3SGTE Gen 2 How much boost?

[DriftSpecStarlet]

Im running .5Bar at the moment.. Whats stock and how much is safe before Bearings come into play? (I know its prone on this) Dunno if it matters but i have a very free flowing exhaust, custom manifold with T3T4 and front mount IC

[Bling]

Do a search. All the info will be there.

[fivebob]

Some people run a lot of boost (20+psi) and have no issues with bearings, others run very little boost and have bearing failures.

Some people know how to build engines, others do not...enough said

[levinguy]

i would run 14 psi max on a gen 2, if it was in great condition, 12 psi if you where sensible still if it was standard-ish. (assuming standard pistons/ecu)

i thought the bearings issue was more because of the pressure relief valve seizing? due to wear etc., but please someone tell me more about it, have heard of gen 3 engines being alot better in this sense with toyota changing quite a bit of the oil system but this is all hearsay, would love to hear from some people with first hand experience with this.

all my first hand experience with 3s series engines have been horrible (big end bearing related)

cheers,

[sergei]

I don't think there is problem with big ends on 3S. There is problem with poor maintenance. Anything will ruin bottom end if it has no oil (or been rebuilt poorly). I believe it is misconception that some how bearing failure has to do with how much boost you run.

[DriftSpecStarlet]

But its a known fact that Piston 1 has the great probability in Detonation with the factory computer being so shit at accepting modifications to the engine that it nails the bearings

[Akane]

But its a known fact that Piston 1 has the great probability in Detonation with the factory computer being so sh*t at accepting modifications to the engine that it nails the bearings

It's cylinder 2 and 3, due to the intake manifold being unable to distrubute intake air evenly.

[iOnic]

All this talk of "how much boost should I run" is irrelevant...you don't know what turbo the guy has on his car. T3T4 could be anything from a chinese t04e to a t70. Telling him to run 1bar on a turbo that size with no additional fuel is literally starting the timer on that bomb...Without knowing the actual specs of the turbo and what sort of fuel system is behind it, everyone is just clutching at straws by trying to give him boost figures.

3S's (early ones at least) don't spin their bearings because of the amount of boost people run they do it because they have a less than average sump that allows oil to move away from the pickup without too much encouragement - especially in MR2's (more centrifugal force, oil pushed to one side, knock knock - who's there?). The gen3's onwards are better for it with the Gen4's having a properly baffled sump. But no wet sumped engine is immune to oil starvation.

I don't think there is problem with big ends on 3S. There is problem with poor maintenance.

There is no problem with the big ends. The problem is with the sumps which is why Toyota updated them over the years. Excellent maintenance does help to an extent, as does avoiding hard cornering in MR2's - but then that would defeat the purpose of owning one

[strx7]

But its a known fact that Piston 1 has the great probability in Detonation with the factory computer being so sh*t at accepting modifications to the engine that it nails the bearings

It's cylinder 2 and 3, due to the intake manifold being unable to distrubute intake air evenly.

the the way the block flows coolant around number 3

[fivebob]

But its a known fact that Piston 1 has the great probability in Detonation with the factory computer being so sh*t at accepting modifications to the engine that it nails the bearings

For a start it's usually piston #2 or 3 that has the problems, and secondly the factory computer is pretty good at accepting modifications, with the Gen II computer being slightly better than the Gen III in that respect due to the use of an afm rather than a map sensor.

The bearing issue is not related to the ECU, boost levels or any other such urban legends surrounding the 3S. In almost all cases I have seen the cuase has been either poor cleaning or poor assembly after a rebuild, poor maintenance, or high mileage (probably with a good dose of poor maintenance as well).

they do it because they have a less than average sump that allows oil to move away from the pickup without too much encouragement - especially in MR2's (more centrifugal force, oil pushed to one side, knock knock - who's there?). The gen3's onwards are better for it with the Gen4's having a properly baffled sump. But no wet sumped engine is immune to oil starvation.

On the track maybe oil starvation is a problem, but not on the road, unless you are really slack on the maintenance and let the oil level get very low, even on a Gen II.

The majority of reported cases of bearing failure I've seen have been straight after someone has rebuilt their engine, often the failures occur repeats itself after the second rebuild.

The engine, as it came from Toyota, runs without bearing problems for several hundred thousand kms, but all of a sudden freshly rebuilt engines start having problems. Surely people with a least half a brain can see what the likely cause is, but alas no, and the urban legend of 3S bearing problems is born

[blitza]

...................but alas no, and the urban legend of 3S bearing problems is born

I'ts great to see the TS ledgend that is, 5bob, still passing out considered yet blunt advice! if only you got a dollar for every time you repeat yourself, repeat yourself, repeat...

[shihad]

is this the motor mike built ?

[CelicaGT8]

hand experience

I couldnt resist.... sorry

But yea, i wouldnt run more than 14psi, its a 3sgte not rb26, bad things happen to people with boost taps

I run 14, and thats nutty enough, i like having my licence... just cant find it...

[kim0663]

well, i run 16psi on mine with a ct20b. Gen2 3sgte. Just the usual intake exhast i/c mods and a mines ecu.

Runs fine, i even ran it on 17psi with the old ct26 for like two years or so.

In the 5 years i've owned a 3s motor, I've had no bearing problems or any failures as such what so ever

I think it's all on how you service it and being able to notice the very slight changes in the car's behaviour and how it runs.

On my car, when the oil level gets low, when you start it in the morning, it has this certain characteristic. It's usually due for a oil change as well when i feel that 'characteristic'.

[CelicaGT8]

On my car, when the oil level gets low, when you start it in the morning, it has this certain characteristic. It's usually due for a oil change as well when i feel that 'characteristic'.

Lol tell me more about that 'characteristic'

I build mine to be thrashed to hell, they wont take my abuse standard.
Pistons are crap and crack ringlands, oil pumps seize and bearings dont handel the jandel.

[DriftSpecStarlet]

Thank you Piece all of your advise together and i have a fairly good idea on what i have to do, No its not the engine mike built as that only lasted 1 week before it spat a rod out the block, I am sourcing new injectors 550cc and a fuel surge tank with inline pump, its the casing of a chinese turbo with very good shit inside (its spooled up by 2500rpm), i use good oil and gave it a full service when i put in the new engine, and baffling the sump? sounds like a great idea that i never thought of (even though i did it in the ITR)

[shihad]

lol 1 week was he running it on 20 pound again haha.who is this btw gisbornes a small place? im shaun

[DriftSpecStarlet]

He rebuilt it, ran 20 launching and gating around, for 1 week ran a bearing, i swapped him for my GTX which i had been through 4 heads and 2 blocks on, i drove it for 3 days until it chucked the rod, then brought a new motor and now its back to bout 6 - 7 pound

[Akane]

But its a known fact that Piston 1 has the great probability in Detonation with the factory computer being so sh*t at accepting modifications to the engine that it nails the bearings

It's cylinder 2 and 3, due to the intake manifold being unable to distrubute intake air evenly.

the the way the block flows coolant around number 3

It's actually the intake manifold. And what you're referring to is the famous carboy magazine mod which attempts to cool cylinder 2 & 3 down more to avoid detonation, this is done by blocking certain water channels and forcing more coolant to cylinder 2 & 3.

[DriftSpecStarlet]

hmmm i have an intake manifold from a gen1? non turbo.. Its a side facing plenum