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Turbo Pinto

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yet another question!


if i get bigger injectors the engine will be running very rich off boost. is there any way around that?

i've seen turbo fuel pressure regulators for carbs but can they work on injection?



or would the better way of getting more fuel in there be doing something like this?


and fitting some extra injectors as well as the standard ones controlled by a pressure switch?


Thanks, Steve

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I went through a few injectors before I settled on the Saab ones,

tweeking the airflow meter will help a little with the fueling

off boost.

Believe extra injectors have been done with good effect not tried

it myself though, think four is a little excessive, read of

someone running a set of DOHC Sierra injectors(bit bigger than

Pinto ones)and two 2.8 Capri cold start injectors mounted near

the throttle body. apparently worked well.

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i think i'm going to go along the extra injectors route

my only problem is the wiring, not sure where to start really!


can you wire injectors in parallel or is it not that simple? i'm guessing not!

or maybe a solid state relay on each injector?


Thanks, Steve

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Hi Steve,


The easiest (if not the cheapest) is to use an aftermarket ECU, then it's easy to get the fuelling to follow boost based on a MAP sensor.......


If you are using extra injectors on a pressure switch, then you don't need to PWM them (they won't be running long enough to overheat, and the control is not required if it's just steady state WOT/one boost level). A relay would be needed if the pressure switch can't handle the current (solid state or electromechanical would be OK)

No need to connect to the extra injectors to the original ones, just use the pressure switch to operate the relay coil and the relay contacts to feed +12V to the new injectors.


It's not very scientific or efficient, but as you don't generally spend much time on boost (only when accelerating) people put up with just running pig-rich on boost (your only method of control would be to size the injectors according to how much extra fuel you need, or use another fuel pressure regulator to alter the pressure to the new injectors)

A low comp pinto will need plenty of fuel on boost to prevent detonation anyway, as the use of a spacer plate will knacker your squish area............


Hope this helps!





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Hi Dan


Many thanks for the reply, really helped clear up the wiring side of things for me!


next set of questions will come in the way of fuelling!


i'll do a quick drawing of how i plan to plumb everything in and see what you reckon.


Thanks, Steve

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apologies for the poor drawing, dont have cad on this pc




the black thing with the green bit on are the inectors/fuel rail.

the red box is fuel pump


that was my initial idea, but one fuel rail might end up with more fuel than the other if they are fed in series.

so figured this way might be better




there will have to be a swirl pot in there somewhere too i would imagine!


again i could be miles off with this so feel free to shoot me down!



also, i'm guessin the standard sierra fuel pump wont be up to the job of supplying the extra injectors? standard fuel pressure is 2.5 bar which is easy to get with a regulator, but i'll need a pump with a higher flow rate surely?

can anyone recommend one?


Thanks, steve

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I'd be happier with them is series, so you know you have the same fuel flow through each (if you have different fuel rails in parrallel I can see them splitting the flow depending on the restriction of the rail by design, so if they weren't identical the flows may not be the same. Think electrical current through tow different resistors in parallel.........)


Whether the injectors get enough fuel is a function of the pump, if you try to inject more fuel then the pump can comfotably flow pressure will drop off dramatically.


I ran my turbo setup on a standard pump (with swirl pot and facet lift pump), and it coped fine. I used a wideband lambda setup to check for leaning out at full throttle.

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both the fuel rails are identical as are the injector flow rates, so parallel might be the best bet.


i'm gunna give the standard sierra pump a whirl i think and see how that stands up to the test!


i've found this drawing



does the regulator really have to go after the injectors? i would have thought it goes after the high pressure fuel pump!


Thanks, Steve

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got the fuel plumbing planned out now chaps after spending an hour looking at it all in the garage.


Thanks, Steve

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Hi Steve,


Glad you've got it all planned!


In answer to you previous question, yes the regulator does have to go after the injectors as it works by bleeding off fuel to maintain/control pressure in the rail, the pressure after the regulator is uncontrolled.............

