I have a b18c1 with ctr pistons, i bought a 94 gsr head and a 90 jdm b16a head. The b16 head was turbo'd and had about 40k miles on it, the 94 gsr head had about 40k on it.


Modified by stock93cx at 1:10 PM 9/9/2003


Modified by stock93cx at 1:18 PM 9/9/2003

 

gsr....

 

CTR pistons with GS-R head = crazy-*** compression.

What block are you putting this crap on?

The CR with the GS-R head might be too much for what you're thinking of...more input/details please.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C5-EH2 &raquo;</TD></TR><TR><TD CLASS="quote">CTR pistons with GS-R head = crazy-*** compression.

What block are you putting this crap on?

The CR with the GS-R head might be too much for what you're thinking of...more input/details please.</TD></TR></TABLE>

ya my set up is, b18c1 with STANDARD ctr pistons, skunk 2 stage 2 cams, crowner or toda (still searching) valve springs and retainers. both head and block are rebuilt with 0 miles. still looking for a b16a2 tranny

 

any others?

 

what kind of comp will that make then, ctr pistons and a gsr head?

 

whats a comp? ctr pistons in a b18c1 long bock

 

comp means compression ratio. do you have anything? or are you trying to ask questions on what you should get? the fact that you put "STANDARD" in there makes me think that you might want to do some researching first ( i know you mean standard bore, but that was totally irrelevant). You do know that if you put the B16A head on that you will have lower compression than you will if you put on the B18C1 head. i guess you're just trying to get out of the 18's huh?

 

no i have both heads should i use the b16 or gsr?

 

you'll make more power with the gsr head. it's about .2 more compression over a b16 head.

Rod

 

You know, for some reason I thought that the b16 head increased the compression versus the gsr head. I checked and i'm wrong....

For you guys out there I calculated the compression as this:

b18c block w/ GSR head: 12.4:1
b18c block w/ B16 head: 12.09:1

All stock headgaskets and stuff using pct (jdmb16B) pistons.

Here's a link to the website that I calculated it:
http://www.c-speedracing.com/h...c.php
Very neat little tool to getting an approximate value of the cp.

On a side note, don't forget to get some nice cams to really let that compression sing! If you use the gsr head, your getting very close to the border line of having to run a higher octane. (I know the bay area, we only get 91 octane.)

 

thanks i was wrong also, i thought the b16 was exactly like the type R except different valve springs, retainers, cams, and the rest of the internals.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EG(6)SR &raquo;</TD></TR><TR><TD CLASS="quote">You know, for some reason I thought that the b16 head increased the compression versus the gsr head. I checked and i'm wrong....

For you guys out there I calculated the compression as this:

b18c block w/ GSR head: 12.4:1
b18c block w/ B16 head: 12.09:1

All stock headgaskets and stuff using pct (jdmb16B) pistons.

Here's a link to the website that I calculated it:
http://www.c-speedracing.com/h...c.php
Very neat little tool to getting an approximate value of the cp.

On a side note, don't forget to get some nice cams to really let that compression sing! If you use the gsr head, your getting very close to the border line of having to run a higher octane. (I know the bay area, we only get 91 octane.)</TD></TR></TABLE>

Exactly why I said in my first reply that the GS-R head will yield some crazy-*** CR for the street.

12.5:1 CR is streetable, but 93 octane is a must and depending on where you live (temp wise) it can still detonate in extreme summer heat.

Also if you don't have a good engine management set-up or you won't be tuning it any time soon on a dyno, the 12.4:1 CR will be a bad idea anyways.

Your overall plans will effect what head you will want to run.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18C5-EH2 &raquo;</TD></TR><TR><TD CLASS="quote">

Exactly why I said in my first reply that the GS-R head will yield some crazy-*** CR for the street.

12.5:1 CR is streetable, but 93 octane is a must and depending on where you live (temp wise) it can still detonate in extreme summer heat.

Also if you don't have a good engine management set-up or you won't be tuning it any time soon on a dyno, the 12.4:1 CR will be a bad idea anyways.

Your overall plans will effect what head you will want to run.</TD></TR></TABLE>

are u saying the gsr is not reliable daily driven with my standard ctr pistons? also my connecting rods should work right?

 

ok i done search and they said it should be fine with ctr pistons on a b18c1 long block. thanks for the help. BTW im going to use my gsr head now

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by stock93cx &raquo;</TD></TR><TR><TD CLASS="quote">ok i done search and they said it should be fine with ctr pistons on a b18c1 long block. thanks for the help. BTW im going to use my gsr head now</TD></TR></TABLE>

Who the hell is "they" anyways?

You can listen to "them" if you'd like, but if you detonate and have tuning issues because you wanted to run 12.5:1 CR on the street then that's cool too.

Do you have any way to tunr your air fuel mixture?

Got a dyno nearby to have it tuned soon after the build?

What octane gas do you get in your state? Some only get 91 as opposed to 93.

Higher CR can make more power for certain, and 12.5:1 is streetable, but what if that head has been milled and you don't know about it? You also need to make sure you have which ever head you use milled just enough to make it flat, and don't go crazy with the GS-R head mill or else 13:1 CR might bite you in the ***.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EG(6)SR &raquo;</TD></TR><TR><TD CLASS="quote">You know, for some reason I thought that the b16 head increased the compression versus the gsr head. I checked and i'm wrong....

