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MG Midget and Sprite Technical - High pressure fuel pump

Been out for a good blast today running in new engine,gear box and diff,everything seems to be bedding in nicely now but one thing Iam not sure about is how noisey the standard metro turbo pump is !
Has anyone else had problems with high pressure fuel pumps being so noisey?
I have rapped sound deadening round the pump and it is mounted on rubbers but still can be heard over the exhaust!
There must be a modern h.p.f.pump that will do the job.
I cant ever remember my Metro turbo being this noisey 20 nyears ago.
Rob Newt

Rob, I assume you are refering to your turbo metro fuel pump?
The answer is no that should not be noisey but if it is then you should be able to replace it by almost any fuel injected pumps. The one I am using at present I think came from a vauxhall. Look on ebay. or at the scrapyard.

When I went down the scrappers and got one they had a nuber off the cars and were using them to scavenge fuel fom the tanks of scrap cars. :-)
Robert (Bob) Midget Turbo

Interesting Rob,, as i'm after a turbo pump, can't help much but i'm watching this thread,
cheers
Brad
Brad (Sprite IV 1380)

Here is the first example I came across on ebay

http://cgi.ebay.co.uk/NEW-Electric-Fuel-Petrol-pump-FIAT-Regata-Ritmo-132_W0QQitemZ280330908503QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item4145063357
Robert (Bob) Midget Turbo

obviously you have a good return and do you use a dropping resistor?
Robert (Bob) Midget Turbo

I have a good fuel return to the tank and no running problems at all,the car is running as sweet as a nut even without being put on the rolling road yet.
I dont use a dropping resistor and I will have to hold my hands up Bob,why would I need one.

Would I be correct in saying that most h.p.f.pumps operate at high enough psi to cope with most modern cars and it just the fuel regulator that limits the fuel pressure to what you need.

I have set the fuel pressure to 2-3 psi on tickover is this correct?

Looked at the fuel pump on ebay and low and behold it says in the discription,common faults :noisy (rattling and whining)so perhaps mine is on the way out.
Rob Newt

Yes that is fine Rob. On my car I could not get the fuel pressure down to 3 psi at tickover with out a high power resistor in circuit to reduce the pressure of the pump slightly. However since then I have installed a larger return pipe so maybe I could also run without a resistor. :)
By the way the MG Metro Turbo used a resistor with its pump to reduce the initial pump pressure. This was with a resistive wire to the pump.
Robert (Bob) Midget Turbo

A little clarity please!!!


You knew this question was comming.

High pressure fuel pump??? How is that possiable, Are you useing fuel injection?

If your hooking it to duel SUs, I want to hear about how this is done. 8^)

prop
Prop

prop read the first post
TURBO!!!!
Onno Könemann

Prop take no notice of Onno he is just trying to confuse you!

Getting high pressure fuel to the carb adds about 15 BHP at revs above 5500. The SU needle at this point has "topped out" and the fuel supply becomes static. causing a weak mixture and loss of potential power at 5500 RPM.
It has been found that running a High Pressure fuel pump overcomes this problem and forces fuel through the jet at these high revs and enables the mixture to remain optimum.

The only problem is that you need to restrict pressure at lower revs, we do this by opening an automatic bypass valve or fitting a high powered resistor.
I thought this was in Vizard?
Bob Turbo Midget England

"Prop take no notice of Onno he is just trying to confuse you!

Getting high pressure fuel to the carb adds about 15 BHP at revs above 5500. The SU needle at this point has "topped out" and the fuel supply becomes static. causing a weak mixture and loss of potential power at 5500 RPM.
It has been found that running a High Pressure fuel pump overcomes this problem and forces fuel through the jet at these high revs and enables the mixture to remain optimum.

The only problem is that you need to restrict pressure at lower revs, we do this by opening an automatic bypass valve or fitting a high powered resistor.
I thought this was in Vizard?"

I don't believe Bob wrote this bollocks !
Who is the troll?
David Smith

Fraid it is me Dave

Not sure it is bollox however ;)
Robert (Bob) Midget Turbo

Prop.
You need to speak to April (on this site sometimes) because she sells the right pump, restrictor and resistor in the USA. Her surname is Furst and she trades as Fools' Gold Racing.

Isn't tht right, Bob?
rob multi-sheds thomas

I have read vizard several times so i must have missed this part.

I assumed it was needed for those gas guzeling turbo's of you Bob.

I must say i've never noticed anny starvation or lean running on my engine's on trackday's
And i have checked the colour of the plugs after high rpm running and they never looked white.
Are you makeing it run overly rich?
Onno Könemann

Hi Rob,
If this is the normal metro turbo fuel pump and regulator,you should have 8mm feed and 10 mm return lines pump to regulator OR a restrictor in the feed line.This pump does not like being fitted higher than the tank,so I used a swirl tank in the boot fed by an lp pump.Mine whines when running,but drowned by engine noise after startup


steve cowling

Wow, if ya go to this much trouble (reference Steve's attached image) for hp ABOVE 5500 rpm (non turbo) and then complain about the noise...

I didn't know these little engines would even GO over 5500 rpm!

(kidding)



But this is for racing, right? Isn't "noise" part of the point?

