3sgte

[bedbull]

hello all i'm new to the forum i have a 3sgte(165) in a 91 corolla wagon i have some guestions .. how much fuel pressure should i be reading at idle,open trottle and at boost because i have a pingging sound at and above 5500rpm......... i live in jamaica and only have 90 octane gas.I do not know what plugs i have in it as i have not pull them out as yet. please if someone knows what plugs i should use let me know

[dawesy]

hi mate and welcome to the club, sounds like its the gas you are using as over here in the uk most of us use 98ron fuel. not totaly sure of fuel pressure but would recomend retarding the ignition a few degrees. should help or use an octane booster if availiable.

have you got any pictures of your car, sounds cool. is it 4WD

[daktari]

Welcome to TOC

You need to either !Removed! the ignition timing..... or stick some octane booster in. Either one should either lessen or stop the detonation (Pinking) If your retarding the ignition do it one degree at a time.

Fuel pressure should read anywhere between 33-38psi throughout the throttle range.

Spark plugs should be NIPPONDENSO PK20R8 or NGK BKR6EP8 provided the engine has not been too heavily modded.

[bedbull]

Welcome to TOC 

You need to either !Removed! the ignition timing..... or stick some octane booster in. Either one should either lessen or stop the detonation (Pinking) If your retarding the ignition do it one degree at a time.

Fuel pressure should read anywhere between 33-38psi  throughout the throttle range.

Spark plugs should be NIPPONDENSO PK20R8 or NGK BKR6EP8 provided the engine has not been too heavily modded. 

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thanks for the advice...-ok but if you !Removed! the timing would you not lose low end power ....33-38psi what sould be the lowest when in boost .... could i just use colder plugs so not to !Removed! the timing maybe even 7 range plug.. remember the highest octane gas we have in jamaica is 90

[mikeb]

There is no way you can run a 3s-gte on 90 RON fuel in stock trim. You have to accept that with the fuel you have, you are going to have to make adjustments to reduce the power output. Your best bet would be to use octane booster. Failing that, retarding the ignition, and reducing the boost pressure are options. You will probably need to use a combination of both to get by with 90 RON fuel.

Minor point Dak, but detonation and pinking are slightly different things. I think this guy is getting detonation.

[bedbull]

what if i use a much colder plug would that work for every day driving and get the power i need without detonation

[dawesy]

not realy as its not that the plug is wrong its the fuel. by running with a colder plug you are more likely to suffer plug fouling. as as been said timing retardation or better octane booster is the only option or a mappable ecu (power fc, motec etc)

[bedbull]

which would be better retardation or octane booster .....which would you use if you were in my position cause i do not want to lose much power ...as i think if it is retarded i would lose some low end power

[mikeb]

It sounds like your problem is detonation/preignition. This happens when the air fuel mixture is compressed/heated too far during the last moments of the compression stroke. The air/fuel mixture ignites itself BEFORE the ignition system has made a spark, just like in a diesel engine. Because of this, I doubt that retarding the ignition will stop detonation.

Your problem is also exasperated by the high air temperatures you must have in Jamaica. The intake charge will be quite warm before the turbo heats it even more, and the intercooler will also be less effective due to the higher ambient temperatures. Detonation will wreck your engine very quickly.

Using an octane booster is definitely your best bet. Lowering the compression ratio with a thicker headgasket would help, but it's not a minor job. Another alternative would be to reduce boost pressure, but you will loose a bit of power. I think the ST185 has the CT26 turbo? You could try a CT20 turbo from a later engine. I think it makes more usable (i.e. cooler) boost at high rpm.

Just for information, pinking/knocking usually happens at much lower rpm under high engine loads. What happens is that when the spark ignites the air/fuel mixture, the flame front starts to propogate across the combustion chamber compressing the remaining air/fuel mixture too much, causing a second ignition point and flame front. The flame front is intended to reach the piston crown just as it reaches TDC, but due to the knocking is meets the piston when it is still moving upwards. Retarding the ignition timing can fix this, at the expense of a small loss in power.

[daktari]

Minor point Dak, but detonation and pinking are slightly different things. I think this guy is getting detonation.

I stand corrected. :D

[dawesy]

retarding would help as detonation is an un controled burn of fuel hence the damage caused. retarding ignition causes the burn to start earlier before it ignites its self and as such the mix burns in a more controlled way.

thinking about it though was the 3S-GTE ever officialy imported to jamaica, if it was then you may be able to find an ecu from one which should have the right map for your fuel.

personaly i would try an octane booster as you will gain power not lose it.

[Cubic Incubi]

i had the ignition retarded by 3 degrees to handle n20 on the 3sge, its a very safe option but benefits from a rolling tune.

octane booster is going to cost you everytime you fill up, retarding the ignition timing is a pretty much end of problem fix. i would however check your plugs, say every 500 miles to check for signs of irregular firing.

good luck..

[mikeb]

retarding would help as detonation is an un controled burn of fuel hence the damage caused. retarding ignition causes the burn to start earlier before it ignites its self and as such the mix burns in a more controlled way.

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No, retarding the ignition means it occurs later in the cycle, advancing it makes it occur earlier.

As I have already said, retarding won't stop detonation. The 3s-gte is designed with 95 RON petrol as a minimum. Adding octane booster increases the effective octane rating of your petrol. I have just stumbled across a useful (Australian?) article regarding octane boosters here

I don't know if any of these products are available internationally though.

[Cubic Incubi]

advancing... yup. thats what you need.

silly us.

[bedbull]

it seems that i'm lost ......i do not know what problem i'm having because i only have it at and above 4500 rpms ..please help i NEED to know what really to do also what if a turn up the fuel pressure

[bedbull]

what about using a better fuel pump

[bedbull]

well i have put in some (7) range plugs, put in a better fuel pump changed to a cold air intake ...now only getting the noise at about 7000rpms so next i'm going to !Removed! the timing to get rid of what noise is left

[daktari]

Have you considered water injection? Lowers charge temp and you can wind the boost up a bit? Earls system costs around 600 GBP. Just an idea.

[dawesy]

good poin actually esp if you use a 50% methanol water mix as methanol inceases the octane of the fuel

[bedbull]

how much boost can the 165 3s take if you have all the fueling right

[andrew98]

im not sure, but as the last 2 guys have said....

Water Injection, (where a fine mist of water is sprayed into the intake, usually just befeor the throttle butterfly) mixed with methanol if it is available where you are would probably help a lot.

This water (or water:methanol mix) would cool the intake charge down in temperature and should allow you to retain the stock ignition timing

In the UK we use water injection to allow us to run the turbo a little harder... As the harder it is working the hotter the charge temperature will be. this can lead to pre-ignition.

The other thing is, presuming you have the correct fuel pump, pressure injectore etc, How long is it since the fuel-filter has been changed? If it is a while it could be that the filter is getting blocked up.

[bedbull]

well i have the engine in a 91 corolla i'm using a sr20 fuel filter i think that should be good enough..... well i have tried a vortexx regulator which is a boost dependent fuel riser now when i tried it,it over fueled the engine till it was smoking like a truck ...i just need to adjust the amount of boost going to it to get the right amount of fuel ..maybe by sat-day i will try and get it right

[dawesy]

dont for get the stock fuel pessure regulator. might be a good idea to check the small vacumm pipe to it for splits etc as a leak here will not increase fuel pressure

[andrew98]

What im saying is the fuel filter could be partly blocked by contaminents in the fuel.

As for fueling it should be set up using a wideband lambda sensor and preferably a rolling road.

[djdna2000]

90 octane (RON+MON/2) is approx 95 RON btw you'll be fine.