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Posts posted by buoy

  1. firstly,

    you can't put a 3sgte north-south easily as there are no provisions for the mounting of the engine in that position. the 3s is always either fwd or awd... (rwd in mr2 but the engine is at the back). if you do want north/south mounting you'll have to do a lot of fiddling and customising.


    the 3s is still in production and can make a heck of a lot more power without as many strengthening mods as an sr20.  puts flame suit on  the block is iron which can handle a heap of punshment and horsepower compared with the alloy sr20 block. the head is flowed by yamaha. it has a forged motor from factory bar the pistons. it has 440cc injectors... standard (on later models 550cc standard). really, just bolting on a PE1919 turbo and winding up the boost to 17psi is all that is really necessary to get to around 300rwhp (above 17 it is recommended forged pistons) as the ignition and fuel system is up to the task, as is the motor.


    With the Supras in the JTCC running 3S-GTE motors, i don't see sr20s being dropped in to the GT-Rs - damn that would be crazy to watch!!! -- but anyway...

    why my post? well, i've kept quiet every time i've seen a "sr20 will make more power than a 3sgte" comment, which there are a gazillion of here lol! Why does it make more power? Ohhh... intercooler... front mount... well, for the mr2 that is a prob, but a 3S up front won't have that problem  and as the valvetrain is setup to rev more freely into the 8000-9000 rpm range, the 3S doesn't have too much trouble when it comes to slapping on massive t[insert massive turbine # here]'s.

    finally, it's true there is a heap of aftermarket for the sr20, and on a budget you'd be able to find someone to do up the sr20 a lot sooner than the elusive 3s-gte...... but in Japan, the 3S-GTE *is* the 2.0L motor of choice.

    Internally, the 3S is as strong as a 300ZX motor... both capable of taking around 600 horsepower with stock internals (well, ok the 3S was proven to 550 on stock internals, but that motor had 150,000 miles on it and was thrashed so they just put the power through the roof to see when it would break lol!). Several thrashed months later, it finally did brake .

    I'd say if you don't have much to spend and don't like mucking about and your hp goal is 300-400, go the sr20 --- can't go wrong.

    if you like to muck around, have more to spend (lol) and have a 500hp goal, go the 3s. you won't need to strengthen the motor at that hp goal... so just spend your money on bolt-ons, cams, ems, injectors, fuel pump etc...


  2. Small bore engines have less torque, but tend to rev higher.

    Well, engines with a short stroke have less torque, buy tend to rev higher. Can't beat those old 1920's Packard Twin Sixes, mate. Side-valve design. Stroke as long-as... bore as tiny as... would produce incredible torque and you look at the hp ratings on it and were baffled at how low it is  cos the engines would only rev to a few grand.


  3. RB20DET: Bore x stroke mm  78.0 x 69.7

    SR20DET: Bore x stroke mm 86.0 x 86.0


    Yes thats right. Let me put a few more figs in:

    RB20DET Bore: 78mm Stroke: 69.7mm

    RB26DETT Bore: 86mm Stroke: 73.7mm

    Over square engines will produce less torque compared with an under square engine of the same capacity and design. The RB20 is designed really to rev as you can see.

    Also, since you've got more cylinders, the power delivery should technically be smoother, as with idle all the way up to redline. Specifically inline six is notorious for producing silky smooth revving nissan engines.


  4. what is your power goal?

    it depends which will be pushed... are you going to be pushing your engine or pushing your turbo? usually its the engine that is the weakest link. but since you did a rebuild i dont know... the 2530 would be what i'd get. it would probably be quicker in 1st and 2nd as you'll be almost as long waiting for the 40 to spool as it is to go around the tacho.... 3rd gear + the 40 will be sweet. so, do you usually wind your beast past 100km/hr? if not. 2530. is your goal quarter-mile timeslip based? 2540. dyno queen? 2540. good all rounder? 2530.

    i guess its up to you. what you want it for. for street, the 2530 is more "street" practical. but the difference are slight depending on who you ask. some people may be hella fine with a 40 spool time. perhaps you'd be happy with it.

    up to u.