(I am making "RrrrRRRRrrrrRRRR, EEEEEECHUCHCHCH, RRrrrrRRRrrr" sounds to myself while I drive)


Norm
Norm Kerr

Steve
Thanks for the pic,looks very impressive with the swirl tank.
I have ordered a Ford Escort turbo fuel pump at a cost of £39.99,so I will be able to post any noise reductions or performance gains next week as long as I get chance to fit it Sunday
I have 8mm pipe flow and 8mm return and seems ok,did you upgrade to 10 mm because you had problems or have you always had 10 mm fitted?

Norm
The original post was to find out if the standard metro turbo pump was meant to be as noisey as the one I had fitted(I will soon find out when I fit the new one)as for the noise I like mine coming from the exhaust!!
Rob Newt

Hi Rob,
The experts recommend 10 mm return to allow the regulator to do its job,otherwise the restrictor in the feed will do it.Remember the pressure to the carb is only about 4psi over boost pressure,so much less than feed to the regulator,hence lots of fuel back to the tank unless you are on full boost.
steve cowling

Only just got round to fitting my new fuel pump (due to a touch of pig flu).
Now it will not start,cranking over well and the pump seams to be working well,there is a good flow to the carb and a good return to the tank.
I fitted the rs turbo pump.
The only thing I can think of is there might be air in the system or the regulator needs adjusting to suit the new pump but I cant adjust it until I get the car started.
Any sugestions folks while get i recharge the battery
Rob Newt

Rob good morning

Was the RS turbo an injected engine? and is the pump therefore suitable for this purpose?

If so then as we have agreed above the main issue is getting the pressure down to at the most 4 PSI above boost.

If the pressure is above this figure then likely as not the engine will be flooded with fuel as the needle valve in the carb will have been overcome with pressure and would have opened allow neat fuel to run directly into the engine.

I have found with the metro regulator that the adjusting screw on the top needs to be backed off of the diaphragm and all will be well.

If you remove the plenum chamber and look into the throat of the carb, you will be able to see if the engine is being flooded with fuel. If the pressure is too high there will be fuel running out of the jet directly into the engine.

I ran my engine as a normally aspirated engine for a few hundred miles when I first started the car. (diconnected the pressure line from the turbo to the carb by removing the plenum) This allowed me to make sure the engine ran right and then if I had problems later it would be the turbo/boost/fuel!
Bob Turbo Midget England



Thanks for the helpful comments Bob,I have in the past set the regulator on tickover at 3.5 psi I will today try and set it not running but just pumping.

Is this an accurate way of setting the regulator??
engine not running ??

After reading your comments,flooding the engine is the most likely fault as there is a strong smell of fuel (no leaks)and the plugs were very wet but I have not taken the plenum chamber off yet to confirm this.

Will report the outcome later today..
Rob Newt

BTW, in order to maintain fuel pressure of 3-4 psi across the needle valve, the regulator reference pressure line must be connected to the inlet manifold (assuming carb has integral float at boost pressure).

A
Anthony Cutler

Hi Rob,
I set mine by taking off the carb piston/needle,running the fuel pump,dial up the pressure on the regulator until fuel wees out the jet,then back off until it stops-been ok so far.
Steve
steve cowling

Well what a day!!
I have always thought I had 8mm return to the tank,when my new micrometer arrived in the post the first thing I checked was the fuel pipes,turns out they are 7mm(did not Know this size existed).

So I have spent the afternoon fitting 8mm return to the tank,set the pressure to approx 4psi and after a few turns of the key she started,run a bit rough for a few mins then backfired and cleared,went for a test drive and WOW what a diference,the only problem now is what made it go so well(bearing in mind it ran well before)new pump,8mm return or resetting the regulator?

Cheers Steve for your method of regulation but I forgot to mention I have a pressure gauge,now its plumbed in I was wondering if it is ok to leave connected or if it will cause problems at a later date.
Rob Newt

Rob,
it seems similar to hydraulic systems i work with, always have the return bigger else you end up with wierd problems, usually we go for the next size hose up on the return.
Brad (Sprite IV 1380)

Nice one Rob pleased for it!!
Robert (Bob) Midget Turbo

Hi Rob,
Welcome to the club!
I left my fuel pressure gauge in,but dont really use it.
steve cowling

Cheers Steve
I have now taken the gauge out as it seemed to be weeping fuel slightly,I was expecting you to tick me off for not using 10mm return but my local car spares only had 8mm in stock and I could not wait!!
So far so good, so I will see how I get on.
Rob Newt

Hi Rob,
Try B&Q!(10mm central heating pipe)
Steve
steve cowling

On the sound issue; Potentaily you have created a more efficient sound path for the pump vibration thru to the vehicle. Probability is that what you are listening to is the structure born sound rather than the air born sound.

I'm not familiar with you application, but I would look to ensure that any mounting of the pump is using the original compliant mountings. I would also check that if the original pump had rubber sections on the in and out, then these have been retained or the material substituted with like for like. I would also consider any plastic or rubber fuel pipes which have been upgraded to metal, as all these will make for a more efficient sound path. You may be running with carpets which again will increase the noise.

If all else fails make sure that there are realy compliant tube sections on the in and out, idealy these should have a bend in them as straight rubber pipe can transmit sound quite effectively down it's length. Also I would ensure the pump body is mounted in a compliant material.

James
J E G Eastwood 1

This thread was discussed between 23/01/2010 and 11/02/2010

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