What's the maximum compression increase that would be safe, keeping everything else (intake, cams, exhaust, etc) stock? The car is obd2 so I can't change timing.

To what extent (compression increase) can the ecu alter a/f to keep it safe?

Does ignition timing change dramatically with compression increase (say 1pt), to the point that it'll detonate?

A hone won't cut it for my block due to taper, and I'd really hate to keep the same compression if I have to get new pistons. I figure that if I can increase the compression in my H22 1pt for now, whatever potential head modifications down the road will have a larger payoff.




Modified by vinuneuro at 4:33 PM 11/28/2007


Modified by vinuneuro at 4:33 PM 11/28/2007

 

1 point should be safe. I put a Mugen headgasket and Supertech flat valves in a B18C5 and it ran fine.

 

Is 1pt the upper limit?

 

too many variables to consider..
you can play with dizzy timing if your having pinging issues.

fuel dont care for timing.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mmuller &raquo;</TD></TR><TR><TD CLASS="quote">too many variables to consider..
you can play with dizzy timing if your having pinging issues.

fuel dont care for timing.</TD></TR></TABLE>

he has an OBDII distributor, like mine. The bottom bracket is locked and cant be moved. If you remove the bottom bolt and try to adjust the timing manually, it will flash a CYP check engine light.

if it was OBDI, that would work...but sadly OBDII is a little limited

what do you mean by fuel dont care for timing? I probably know but your wording was a tad boggling (red eyes )

 

Something else to consider: could I viably use a thicker headgasket to knock off some of that comp?

 

i agree with aquafina here. 1pt is a safe bet, might want to go more while your at it. swap to OBD1 its a cheap option in the long run and have no issues.

 

Ideally, I would like to use the Mahle goldseries 11.5:1 pistons.

Can't go to obd1. I need the stock ecu to retain ATTS.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 98vtec &raquo;</TD></TR><TR><TD CLASS="quote">

he has an OBDII distributor, like mine. The bottom bracket is locked and cant be moved. If you remove the bottom bolt and try to adjust the timing manually, it will flash a CYP check engine light.

if it was OBDI, that would work...but sadly OBDII is a little limited

what do you mean by fuel dont care for timing? I probably know but your wording was a tad boggling (red eyes )</TD></TR></TABLE>

well that sucks doodo h22 obd2 dizzy dooddo
lol yeah mm, it kinda dont make sense, i meant that that changing ignition timing wont have an impact on AF ration needs.
maybe out of context..mmm... spacing out again

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vinuneuro &raquo;</TD></TR><TR><TD CLASS="quote">Ideally, I would like to use the Mahle goldseries 11.5:1 pistons.

Can't go to obd1. I need the stock ecu to retain ATTS.
</TD></TR></TABLE>
Get yourself a Greddy Emanage, i heard those piggybacks control timing and Fuel, so you should be ok.


Edit: IMO the ATTS is useless, is too sensitive, and a stock lude with a Quaife LSD handles much better than the flawed ATTS system, just my opinion though.

 

I think ATTS performs outstandingly. What about it is sensitive? My engine won't produce a ridiculous amount of power/tq, so I can't imagine that being the issue. Imho, the only advantage for me to ditch ATTS would be for tunability. I'm not willing to drive the car open-diff, so if/when I do get rid of it, it'll be for a non-n2u4 trans + Quaife. And that means $1500+.