fuel system

[fccool59]

i plan to run 2x 2" SU's on a supercharger @ 10psi.
recently i noticed my previuos fuel pump was cracked around the outlet wich sucks becuase under the car is painted already with holes to suit that pump.
I went to my local robbos to see what pumps were available and the guy there reckons that it gets tricky with the SU carbs on the supercharger as they dont like much pressure but without adequate fuel supply it could lean out and melt the pistons.
he suggested a holley regulater with a return line back to the tank and a pump with adequate g/ph like a holley or mallory, only problem there is that my old barrel type pump only just fitted were i had it, I have twin exhaust wich splits into a y behind the diff housing and goes in front of the tank and up the side and the diff housing just missed it.
is anyone using a bigger external electric pump like a holley or mallory in a wagon, ute or van, and if so were is it and how was it mounted?
also has any one run a return line back to the tank, do you need to weld on a boss to take the line?

[Spinner]

Leon,

For some advice on SU Carbies, talk to Midel Pty Ltd.  They are at 4 Frazer Street Lakemba 2195.  Their 'phone number is (02) 9759-5598.  Their website is at: http://www.sumidel.com.  Email enquiries to: info@sumidel.com.  The bloke who runs the place is Bill Bressington.

This info comes from Australian Classsic Car Monthly.

Cheers

Brett

[fccool59]

I spoke to midel, they seem cluey but had doubts that the two SU carbs will be upto the job,  he said they dont get involved with supercharged or turbocharged cars but they suggested holley float chambers wich the guy that did my machining also said something about.
has anyone adapted holley bowls to SU's. At this stage Eldred Norman would be a handy guy but its not a option.
I asked what other carbs would be suitable and he said all would give simular type problems unless i went injection wich also creates a new bunch of problems to work out, eg water/methanol damge to injector tips and o2 sensors.
so how do all these cars run superchargers?
I might try and find some carb or supercharging specailists.
I need to work out my fuel pump, pick up and return lines in time for when its ready for everything to go back under to get it rolling again, wich it nearly is.

I just bought a $40 book on supercharging and it has no usefull info, hate them seeled in plastic lucky dip books.

[Glenn 'Stinky' Stankevicius]

CRS list a 350 Holley or the more "powerful"   SU in their kits. I'd be more inclined to fit up a Holley, but only because I know less about SUs than Holleys (and I know f all about holleys ).
The guy that built my motor had a "mess-around" car in his shop ages ago with a Red 6, GM 471 blower and a set of triple SUs hanging off it. Not sure how it went but it looked pretty tuff, I'll drop him an email and see what he thinks.

[fccool59]

I think the single SUor holley they recomend is for more standard set ups, with mine leaning out could cuase pretty expensive damage.
I am going for about 10 psi, fuel pressure should be 3 psi above that to prevent engine melt down, the SU carbs wont take that pressure and it will also empty out the chambers, the crs kits are set to run much lower boost.

I wonder how sorted the guy that built your engine got that set up, the guy at midel said it would create a few headaches going for more than one carb but one wouldnt be able to deliver enough fuel.
do you speak to the guy that built your motor often?

[Ed]

Leon,

I have two fuel pumps 1 low pressure (carter), and 1 high bressure Bosch.

1 is mounted below rear floor (in line with tank), the other is mounted on chassis rail, also have fuel surge tank mounted under floor and twin exhausts...

it took a hell of a lot of thinking to work out where to put everything but I think I got it right.  you should be able to see them in my exhaust shots in another thread.

for return line, you can weld an Earls fitting into tank or use a swagelok flange fitting.  I have a fitting welded in as I am using a Streetneat/Marty Dean tank.

on the subject of fuel pressure, you will need a "RISING RATE" regulator which matches your boost, I am not entirely sure of the principles of operation.

this is akin to what turbo cars use.

is your set up blowing thru the carbs or sucking thru the carbs??

Cheers

Ed

[TorqueFC]

Leon,
        To me the most simplest way to solve your problem would be to get a Holley 4 barrel blower carb. You can source them from places like Rocket Industries and VPW Australia. As the name suggests the carbs are designed to be used on supercharged motors, and are built so they dont lean out yr motor at high revs/boost.

