d16tuner

I'm having to rebuild my engine, and I'm looking at some Wiseco pistons. They seem to be a great value with some nice features. Anyway, the ones I've seen claim 8.5 to 9:1 cr depending on deck height. I'd like to leave my deck un-cut, which would give me a cr of 8.5:1. IN YOUR EXPERIENCE what would it be like to drive? I've got a d16y8 with a T3-60 HMT setup.

That cr is safer for boost, I'm just afraid it'll really suck big time off boost, and probably wouldn't be too good for economy (hey, gas is getting expensive!). Think I should go with a higher cr? How much is involved with cutting the deck? I don't really want to have to worry about interference and stuff. Anyone used the wiseco pistons in this particular app?

11psiTurboSI

most people run 9:1cr which imo is the best way to go

ATS*Mark

thats what im running

d16tuner

oh yeah. and the y8 comes stock with a 3 layer gasket, right? So could I just use a 2-layer and bump my cr up from 8.5 to about 8.7 without messing with the deck height? That seems to be what the compression calc indicates - http://www.knology.net/~jediklc/D.htm . Does this seem safe?

ATS*Mark

thats fine , cometic also makes good headgaskets

94dxt

9's the usual, but I recomend 10-10.5 if you have a good tuner! (more power @ less boost, faster turbo spool, just better).

d16tuner

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 94dxt &raquo;</TD></TR><TR><TD CLASS="quote">9's the usual, but I recomend 10-10.5 if you have a good tuner! (more power @ less boost, faster turbo spool, just better).</TD></TR></TABLE>

Hmmm. I blew my engine after &lt;1 day at 9psi (and weeks at 5-8psi before that). What does that say about me as a tuner?
Ok, this time I plan to dyno tune my setup to make sure. But sheesh, you'd think it'd last more than a day on a "conservative" uberdata tune!!!

I sure don't wan't to do anything over stock compression, but I'm not real comfortable with 8.5 either. I guess it wouldn't be a bad idea to run a 2-layer gasket and bump it up to 8.7:1 or so. OR I could just use some CP 9:1 pistons instead of the wisecos. Any other opinions on the best way to go?

EDIT: Oh yeah, and does anyone know for sure if they take the overbore into account when they rate the cr on these things? I imagine so, but if they didn't and I got them in the .20 shelf overbore it would actually put me at close to 9:1 with the thinner hg. Nobody probably knows this, but just thought I'd throw it out there in case. I should probably call Wiseco, huh?

ATS*Mark

dood there are daily driven 10 second cars on uberdata , you will love uberdata

tgreaves

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 94dxt &raquo;</TD></TR><TR><TD CLASS="quote">9's the usual, but I recomend 10-10.5 if you have a good tuner! (more power @ less boost, faster turbo spool, just better).</TD></TR></TABLE>

Exactly..

RyanEJ8

Lowering compression a whole lot isn't a good fix for bad tuning. Have someone else tune your car.

d16tuner

Hey, good news. I finally got the engine apart (Arrgh I hate that crank pully - took about two weeks, after which actually pulling the head, engine, tranny, etc apart took a few hours - make note to get bigger compressor and impact wrench).

The damage isn't that bad! The pistons and sleeves look great. Head looks great. Head gasket looks great. Absolutely no signs of detonation that I can find. Guess that means my tune wasn't that bad after all! I did set it conservatively, so I didn't think that would be it. My initial idea was that the head lifted, and I'm gonna stick with that because the coolant was all over the engine bay immediately when it happened. The coolant overflow is directly over my intake. Bad idea. Guess the rods just couldn't take the pressure. Anyway, I know at least two rods are destroyed cause I took the oilpan off to check before I even pulled the motor, and I'm worried about some damage to the bottom of the cylinders where the rods beat them up some, but just knowing I didn't kill it thru my tune will let me sleep better!!

Hmmm, I may just save myself some money, leave the pistons in there, install new eagle rods and arp studs and call it a day... But then, I don't really feel like going thru pulling the motor out again if I get boost happy later... How much pressure/whp should the stock pistons be able to take?

11psiTurboSI

I'd save for pistons and get it all dun together (pistons/rods)... now that you have the motor apart imo!