switched over to t-piece now and seems to run better. no more overfuelling at idle, and less pinking on top end. win win!

Edited 27 July, 201115 yr by erixtar1992

I run two regs and the original mk4 pump, shall i tank it and see what i get?

I run two regs and the original mk4 pump, shall i tank it and see what i get?

go for it lol, I've dun 190 miles on 30 litres (40 quid) so not great lol

That aint too bad. I get around 120 miles from £20, mines a pretty high spec motor too!

Mine seemed to whoop fuel before, advanced the timing a bit, and it was loads better.

I'll tank it to the brim and see what i get to the tank.

That aint too bad. I get around 120 miles from £20, mines a pretty high spec motor too!

yeah worked it out and thats 30mpg so nothing majorly bad, most of it was normal driving and was halfway between quater-half a tank after about 130 miles, then last night was up the ace cafe giving it death and it went below a quater after about 30 miles haha!

t piece has been more efficient though, id get about 160 miles if using the regulator. may try using both?

No point using both.

Its been said before but I'm a bit confused.

Unless your bowls are overfilling then there should be no difference between a t piece and regulator.

I've got a regulator on my AFHand I'm running about 36mpg but the carbs themselves are a bit lean at the moment.

Every bit of advice i have recieved is to get a regualator so you have a consistent amount of fuel going in, then take it to Boggs Bros.

£80 to get setup was my last quote and although it was a brief phone conversation... they seemed to know their stuff!

everythings was st up. regulator was set to 3 psi same as the bik pump, just used loads of ful on idle ect du to not having a return. uses much less now

iirc more than about 6psi will get past the float seals...3psi shouldnt be a problem though..even without a return..unless was coming out of vents or something :S

I'm not convinced with this tpiece lark. i understand how it works, and that it shouldnt build up pressure providing the return is equal size to the feed..but anyone i ask whos to do with engines etc says its not the right way to do it and its best to regulate..i think I'm gonna reg the standard like leeds finest has...or use a bike pump as has pressure cut off

yeah i hear a lot of 'oh its a bad way of doing it' but at the same time some people say it works well, i had a t piece lying around so i thought why not give it a try, then found it works better than with the regulator lol, well in my car anyway. i think I'm gonna stick to mine, i still hav th regulator bolted into my engin bay so can always switch back with just a screwdriver

i can understand the theory...

on a mk4, its a high pressure pump in tank...so lets say 45psi for ease.

carbs require like 3psi, so its like 15 times less pressure.

t piece the fuel will flow down the feed, to the carbs and down the return...so if the carbs dont want anything, your relying on the float seals to force the fuel back down the return...which in theory is fine, and seems to work in reality...so having that pump, does this mean there would just be a highflow rate in the fuel lines, not pressure? :S

well mines a facet on a mk2, so only about 5 psi, i have the return facing upwards towards the sky, so naturally th fuel will go straight to carbs, and then the back pressure will force fuel against gravity up th return pipe ect.. duno if the same will apply with 45 psi, cant you change your pump? could always try it and find out? it could work in theory just alot mor pressure pushing the fuel about so will be travelling down your return quite fast!

I didn't know if a facet would be powerful enough to manage a return...and just simple isn't it if the pumps installed and wired in already...I'm not too sure how another pump would like dragging fuel through the current fuel sender unit

yeah it seems to manage fine, and yeah i spose it is lol

I didn't know if a facet would be powerful enough to manage a return...and just simple isn't it if the pumps installed and wired in already...I'm not too sure how another pump would like dragging fuel through the current fuel sender unit

I think your completely mis-understanding how it all works....

The best,safest and cheapest way to do it is to use the low pressure facet pump coupled with a T peice. The carburettor's supply line of the "T" peice or "Y" peice wants to be on the nipple that has the easiest route from the fuel supply line, this is so the low pressure, yet moderate flow of fuel is easily supplied. The float valve then shuts off when the bowl is full, the fuel then backs up and goes down the second easiest route which is the tank return. This way, there is no high pressure build up, unlike using the standard pump with T peice, or standard pump with regulator.

Also, using a regulator means that fuel is being constantly fed to the carbs, at moderate pressure, wether it needs it or not, this can lead to leaking out of fittings, or even past the seals in the carburettor, causing incorrect fueing. Unlike the "T" piece method which offers a constant supply of fuel at very low pressure.

Also, the highlighted part.

The 1.5-4psi pump (Which i use) will keep on pumping fuel untill the pressure differential reaches around 4 PSI. With a return, you never see that pressure, so it will keep on supplying fuel (remember, No pump produces pressure, it is the obstruction of the output that causes it, the pump is rated to 4 psi so that is the maximum pressure it will ever reach with obstruction). Having a return line doesn't offer any more work for the pump, its still only pumping fuel down the same size fuel line.

Hope that helps

Edited 28 July, 201115 yr by MaxMax

Ah right, so the t piece is not to be used with the high pressure injection pump lol.

I'm gonna order a facet...shall i get a 1.5-4 or 4-7psi one? then ill just tpiece it, cba with regs :p

also, if i simply disconnect my statndard pump...with the facet drag the fuel through it ok? or will i have to rip the standard sender unit apart and gut the internals :S

Well, i don't know for certain with the 6n, but the mk3 series have a lift pump in the tank, then the injection pump (under the offside rear wheel area).

You keep the lift pump for obvious reasons, and i removed the injection pump and replaced it with some fuel line, this way there is no restriction....

You then want to wire in the lift pump and the facet solid state pump onto a ignition switched live relay.

I originally looped my send into my return and T pieced off that into a low pressure regulator and then off into the carbs. It worked fine, but i was told it wasn't correct by a motorsport engineer, who told me i should run a 3 way regulator so the 'fuel in' went into the regulator, the 'fuel return' came out of the regulator, and the 'fuel feed' to the carbs went to the carbs.

I currently run the 3 way regulator, into a secondary regulator for fine tune, then into the carbs.

Drives fine, no irregularity in the way it performs, although the upper seal on the fine tune regulator seems to be leaking. Don't think it;s because of a built up in pressure though...

hi do i need a faccet and has anybody got any pictures of these set ups with t-peices on cbr 600 carbs I'm using a 1.6 aee lump into my mk4 polo and any help will be gratefully recieved.

I think the 6n's just have a pump in tank and that's that lol

I think the 6n's just have a pump in tank and that's that lol

Nah, they wont do mate.

You have the lift pump and an injection pump somewhere surely.

Slightly of topic, but which live relay is if best to wire the facet to?

Also, who has used an initia switch for safety? And how was it wired?

Slightly of topic, but which live relay is if best to wire the facet to?

Also, who has used an initia switch for safety? And how was it wired?

Your best just buying some extra relays to be honest. When you ditch all the old ECU stuff the relays are left redundant.

There is a IGN live under the steering couling, think its a thinnish black wire. This powers up all the relays, then they all get a live feed from the battery obviously.

Inertia switches can be had from scrappys with cars that used them, but its probably best and cheapest just to use your oil pressure switch to cut the fuel pumps when the engine isn't running.

Its something i intend to do in the future!

I like the idea of that. Do you just splice it in line with the oil pressure switch, or do I need a relay first?

I'm actually using an mk2 Ignition setup with a 6n engine. I have just noticed that the old mk2 doesn't have an amp(? Small, flattish item with about 7pins on, mounted on a brass bracket under rain tray). I'm using a late mk2 dizzy. Am I going to have to run the amp from a late mk2 aswell?