james-wrx

guys been trying to get to the bottom of why im getting knock over 7k revs
I have changed plugs, lower boost to under 1 bar upped fuel pressure etc, i bought a 2nd hand MAF a few months ago, old one was knackered and i bought a cheap 2nd hand one, would the MAF give me similar symptoms i.e cause knock at high revs?

It's a built 2.2 L engine, i have checked for things rattling and canbt see anything, the heatshield was loose on the uppipe and it's now not rattling as much as it was but would this cause knock at over 7k I would have thought it would do it all the time?

The only thing I havent tried ius a brand new MAF!

Incidentaly if i wind the boost right up it's still the same only knocks over 7k

Very very odd!!!!!!!!!

jaytc2003

iTrader: (1)

as per previous thread, quite possibly noisy valvetrain
If you rev it to 7k out of gear does it knock then?

best bet as previosuly said is to get it checked out with det cans

Scott.T

iTrader: (2)

get it checked with detcans as may not be knock.
are you sure it's not the rev limiter causing the knocklink to flash (I assume thats what your using)
Alot of Subaru ECU maps only go upto 6800rpm with a rev limit at 6800-7100rpm. Unless it's been mapped to run that high, that will be beyond the range of the rpm scale on the fuel & ignition maps. It's also beyond the knock control range.
They will need rescaling if you intend to drive it at those rpm on a regular bassis, or add fuel/pull timing on the 6800 row/column and sacrifice performance there to make it safe higher up.

james-wrx

Thanks for the ideas guys I will try revving it out of gear and see what happens, if it's valvetrain whats the answer?
I think it has solid lifters in it as well, do they need adjusting annually or something?

james-wrx

Thanks for the advice, it used to rev to the redline with no action on the knocklink and at 6.5k revs it had another burst of accelleration through to the redline @ 8k It now pulls strong all the way but not as strong after 7k hence i think it is knock and change gear under 7k !

Jolly Green Monster

iTrader: (4)

is it mapped for the 2.2?

james-wrx

Hi yes mapped for the engine hybrid turbo etc, the only thing i have changed is the MAF and plugs, im running 6b's instead of 7b's would this make a difference?

Jolly Green Monster

iTrader: (4)

plugs may effect it.

You should speak with mapper and get it checked.. before you damage it.

Simon

james-wrx

The problem is the guy that mapped it no longer does Scoobys, can anyone check it with the "cans" ?

I cant see how it's knocking if it does it on 0.75 bar boost as well as 1.4 bar boost but only over 7k?
Where are you based simon?

Jolly Green Monster

iTrader: (4)

south east but mobile..

Simon