I dont think my fuel pump is up to the job of supplying sufficient fuel for my mildly tuned 3.8 xk enigine (larger inlets valves, cleaned up ports, rob beere su cams, classic fabs exhaust system, twin hd6 carbs).
What pump would you suggest i use? What do you use on your tuned engines?
I have the original su pump and a ecco fuel flow of similar spec. Would the su azx1495 be the choice or should i go for a facet silver top or similar?
The default pump will be sufficient when using dual HD6 carbs.
XK150S models had dual fuel pumps ( parallel connected ) and dual HD8 carbs.
The stock fuel pump should be more than adequate for a tuned XK engine on the street. I have a 4.2 with large valves, porting, sport cams, Classic Fabs exhaust, and triple SUs. All very happy with an electronic version of the stock SU pump.
If the float bowls are staying full when running, then your issues lie elsewhere. You may want to measure your fuel flow and pressure to ensure your pump is performing as it should. If so, use a gas analyzer to check fuel mixture at various rpms. I would try richer needles before I replaced the pump.
Two HD6s, which flow something like 220cfm each, should be adequate for a 3.8 street engine, btw.
Above advice is right on. I’m in process of restoring my Mk2 with some mild modifications (3.8 liter, HD8 carbs, larger intake valves, mild cam, and EDIS ignition). I opted for a Facet pump that puts out more pressure than needed (FAC-476459) along with an Aeromotive pressure regulator. May be overkill, but I was led to believe a higher pressure pump with a regulator was the ideal setup. That said, I probably could have gotten away with the stock setup, but isn’t it fun to over-engineer things?
The XJ6 and E type do fine with the standard single pump AUF301/AZX1307 and the 4.2 engine with twin HD8, and I believe triples make just a small difference, unless you want to go flat out at 5500 rpm for a long while I‘m sure the normal single pump in good condition is enough, they pump out plenty of fuel?
The V12 pump will certainly deliver enough for your needs and looks good. Dyno testing would tell and I think it makes a lot of sense, they‘d catch it if the engine goes lean from lack of fuel.
A standard upheld by MANY on JL…