Rb25Det Unique Problem

[abr33]

G'day guys, my r33 gtst auto has a problem. When at wot it goes like the clappas until 5k, then holds back. If in 3rd or 4th it will sorta cut out as well, 1st aint so bad, running 11psi but when about 6500-7000 it pulls hard again.

Mods... top mount t04z, 50mm wastegate, port n polish, forged bottom end, fmic, new split fire coil packs, plus alot more... all stock electrics, new 02, good clean afm, timing is at 15btdc, idles at 650-700 rpm, all seems well except the big flat spot, tried resetting ecu etc, no boost leaks at all, wiring all looks intact. I built the car slowly over 3 years and used to rev fine but with new stuff i cant sort it out. oh and fuel is running about 40psi ish. its driving me totally nuts. please help me before i go loopy. thanks in advance guys.

[The Mafia]

Unique problem? You mean poor setup problem?

How can you expect a stock ECU to behave properly with all of that stuff bolted to the car?

You won't fix this. Get a tunable ECU.

Edited February 7, 2011 by The Mafia

[abr33]

hardly, all exactly the same as it used to be when running spot on, only big difference is the turbo, which is running less pressure than when i had the stock one on, all plumbing etc is as it was before... its not the ecu (i think) because its not working any harder due to similar boost and same timing etc etc. got me stumped.

[jrm]

With 2 posts, that has to be a troll, right?

Dude, drop your boost at the very least.

You honestly can't expect your untouched ECU to handle those mods - the extra airflow is sending your ECU into a tizz. Even a stock turbo on an R33 will go batshit at 9-10psi, you expect it to be okay with a bigger turbo and more airflow? Craziness.

Hell, you've spent all that money building your engine, adding a big turbo, and you really expect it to run on the factory ECU?

Seriously - use the search function, you look like an idiot.

Edit: Ugh.. just found another thread you made a few weeks ago:

http://www.skylinesaustralia.com/forums/topic/350357-r33-issues-can-you-help/

Hi all, im new and have a problem that no search on here or google can solve.

Ok, so iv got an r33 gtst auto rb25det.

Iv fully rebuilt the engine, 1mm oversize, cp forged pistons, eagle H rods, full port n polish, custom extractors, top mount t04z, 50mm greddy wastegate, 3" straight through system, fmic, plus heaps i have forgotten.

Problem is i cant get it to run right, to have it idle and drive nicely, timing is set at about 25 degrees (shit loads) but doesnt detonate at all, and less advance it dies off. When i hold it wide it gets to 5000 revs and has a bad flat spot untill a spike in power at 6200. I have the stock ecu, all electrics are stock so i can get engineered. even if i hit the throttle at idle and it revs to 3000 it sometimes dies or struggles to get a smooth idle back. And its especially bad when driving even very lightly on throttle, i have to hold it on a bit when i back off to stop it stalling.

Any ideas would be great as its driving me nuts iv tried heaps like new afm, o2, reset ecu and all plugs, its got no leaks (air).

Everything electric is same as it was before i pulled it down and it used to run spot on. Its not running rich either (about 11-12L/100k)

Cheers!

This is nuts.. I especially love the 'all electrics are stock so I can get it engineered'... *groan*

[The Mafia]

hardly, all exactly the same as it used to be when running spot on, only big difference is the turbo, which is running less pressure than when i had the stock one on, all plumbing etc is as it was before... its not the ecu (i think) because its not working any harder due to similar boost and same timing etc etc. got me stumped.

So you think that 10psi from a T04Z is the same as 10psi from a stock turbo?

Good luck with the engine rebuild.

[JonnoHR31]

it wont kill the engine, the standard ecu wont let it. turn the boost down until you get some aftermarket management and bigger injectors, simple

[The Mafia]

it wont kill the engine, the standard ecu wont let it. turn the boost down until you get some aftermarket management and bigger injectors, simple

ummm, that is very bad advice...

Seen plenty of cars die from Factory ECUs pinging, too much boost etc.

[abr33]

OK OK,,,, i reposted cause i thought i put it in the wrong section... And i realise most of whats said, but i used to run 13psi with stock turbo with no issues, and i do intend on getting the ecu done and a full tune, however i was hoping for any suggestions to settle the issue, i will reduce the boost to about 8 and see how it goes. And as for the comment about the engineers cert i dont quite get it?

