Standard Turbo and Computer with a higher boost???

[JAS-25T]

ok ive done a search but didnt really come up with a good answer

waht i need to know is

will the standard computer handle about 10psi once i install a boost controller and set it at 10psi?

is there anything that will "shit" itself under this pressure

car is standard except filter and exhaust r33 gtst

[MJ]

It will be fine except for the car running rich you may find a couple of popping noises come out of the exhaust when giving it a hard time. A s-afc or power fc can fix the A/F ratio's for ya though so that is normal

[JAS-25T]

i dont want to get a new coputer just yet

it will be on the shopping list

but how much boost do you think is safe with everything else as i said

only exhaust and filter

[Dice]

I had mine up around 13psi for a while. Nothing broke but it did develop a few flat spots. So I took it back down to 10.5. Runs fine.

[Guest INASNT]

u sure u searched properly?? because boost questions have been answered 1 billion times already

[JAS-25T]

i did a search for "boost controllers"

cause i also wanted to know what kind of boost controllers people were using on this similar setup

[lukits01]

I have a profec B and the car is totally stock except for air filter

I turned up the boost to 13 PSI but it also had the problem with dead spots at high RPMs

I turned it down to 10-11 PSI and its fine there

Does anyone know why these dead spots occur? or how to fix it? I allready have .8mm spark plugs installed so thats not the problem

[Sydneykid]

Hi lukits01, R33 GTST's have overboost protection built into the ECU. When it sees too much airlfow (via the AFM) or boost (via the boost sensor) it cuts the ignition, hence hesitation. Anything more than 12 psi seems to generally trigger the protection mode. There are exceptions of course, as with all things mechanical there are always exceptions.

A so called "boost cut defeater" will fix this. You can buy all sorts of types. I am sure a search will reveal all about those.

Hope that helps

[Penfold]

Could this be causing my situation as well?

http://www.skylinesaustralia.com/forums/sh...ead.php?t=30533

Thanks

[rb25]

10psi seems to be fine on my 33. Bit of a flat spot at 3000-4500. my theory to this is the factory setup has lower boost where im flatspotting (3-4.5k rpm) and has a fuel map change or something and is not used to the full boost at those rpms. doesnt seem to be a problem.

-rb25

[RBVS]

you can try and reset the standard ECU by disconecting the batary and letting go flat. then when conected again the ecu will adjust to new conditions.

settings like boost cut and so on will still operate but you should fined a better tune. I would run 12psi as i think its best suited to standard set up. I also found that running 14psi there is little to no gain on the standard turbo as air is much hotter. I Have a larger cooler as well. its more important to hold the boost and not have it bleed back 2psi which happens alot.

as for a controler to use, i would buy a $100 bleed valve

or go all out and get a ecu that can control boost

[GTRman1992]

I run the standard management, untouched at 20psi and it is perfect. Been like that for close to 3 years. Don't underestimate the standard ECU. Just has to be set up properly, no problem with boost cut on GTR, but as SydneyKid said these are easy to get for GTS.

[benm]

So a 230-250rwkw turbo on a r33 gts-t with standard ecu would still work? I'm guessing that an S-AFC would be required just to make it actually work though or could you just bolt on the aftermarket turbo, reset the ECU and just put up with what you get ?

[Stan]

Hi lukits01, R33 GTST's have overboost protection built into the ECU.  When it sees too much airlfow (via the AFM) or boost (via the boost sensor) it cuts the ignition, hence hesitation.  Anything more than 12 psi seems to generally trigger the protection mode.  There are exceptions of course, as with all things mechanical there are always exceptions.

A so called "boost cut defeater" will fix this.  You can buy all sorts of types.  I am sure a search will reveal all about those.

Hope that helps

Sydneykid, If I install a boost cut defeater, won't the AFM still register too much airflow?

If I install a boost cut defeater, will I then have the incorrect fuel and timing for the actual amount of boost possibly causing detonation?

Hope you can help

Thankyou

[Guest INASNT]

So a 230-250rwkw turbo on a r33 gts-t with standard ecu would still work? I'm guessing that an S-AFC would be required just to make it actually work though or could you just bolt on the aftermarket turbo, reset the ECU and just put up with what you get ?

no tuner would recommend u keep the stock ecu when u spent all that $$ on other mods to get to 250rwkw! Ofcourse the ecu will still work but would be very inefficent

[GTRman1992]

I would not be too quick to write off the standard ECU. An air flow meter measures air into the engine so the ECU can mix the right amount of fuel. I think the time to upgrade to aftermarket ECU is when the standard injectors are no longer up to the task of delivering the fuel you need for the power. Then you need an after market ECU to re-program for bigger injectors etc.

Like I said earlier, I'm running 20psi boost with factory ECU and the car runs like a dream. Been like that for close to 3 years.

[Sydneykid]

Hi guys, just because GTRman1992 has got away with 20psi for 3 years doesn't mean that you will. It has been my experience with a number of GTST's that,

more than 10 psi on the standard turbo is flirting with danger. The ceramic turbine doesn't like it and the car runs very rich over most of the rpm range, except at that 1,000 rpm or so of building boost. This is where the standard fuel maps are too lean and the ignition is too advanced and detonation is not unusual. This is sufficient to cause ring land and/or head gasket failure.

I would also respectfully suggest that, over 3 years of rich running, he may well have saved enough money on wasted fuel to buy a PFC. False economy you could say.

Based on our experience on the dyno with over 20 Skylines, I would say at 20 psi he is loosing over 25 rwkw because of poor tuning. That's probably more power than he gained by any other single change he made. More false economy perhaps.

This is of course based on my personal experiences, others may have different results. That's what makes forums so interesting.

[GTRman1992]

Your delightful sarcasm aside, Sydneykid you are finally starting to get to a question I have been trying to get answered for a while. "Without changing boost, how must gain do you get with an Aftermarket ECU".

I am not claiming to be the authority, just stating what I have. My turbo's are steel wheeled with 360deg thrust bearings and the car is a GTR not GTS. It also has head porting, matched port manifolds, large exhaust, high flow filter.

[riggaP]

JAS-25T, If you want to increase the boost my first suggestion is to regap your spark plugs to 0.8mm. Doing this with the standard ECU should allow you to run about 10-11psi. After that, as others have already mentioned, "overboost protection" sets in and misfire problems occur.

I upped the boost with a bleeder (to about 9psi) and ran into misfire problems above 4500rpm. I then regapped my spark plugs and could run 10-11psi without it being an issue. However, the real gains from the boost increase were noticed once I got a hold of a chipped ECU which has far better ignition timing than standard. Boost comes on earlier, more midrange responsiveness, and redline is acheived quicker. I can now also up the boost until the turbo goes bang I'm currently running 13psi.

Regapping the spark plugs to 0.8mm can help (and is cheap i.e. $0) but better engine management is the real key.... if only the stock ECU could be reprogrammed....

[Guest INASNT]

I would also respectfully suggest that, over 3 years of rich running, he may well have saved enough money on wasted fuel to buy a PFC. False economy you could say.

exactly what i was saying, GTRman if u drove a car with the same mods as yours but with a pfc or other aftermarket ecu u would know the differences.