All Things Mk5 > Performance Modifications

Bluefin Stage 2 too much boost .. not enough fuel pressure?

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Mark_GTIV:
Hi there,

Now I've got VCDS I decided to do a bit of logging - I've been experiencing a couple of flat spots in the delivery of power from my stage 2 bluefin mapped car.

Well.. I've noticed what the problem is : the car is boosting slightly over the specified boost up to 1.4 BAR achieved and this is causing fuel delivery issues, where the fuel rail pressure achieved isn't matching up with the requested on wide open throttle, with the engine heavily loaded in 5th/6th gear pulling through 3000 to 4500 rpm.

Here is a graph



I think I need to contact superchips to see what they can do first thing Monday.

Anyone had this with bluefin stage 2?

I've got a Milltek hiflow downpipe, Milltek hiflow cat, milltek exhaust, Forge DV and Carbonio CAI with ITG panel filter.

Greeners:
At the last RR day I went to mine was losing boost high up (over 6k) and I'd noticed it for the first time on the way there that very day!

Going to get SC to look at it whilst at the RR day next week!  :happy2:

gadge:
From what i know over on the VXR's. Bluefin/SC tend to run higher boost levels.

Mark_GTIV:
The ECU is usually requesting 0.1 to 0.2 bar less than the car actually achieves. When the car is achieving 1.43 BAR boost, its seems its too much for the fuel rail because you can see the pressure drop away by 10 to 20 bar from the requested fuel pressure when the car hits that boost. Slightly lower boost and its fine.

You can see it clearly from the graph. The top two lines are Boost Requested and Boost Achieved - i've scaled them if you add a 0 to the end of the number you get millibars and then deduct atmospheric pressure of 1080 millibars and you get boost pressure

The next two lines down are the fuel pressure requested on the rail (in blue) and the fuel pressure achieved (in red) - they are measured in bar.

The horizontal axis is RPM.

And the bottom green line is the differential between the requested and the achieved for the rail pressure - also measured in bar. When you see the differential line spike - there is the problem - both times at peak load in the 3000 to 4500 rpm peak torque zone where the car is running 1.43 BAR boost.

vwrascal:
^^ Wow, sounds like you know your stuff! quick Q? How do you log that data? I have vcds hex-can, do I need to go into 'applications' and then 'transport mode'??   :confused:  sorry for going off topic   :ashamed:

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