R33 Gtr performance issue

[Dose Pipe Sutututu]

5 minutes ago, BK said:

I don't know what cat he's running but the current 80mm Apexi super cats are 130cpi which is awesome.

They are also $1200 - $1400....

ouch.

Probably as awesome as their cat backs with 2.5" reducers inside.

Back on topic, I reckon with the de-cat his problems will go away, if not I think there's a "boost" rag somewhere in his pipe work. We've all been there before  

[Chrisko33]

Ok so the car has been chucked on the Dyno and it pulled 282kw with the de cat still a bit of where it should be

 

Edited October 9, 2019 by Chrisko33
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[KiwiRS4T]

5 hours ago, Chrisko33 said:

Ok so the car has been chucked on the Dyno and it pulled 282kw with the de cat still a bit of where it should be

 

If they won't dyno it with the exhaust dropped do it yourself at home.

[Dose Pipe Sutututu]

who is tuning it?

I see a ripple in power, wonder if it's your Attessa doing it OR it's timing scatter from your OEM CAS.

[Chrisko33]

1 hour ago, KiwiRS4T said:

If they won't dyno it with the exhaust dropped do it yourself at home.

Yeah I will do that for sure

[Stixbnr32]

What size is that Nismo exhaust?  Surely its to much back pressure somewhere.

[BK]

Yep, maybe the catback section to the muffler is more restrictive than the cat itself. Needs to be dynoed with front pipe only as I originally suggested and done myself to get a clear baseline of what's what. Are they saying they won't dyno it like that ?

[Chrisko33]

4 hours ago, BK said:

Yep, maybe the catback section to the muffler is more restrictive than the cat itself. Needs to be dynoed with front pipe only as I originally suggested and done myself to get a clear baseline of what's what. Are they saying they won't dyno it like that ?

Currently making them do that right now 

[Chrisko33]

Ok so I took the cat straight off back on the dyno made 292kw boost spiked half a pound so there wasn’t much loss between previous run of 282kw with de cat and exhaust. I was expecting to see boost come on quicker still took until 4100-4200rpm. I’m being told valve springs are the issue and change the cooler 

[GTSBoy]

There's no evidence of valve springs on the charts, so unless they have good reason to say they think there's float, do the cooler first.

And by "do the cooler", I don't mean replace it. I mean tap into the pipe up and downstream of it and check the actual pressure drop across it.

[KiwiRS4T]

A 10 kw improvement suggests there is an exhaust restriction so check the rear muffler at least. Stock cooler should be capable of more so as above check pressure either side. And consider trying another tuner.

[Chrisko33]

I’m changing to a 3.5inch x force exhaust now and also doing a cooler pressure check, dare say I’ll be changing the cooler I gained 25kw just in exhaust restrictions so far. What’s to say my cooler isn’t stuffed at this point.Not gonna throw money at springs and cams just yet I’ll do a power run and report back also on the last run it had some slight mis fire on the 292kw run coil pack harness seems to be the suspect as I have brand new coil packs 

[Dose Pipe Sutututu]

That slight misfire could also be CAS related, see if they've got the CAS filter enabled, I find Level 1 ~ 2 works well, but a brand new CAS or a trigger kit (crank, better cam, not as good as crank but better than the CAS) will fix heaps of problems.

[KiwiRS4T]

2 hours ago, Chrisko33 said:

I’m changing to a 3.5inch x force exhaust now and also doing a cooler pressure check, dare say I’ll be changing the cooler I gained 25kw just in exhaust restrictions so far. What’s to say my cooler isn’t stuffed at this point.Not gonna throw money at springs and cams just yet I’ll do a power run and report back also on the last run it had some slight mis fire on the 292kw run coil pack harness seems to be the suspect as I have brand new coil packs 

Just checking - what coil packs did you get?

[Chrisko33]

34 minutes ago, KiwiRS4T said:

Just checking - what coil packs did you get?

 oem Gtr ones

[TXSquirrel]

How is your fuel pump wired?  And how is the A/F ratio and injector duty cycle? 

I am asking because I had an episode with my pump not getting enough voltage.  The A/F ratio was fine but injector duty cycle was maxed out prematurely, and I lost about a good 40kw.  

[Stixbnr32]

Yeh but surely the tuner would figure that out pretty quickly.

[TXSquirrel]

3 hours ago, Stixbnr32 said:

Yeh but surely the tuner would figure that out pretty quickly.

The tuner figured out OP needs a cooler and valve springs.  I think it's pretty obvious those two items are getting the no confidence vote here.

[Chrisko33]

10 hours ago, TXSquirrel said:

How is your fuel pump wired?  And how is the A/F ratio and injector duty cycle? 

I am asking because I had an episode with my pump not getting enough voltage.  The A/F ratio was fine but injector duty cycle was maxed out prematurely, and I lost about a good 40kw.  

Fuel pump is getting getting 12v that was checked when on the Dyno. Not sure what the duty cycle on injectors are I’ll find out.

[KiwiRS4T]

Is you Walbro directly wired? Pretty sure the stock wiring will not supply enough power.