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Looks like you need some info mate.



Standard EFi setup will easy run 7psi of boost. The main thing is to add a pressure switch that will close under pressure, 1 psi upward. This needs to be wired to the octane wires from the ecu so it is earthed when the switch closes. This will retard the ignition about 8 degs under boost.

This will give you 50bhp at 7psi extra on a 2.0 pinto.

Mine runs fine at this.


Using the injectors as you have got in the pic will over fuel big time. Take care or bore wash will kill the rings.






Some Pinto engine info



Standard cast pinto pistons are only good for 12psi with a correctly mapped ecu and no Detonation. Any Detonation will crack the ring landing in no time. It is possible to run more boost, a mate of mine ran 20psi. But as he found out the pistons dont last.

Mythbuster: Transit pistons (low comp) should be used for a turbo pinto. ..NO. They are the same as the standard piston but with a lower crown height so lower CR. No better at all, they still fall apart under the same boost and the engine doesnt have the pulling power of the higher CR standard pistons.


The only upgrade is to fit forged pistons. I have now gone for Cosworth pistons, rods and oil pump/spray bar. Cheap, proven for 400bhp and easy to get. You need the oil pump/spray bar as the cosworth rods dont have oil squirter hole like the pinto ones.


My current build is a 2.0 efi pinto with the Cosworth pistons, rods and oil pump/spray bar with a cosworth L1 ecu and T3 turbo. Same spec on my mates But with a T4, ran 265bhp at 24psi before the clutch slipped

Edited by Robin Allison

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...whatever injectors you use make sure they are High Impedence ones.

Don`t use Cossie ones these are low impedence.


Without meaning to hijack the thread, can someone give me an idiots guide to injector impedence? What difference does high and low make?

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The dual injector rail systems usually fire the first set until more fuel is needed then fire the second set,

There is a minimum firing time for injectors and a maximum cycle time.

You will need beter control of the fueling so a programable ECU and a Lamda sensor is the minimum or it's just all gues work

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Here's my set up...


Ford 2.0 'Pinto' with low compression pistons

Lightly ported EFi unleaded head, standard injection cam.

Standard EFi inlet manifold

Custom tubular T3 turbo exhaust manifold with Cometic gaskets

Garrett T3 turbo with integral wastegate

Custom exhaust manufactured from Jetex parts with RH straight-through silencer. Lambda sensor boss in downpipe.

Shortened steel sump with side reservior for improved capacity.

Modified crank pulley to accept American Ford 36-1 trigger wheel (side mounted crank sensor from trigger-wheels.com)


Engine Ancilliaries:-

Thermo-viscous fan removed - now running electric pull fan with stand-alone thermostatic controller (sensor in radiator top hose)

Standard sierra Alternator re-mounted lower on engine to clear steering column.

Standard water pump

Standard oil pump (with shortened pick-up to suit custom sump)



Ford EDIS ignition controlled via Megasquirt

Modified distributor to remove timing gear - wasted spark coil-pack mounted on dizzy

NGK spark plugs (currently one grade cooler than standard)



Rear mounted lightweight aluminium fuel tank

Facet solid-state pump (with pre-filter) feeding side-mounted aluminium fuel swirl pot

Bosch high pressure pump (standard sierra) feeding fuel rail via engine bay mounted fuel filter

Standard fuel pressure regulator

Weber Cosworth 'Yellow' low impedance injectors


Air Intake:-

Inlet pipework constructed from Silicon hoses and Aluminium tube joiners

Front mounted Audi 1.8t intercooler

Sierra Coswort fast-acting inlet air temp sensor

Vent to atmosphere dump-valve

Standard PWM idle control valve controlled via megasquirt (megasquirt was modified for PWM control)



Sierra 2.0i clutch

Burton Power cosworth clutch cable

Ford Type-9 five speed gearbox with shortened gear lever

'Dave Mac' high-spec propshaft (http://www.davemacprops.com/dmphome.html)

Sierra differential and drive shafts

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