must RV8 AFM be mounted horizontally?

[350zwelgje]

Posted under wedges as well.
Replacing my air inlet hose on flapper TVR 350i, new one is not flexible (a samco one), and for perfect fitting would need to angle the AFM a bit. Is this a problem or not?
Will try to mount AFM horizontal, but hose will be a bit distorted then. Any tips or information appreciated.

Rob

[Stu R]

As long as it gets a representative airflow you can mount them however you please

[Mikey G]

Stu R said:

As long as it gets a representative airflow you can mount them however you please

Are you sure? Ive seen people have problems with the flappy type of AFM due to the weight of the flap when fitted in the vertical position, can cause leaning or enrichment depending on which way up it is, this is due to the spring being calibrated for the AFM to be horizontal so the weight of the flap is taken out of it.

[steve_d]

Have to agree, the flap has a spring resistance so any change in angle will bias the reading one way or another. More plumbing required I'm afraid.

Steve

[350zwelgje]

Thanks for the information, and confirmation.

So now I wonder how other people replaced the inlet hose with a samco one an a TVR wedge (have seen many in pictures). They must have had the same issue, as the AFM + air filter is at a height not to interfere with the low wedge bonnet and the plenum sitting higher.

Another thing that popped up while reading the replies: Does accelerating/braking influence the metering of air as well? As the mass of the flap tries to move as a reaction to it?

Rob

[steve_d]

350zwelgje said:

........Does accelerating/braking influence the metering of air as well? As the mass of the flap tries to move as a reaction to it?....

If you were talking about an Ultima doing zero to 100 and back again in 9.4 seconds then you may have a point but a Wedge? I don't think so.

Steve

[Mikey G]

steve_d said:

350zwelgje said:

........Does accelerating/braking influence the metering of air as well? As the mass of the flap tries to move as a reaction to it?....

If you were talking about an Ultima doing zero to 100 and back again in 9.4 seconds then you may have a point but a Wedge? I don't think so.

Steve

Also to note, there are more G-forces involved when going over a bumpy road than acceleration, so your flappy AFM will be going nuts over them if vertical. And when braking you are off the gas anyway.

[GreenV8S]

Surely the flapper meters must be mass balanced, because you can easily get over 1G lateral/longitudinal acceleration and if this affected the AFM reading they'd be all over the place.

[Mikey G]

They do contain a damper system that consists of another flap and a chamber (the sticky out bit on the side) but this is mostly for when sudden throttle openings take place to stop the flap bouncing open. This is not a counter weight though. The only thing that holds the flap shut is the big circular spring on the top, this has adjustments dialed into it to tension the spring, you can move this to alter the fueling curve.

[rev-erend]

Here is my wedge filter installation..

Why not just have a straight pipe instead ?



Note - my AFM is an 80mm Bosch unit..

[350zwelgje]

rev-erend said:

Here is my wedge filter installation..

Why not just have a straight pipe instead ?



Note - my AFM is an 80mm Bosch unit..

Rev, would like that, but.... It is a LHD, and all the braking stuff (master cylinder, etc.) is there! Otherwise I would have done it that way immediately. Always nice to have an original LHD, but there are sometimes a few drawbacks. Another drawback is that you get additional yards of cooling hoses under your bonnet, as expansion tank is at the other side (your driver's side)! Will optimise that when installing new hoses.

Seems that your project is still on schedule (and budget), engine is back in ;-)

Rob