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MG MGF Technical - Power Boost Valve

does anybody have any experience with the power boost valve from Brown and Gammons? Or can somebody explain whether or not such a valve and the consequent raise in fuel pressure could make sense in connection with a K&N? Does it really bring more power?

Thanks for your comments,

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Hi Nikolaj,

No more power, but the throttle response is better.

- Andy
Andy Gilhooley

If the existing regulator is working properly, and there is a degree of 'production tolerance' that means that you do see slight variations in normal operating pressures, then you are unlikely to see any power gains. Throttle response almost always becomes much sharper which is a useful benefit.

If however the existing regulator is faulty or operating at a slightly lower pressure you may see a small increase in power on top of a more pronounced improvement in throttle response. It may be more than coincidence that on the engines that I have had direct control over with the fitting of an FSE valve, the ones which provided more power were higher mileage and slightly older examples.

I can add one more quite relevant observation with a 1.4 Metro GTi, which with a Pipercross filter and FSE valve was producing power at the wheels close to a 1.8MPi. These were significant gains over the car in standard form. These same parts later moved to a 1.8MPi engine of considerably less age and mileage resulted in no difference in power, just the changes in feel and response!

Roger Parker

Hi all,

so maybee it should be renamed "Torque boost valve " then ? I do fully agree with Rog, a much more responsive pickup at lower revs - but not sure if the fittment of the boost alone will give any bigger change. Once again a product that works best together with a K&N / Pipercross and a good sports-exthaust system

Regards , Carl.

Can anyone tell me if the Power Boost valve, from B&G, is easy to fit.
Many thanks,
Tim Sanders

Perhaps not a 'torque boost valve' Carl, but I understand what you are saying.
Power curves are performed with revs increasing relatively slowly (when compared to snapping open the throttle)- so a steady state at a particular engine speed is readily attained.

Snap open the throttle, and the expected torque from a given engine speed will not be obtained because of a relative weakening of the mixture- momentary until the management system/ fueling compensates. The boost valve will reduce this lag time- reaching rpm-predicted torque more rapidly by being able to get more fuel to the engine by virtue of higher fuel line pressure.

I wonder what the down side is? Probably poor emissions and lower fuel economy...

Rob Bell

The management system is fully aware that the throttle has been cracked open and does provide momentary extra fuelling to cope with this (similar as the old accelerator pump in the days of carbs). However the amount of extra fuelling programmed in (and hence the response) is compromised for the sake of emissions. As others have said, once you're in a steady state (like a fraction of a second after you've stopped moving the accelerator pedal) the 'Power Boost' valve has no effect. It's certainly optimistically named.

Mike Bees

Hi Tim,

Yes ,it is fairly easy to fit even if You have a rather limited toolbox. Be sure to let the car be left for a few hours before starting the job. This to ensure that any remaining fuel-pressure in the system is gone. NOTE: There are several "Boost valve"- boxes containing different small parts for assembly. Be sure to get one specified for the VVC "F" !

Regards , Carl.

I think that the crux here is that the engine managment is very fully mapped to provide for the conditions of acceleration and the increased injector open time that occurs during these phases. Where I think that the standard system can fall short, but only very slightly, is with the production tolerance in the fuel rail operating pressures. I mentioned before that there is an acceptable 'float' in fuel pressure readings and here there may be a slight mismatch against MEMS values. Not enough to cause any emission problem or poor running, but enough to slice off a little of the'cream'.

In these circumstances the FSE provides a degree of 'overkill' so that there is always more fuel available. The excess will go to alter emissions for the worse, but since most test cycles do not measure acceleration phase emission this should not be a problem for owners. It would be for the manufacturer as he does have to comply in these areas.

Roger Parker

Thanks for the info.
Tim Sanders

This thread was discussed between 20/11/2000 and 24/11/2000

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