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Speedricer
04-04-2011, 10:51 PM
Does anyone know what the boost cut is on a stock ST215 ECU?

T-spoon
04-05-2011, 12:14 AM
I don't really know the answer to any of the possible questions you're asking, but just to clarify, do you mean the stock wastegate pressure, the stock fuel cut, or the highest boost the ECU is mapped for?

Speedricer
04-05-2011, 12:11 PM
Stock fuel cut. Yeah I wasn't very clear on that, the mapping would be nice to know now that you say that.

v8killer
04-07-2011, 02:02 AM
pretty sure its the same as gen3 so 18 psi

lalojamesliz
04-07-2011, 05:11 AM
Aren't the rods smalller/weaker on that engine?

Speedricer
04-07-2011, 02:33 PM
pretty sure its the same as gen3 so 18 psi

Looks like you are right, I was going to say 20 psi. This seems to be where I hit fuel cut.
Does anyone know how to defeat fuel cut on this ecu? I'm pretty sure you can't just use a fcd because the ecu uses the pressure sensor for the fuel map. I could be wrong.

T-spoon
04-07-2011, 03:44 PM
Yeah, the 3rd and 4th gens are MAP rather than AFM controlled IIRC, so it's likely you have to use an electronic FCD rather than the easy pull of a vacuum hose like the 1st and 2nd gens. I'm not 100% sure on that though as I've never dealt with a 3rd or 4th gen personally.

v8killer
04-11-2011, 05:16 AM
u can unhook the tvsv and put in any boost controller, and no those rods arnt weak at all the gen4 is the best of the 3sgte engins

lalojamesliz
04-11-2011, 05:07 PM
http://www.mr2oc.com/showthread.php?t=403509 :)

Tecker184
04-12-2011, 02:34 AM
I hit 22 psi on the way home tonight on my gen4 3sgte no fuel cut.

lalojamesliz
04-13-2011, 12:53 AM
damn! stock turbo?

Tecker184
04-13-2011, 02:37 AM
Yea stock turbo pulls like hell, i turned up the boost because i found one of my cylinders has low compression. So i figured what the hell, i will be pulling the motor soon and replacing it with my spare. So yes 22psi stock turbo no fuel cut.

Speedricer
04-13-2011, 03:00 AM
Yea stock turbo pulls like hell, i turned up the boost because i found one of my cylinders has low compression. So i figured what the hell, i will be pulling the motor soon and replacing it with my spare. So yes 22psi stock turbo no fuel cut.

I've seen 24 psi out of the stock turbo but I can only give it 3/4 throttle, if I go full throttle then the fuel cuts. I can't believe the stock turbo is much more efficient than a hair drier above 20 psi. It pulls pretty hard though.

Speedricer
04-14-2011, 12:10 PM
Well I have a new development... It appears to only cut when the air outside is cold. I bumped my controller up to 20 psi yesterday and it ran great. It was 65 degrees. This morning it was 40 and my fuel was shutting off around 18 psi. Unless my car just doesn't like going to work or it is scared of the dark.

bloodMoney
04-14-2011, 01:40 PM
I agree with the latter. Too many Cobalts creepin around in the dark. :)

T-spoon
04-14-2011, 03:31 PM
Are you sure it's the same actual boost that you're hitting when it's cool and when it's not? A peak hold boost gauge would be really handy for that, because what your boost is set at is not the whole story, it's what it's actually hitting.

Speedricer
04-14-2011, 04:24 PM
Are you sure it's the same actual boost that you're hitting when it's cool and when it's not? A peak hold boost gauge would be really handy for that, because what your boost is set at is not the whole story, it's what it's actually hitting.

I agree. It appears it is the same on the gauge both scenarios.
Is there a temp sensor on this motor?

v8killer
04-16-2011, 05:18 AM
hm then its just the block thats the stronger of the gen's now i gotta tear one appart to measure that stuff

ChrisD
04-16-2011, 04:38 PM
u can unhook the tvsv and put in any boost controller, and no those rods arnt weak at all the gen4 is the best of the 3sgte engins

As lalojamesliz pointed out, yeah they are weaker. Where they fail? Not sure. But definitely there have been more 4th gen rod related failures than 3rd gen. I'd probably be inclined to keep the boost at a moderate level personally. (~15psi) Heck, I've had my ST205 at 14psi for a long time and I know I could run higher, but I don't because I'm completely happy with its performance right now. (also, I still have the primary cat, which is another reason....)

