Help with diagnosis of my Rolling road result

[Chris_w]

Took my car to the RR at the weekend.

Its is standard apart from homefries remap and Roose boost hoses.

Results were -

max power 258.1hp @ 5795rpm
max torque 287Lbs/Ft @ 3345

peaking at 1.2bar boost pressure, but its fluttering

AFR 13.6:1 at max throttle, thats pretty lean!

Power curve isnt particularly stable, and drops off at 4750, then goes up again at 4900ish

any ideas guys? 1.2 bar would make me think boost leak, but running lean would suggest otherwise.

Car has had new WGFV, new 710N, new f5dpor plugs.

[Rusty]

Yeah, boost leak doesn't usually = lean. Need to get VAGCOM on it really to identify if any sensors are out. Boost leak test is always a good plan for peace of mind.

[Jamo]

13.6 at WOT i'd expect it to be a lot lower than that to make power in the 12's as a turbo car does want it a little bit richer.

I think you have a boost leak or your divertor valve is not working, on homefries you should be seeing 1.4 bar boost

[Rusty]

Yes, should be 12 dropping towards 11.5 @ redline.

This is off my car running 294bhp

[Chris_w]

Ouch, i'll try and get a vag com on it asap, sounds like ive got a couple of issues.

last time it was vag commed iirc it came up with engine speed sensor, vehicle speed sensor (engine was OFF) and lambda out of range.
Those were cleared, engine run again and the faults didnt show up. That was a month or so ago though.

Will try and leak test it asap too, might look at one of those forge 007p's, as the 710 felt like it would break if i stared at it for too long, let alone ran 1.2 bar through it.

[driftin jo]

It can't be a boost leak , that would make it rich, it could be a leak in the MAF to turbo hose as this would allow unmetered air and cause a lean mix.
That said you could have bad fuel pressure regulator , blocked fuel filter or a fuel pump on the way out or possibly clogged injectors.

[GazzaG60]

check the line on the fuel pressure regulator to ensure its fitted properly and not damaged too

[Jamo]

Why can't it be a boost leak? not reaching full boost and unmetered air entering the system. A "leak" can work both ways of letting in and out

[S2central.net]

Air leak under boost after MAF usually results in rich running - as more fuel is injected for the remaining amount of air...

That said - a bad MAF would cause poor mixture control... Tis worth checking all major and minor hoses are good and airtight.

And get fuel pressure & flow rate tested too - kakked fuel filter can give this lean condition.

Wouldn't hurt to refurb injectors unless you know they are good.

Spark plugs correctly tightened ?

[Chris_w]

its booked in next wednesday for a fuel pressure and boost leak test, so we shall see.
Im tempted to get the injectors tested / refurbed but moneys a bit tight so thats staying as a last option.

As for spark plugs, theyre done up tight, not torqued though as someone felt the need to use my torque wrench as a hammer.

[andyg plym]

chris i regularly come to helston to pick my boy up, im running a homefry in my avant too, more then welcome to compare

[Chris_w]

That would be ideal, would love to go out in another one to compare, its not like my old golf days when all my mates had them to try out!

[andyg plym]

there are a few s2's down your way.
not all drivers are on the forum though