I'm building my D16A6 with the now common eagle rod / Vitara piston combo.

As many know, the Vitara pistons yield about 7.9:1 compression and sit well below the deck height.

When I finish swapping in the motor I will be starting it up and running with a stock P06 ECU. My question is, will the lower compression make the a/f ratio leaner or richer. I was going to say it would be leaner because the same amount of fuel would be filling a larger space.

 

Its not going to burn as efficiently, so it may require a little less fuel. It shouldn't matter much if you're running an O2 sensor, since it will correct for the little difference it will make. Even if it does go a little lean, the lower compression means its less prone to lean-burn detonation. I broke my 8:1 D16 in on a stock P28 w/o any issues, to give you an idea. I just made sure the O2 sesnsor was decent.

 

I figured the difference was negligible, I just wanted to make sure I didn't wash out the rings or anything ridiculous like that running it for a while on a stock ECU.

 

holy **** that is low not goin to go nowhere unitl spool but ya o2 will make up for it

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by stockb18c &raquo;</TD></TR><TR><TD CLASS="quote">holy **** that is low not goin to go nowhere unitl spool but ya o2 will make up for it </TD></TR></TABLE>let me guess, you never driven one huh ? stop making ASSumptions.


op, hate to brake it to you, but the a6 will have even lower comp then that. that comp is in the z6.

http://web.archive.org/web/200....html

 

I don't see how you're getting that. I got a static ratio of 8.2 with that calculator. I'm using 75.5mm pistons.

 

how did you get the 7.9:1 then ?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by zex_cool &raquo;</TD></TR><TR><TD CLASS="quote">how did you get the 7.9:1 then ? </TD></TR></TABLE>

haha i hate it when people say to different things when were trying to help

 

TurboD16 said that's what it would be.

Doesn't really matter, question still applies the same.

 

td16 = bunch of tards !

with the a6 it will be low 7:1 comp. a6 block has .020 MORE deck hight and the head has a bigger comp chamber. 38cc vs 34.6cc with the z6.

that cal also takes in account that there has been NO material removed from the head or the block. which is never the case on 15+y/o motors. one more reason to invest in an adjustable cam gear.


to get back to your original question, i doesn't matter. rich or lean you should never start a new motor w/o the ability to alter at least the fuel. why risk a newly built motor ??

 

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

with the a6 it will be low 7:1 comp. a6 block has .020 MORE deck hight and the head has a bigger comp chamber. 38cc vs 34.6cc with the z6. </TD></TR></TABLE>

That calculator you showed me still says 8.2.

 

with what piston dome cc ? its -15.00 to -15.30 cc by the new measurements.

 

i always heard that setup was around 8:1 comp. my friend has that same setup and he doesn't have an o2 sensor and his pops after like 3k rpms lol.

 

I ran my built 8.5:1 motor on a stock ECU to brake the motor in a little, I monitored A/F and the stock ECU did a pretty good job of keeping the AF ratio close to where it should be, just drive it and dont beat it.

 

and yes friend has a 8.5 compression single cam and does want to go anywhere until the turbo comes so dont blam out **** you dont know about someone

 

are you illiterate or retarded ?

YOUR friend must be in a close second, right behind you. MY vitara setup ran great in and out of boost, and so do many other vitara builds. but hey, how am i ? im sure you know more about how your cousins brothers friend's car runs.

oh and guess what, that 8.0:1 comp is still faster then what you have in your sig.