8:2:1's = more boost?

[bentvalves]

Hi guys,

I purchased forged Venolia pistons for my ca18 during my build. They are either 8-2-1, or stock 8-5-1 pistons. I have 150 across the board for compression so Im assuming they are of the 8-2 variety.

My question Is can I run a more agressive timing curve, or more boost with these lower compression pistons?

Or is my s15 t28 maxed at 20 psi, no sense in pushing it type thing?

[float_6969]

The turbo is maxed out at that psi. You MIGHT be able to get more power from more timing, but you'd be smart to not start messing with the timing unless you're on a dyno to confirm whether the advance is gaining you anything.

[bentvalves]

What kind of options do I have for a thinner headgasket?

As I said before, the exact compression Is unknown, but I am getting 150ish across the board.

With that being said is it likely they are 8-2's?

I have an experienced pfc calibrater pushing the buttons.

full boost at 4k rpm at which point id expect it to start getting rowdy approaching 5k, loud and on the cam.

this does not happen until about 6-65k and it sounds and feels rowdy up to 7500 limiter.

it just feels all peaky and shyet like I have some 272's that would shift my power way up.

not the case though, just some 256's.

[c-rad]

With lower compression, you would experience even more lag. Also to note, I don't know what you are using for engine management but messing with the CR will wreak havoc on an OEM ECU type setup.

[bentvalves]

nah man pfc.

wish I woulda went with the 2871 at whatever they're good for (22 on 93 I think?)

Id like to research headgasket options at this point, and find out a way to get a rough idea of what compression pistons these are without gutting it.

[float_6969]

You don't have ANY info on the pistons? That PFC in it's stock form is a pretty peppy tune. I can't imagine going from 8.5:1 - 8.2:1 would make it that much more laggy.

As far as HG options go, you're going to have to pull the head to change the HG, you'll be able to tell some about the pistons at that point anyway.

Do you have pics of them? were they dished? Was the wrist pin moved up? Maybe they were designed for a longer rod or something....

[bentvalves]

no pics but they looked identical to stock.

at TDC, the piston sat flush with the top of the deck like it should.

The car just feels to peaky, but Im assuring myself its ignition timing in the map.

The map that was put on my pfc took HOURS.

the base map, and the map provided in the fc datalogit user group wasnt even close.

vg30 afm was being maxxed at 15 psi initally, and had to be totally rescaled in fc datalogit....something that could not have been done with the hand commander only.

[Masterdebater]

dam let me get that pfc off ur hands!!150 across the board isnt bad tho...pull the head and see the headgasket. have u changed it before?

[bentvalves]

its a fresh motor, brand new OEM headgasket.

im almost positive it just needs a few more degrees of timing from 4-6k and she'll rip my tits off.

[themadscientist]

That is a disturbing image. You should go to remedial metaphors