stock b16B's compression is 10.8:1. Now if you have ever seen PCT pistons in a B16A engine you will notice how much more they stick out of the block compared to the B16B. That little bit of area makes a difference in compression.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by WAFFLEStheDude &raquo;</TD></TR><TR><TD CLASS="quote">

there's your problem. C speeds calculator is off by about .2. I don't really like it.
A stock b16B's compression is 10.8:1. Now if you have ever seen PCT pistons in a B16A engine you will notice how much more they stick out of the block compared to the B16B. That little bit of area makes a difference in compression.</TD></TR></TABLE>

Hmm.. Well, I guess that makes my compression around 11.5:1. Oh well. Seems to run just fine on the lovely CA 91 octane.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Na99Si &raquo;</TD></TR><TR><TD CLASS="quote">

Hmm.. Well, I guess that makes my compression around 11.5:1. Oh well. Seems to run just fine on the lovely CA 91 octane.</TD></TR></TABLE>

I've heard its about 11.3-11.5 in a B17...not like the numbers are all that important. How do you like the b17 compared to the B16?

try http://www.bojangs.com/calculator

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by WAFFLEStheDude &raquo;</TD></TR><TR><TD CLASS="quote">

I've heard its about 11.3-11.5 in a B17...not like the numbers are all that important. How do you like the b17 compared to the B16?

try http://www.bojangs.com/calculator </TD></TR></TABLE>

I can't really compare the two fairly. I used to have a 99 Si.. Turbo'd it, blew the **** up racing my friends NSX one night on the highway.. Then tried the all motor route. Eventually I sold the Si in favor of a cheaper car. Got myself a hatch and did a swap. The swapped hatch traps 3mph faster then the turbo Si and .2 tenths quicker in the 1/4 mile. I would MUCH rather have this hatch then the Si, but like I said... not really a fair comparison seeing as how the hatch is 600lbs lighter.

 

How does the CTR pistons in a B16A feel compared to the stock PR3 or P30s? I might end up having to do the same setup, but it's going to be in a DA. I just want to know if it's worth it?

 

this guy in L.A. told me that ctr pistons in a b16 with the high compression would make the pistons melt in a matter of months. Also it would make the compression ratio be 12 something....i've decided to go with another set up...jdm itr pistons...compression won't be too high...and hopefully i will be able to use 91 octane.

 

with ITRs, are compression might be around 10.4 or a little higher. I don't think it's worth the money.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by emissionsux &raquo;</TD></TR><TR><TD CLASS="quote">with ITRs, are compression might be around 10.4 or a little higher. I don't think it's worth the money.</TD></TR></TABLE>

Thats just plain incorrect. Don't go telling people false compression ratios when you have no idea what you are talking about. There are plenty of compression ratio calculators out there that are faily accurate, and all of them are within about .2 of your actual numbers. You realize that by telling him this, that he would actually have about a 9.8:1 compression ratio (with USDM pistons), which if he actually did it would be a total waste of money since hes trying to go all motor?

 

i'm not telling anyone about the compression, like i said...a guy who was selling some pistons told me this...since he was selling the whole pistons set with rings for 270. And plus i was the one who posted this thread up...wanting to know what compression my motor might be in if i put ctr piston in it....so don't be saying i'm giving people wrong things....i'm just telling what i was told....since no one hear seems to know or have not answer my questions...read the 1st post and reply to me what the compression would REALLY be.

 

just do the PCT pistons.. 11:1 is perfect for a mild all-motor setup..

(working on same setup but GSR motor &lt;12:1&gt; -hk)

 

cool, i'll go with the ctr pistons then...thanks for the reply.

 

In a unmodfyed B16a1 block (1st gen B16) and a unmilled head the CR will be 11:1

 

LOL... funny reading some of the posts.

I don't trust any of those online calculators because they don't use the corret formula and that there are some variables to take into consideration. Those calculators usually read too low... one guy was totally set on believing that his LS/VTEC setup w/CTR pistons & B16 head was 11.5:1 comp, when really his car was 12.5:1 cr. Using bore size, rod stroke, crank, deck height, cc size, etc, we usually do the math ourselves.

B16A w/PCT CTR pistons will yield approx 11.0-11.1:1 comp
B16A w/US ITR pistons will yield approx 9.6-9.7:1 comp
B17A w/PCT CTR pistons will yield approx 11.4-11.5:1 comp

If you have a stock B16A and mill the head .004, then you'll bump it up .8 to 1 full point of compression.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by methos713 &raquo;</TD></TR><TR><TD CLASS="quote">this guy in L.A. told me that ctr pistons in a b16 with the high compression would make the pistons melt in a matter of months. Also it would make the compression ratio be 12 something....i've decided to go with another set up...jdm itr pistons...compression won't be too high...and hopefully i will be able to use 91 octane.</TD></TR></TABLE>

Now that is a HUGE load of crap. Been running mine for quite some time now with 0 problems.