For you guys out there I calculated the compression as this:

b18c block w/ GSR head: 12.4:1
b18c block w/ B16 head: 12.09:1

All stock headgaskets and stuff using pct (jdmb16B) pistons.

Here's a link to the website that I calculated it:
http://www.c-speedracing.com/h...c.php
Very neat little tool to getting an approximate value of the cp.

On a side note, don't forget to get some nice cams to really let that compression sing! If you use the gsr head, your getting very close to the border line of having to run a higher octane. (I know the bay area, we only get 91 octane.)</TD></TR></TABLE>

I don't know what you did, but you sure as hell didn't calculate that correctly.

Using C-Speeds Calculator:

B18C1 Block, B18C1 Head, PCT Pistons, OEM Headgasket, OEM B18 Piston-to-Deck Height = 12.042422511586593

B18C1 Block, B16A Head, PCT Pistons, OEM Headgasket, OEM B18 Piston-to-Deck Height = 11.751778779507741

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b16a ferio &raquo;</TD></TR><TR><TD CLASS="quote">

I don't know what you did, but you sure as hell didn't calculate that correctly.

Using C-Speeds Calculator:

B18C1 Block, B18C1 Head, PCT Pistons, OEM Headgasket, OEM B18 Piston-to-Deck Height = 12.042422511586593

B18C1 Block, B16A Head, PCT Pistons, OEM Headgasket, OEM B18 Piston-to-Deck Height = 11.751778779507741</TD></TR></TABLE>

Sorry bro, you must be doing something wrong, because I too get 12.4:1 Cr with PCT slugs with a stock B18C1 block and B18C1 head.

Did you use the wrong value for the piston-deck clearance? Use the .020 for the piston.

EDIT:

Confirmed. You don't use the .030 from the B18 pistons, you'd use the .020 from the B16A/B pistons. This is a common mistake when calculating CR, and it could be a pretty big deal if you're basing an engine build from your sole CR calculations with a wrong piston-deck clearance.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b16a ferio &raquo;</TD></TR><TR><TD CLASS="quote">

I don't know what you did, but you sure as hell didn't calculate that correctly.

Using C-Speeds Calculator:

B18C1 Block, B18C1 Head, PCT Pistons, OEM Headgasket, OEM B18 Piston-to-Deck Height = 12.042422511586593

B18C1 Block, B16A Head, PCT Pistons, OEM Headgasket, OEM B18 Piston-to-Deck Height = 11.751778779507741</TD></TR></TABLE>

I believe this is correct as well. The deck height on all B18 blocks are the same. Why would you use a B16a piston/deck height on a B18C calculation?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AzSi22 &raquo;</TD></TR><TR><TD CLASS="quote">

I believe this is correct as well. The deck height on all B18 blocks are the same. Why would you use a B16a piston/deck height on a B18C calculation?</TD></TR></TABLE>

I still say you guys are wrong.

Here, read this chart:

http://www.muller.net/sonny/cr...t.gif

Now how on earth could the same exact D series blocks have different piston-to-deck clearance numbers if your theories are correct?

...because the PISTON itself determines the piston-to-deck clearance, not the actual block or head y0.

Look at the D16A1 engines listed there.

One is a 1986-1987 D16A1 with the PG6 piston and it reads a piston-to-deck clearance of .000.

Now look at the 1988-1989 D16A6 engine listed with the P29 pistons - the piston-to-deck clearance for that engine is .040.

So you tell me what's the deal then considering both engines use the EXACT same block and head, but yield different piston-to-deck clearance numbers?

The answer is the only difference in those engines is the pistons themselves.

 

Deck height is dependant upon mulitple things like B18C5-EH2 is explaining.

The rods must be the same lengh.
The pistons must also mount with the same distance between center pin and piston top.
And the decks must be the same size in lengh.

Since the B16s have shorter strokes than the 18Cs they have different rods and piston mounting points.

That is why when you purchase a stroker kit you need the new pistons and rods as well as the crank.

 

But if you are talking about B16B (pct) pistons, you are talking about identical blocks as a GSR or ITR. If you calculate with a .020 piston to deck on a B18C block and B16a head motor with USDM ITR pistons, you get 10.8:1 CR, which is not correct. If you use JDM ITR pistons in this combo you get 11.4:1 CR, which is also not correct. So you guys are saying that every online calculator that has been made for B series compression and displacement are wrong?

I know what you are saying from pistons being different, but I don't think that its the case in this situation. Unless you mic everything when you put a motor together, I don't think there is a definate answer.

 

But different rod lenghs due to the different crank!

 

Like I said, unless you measure the actual piston/deck height, I don't think there will be a definate answer. And if this is the case, I know some people that are running 12.6:1 on 91 octane with no detonation and no tuning.

 

Bare with me here bro, I'm honestly trying to settle this for real without flames:

The B18C5 and B16B share the exact same block - this is fact.

Having said that, then why is the piston-to-deck clearance for the B16B different than the B18C5?

It's either the piston itself, or the crank that makes it different, not the block itself or else there'd be no way for the two identical blocks to have two different piston-to-deck clearances.

See my point?

The B16B piston-to-deck = .020
The B18C5 piston-to-deck = .030