Just picked my XC up from latest dyno tune. Mixtures, timing etc all good. Made 240rwkw. No problems at dyno. Drove car home and gave it a couple of flat out 1st, 2nd, 3rd 4th gear runs. On the third occassion, 4th gear 4000rpm the car lost power. Defiently fuel surge. I'm running standard long range fuel tank, bigger 3/8 pick up, carter black fuel pump, 3/8 fuel line and fittings, holley regulator with 2 outputs (only using one tho) RYCO 3/8 Z153 fuel filter and speco standard twin fuel rail.
I'm thinking of bridging (for testing) the fuel filter with 3/8 fuel pipe to see if it elimantes problem. Does anybody know a good 3/8 fuel filter that flows well? Or does anybody know what may be causing this issue?
G'Day Xcandy........welcome to the forum.
Yeah, sounds like you have a supply problem somewhere along the line.
You mention it was OK on the dyno, but running thru 4 gears on the road takes a lot more fuel than a single power run on the dyno. Sometimes if it only works OK on the dyno it can be a pickup problem as fuel sloshes away from the pickup as you accelerate compared to standing still on the dyno.
What level is the fuel in the fuel bowls at idle? Check the fuel is right up at the sight window/plug.
What pressure is the fuel reg set at? It's always good to have a little gauge on the line after the reg to ensure you have the right pressure. You'll need about 6psi otherwise the reg may be holding back some fuel flow.
Sounds like you're emptying the fuel bowls quicker than you're filling them up....just as you get into 4th gear the demand is now more than the supply......could be pump capacity, fuel line size, smaller restriction along the fuel line, filter flow, blocked filter.
I'd take the fuel filter out just to check it. Some just aren't made to flow fuel too quick. There's quite a few filters availble with high flow filters that you could get from most performance shops.
Let us know how you go.