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MG MGF Technical - Power Boost Valve

Is a power booat valve worth it ? - has anyone fitted one and how does it compare to fitting a K&N ? - where is the best place to get it from ?
Danny Morris

Can anyone comment on what are generally the "best" (I know this is inevitably going to be subjective) mods to make in terms of performance for budgets of, say, 250, 500 and 1000?

Specifically, has anyone fitted the Pipercross rather than the K & N air filter and what was the result? Has there been a test comparing different air filters as there has (or is to be?) with exhausts?

M

Martin

For what its worth, I fitted one to my VR6 Golf and without a doubt it improves acceleration! You probably know that the unit monitors the inlet tract depression. When you accelerate the manifold pressure drops and the boost valve increases the fuel supply like an accelerator pump on a carb.
robert pulleyblank

>>Can anyone comment on what are generally the "best" (I know this is inevitably going to be subjective) mods to make in terms of
performance for budgets of, say, 250, 500 and 1000?<<

In order, in terms of value for money:

1. Air filter- offer very good value for money for a usable improvement. Cone filters yield up to 8 bhp on a 1.8i and 15 bhp on a VVC. You are looking at between 0.08 to 0.12 bhp per GBP.

2. Performance exhaust- there's an observable gain here both in torque and power (with particular systems) but the higher cost depressed the value for money quotent significantly

3. Next step depends on whether you have a 1.8i or not- a 1.8i has a small valve area, so to improve the breathing, some simple porting and larger valves yield big gains. But now you are getting into the thousands of pounds range. Expect a bhp per GBP of around 0.008 (i.e. a tenth of the value for money of a filter...)

You'll note I haven't mentioned either chips or power boost valves. The latter, as has been implicated by BobP only really acts to improve throttle response by increasing fuel line pressure- more fuel is available when you put your foot down on the 'gas pedal'. Under constant state situations, there is no gain at all. These cost cira 100 GBP, and are available from Moss, and I suspect, Brown and Gammons.


Chips you should be wary of- one only needs to be read of Dirk's problems to realise this. And they haven't been independently tested to check their power gains. Roger has espoused the effectiveness of the standard MEMS management chip, and frankly I am inclined to go with his opinion.

>>Specifically, has anyone fitted the Pipercross rather than the K & N air filter and what was the result? Has there been a test
comparing different air filters as there has (or is to be?) with exhausts?<<

You bet- we did this a little while ago- the article was published earlier this year in MG Enthusiast. Cone filters were split into two groups: the pipercross cones which were cheap and cheerful, and the Ramair and K&N products which cost more but give more at the top end.

From my own experience from these filters, if you own a VVC, buy the K&N 57i kit (it is cheaper than the equivalent Ramair item). No contest.

A 1.8i is more complicated as the Pipercross cones are very cheap, and mounted where they are give more meaty low end torque that suits the engine well- but to the detriment of top end power. However, the K&N filters probably filter better than foam filters (important for long term longevity), and futhermore come with cooling ducts to reduce intake temperature- to the benefit of power. It is a K&N 57i that I have fitted on my car.

The power curves should hopefully be on my home page shortly. http://go.to/mgfgallery

HTH

Rob
Robert Bell

Thanks Rob - really useful advice. Since I've got a VVC, it sounds like the K & N is the first thing to do (followed by an exhaust with a more "sporty" sound - is the exhaust test going to give a verdict on this, as well as power - friend's RV8 has fantastic exhaust note, ie - doesn't sound like a hatchback).

One further query - is there any disadvantage to fitting the K & N air filter (eg - lack of low end torque?)

Thanks

M
Martin

Martin

Some of the aftermarket exhaust systems make the *F* sound great - but you will never get a straight 4 to sound like a V8.

Ted
Ted Newman

Ted,

I take your point; I'd be happy with the half the sound of the RV8 - I definitely want something sounding a bit purposeful than the standard set up, anyway. Anyone have any suggestions? (I'm kind of hoping that Mike Satur's Daytona system is going to be highly recommended in the sound stakes because it just looks so damn good.)

Martin
Martin

Martin

If its noise your after, then you have two choices:
1) Trevor Taylor
2) Mike Satur

In that order.

Opps, should I have said that?

But then there is the question of power gains....

Paul
P9 VLS
Paul

Paul,

Looks, sound AND power gains - isn't that a bit greedy? I guess I'll wait until the test results before deciding which offers the best combination.

Haven't heard of Trevor Taylor - do you have a number/website address for them? Don't suppose they do a quad tailpipe system?

Thanks

Martin

Martin

Martin

I can recommend the Janspeed with cat bypass for noise level.....

But where did my Janspeed come in the exhaust results.......well I couldn't possibly say until MG
World publishes the results!!!!!!!

matt
M66 MAT

matt

Well I think I'm gonna try a power boost valve next year. All the things that Rob talks about are exactly what my car's performance needs.

I took off the K&N rubber tube, it improved things a bit, but not as much as it messed up the mid/top end. I have put the pipe back now, so still need a bit of low down oomf while accelerating (you know to race all the RS's and CRX's at the lights :-)

The K&N fuel saving will be lost, but my grin addiction will be better satisfied. I'll let you know if it really is a gota have part to add to the K&N SP combination when I get round to it. My year 2000 MGF budget starts soooooon.
Tony Smith

This thread was discussed between 16/11/1999 and 17/11/1999

MG MGF Technical index

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