Question: Kink in the Fuel Return line

[A_Tiny_Chipmunk]

Hi all,

 

My engine is suffering over 6-6.5k .it just doesn't want to know about it, knocking etc. and also on high boost, misses and stutters.

 

Last night when i was prepping it for a track event (plan is to keep it on low boost and under 6k, this has been ok'd by the tuner and verified on the dyno) I noticed my fuel return line and a sizeable kink in it.

 

Could this be all of my problems? I've emailed the tuner and am waiting for a response, wouldn't mind a few opinions to however.

 

NB: Car has split fuel rail mod to, if that makes any difference.

 

thanks guys 

[Leufkax]

That would cause an excess of fuel I would think..

[Technikhaus]

Could be too much fuel, and hesitating as it can't ignite it?

[boon]

If anything this would cause issues at the low end; the return is for the regulator to bleed fuel back to the tank to keep the pressure down to the required level.

At lots of brum, not only is the fuel pressure going to be much higher (differential pressure means more boost = more fuel pressure required) but your engine will be eating lots of the fuel, so the flow through the return will actually be lower.

 

You have a good mystery on your hands. Great IAT, good size turbo, lots of fuel and yet it's knocky.... weird.

 

EDIT: Would be a great candidate for in-cylinder pressure sensing. What CR are you running?

[A_Tiny_Chipmunk]

Yeah took it for a drive, no change in how she runs. if anything a little bit more "poppy" on idle.

 

CR should be a bit higher than factory, similar sized head gastket and 8.5.1. pistons

Edited March 23, 2017 by A_Tiny_Chipmunk

[gotasuby]

Poppy at idle is usually too lean