  5. yep. although its probably something simple, here are some possibilities:

    * idle rpm may be too low

    * afm sensors clogged up

    * perhaps your thermostat sensor is gone? and the engine is running overly rich on idle

    * or; your o2 sensors are shot which would make the closed loop not even engage and idle very rich or very lean

    * your o2 sensors could be plugged in the WRONG WAY! So say cylinders 1 & 3 and 2 & 4 are the other way round, so the ECU is reading the output of 1 & 3, trying to compensate but its actually the reading from 2 & 4. So the ECU is running super rich then super lean ... yadda yadda yadda.

    * Fuel pump may be on its last legs?

    * Injectors need a clean

  6. Sometimes you can't really tell if its not too lean.

    Easy way is to pull your plugs.

    Inspect the plug.

    If it is

    a) black - you're rich!

    B) white - you're lean!

    c) clean - you're stoich! lambda. tuned to perfection.

    nb: after HARD driving even a tuned car should show plugs that are a bit black... cos at w.o.t. it is safer to be rich than lean.



  7. maybe you could use some sort of CO2 injection system,

    Well...... seeing as this is an internal combustion engine, and CO2 is the resultant gas post-combustion, it wouldn't really do anything except pass through the engine and perhaps give a bit of cooling. Hmmmm..... naah I dont see any point. If it was O2...... then thats a different story .

  8. you can but its expensive stuff...... they make the piping very narrow which minimises lag, but because of the distance and air velocity, you get a hesitiation of up to a third of a second more than usual. A third of a second is quite a lot when we're talking about on/off throttle...tsk tsk! --- I dont think its worth it. I havent seen anyone in this country at least do a FMIC on a 2 lol!

    This CO2 ic stuff will be good. Spray for 2 seconds and that blindingly hot summer's day the car's been feeling sluggish in suddenly starts running as if it were the middle of winter! lol!

  9. Yeah I spoke with Brett and Marcus from MRT. They are in the process of importing the kit in to Australia. They are getting back to me today or tomorrow.

    DaFROG: Well the CO2 is damn cold when it comes out. It's as cold as NOS when it comes out (approx. of course) but of course CO2 is peanuts to refil as opposed to NOS. Enough to un-heatsoak a heatsoaked IC. It's been pretty successful in the US, so I'm going for it. Beats water spray (but not water injection like aquamist).

    Just before a run, or "drag", you spray and basically the car responds as if it was a cold night. I'm not a professional on the drag circuit so my cooling goals are quite modest.

    Cost around $2 per pound to refill the tank and the tank is around 10 pounds. One tank is said to be enough for 90 "sprays" and if you're only using it as a heatsoak / hot summer's day on high boost precaution then I'm thinking its worth it to me.

    I hope its around ~$450 mark. Any more and I might as well just get a bigger i.c. from Plazmaman.

  10. if I keep my car for another decade or 2, or am still interested in the little MR2, I'll remove the wall between the engine bay and the boot to make one big engine bay and somehow I'll put a bloody great big twin turbo v8 into it. Yeah. Perhaps when I'm going through my 40th birthday mid-life-crisis stage. lol... or just do like everyone else and buy a 911 turbo. hrm.......

    Variety is the spice of life! If it brings you joy, do it. f**k what everyone else thinks. If you do what OTHER people think, you're not going to be happy.

    So, be happy! Thats all everyone wants in life. To be happy.


  11. usually an ecu will have a fuel map for boost and rpm but above a certain boost it has no idea how much fuel to use... so it just goes nuts and dumps as much fuel as it can into the engine.

    if you see the "haze" from the headlights of the car behind you, then that should be unburnt fuel. I have tested this on my own car with and without the switch. It only happens with the switch on. In fact, sometimes it is so rich in my car with the switch on, I can see it during the daytime in my rear view mirror.

    So to answer your question, your ECU will dump more fuel if it doesnt know whats going on. But better get the AFR's via a dyno just to make sure. As for the cat problem... the only way to save your cat is via a proper tune. This would require *minimum* an air/fuel computer... eg S-AFC. Better yet an aftermarket or piggy ECU.


  12. I just reread my post above and it stinks  lol and i cant edit it.

    Under load, turbo cars especially move to rich even if they are stock. 12.6:1 is the figure to be at for maximum power under load. But that shouldn't make the egg smell.

