Korenwolf

Are, as I've read somewhere here, the 16v head combustion chambers a better shape than those in the 8v head, hence more detonation resistant, thus allowing a (probably only slightly) higher static compression ratio ?

For those actually with a 16 V Turbo, what was the static compression that you aimed for... ?

gt37vgt

I'm building mine for 10.7:1 but I'm using 105+ fuel a very different charge cooler good ignition knock box and i like water injection .
If i were to build a 16v car for 94-98 gas i would be go mid to low 9's

Duke

I built my 3.0l 16v turbo with 9.5:1 compression. Highly recommendable with the right setup of turbo, tune etc.

Paulyy

Where you finding 105 fuel from? or you're talking about race fuel or E85?

from what i've read here in the past year, 9.5:1 would be the best CR to go for, duke is on 17psi safley and i've seen others run 15 psi getting good numbers. and also can straight tune for E85 also. and no lag...

evil 944t

You need to tell us what you want to use the engine for, ie. where you want your boost, how much boost, rpms, type of fuel, etc..

Korenwolf

>gt37vgt
>...for 94-98 gas

I'm in the UK, and I notice you're in Oz, do you mean RON or MON on that octane rating ? In the UK they use RON, so Super 99 RON, would probably be about 90ish MON...

>Evil
Street mainly, with occasional trackday usage, though I have a very heavy right foot - I used to own a 500bhp Ultima GTR...

I'm considering a sleeved block as an upgrade, dry or wet, with perhaps a capacity increase to the 3.2-3.3 mark, so would ensure the engine could run a good 20psi at least.

I guess the higher I want to boost it, the lower I'd better make the static compression, so if my goal with a 3.0-3.2 L 16 valve, was a solid 450rwhp/500crank with a fairly nice spool, what would you recommend on the boost/static compression front ?

evil 944t

personally, I would stay 9:1 or less and pick your cam/turbo combination carefully.

Korenwolf

For the Turbo, I've been thinking of a GT3076R, but the cam(s) I'm still pondering...

Paulyy

You're pushing it going 3.1 + displacement. i wouldn't want a 3.2L 4 cyl reving to 7000RPM also.

In australia we use RON.

Black51

How's that car holding up by the way Duke? Although mind you, you probably haven't had it out recently with the weather there which, I imagine is similar to here. Was it you who was going to transplant the engine to a different track car?

Duke

The engine is holding up great, but I haven't been driving it for a couple of months now due to winter weather. Yep that engine will end up in my new race car along with a few upgrades

gt37vgt

i have e 85 down the street but I'm talking LPG all over town Pauly winch is about 103 and Super gas have strait propane on pump on about 6 or 7 sights around Melbourne witch is around 110.. RON numbers and we do have 98 all over town but I'm finding gas is half the price at the pump and the fuel system is cheaper also
I really believe cams are not a priority in a cost effective build.

this is my priority list when engine building.

Head gasket stuff
oiling bottom end .
reduce weight were possible
tidy up ports .
address cam timing with cam wheels so its adjustable to separate lobe centers.
turbo selection .
good ancillaries. breather perhaps vac pump high mount injectors wiz bang ignition. good inter cooler.good pipes .water spay ..

the cams bolt on the top you can always come back to them..

So Far i have seen no evidence that $1000 can be justified on changing cams on a 4valve per cylinder turbo engine..

If any wants to school me on this please do

Paulyy

wow LPG, When you start putting bits together let me know, id love to take some notes. And who's doing the Tuning? i wouldn't mind taking notes there also! LPG is 50-60c as to 98... i went to fill up and fainted when i saw $1.53 L
this is when E85 is starting to look better since i also have a local E85 station, but not enough around melbourne to use as a DD.

95ONE

Just for perspective. We run Acura RSX's on 93 octane at 10lbs of boost on stock compression. (11:1) I don't think you should worry too much. It of course, depends on your max hp you want to run on gas.

Korenwolf

>i went to fill up and fainted when i saw $1.53 L

In the UK, they don't have E85, so I'm stuck with Shell Optimax 99 RON or equivalent and as for petrol prices here, well, the local Shell is around UK 1.30L so don't feel too hard done by !

I'm not in any rush on the project, and I'll wait for the main components to come up at decent prices, given that I'll most likely be combining the 2.7 block with an S2 head and crank it may take quite a while to source the two doner engines - might be easiest getting non runners and stripping them out !