Power Boost Valves
Discussion
Go for a good quality pressure regulator rather than a cheap and nasty one prone to going soft.
Those 'power boost' valves are designed to increase the fuel pressure across the injector as the load increases. On a standard engine this makes it run rich under power which isn't particularly clever but is one way to bodge the fuelling if you have improved the air flow and don't want / can't be bothered to adjust the fuelling to match.
Given that you will have complete control over the ECU you will be able to get the fuel right. Having the 'power boost' valve will if anything make the mapping process slightly more involved (because fuel flow no longer depends just on injector duration).
Those 'power boost' valves are designed to increase the fuel pressure across the injector as the load increases. On a standard engine this makes it run rich under power which isn't particularly clever but is one way to bodge the fuelling if you have improved the air flow and don't want / can't be bothered to adjust the fuelling to match.
Given that you will have complete control over the ECU you will be able to get the fuel right. Having the 'power boost' valve will if anything make the mapping process slightly more involved (because fuel flow no longer depends just on injector duration).
chrispitman said:
I have been looking at this as well, as I about to do my emerald install, is it not better to get an adjustable 1:1 regulator so the pressure can be increased on the rail then use the ECU Injetor timing to do the rest.
I thing you are confusing the rising rate with the non rising rate..I've not asked Emerald this and I'm not sure of the answer but does the emerald want a fixed rate to the fuel rail - if the pressure regulator has a vacuum pipe - should it be disconnected ?
rev-erend said:
chrispitman said:
I have been looking at this as well, as I about to do my emerald install, is it not better to get an adjustable 1:1 regulator so the pressure can be increased on the rail then use the ECU Injetor timing to do the rest.
I thing you are confusing the rising rate with the non rising rate..I've not asked Emerald this and I'm not sure of the answer but does the emerald want a fixed rate to the fuel rail - if the pressure regulator has a vacuum pipe - should it be disconnected ?
There are essentially three ways you can control the fuel pressure. Constant fuel pressure means just what it says - fuel pressure is set to a constant value regardless of manifold depression. This is what you get if you leave the manifold vacuum line off. One advantage of this is that you can put a simple pressure switch on the fuel line to see whether it is maintaining pressure under load.
1:1 variable pressure regulators have a vacuum line supply the manifold reference. As the manifold pressure goes down, the fuel pressure goes down. This means the pressure difference across the injectors is constant which makes it easier to predict the fuel flow just from the injector timing. This is what the standard Lucas systems use.
The 'power boost' (sic) valves are similar to the 1:1 variable pressure regulators but the fuel pressure changes by more than the manifold pressure. This means you get less pressure difference across the injector off load, and more when it is on load. If you are trying to get the maximum possible range from your injectors then you might want to resort to this, it would also be a useful bodge if your engine is running lean but you can't afford/be bothered to remap it.
Given the comments on here it would suggest the best set up running red top's for example would be the 1:1 constant ratio regulator, referencing to manifold pressure using the injector pulse length to control the required fueling.
This is given that the common consencus is rising rate are falible and more difficult to map, and a constant reliable regulator would be more consistent for mapping purposes and less prone to irregular variances in pressure.
Say a constant 3 bar ?
This is given that the common consencus is rising rate are falible and more difficult to map, and a constant reliable regulator would be more consistent for mapping purposes and less prone to irregular variances in pressure.
Say a constant 3 bar ?
A rate greater than 1:1 makes it more difficult to map, but not exactly a nightmare... But why buy a problem when you don't have to? 
Using a fixed reg wouldn't be ideal at all - the injectors would seem bigger at idle and low loads and smaller at high loads - the opposite of the rising rate case. This one would make mapping a nightmare because you could easily have problems with atomisation at high load or problems of needing to use something less than the minimum injector pulsewidth at idle.
My preference is definitely for 1:1 - it just makes everything simpler.
Using a fixed reg wouldn't be ideal at all - the injectors would seem bigger at idle and low loads and smaller at high loads - the opposite of the rising rate case. This one would make mapping a nightmare because you could easily have problems with atomisation at high load or problems of needing to use something less than the minimum injector pulsewidth at idle.
My preference is definitely for 1:1 - it just makes everything simpler.
dnb said:
A rate greater than 1:1 makes it more difficult to map, but not exactly a nightmare... But why buy a problem when you don't have to?
Using a fixed reg wouldn't be ideal at all - the injectors would seem bigger at idle and low loads and smaller at high loads - the opposite of the rising rate case. This one would make mapping a nightmare because you could easily have problems with atomisation at high load or problems of needing to use something less than the minimum injector pulsewidth at idle.
My preference is definitely for 1:1 - it just makes everything simpler.
Whats the difference between a fixed regulator and a 1:1 one then ?? You say fixed would be a nightmare and 1:1 makes it simpler....Using a fixed reg wouldn't be ideal at all - the injectors would seem bigger at idle and low loads and smaller at high loads - the opposite of the rising rate case. This one would make mapping a nightmare because you could easily have problems with atomisation at high load or problems of needing to use something less than the minimum injector pulsewidth at idle.
My preference is definitely for 1:1 - it just makes everything simpler.
Slatter said:
Whats the difference between a fixed regulator and a 1:1 one then ?? You say fixed would be a nightmare and 1:1 makes it simpler....
A fixed regulator gives you constant fuel pressure relative to atmospheric - the pressure difference across the injectors changes with load as the manifold depression changes. And it changes the wrong way - more difference at part load, less at full load.A 1:1 regulator gives you constant fuel pressure relative to manifold depression. The pressure difference across the injectors is constant regardless of load (manifold depression).
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