Why can't we turbocharge a 3s-ge?, Compression ratio related Options

[dudeofchaos]

I know that the 3s-ge engine has a higher compression ratio than the 3s-gte (which I guess means that the pistons' head are thiner right?), but what does it change so that we can't (or shall not) turbocharge the 3s-ge?
Is it because it would (I don't know) be too much compressed exhaust gases for the turbo to hold?

BTW: what does the last number in the compression ratio mean? (Like in 10:3:1)

This post has been edited by dudeofchaos: Jun 26, 2011 - 10:51 PM

[Edophus]

vvti doesnt kick in, the i on the end means its always moving, it is programmable based on a various other inputs, it adds a lot to a turbo setup as it can affect exhaust flow, and therefore spool up, and thats a cycle that ends up with more boost earlier and more power.

as for the na engine vs turbo engine it depends on the revision of engine your talking about, the rev 2 na vs rev 2 turbo i'd take the na because the acis head is better than the tvis head as the tvis head has massive ports that taper in badly, but ultimatly once worked enough this isnt that much of an issue, but your still better starting with the na head. the rev 3 engines it doesnt matter. if you leaving it stock, a rev 3 na 3s-ge has the same pistons as a rev 2 3s-gte but with a larger crown for more static compression, and bigger cams that mean in reality there probably isnt a lot in terms of dynamic compression and actual engine endurance between them. I'd wager a rev 3 3s-ge will boost everybit aswell as a rev 2 3s-gte.

beams turbo's despite more agressive cams in terms of lift and duration get on boost sooner, and for much longer than non vvti engines, they can also run higher static compression ratios, this down to a mix of the more agressive cam, and the fact that the cam timing can move around. seriously research dynamic compression ratio, and realise that the static ratio is only one peice of that, its a whole world more complex, your cam timing changes it, your boost pressure changes it, its a whole different game.

This post has been edited by Edophus: Jul 2, 2011 - 7:17 PM

[delusionz]

edofus i bet a 3sge unbuilt would max out somewhere well short of 250hp before major pinging on pump gas would require such retardation of timing that u wouldnt be able to capture any more power or otherwise cause damage to the engine.

on the other hand a 3sgte will handle 300hp+ atw all day long, we know it because we do it. 3sgte is hell detuned from factory, its good for some serious power right out of the box.

the first instance is a waste of a turbo, most turbos are at their best at 14+psi,,, they like to swing up to about 1bar and thats where they are most efficient for mid sized turbos such as the stock one, and even the one i run. 6psi ? maybe 8psi tops is what you could run on a 3sge+t, and then in that case you may as well get something so tiny that it comes on boost at idle and gives u 6psi till redline... and then u really gotta say... i just spent a fortune on a new turbo setup and all i got was a pathetic little peashooter?

all your google theory stuff is best left at that, we dont need your rocket science when we're talking about an engine that can only handle 8psi tops

if you gonna boost your ride, you may aswell use common sense start with a boosted motor and boost it more, have something nice in your engine bay rather than a pathetic tacked on peashooter turbo.

This post has been edited by delusionz: Jul 5, 2011 - 10:56 AM

[Edophus]

all your google theory stuff is best left at that, we dont need your rocket science when we're talking about an engine that can only handle 8psi tops

would be interested to know how you've come to the conclusion it can only handle 8psi tops, and fyi none of my knowledge or theory's come from the internet. Nice argument though, whatever the point is your trying to make .

no one would argue with the two sitting infront of you its more cost effective to start with the 3s-gte, the higher the power you build for though, and the more you spend, the less important it is which one you start with, and in a few cases (such as the gen 2 3s-gte) if your doing a full build then you are better starting with one of the na versions.

also its worth noting that there are people who have done exactly what your saying cant or isnt worth doing, its quite cheap to take an na 3s-ge if thats whats in your car already and using hand-me-down parts from gt-fours such as the manifold/turbo/ecu and some other bits and peices which makes a very cost effective power upgrade if you get the parts cheap enough. It does however require you to know what your talking about.... Ultimately it is not black and white, and the point i was alluding to is that static compression is only one part of a very large puzzle, it is foolish to assume what can and cant be done based solely on that.

This post has been edited by Edophus: Jul 15, 2011 - 10:38 AM