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Weird Power Curve After Dyno Tune

s13-steve

By s13-steve,
in Western Australia

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s13-steve Collaborator

s13-steve

Posted
Posted

Hey guys,

I got my r33's apexi neo tuned at allstar garage last week - the result was 260rwhp

When i picked the car up one of the guys told me that there is a drop in power through the mid range and that this is normal for an rb25 and the only way to get rid of it is with a full computer - however after doing some research I have seen dyno graphs of Rb25's with safc tunes that dont have this dip in the power curve???

i have attached my dyno sheet and am looking foward to hearing your comments - its annoying to drive with the dip in the mid range and your basically sitting wait for the power to come...

Comments/ Advice?

post-68071-1278334902_thumb.jpg

Steve

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SimonR32 Grand Master

SimonR32

Posted
Posted

Seriously... It's rich and retard, when the AFM reads a certain amount of boost (being too high) it pulls heaps of timing out and adds lots of fuel!

You can clearly see on the graph that the boost just spikes a little in the midrange and then car dies in the ass, get a aftermarket computer to solve your problems :P

s13-steve Collaborator

s13-steve

Posted
  • Author
Posted
Seriously... It's rich and retard, when the AFM reads a certain amount of boost (being too high) it pulls heaps of timing out and adds lots of fuel!

You can clearly see on the graph that the boost just spikes a little in the midrange and then car dies in the ass, get a aftermarket computer to solve your problems :P

ok i will look into this - i have seen other rb25's with an safc tune that dont have this problem??

should i turn the boost down 1 psi to avoid entering R &R mode for the time being? im keen to head down to the drags but i think this may mess up my times a bit.

  • Like 1
bubba Grand Master

bubba

Posted
Posted (edited)
Seriously... It's rich and retard, when the AFM reads a certain amount of boost (being too high) it pulls heaps of timing out and adds lots of fuel!

You can clearly see on the graph that the boost just spikes a little in the midrange and then car dies in the ass, get a aftermarket computer to solve your problems :P

+1 you can even see where the boost drops back down the curve recovers itself

ok i will look into this - i have seen other rb25's with an safc tune that dont have this problem??

should i turn the boost down 1 psi to avoid entering R &R mode for the time being? im keen to head down to the drags but i think this may mess up my times a bit.

I really doubt you'd notice a 1psi drop but it may be enough that it no longer hits the airflow cut, but really.. if you're worried about 1psi affecting your times, what do you think a big dip in your curve is going to do to your times??

Edited by bubba
s13-steve Collaborator

s13-steve

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  • Author
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+1 you can even see where the boost drops back down the curve recovers itself

I really doubt you'd notice a 1psi drop but it may be enough that it no longer hits the airflow cut, but really.. if you're worried about 1psi affecting your times, what do you think a big dip in your curve is going to do to your times??

sorry mate i meant i was worried about the dip in power affecting times and therefore considering dropping it 1 psi to avoid it... noob question but as the car has been tuned to whatever psi its running at the moment, if i simply drop it down 1 psi do i need to get it re tuned to this boost level?

StealthX Veteran

StealthX

Posted
Posted
sorry mate i meant i was worried about the dip in power affecting times and therefore considering dropping it 1 psi to avoid it... noob question but as the car has been tuned to whatever psi its running at the moment, if i simply drop it down 1 psi do i need to get it re tuned to this boost level?

1psi won't make a difference to your tune, and i dont think that 1psi will make the difference so stop rich and retard, so I'd suggest dropping the boost by 2psi increments untill you feel the car has a smoother power band and it's not hitting r+r anymore.

JonnoHR31 Grand Master

JonnoHR31

Posted
Posted (edited)

perfecty normal for 33s. the safc will help a little but you cant completely get rid of it when running higher boost without an aftermarket ecu. the small rise in boost is normal too, its from the stupidly retarded timing around that part of the map

this is my 25 when i had a stock ecu, was like hitting vtec

17052008009.jpg

Edited by JonnoHR31
bubba Grand Master

bubba

Posted
Posted (edited)

It's an airflow cut anyway, 8psi on one stock 33 turbo isn't going to be quite the same as another stock 33 turbo, especially when you bring china fmic/piping and other individuals setups into the equation. Boost is just a measure of restriction afterall.

Edited by bubba
JonnoHR31 Grand Master

JonnoHR31

Posted
Posted

exactly. and its not a sudden thing, it'll gradually get worse with more airflow. you could even say a 100% stock car is hitting r+r as it runs a little rich and the timing isnt optimum. or from another point of view you might not call it r+r until it takes less than 1 tank of fuel to turn your white rear bumper black and the combustion event is happening more in the turbine housing than the cylinder

+1 for nistune

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