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PFC - Before & after dyno - comments?

Bill

By Bill,
in Engines & Forced Induction

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Bill Collaborator

Bill

Posted
Posted

First apologies for those on dialup :)

Ive just had a PFC fitted to my R34 GT-T

Yes, I know they are done on 2 different dynos, but "Seat of the pants" wise there is a noticeable difference. I am getting it red dynoed on the one that did the origional one for an accurate comparison though.

Mods are

-FMIC

-Pod filter

-3" exhaust, turbo back

-E-Boost

-Coilpacks

-PFC

(PFC and coil packs were after the first Dyno results.)

Pic below is the before dyno.

Boost was about 9psi.

Note the horrible hole in the power curve. This seemed to be where the stock computer was bitcching about too much boost.

_power%20boost-19-7-04.jpg

Now we have the after result.

The Blue line is 15psi, the red line is 9psi (same as the origional dyno).

About 4300rpm you can see the boost just drop away if Im running at 15psi.

I would assume that the turbo is too small to flow enougth air after about 4300 to maintain boost?

Any Cost effective suggestions?

_power%20boost---26-11-04.jpg

One thing that I noticed is how crappy the stock computer is at maintaining a good air /fuel ratio.

Just look at this before PFC dyno.

_power%20air-fuel-19-7-04.jpg

Now compare the after result.

_power%20af-ratio---26-11-04.jpg

Is my before result typical for a stock computer?

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https://www.sau.com.au/forums/topic/57313-pfc-before-after-dyno-comments/
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cameron Mentor

cameron

Posted
Posted

Yes the standard ecu is like that. Some are different to other model's - 95mld is know as a freak ecu as it can get upto 200rwkw's with the right components with it. Other carn't.

Other wise you've made a nice gain over stock, the only limiting factor now is your turbo. Thats the reason why it droped off at 15psi as the efficency of the hairdryer ran out at high rpm.

Next thing i'd do would be the fuel pump. Then after that look at injectors & turbo.

:)

Jun

Tigger Collaborator

Tigger

Posted
Posted

Ummm just a question...

How do the differing AT and IT figures play into the comparability of the readings?

I noticed that the after PFC readings have both temperatures being about 15-20 degrees higher than the initial reading. I read on another thread that the dyno computer adjusts the reading to standardise the figure based on the intake temps. So in theory, since the intake temp is higher in the second one, the reading is an overestimate when comparing with the first dyno run?

Can someone confirm please?

cameron Mentor

cameron

Posted
Posted

All dyno's are different,

You will get different reading's on any day due to air temps, calibration of dyno. You can make a 200hp car read 500hp if you really wanted to.

The best way is to stick to one dyno to see what your car gains over stock which is what Bill is going to do. ;)

:)

Jun

Beer Baron Grand Master

Beer Baron

Posted
Posted
Ummm just a question...

How do the differing AT and IT figures play into the comparability of the readings?

I noticed that the after PFC readings have both temperatures being about 15-20 degrees higher than the initial reading. I read on another thread that the dyno computer adjusts the reading to standardise the figure based on the intake temps. So in theory, since the intake temp is higher in the second one, the reading is an overestimate when comparing with the first dyno run?  

Can someone confirm please?

You maths is very bad! lol 34-24=10 (degrees difference) not 15-20...

Yes the higher IT would make a difference but 34IT on a 24 degree day is not such a stretch. How much of a difference is beyond me.

Richard

Sydneykid Grand Master

Sydneykid

Posted
Posted

Hi guys, both dynos are in Shoot Out Mode, so the power outputs should be totally comparable. That's why Dyno Dynamics "invented" shoot out mode" so the numbers are comparable no matter what temperature the day is, or the humidity or the altitude. The higher inlet temp on the second dyno run would result in a real world lower power output, so SOM compensates. Thus the 157 rwkw (before PFC) is totally comparable with the 204 rwkw (after PFC).

Whether the 157 or the 204 are perfectly accurate is a totally different question:cheers:

Tigger Collaborator

Tigger

Posted
Posted

mmmgtir:

Sorry for the confusion. I was actually comparing the AT for the AT, and IT for IT, before and afters.

Before PFC AT = 11

After PFC AT = 24

Difference = 13

Before PFC IT = 15

After PFC IT = 34

Difference = 19

So technically i should have said 13-19 but i just rounded to nice figures of 15-20 instead.

Bill Collaborator

Bill

Posted
  • Author
Posted
 

Next thing i'd do would be the fuel pump. Then after that look at injectors & turbo.

 

:P

Jun

Im a little curious as to why the fuel pump next?

Is there anything to indicate that the pump cant handle the load now?

Beer Baron Grand Master

Beer Baron

Posted
Posted
mmmgtir:

Sorry for the confusion. I was actually comparing the AT for the AT, and IT for IT, before and afters.

Before PFC AT = 11

After PFC AT = 24

Difference = 13

Before PFC IT = 15

After PFC IT = 34

Difference = 19

So technically i should have said 13-19 but i just rounded to nice figures of 15-20 instead.

ahh. I see! Sorry, I'm just used to looking at ATvsIT. :rofl:

Richard

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