very lean AFR @ +/-3000-3500 rpm [SOLVED]

[RJBijsterbosch]

Interesting when you think about it, possibly a resonance causing a pressure wave and unstable rail pressure ...

Interesting indeed, i think that the injectors will certainly cause a resonance in the fuel rail.

The good thing about this, is that i learned a lot.

[Torque]

Yes, never remove something you're not sure about

[RJBijsterbosch]

Yes, never remove something you're not sure about

The reason why i removed everything can been seen in the attached pictures.

I gave the enginebay/engine a fresh layer of paint. All done by myself. I am very proud of the end result. Never done this before.

But now i'm getting a little bit of topic.

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And a picture of the car then.

[Torque]

Looks nice!
Did you notice any loss of low down torque with that intake plenum?

[RJBijsterbosch]

Attached some photo's to show you what happened.

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This is when the Nistune ECU was placed in 2012. Blue line is before Nistune, Red line is after Nistune. With stock turbo, larger intercooler, boostcontroller 0.86Bar, Walbro pump.

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This is when the intake was fitted with the larger injectors.

Because the stock turbo is very small, it spools up very quick in combination with the new intake, the torque is increased @ low RPM.

I see that the rpm scale is not the same @ the photo's. But you can compare certain points.

[Torque]

Hmmm

It's difficult to tell from the graphs and in the first dyno the torque graph is all over the place.
It looks as if there was slippage on the rollers of the dynometer?
Are both graphs with the OEM Nissan turbo?

[RJBijsterbosch]

Hmmm

It's difficult to tell from the graphs and in the first dyno the torque graph is all over the place.
It looks as if there was slippage on the rollers of the dynometer? Why do you think there was slippage?
Are both graphs with the OEM Nissan turbo?Yes, both graphs are with the OEM Nissan turbo.

[Torque]

I think because the torque graph (1st picture) is very inconsistent it never goes into up and down valleys like this.
Torque curve is usually a consistent graph (as in the second plot)

What type of boost are you running ?

[RJBijsterbosch]

A very sharp comment. I was thinking what it was, but now i remember. It's a few years ago . After tuning on the dyno and driving back to home, i found out that the clutch was slipping a little bit. Replaced it for a competition clutch stage 4.

I'm running 0.86 Bar boost pressure. With a greddy boost controller.

[Torque]

That's a very good result given it is the OEM turbo and the low boost.
The downside is that the turbo runs out of steam from about 5700rpm onwards.
(you possibly can feel it somewhat earlier)
I was at that stage once, and I think it's the best performance you can have for the money invested.

Also the small turbo is pretty responsive and it's a lot of torque early on.

[RJBijsterbosch]

It's been a while but i did something to the car that even made better improvements.

The stock fueldampener was after the fuel pressure regulator. I did some fuel pressure measurements with a very acurate pressere transmitter and there where still some fuel pressure spikes. I switched the fuel lines, so the stock fuel dampener is now before the fuel pressure regulator. And that made the performance of the engine even better.

Greetings robbert