AFN low boost

[Cableguy]

Have been waiting for something to rear its ugly head:-(
Have no boost low down, it eventually tips out at 10 psi if you floor it and rev it to 3k.
I've had a good search on here and I reckon it must be a leak of some kind.
I've checked all the hoses, but can't see anything obvious. Is there any way of testing for a leak?
Cheers

[syncroandy]

Hi Ray, on mine I find the first signs of boost a little below 2k rpm, under moderate load, and it will go up to .1 or .2 bar. Above 2k rpm, and under a bit more load, the boost will typically peak at around .5bar or 7psi. In normal driving on levelish roads the boosts is fluctuating between 0-.5bar. On a hill, and when booted, the boost will go up to 1.3bar, but this is only occasional. The boost is more dependant on engine load than speed, but my motor will rev well past 3k rpm if needed, though 3k is my normal 'change down a gear' revs.

The VNT's can lose boost if the vanes inside become partially restricted in movement due to buildup of soot etc. or if the actuator goes out of adjustment. If it wasn't stripped/checked/adjusted when you had your install done, it may now be time to do this. The first thing to do though is visually check the adjustment locknut hasn't become loose and caused a restriction in the movement of the actuator rod. When checking the movement a mityvac is used to check the actuator has full movement from its rest position (no vac) to the limit stop. The limit stop is set in the factory and must not be changed.

[Cableguy]

Thanks Andy, good advice. Will have a tinker

[syncroandy]

Have fun ! Also i should have said a readout of any DTC's would be useful. IME a low boost state may not put on the glow plug LED, but will probably log a control difference on the manifold pressure.

[Cableguy]

Sorted, found a split in one of the vacuum hoses. Normal service resumed

[si&helen cali89]

just wondered on your afn conversion where have you got your intercooler mounted and how do you keep it well ventalated

[Cableguy]

Hi,
My inter cooler is mounted above the gearbox and has some big scoops each side that direct air onto it.
Works a treat. Intake temps on my scan gauge prove that it's a very effective solution.
How is yours set up?

[ninja.turtle007]

just wondered on your afn conversion where have you got your intercooler mounted and how do you keep it well ventalated

Hi, is the 140bhp proven or an estimate? What set up do you have?

Sorry for the hijack.

[si&helen cali89]

mine is also mounted on the gearbox and has a cowl around it which has a alumium flexi duct pipe that hangs down and points to the front of the bus dont like the idea of the flexi your idea sounds better any photos

[si&helen cali89]

had it remapped to 140 so perhaps around 138bhp they told me

[Cableguy]

My scoops are about 250x150 and also use 100 flexi to connect to a cowl around the i/c.
I'm not 100% happy with the job, but the figures prove it works. One day I'll have a look at tidying it a bit.
I'm working on an oil leak this w/e, so will take a pic for you.
Incidentally, who did the remap?

[keith]

what inlet air temps are you getting ?

[Cableguy]

Between 20 and 30 normally, upto 40 when caning up long hills

[si&helen cali89]

just a local firm near where i live theres plenty of companies about

[keith]

Between 20 and 30 normally, upto 40 when caning up long hills

Thats good...