    Usually some run down injector or carby system with clogged fuel system will cause this... and/or a car that can't get back into closed loop operation and begins to idle really rich (after being really lean while driving). Thus when they "go" again at the lights, all this rotten egg smell comes out of their exhaust.


  13. no no no no.

    If your car is running lean (ie AFR higher than stoich or 14.7:1) for prolonged periods of time, then running rich, this causes it.

    While running lean, the cat is turning sulphur into sulphur trioxide.

    While running rich, the cat then suddenly turns the lingering sulphur trioxide into hydrogen sulphide (rotten egg smell).

    A catalyst is something that needs to be there in order for a chemical reaction to occur, but the catalyst is not changed or used up after the reaction. Hence the name, catalytic converter. Catalytic in that it has a precious metal that is required as a catalyst for a chemical reaction (ie poisonus gasses coming from engine via exhaust), converter in that it converts these poisonous gasses into forms that are less harmful or not harmful to the atmosphere.

  14. Firstly, this is an MR2 I'll be talking about - just so there is no confusion.



    After boosting the original engine from 9psi to 14psi and removing the original plugged catalytic converter, I dynoed the little MR2 at a nice and healthy 156rwkw on a Dyno Dynamics Dyno. I was happy. New cat. Feels fast. Sweet.

    -- cut to 3 months later --

    Probably getting used to all that speed now. When I hit 'the boost switch' as I call it, you get the power (we all like the power!) but at night I notice this pile of black smoke out the back. Obviously the car is running a little rich. How rich? A little... but was I in for a shock.

    I take it to the Ricol Automotive Dyno Day. My car gets put on. Dyno Dynamics again... revs it up. 128rwkw mate.  wtf? Do it again! Yep... same. Why? Well, she's running really rich. LESS than 10:1 AFR. .

    Now here's the thing: How can you lose 30rwkw over 3 months? Firstly, I think its not really 30rwkw. It's probably really close to the same power output, but its a different dyno. I do believe it is producing less power as it doesnt feel as fast, but that is subjective.

    The problem is, on the 3S-GTE, the engine comes standard with 440cc injectors. Standard (The type III 3S-GTE comes with 550cc and MAP sensor, but mints AFM). Unfortunately 440cc injectors running flat out at only 14psi boost can really richen up the mixture. So much so, that it can clog up the cat!

    The more clogged the cat gets, the more a restriction in the exhaust it becomes. The more restriction in the exhaust, the less efficient the exhaust becomes. The less efficient the exhaust, the less powerful the engine. Thus, we've arrived at the source of the entire dilemma.

    So, what to do? The cat will eventually crap itself if I keep flipping the switch. Basically that is the blueprint of having a fang in the car. Flip the switch. Give the throttle a bootful. Then... well... stop! Thus SJM Auto-Technik describes the situation in which a catalytic converter will melt on their web page:

    http://www.sjmautotechnik.com/exhaust.html : Catalytic Converter meltdown can occur with overly rich mixtures at sustained full throttle running when immediately followed by normal lean running or idling.

    So there you have it.

    I'm keeping my car off the high boost for now. I'll have to do the following:

    1. Purchase another CAT (as this one is perhaps half melted already!)

    2. Invest in an S-AFC to lean out the mixtures on high-boost. I'll have to pay for dyno time etc. Prolly Ricol can do this as that is what they suggested.

    So the moral of this story is what? If you're running too rich! You're gonna kill your cat!  Even though the SR20 only has 370cc injectors stock, thats still enough to kill a cat I'm sure. So, if you notice your car is getting a bit slow over the last few months (but you mistake it for "getting used to the power") and you've just installed a boost tap... remember this post! lol!



  15. Ever been driving and wondered who farted? But theres nobody around but you and some traffic? Well you aren't imagining things! You were smelling some other vehicles CAT! lol!



    The sulphur smell from the exhaust, is actually caused by running the engine/cat convertor slightly lean for long periods and then running under a rich condition (ie going up a hill under heavy load) This is when the sulphur smell (rotten egg) is produced.


    Under relatively lean conditions, the sulphur found in gasoline is converted to sulphur trioxide, then during the rich running condition the sulfur trioxide is converted into hydrogen sulphide (rotten egg smell) within the catalytic converter.