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

[Rusty]

Variable Length Intake Manifold (with info regarding ACIS and turbo) Actually the ST162 1st Gen 3S-GE had TVIS, did you mean to write ST215 intake manifold by chance? I guess would be up to personal preference which either intake manifold you use... but maybe not one of the TVIS manifolds



Can't swap a blacktop 3SGE into a ST20# engine bay, due to a lot of reasons and costs. You also cant mix BEAMS blocks/heads with a 3SGE or 3SGTE, due to a different cast

Hondas
VTEC - Varies duration, timing and lift by switching between two different sets of cam lobes.
i-VTEC — In high-output DOHC 4 cylinder engines, the i-VTEC system adds continuous intake cam phasing (timing) to traditional VTEC.

Toyota
VVT-i - Continuously varies the timing of the intake camshaft, or both the intake and exhaust camshafts (depending on application).
VVTL-i — Continuously varies the timing of the intake valves. Varies duration, timing and lift of the intake and exhaust valves by switching between two different sets of cam lobes.

Nissan
N-VCT - Continuously varies the timing of the intake camshaft, or both the intake and exhaust camshafts (depending on application).
VVL — Varies timing, duration, and lift of the intake and exhaust valves by using two different sets of cam lobes.

(I'm going to create a NEW sticky which will have this & more info for easier reference)

as I posted before

Slightly offtopic, but Tom's Racing did a "280T" Altezza, it was turbo and limited to just 100. Also the altezza's blacktop 3S-GE has alot of readily available turbo kits from Trust/Greddy, biltz and I think even HKS do one aswell. Plus all the cheap knock offs.

[Edophus]

Variable Length Intake Manifold (with info regarding ACIS and turbo) Actually the ST162 1st Gen 3S-GE had TVIS, did you mean to write ST215 intake manifold by chance? I guess would be up to personal preference which either intake manifold you use... but maybe not one of the TVIS manifolds

if you mean what i said then no, st162 inlet manifold is an alternative to the centre feed inlet manifold of the st185, its side feed and seems to be an improvement, the tvis heads have huge inlet ports on them so you need a manifold that will match that, these large ports are undesirable really, the rev 2 3s-gte has very large port openings which taper down very aggrsivly to the valves and its not good for flow. Hence why the small port rev 2 3s-ge head is a better starting point when doing a ground up engine build.

The exhaust manifold stud patterns are the same between the na and turbo versions of each revision, they however change on each revision, so rev 2 3s-gte manifold fits a rev 2 3s-ge, and so on, this isnt true however of the 4th gen 4s-gte, which shares its stud pattern with the rev 3 3s-gte, whilst the 4th and 5th gen 3s-ge's both share a unique manifol stud pattern for both intake and exhaust.

as for vvti/vtec they are different things, the vtec is two seperate sets of cam lobes on one cam, and it switched between them at a set rpm, vvti alters the phasing of the cam, so the cam timing relative to the crankshaft, and it does this constantly changing depending on throttle input and rpm.

vvti is a power gain, it allows you to run a more aggresive cam for better top end, whilst being able to vary the cam phasing means you can retain or gain lower to mid range power that would have been otherwise lost from the more aggresive cam. In a forced induction engine it allows you to tune the cam timing for different rpms so you can help build boost sooner and extend the power band of the engine. In the past vvti was seen as an added complication but its so prevelant among cars now that its not a problem anymore and is a definite gain.

the vvti 3s-ge heads are a different casting to previous 3s heads, both the redtop and blacktop are the same with some minor differences in water outlets, they are however a unique casting in relation to the previous 3s engines, they have a narrower valve angle and the head is in general a lot narrower than previous 3s variants, and as i've mentioned before they have a unique stud pattern. Block wise they are the same as previous 3s engines, apart from they have an extra oil feed to the head for the vvti, i'm not sure if that could be added to a pre beams block, either way unless your stroking and need a 5s block it doesnt matter as the beams blocks are reputed to be the strongest castings of 3s engines to date, and the same as the motorsport blocks, altezza blocks have been used in gt-fours as a basis for rebuilds due to this, but using rev 3 head and sump. The blacktop has apparently the highest output oil pump due to the two vvti controllers which are oil pressure driven, but in order to use that oil pump on a non beams engine you will need a redtop sump, as both the sump and the oilpump have a recess for the crank angle sensor. Due to the head being narrower the vvti heads also need a different timing belt.

you can mix and match the heads as much as you like but obviously only the beams blocks have the vvti feed, and you will need compatible manifolds for whichever head you use, but you can fit normal cam gears instead and lose the vvti, you'd probably still gain power thanks to the newer head casting and inlet manifold etc, the valves are larger as standard on the vvti head as well as some nice features such as sodium filled exhaust valves on the redtop and titanium inlet valves on the blacktop which are 1.5mm larger than a 3s-gte. If you wanted to fit a blacktop into a celica though you need to swap the manifolds/sump/oilpickup and depending what you do with the water ways you may need to change the headgasket for a redtop. The exhaust side vvti controller will clash with the engine mount on that side but in all honesty it doesnt gain you much so fitting a normal cam gear instead would be a simple fix. Redtop obviously doesnt have that issue.

If you were building the ultimate 3s-gte you'd start with a redtop or blacktop/redtop hybrid and retain inlet vvti. Hks back in 99 used a redtop beams engine built for turbo to set the fwd drag record in a celica, although at the time they chose not to use vvti, understandable in a drag car as your only interested in a narrow power band. For any full on 3s-gte engine build that is going to require headwork, ie larger valves and more aggressive cams, it is worth thinking about instead of spending the money on the head, spending it on a redtop as the starting point due to its already 1m oversized valves, and more aggressive cams, and it will come with the bonus of inlet vvti, and the strongest block casting, and as an added bonus it already has a crank angle sensor so when you go for an aftermarket ecu, the engine already has the sensors needed in place to run it. the only downside of using the beams for a turbo application is the need to fabricate an exhaust manifold, but for many that isnt a problem.