Weird Power Curve After Dyno Tune

[s13-steve]

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?

Steve

[snozzle]

how was the drive before it got retuned

[StealthX]

I got my r33's apexi neo tuned

Hate to point is out, but that's probably most of the problem.

What's you boost control like? (i.e. manual boost tee, EBC, upgraded actuator???)

[snozzle]

lol i wonder how much money you wasted on that safc tune >.<

[SimonR32]

It's hitting rich and retard... Gay 33 standard ecu

[GTS-t VSPEC]

They do tend to have a power dip, but your's is very pronounced. A dyno graph versus AFR would be more useful to tell you more.

[s13-steve]

Hate to point is out, but that's probably most of the problem.

What's you boost control like? (i.e. manual boost tee, EBC, upgraded actuator???)

The car gas has a greedy ebc...

[SimonR32]

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

[s13-steve]

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

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.

[bubba]

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

+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 July 6, 2010 by bubba

[s13-steve]

+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?

[bubba]

Less boost is fine, more boost would require a retune.

[StealthX]

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]

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

Edited July 6, 2010 by JonnoHR31

[N I B]

www.nistune.com

This is all you will ever need. Find a cheap Z32 ECU and send to these guys and get them to set it up for an R33.

Any reasonable tuner in Australia can then tune it for you.

Very cheap and effective ECU upgrade.

[XxNinjaxX]

if it helps, though testing on my own R33 i found 8psi to be the maximum boost you should run on the standard ecu to safely avoid the R&R + fuel cut while still having decent power

[GTS-t VSPEC]

if it helps, though testing on my own R33 i found 8psi to be the maximum boost you should run on the standard ecu to safely avoid the R&R + fuel cut while still having decent power

8psi ? Can easily go higher than that.

[bubba]

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 July 7, 2010 by bubba

[JonnoHR31]

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

[Pal]

i run my car with safc2 for years and never hit r&r and i was running up to 280 rwhp and 12-13psi on the stock turbo! i did have the nasty power dip half way up the power curve though.