:)

Speedricer
04-16-2011, 07:36 PM
I'm not worried about blowing up the engine, I'll just buy another one, they are cheap. The wiring is the bitch and that is done. Besides I put a thicker head gasket in to lower the compression so I can run higher boost. It's no fun being slow.

ChrisD
04-16-2011, 10:01 PM
Well then, crank it up. To bypass the fuel cut you'll need a FCD or wire in a zenier diode to clamp the voltage just before it hits whatever V 18psi is at.

v8killer
04-16-2011, 11:55 PM
well just trow in stock gen3 rods and forged pissed-ons and have a happy 550hp block =)

zen
05-09-2011, 10:40 AM
yes, its already been documented that the caldina rods are thinner. therefore, they are much weaker that gen3. gen3 rods plus shot-pinned would work out just fine for a build.

C-dubb
05-09-2011, 10:44 PM
Stand alone EMS and tune...call it good. haha.

Luni
05-10-2011, 06:31 AM
At 1 bar absolute (sea level), 0 humidity, etc. Fuel cut on a Gen3/Gen4 would be ~19 psi.

Now, when air density changes, so does the "weight" of the air on a map sensor. More dense air will be "heavier" on the sensor, while thinner air will be lighter. Even though when you turn the key to on, the sensor does an atmospheric check (to find out what is considered 0), the scale isnt quite perfect, so it will vary based on temprature, altitude, humidity, etc.

But for the most part, its pretty close to ~19 psi. I get more PSI before fuel cut than someone in CA or FL cause Im in Utah and Im at 4800 feet base elevation and my air is quite a bit thinner so "lighter" on a map sensor.

And Gen4 engines have weaker rods. And both Gen3 and Gen4 engines have weaker pistons. So, be careful running too much boost, youre not likely to throw a rod, but you ARE likely to pop a ringland. Happens ALOT. Even more than on Gen2 engines.

v8killer
05-11-2011, 12:17 AM
all truth right there------^

Speedricer
05-12-2011, 12:02 PM
Stand alone EMS and tune...call it good. haha.

Thanks... Smart Ass
Looks like greddy e-manage for me, too many fast cars in town this year.
I have your gauges with me, let me know when you are back in town.

Speedricer
08-19-2011, 03:12 AM
Well I'm back to needing more boost. I installed my new turbo which holds 18 psi to redline but it is begging me for more.
Does anyone know how to defeat the boost cut? Will Greddy Emanage control boost cut?
Here is a pic of my latest setup.
http://i235.photobucket.com/albums/ee289/Oosterbaan/DSCN1597.jpg

Speedricer
08-19-2011, 03:14 AM
Here is a better pic of turbo inlet
http://i235.photobucket.com/albums/ee289/Oosterbaan/DSCN1596.jpg

celica9303
08-19-2011, 03:40 AM
I can't wait for september :-D I'm preety sure emanage will do what you need it to, or aem maybe?

Speedricer
08-19-2011, 03:46 AM
I know aem will do it but I'm not ready to do that yet. Emanage is cheap enough to try... if it will control boost cut.

celica9303
08-19-2011, 04:41 AM
What do you have by you for tuner wise? What do they know/recommend? No since in getting a unit no one can tune.
What about MAP-ECU, I know it can do boost cut????

E-manage ultimate will do boost cut, the regular emanage I'm not sure of

Change
09-04-2011, 07:45 PM
Im thinking 12 psi.. I had a stock gen3 3sgte in my mr2 and had boost cut at 18

Change
09-04-2011, 07:47 PM
Power fc is a good stand alone and is way cheaper than aem. I had a aem and it's a good ecu but power fc is almost as good but don't have some of the options the aem does