And "the mafia" BOOST is BOOST 10 psi out of a stock turbo is still the SAME pressure as 10 psi out of a big turbo... only difference is spool time... general physics mate....

[The Mafia]

And "the mafia" BOOST is BOOST 10 psi out of a stock turbo is still the SAME pressure as 10 psi out of a big turbo... only difference is spool time... general physics mate....

Actually, you are so very wrong.

If 10psi from your stock turbo, is the same as 10psi from a T04Z, why did you upgrade?

Its the same right? So no point in putting a bigger turbo on?

[Sir Lord Van Von Vader'ham]

omg. he totally went there

[abr33]

Because my eventual intended boost of about 18 will kill the stock one... 10 psi in the intake is EXACTLY 10 psi in the intake... Anyone else feel free to explain this too...

I love you peoples nagativity... quite interesting...

[The Mafia]

So why don't you just turn the stock turbo up to 18psi? AS you said, 18psi is exactly 18psi right? Why the need to upgrade? The factory Turbo will do 18psi.

I'm not even going to waste my time, because if you think 10psi from a stock turbo is the same as 10psi from a T04Z, you are clearly a retard.

"Its just physics mate"...

And expecting a T04Z with a factory ECU to play nice. Very smart.

Maybe add a Big ATMO BOV, an electric supercharger, and a Super Cap. That will fix the problem.

Oh, and make sure when you run 18psi with the T04z, you still have the standard AFM. Its just a Meter, right?

Awesome.

Edited February 7, 2011 by The Mafia

[PaulosECR33]

why spend all that money and run 10psi, what a waste.

its about air flow dude a bigger turbo can move way more air, and even if it was about spool time the stock turbo would spool faster than a to4z anyway

[abr33]

Wow, did i hit a wrong note there? you seem to have gotten a little upset? sorry about that...

Cheers for all the constructive ideas!

i wasnt looking to get more power out of the stock goodies... just to fix the flat spot. Enough negativity yet or is more in store?

[PaulosECR33]

Wow, did i hit a wrong note there? you seem to have gotten a little upset? sorry about that...

Cheers for all the constructive ideas!

i wasnt looking to get more power out of the stock goodies... just to fix the flat spot. Enough negativity yet or is more in store?

injectors and tunable ecu

[The Mafia]

No, I am just amazed at your stupidity, and clogging up SAU with this shit.

Tell me, honestly, do you really think that 10psi frpm a stock Turbo is the same as 10psi from a T04Z?

And do you even know about the rich and retard mechanism in the stock ECU? The retard bit definitely applies to you.

[abr33]

why spend all that money and run 10psi, what a waste.

its about air flow dude a bigger turbo can move way more air, and even if it was about spool time the stock turbo would spool faster than a to4z anyway

Thankyou for a reasonable comment, i know that mate i will be getting a full tune eventually and was just running that boost because it was happy with that before, just thought someone may have had the issue before, thanks

[PM-R33]

TO4Z on a stock ECU?!?!?

You gotta be kidding me.

[GTScotT]

Hey mate, I get the impression you are being serious... So I will give you as best a response as I can.

The above guys are actually correct. Your problem is your ECU. The ECU is not able to cope with the change to the new turbo.

To put it simply, pressure (boost) and volume (actual amount) are not relevant to each other. That means that 10psi from the stock turbo will be far less compressed air (power to be made) than 10psi from the T04Z.

Your car is literally a ticking time bomb, and I can assure you that if you persist you will blow the motor very soon.

You will need the following items ASAP:

700cc+ injectors

A good fuel pump (if you dont have already)

A map based ECU (running a Z32 AFM wont cut the mustard for a T04Z)

To all experienced forum members, can you please simply +1 my post if you agree. I believe the guy is being honest and is not long off wasting 3 years of hard work on his car and motor.

GL

[bubba]

I think what is trying to be said here is that a bigger turbo will flow more air for a given pressure, hence being a "bigger" turbo.

A small turbo such as your stock one will flow considerably LESS at 10psi than a big turbo such as the T04Z (800hp turbo?) at 10psi.

Our stock ECU's read air FLOW, not pressure.

My guess as to what is happening is that the T04Z is pushing so much air that your stock ECU is throwing a fit, you've also most definitely maxed your airflow meter.

Edited February 7, 2011 by bubba