Or you could go for a Demon Blower carb but im not sure as to what sizes these come in...

Another person to have a talk to would be Nigel at Xtreme Fuel Systems. He has now done 5 carbs for us, and have never had any troubles. (plus a heap of guys on here have used him!)

cheers

[FC-225]

About 12 years ago,I did some work on a 4/71 blown red motor (192 I think ) with twin 1 3/4 or 2" SU's in a 48 215... and I can tell you it was a nightmare to try and keep running with those carbs !!
Could not get it off idle,and into the powerband ! as I remember the SU's do not have a normal 'accelerator' pump deal making it nearly impossible to pull fuel through the blower. Never got to the end of it,and I informed the owner to go to a holley ..

AL

[fccool59]

i am sucking through, Eldred Norman made out these to be the ultimate carbs for supercharging a six but it doesnt seem to be the way, maybe he new some secret tricks or maybe he was using small boost.
Ed, my right side pipe wraps around the back of the tank wich loses room i would have if i went. I was just thinking today that i might need two pumps, one to bring up the pressure when its need of a hobbs switch. or do you use a rising rate reg and one pump with about 15 psi.
i guess to have a bigger outlet you have to remove the top of the tank.

Any one want to by any 2" HS su carbs?

[Ed]

Leon,

Not sure if you need two pumps, I would guess and say not.
never heard of a Hobbs switch so lost me there.

the rising rate regs meter the appropriate aount of fuel in relation to boost.

to run bigger diameter fuel line....

what you can do is use a fuel filter with a 5/16" inlet (Std)  and 3/8" outlet before the fuel pump then run 3/8" from there  I think the Toyota Hiace has this sort of fuel filter so you can get them over the counter.

.. of course your limiting factor will always be the diameter of the line before the filter.  

Easier than remaking the entire fuel pick up in the tank.

You may need to remake your tail pipes if you wish to mount your pumps inline or below the tank.  the other alternative is to mount them inside the wheel well above the tank..

Personally I dislike the idea of any fuel lines running inside the vehicle cabin space, and also having pumps mounted above the fuel line (altho it works).

many new cars have rubber fittings on to fuel outlets and breathers running immediately behind or under the back seat.. imagine if there was a leak??

or if one let go in a big impact... not a good thought.. although the car manufacturers plunge $$ into R&D and safety testing so apparently it is safe enough for your average family... I beg to differ... anyway.

keep in mind you will need to wire the pump up to an oil pressure switch, so in the event of no oil pressure the pumps shut down... just a safety measure as well.

my exhaust runs under the diff to avoid excessive heat to the fuel pump.

HTH

Ed

[Glenn 'Stinky' Stankevicius]

Hey Leon, I finally got an answer from the mechanic. Short and sweet, why mess around with carbs? go with injection or a Gasresearch LPG carby.

[fccool59]

injection could be trickier to do with the m90 but easier with the sc14 wich probably wont make enough boost, I have a efi vk here if needed but would probably use something like a wolf 3d computer and bigger injectors with a vl turbo pump.
i prefer carbs becuase the injection looks to ugly and high tech.
i am now trying to decide between SU's, a 4bbl or efi.
the injection at present is looking like the safest way to aviod a engine melt down.

[Ed]

i prefer carbs becuase the injection looks to ugly and high tech.

You've been looking at the wrong injection set ups in that case!

Cheers

Ed

[fccool59]

Ed, how hard would it be to do a set up like yours?

[Ed]

Hey Leon,

would be pretty easy I think.

the base of  my throttle body is similar to Holley 4bbl. so just get or make an adaptor plate.
uses a VT series 2 or JE camira Throttle position sensor (TPS).
it flows up to 1000 cfm supposedly.

see http://www.efihardware.com.au

then you just need the injectors etc which would probably all be on the VK inlet manifold.

may as well run the Delco 808 too that being the case, Smithy is doing that to his motor as we speak.

was reading a bike mag last night and there is a guy with a supercharged VTR1000 and is using a single SU.

Cheers

Ed

[fccool59]

Ed,
how much does that throttle body cost?