Icarus60 Posted January 12, 2020 Report Share Posted January 12, 2020 I am steadily sorting out my TR4 fitted twin 45 dcoe Webers and I would like to get some advice regarding a suitable fuel pump. The engine should be capable of upto say 150 BHP. Currently it is running with a modern unbranded small electric job , of unknown history or pedigree , next to the fuel tank which functions but may become a limiting factor as I continue to develop the car. This fuel pump makes a near constant pumping noise, so does not indicate when sufficient pressure has been reached on start up. It also appears to allow fuel to flow out when not powered. I also suspect that the static pressure may be too high but no pressure regulator is fitted. The mechanical pump is blanked off. i would appreciate your thoughts and experience on the best type and brand of fuel pump to fit and whether of not a pressure regulator, to get a reliable setup. Many thanks and regards Rog Quote Link to post Share on other sites
Tom Boyd Posted January 12, 2020 Report Share Posted January 12, 2020 A facet ‘red top’ will be adequate and the fitting of a filter king in the engine bay. tom Quote Link to post Share on other sites
stuart Posted January 13, 2020 Report Share Posted January 13, 2020 And a collision switch. Stuart. Quote Link to post Share on other sites
MadMarx Posted January 13, 2020 Report Share Posted January 13, 2020 (edited) I'm using Mitsuba from Japan. No regulator, no extra filter, pump in engine bay for easy access. Beware of Chinese copies....they don't work good. Edited January 13, 2020 by MadMarx Quote Link to post Share on other sites
Icarus60 Posted January 14, 2020 Author Report Share Posted January 14, 2020 Many thanks to all. I'll look at the functionality, cost and availability of these option and yes Stuart I will include a crash switch. In an ideal world I would choose a pump that, as well as reliably doing the basic task , is only audible whilst actually moving fuel and does not allow fuel to flow from the tank when the pump is not powered up. Ill keep you posted regards Rog Quote Link to post Share on other sites
Tom Fremont Posted January 14, 2020 Report Share Posted January 14, 2020 What would be wrong with the original AC mechanical pump? I've logged 135K+ blissful miles on triple 40s with them. K.I.S.S. was the guiding principle in my case. Tom Quote Link to post Share on other sites
MadMarx Posted January 15, 2020 Report Share Posted January 15, 2020 15 hours ago, Tom Fremont said: What would be wrong with the original AC mechanical pump? The original pump doesn't provide enough fuel for high speeds. No so much of a problem in USA but in Germany it is, if you are reach for 120mph or more. Quote Link to post Share on other sites
PhilipB Posted January 15, 2020 Report Share Posted January 15, 2020 Rog Replaced mechanical pump last year and very pleased so far Twin 45 Webers and probably 140 bhp ish Hitachi/Huco (or Hueco) 133010 suction pump fitted in engine bay (high volume low pressure to suit Webers), Malpassi 85mm filter & regulator. Controlled by Huco 132020 fuel pump relay that is powered from the ignition switch and also takes a feed from the coil to shut off the pump if the engine stops turning and an impact sensor (Ebay). 8mm ID fuel line and cut off tap. No noise and no fuel leakage Beware of imitation pumps on Ebay Phil Quote Link to post Share on other sites
Chilliman Posted January 15, 2020 Report Share Posted January 15, 2020 Quote Hitachi/Huco (or Hueco) 133010 suction pump fitted in engine bay Exactly the same as I use - & a very similar set up - never had any issues with it at all, a good reliable unit. Quote Link to post Share on other sites
Tom Fremont Posted January 15, 2020 Report Share Posted January 15, 2020 3 hours ago, MadMarx said: The original pump doesn't provide enough fuel for high speeds. No so much of a problem in USA but in Germany it is, if you are reach for 120mph or more. Kastner advised removing the mechanical pump for electric more than 50 years ago, so that seems to be the conventional wisdom. But does anyone have first hand experience with fuel starvation using the mechanical pump? I don't, though the max I've taken my cars is 115 mph and it wasn't sustained for more than a few seconds, with 100+ mph for a bit longer and no issues there. My Webers have 175 inlet valves, or 1.75mm diameter. (3) of these present a much smaller total opening size ( less than 1/2 ) of the fuel line size of 3/16" / 5mm diameter. Given the pressure limitation of the Webers is similar to the mechanical pump pressure the claim of inadequate fuel delivery doesn't work on paper. I do have doubts about the mechanical pump at max rpm, thinking it may just flutter on the cam lobe and not give full stroke. Tom Quote Link to post Share on other sites
MadMarx Posted January 15, 2020 Report Share Posted January 15, 2020 I started back in the 90ties with standard pump and Webers and had starvation at full throttle and especially on the Nordschleife. I moved over the Mitsuba and the problem was solved. That was long before I started racing. Quote Link to post Share on other sites
Tom Fremont Posted January 15, 2020 Report Share Posted January 15, 2020 That counts for something, Christian - thanks. I have found some pump springs stiffer than others, with significant pressure variance resulting. The factory manual specifies 1-1/2 to 2-1/2 psi as the range, a variation of 67%. Mine have the stiffer type . Tom Quote Link to post Share on other sites
MadMarx Posted January 17, 2020 Report Share Posted January 17, 2020 I run 5-6PSI Quote Link to post Share on other sites
Icarus60 Posted January 17, 2020 Author Report Share Posted January 17, 2020 Thanks for all the inputs. I've been thinking the same Tom but the PO replaced the original AC Pump with a matchbox sized electric thing for some unknown reason. Thanks for info on the Hueco pumps and I will have a good look at them . Point taken on avoiding the fakes. I have now purchased a pressure regulator and filter and whichever pump I finish up with I will measure the fuel pressure at varying operating conditions. Again - many thanks Rog Quote Link to post Share on other sites
Waldi Posted January 25, 2020 Report Share Posted January 25, 2020 I’ve had an XK140, but with an original 3.8S engine from a 150S. So I installed 2 new SU fuel pumps in parallel (tickerdetick) to feed the 3 2” SU HD8 carbs. In Germany I drove 220km/hr on a quit stretch of the Autobahn for quite some time on our return from a rally in France (tourist class), and with no fuel starvation (I did not run flat-out). I thought I needed the 2 pumps for that. But later on, I found one of the pumps was not working, contact point issue, so I have probably run on one pump all the time. If you do the math, and say you use 1 liter/4 km at full throttle and do 220 km/hr, you need 55 liter/ hr, so just under 1 liter/minute. Waldi Quote Link to post Share on other sites
Waldi Posted January 25, 2020 Report Share Posted January 25, 2020 This may help: https://www.mg-cars.org.uk/mgtd/files/SU_Fuel_Pumps_101.pdf Looks like a single low pressure SU pump can just deliver that, but a double pump (one body) certainly can. Waldi Quote Link to post Share on other sites
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