Apexi Power FC limits

[BlockHead]

I have heard that if you put the apexi pfc on the rb25det its very hard to get it to tune over 450hp. Is this an actual problem or have I heard the wrong information. I am in the US and will be in need of complete engine management. This sounded like a good choice unless it will only tune to 450hp. Thanks

[meggala]

I think you have heard the information form some oenwho doesnt know the power fc because there are a number of car on this board tha make in excess of 500 hp that use the power fc in fact the power fc is the ecu of choice cause all you have to do is plug it in no messy installs. btw that is assuming you have a suitable turbo injectors, fuel and afm.

cheers

[Jay95R33]

The limit you hear of may apply to the stock AFM.

Changing it to a Z32 iteam will give you more resolution.

J

[BlockHead]

I heard something about a version that was called djamic or something and it seemed to have limits. Also what is the difference between the PFC and the PFC PRO? Thanks

[JNR24]

I think the version you are refering to is the Djetro....

This is just means that the primary sensor of the computer is undertaken using the MAP sensor rather than AFM. Hence no resolution limits using AFMs! (allthough AFM are more accurate)

Heres a power restriction guide for you if your going to run a AFM setup:

1 X RB20/25 AFM = 370 bhp = 220 rwkw

1 X Z32 AFM = 420 bhp = 260 rwkw

2 X RB26 AFM's = 475 bhp = 300 rwkw

2 X Z32 AFM's = 700 bhp = 470 rwkw

1 X Q45 AFM = 480 bhp = 300 rwkw

2 X Q45 AFM's = 850 bhp = 550 rwkw

I havent seen anyone using a Djetro version of the FC so i cant say how it performs. And as for the diffrences regarding the computers i wouldnt have a clue!

Cheers,

Trev.

[Steve]

PowerFC PRO has launch control

[predator]

I hear there is a new version of all the PowerFC's out... Which were released a month or two ago.

Is this correct? and what are the new features included in these new models over the old??

[aza]

wood the apexi afc get around the problem of the power restrictions or it dusnt mater the afm has run out of of puf

[predator]

The S-AFC just uses the AFM sensor itself, so no

[aza]

so have can u get around this problem

[Steve]

Having a correct sized afm enables better tuning at higher load/rpm. when you dyno the car, usually they will use an O2 senor, so it is still possible to tune after the AFM has run out of resolution, but not as accurately.

[aza]

so there is no limet its just not as accurat

[raist60]

my PFC just stays in the last map, i dont know much about tuning ECUs but i didnt think you could really tune past this point. Rather just richen up that last map something shocking to compensate?

[Steve]

aza, yes as far as I know/understand.

raist60, definately can tune past that point, my stock afm ran out of resolution at 4500rpm, and the AF ratios above there stayed pretty much the same. Probably just tune by rpm at max load? (just guessing)

[Sydneykid]

Hi guys, there is a lot of AFM paranoia floating around. People forget that the AFM is not the only method by which an ECU determines how much fuel to add. It also relies on throttle position and engine RPM for example. The standard ECU is programmed to add fuel and retard the ignition when it sees 5V, you don't have to program a Power FC that way.

When you build a fuel map in a Power FC you can table the air flow up to 5V via the AFM and then rely on RPM to table the fuel required once past 5V. RB engines are very linear (with RPM) in their fuel requirements at that level, so this is not a difficult or dangerous proposition.

Using an AFM with resolution available at higher airflows would make this process even more accurate, but there are plenty of engines around running perfectly fine without it.

As I do with everyone, I suggest you fit the PFC, have it fine tuned properly and then read off the AFM voltage from the Commander. We have seen 250 rwkw on the standard AFM at max voltage.

If and when you reach that level, then a Z32 (80 mm) or Q45(90mm) AFM is an easy upgrade for a few hundy.

Hope that helps

[GTS 33]

Hey People

Just after some help. I receantly got my power fc with h/c, boost control and exhaust cam gear installed on my 1993 GtsT.

It already had 3" exhaust with dual dump pipes, Apex GT intercooler and pod air filter. Since the new gear has been installed I have only recieved about an extra 22rwhp. Does this sound right?

I ran a thread before I bought the PFC, boost cont and cam and was told I should have been able to get close to 200rwkw. I'm only at about 187rwkw. Any advice would be great.

Thanks

Chris

[Guest RedLineGTR]

What boost are you runnning...it also depends on how they tuned it...how good/shit the tuner is..

[GTS 33]

From memory think it's 13.1 will have to check when at home. The tuner I used has pretty good rep. 25GTT uses same tuner has similar gear and is producing 275+rwhp.

Chris

[Sydneykid]

Hi GTS 33, unless the dyno room is airconditioned, ambient temperature could easily account for the 8% difference. Remember a decrease of 8 degrees Celsius = 5%.

We had a super cold day last weekend (6.5 degrees) and I whipped the GTST on the dyno and it pulled 230 rwkw. Previous best was 210 rwkw at 25 degrees. No modifications since.

Comparing different cars on different days is waste of time.

It's the 22 rwhp increase over the day that is more interesting. Experience would say 5 to 10 rwhp for the exhaust cam gear and 15 to 20 rwhp for the PFC. Then you would have to add the additional hp from the boost increase, if you had any. So 22 rwhp looks a little on the light side.

I would look at the air fuel ratios, the ignition timing and the boost and make sure they are all optimised. Also check the exhaust timing, it should be around 4 degrees retarded for max hp.

Hope that helps

[GTS 33]

Hey SydneyKid

Thanks for that info. Not really clued up on the pfc as yet, still gotta have a play. Do you have any advice of what the air/fuel ratios, ignition timing and boost should be set at for best results without damaging anything?

Pretty sure my boost is set at 13.1, spoke to 25GTT he says that might be a little hi.

Thanks for your help