Ram tube specs

[spinster]

Does anybody have the specs for 4age ram tubes?
I have different opinions from people with angles varying from 7-15degrees and the differences in radius at the top, also should it just be a slight lip or roll right round to 180degrees?
Opinions????

[Mr Revhead]

complicated!

certainly the openings should be fully rolled

as for the rest...... magic!

well, not really but the maths is more than i am comfortable with

whats the use of the car?
what other mods are there?
what are you doing for air filtration?

[spinster]

I've been asked to make some for other people and they range from road cars to track cars so i'll probably make them a few different lengths to work for each application...just have to work out the finer points

[QikStarlie]

7-15 degrees is too much if your talking about taper. plus by the time you get to the bellmouth with that much taper (with decent length) this isnt going to be much room left for a decent bellmouth.

dyno time is probably the only way your going to find out the best shape and taper.

[jondee86]

Getting a nice shape at the entry is probably more important than
taper. An eliptical curve on the entry, or even better, parabolic, will
give the lowest entry losses. A fully rolled lip is best, but a lip that
turns out a little more than 90 degrees is nearly as good.

As said above, 85 outside diameter is about as much as you can
go before the bellmouths touch (87.5 centres on the ITB's).

Cheers... jondee86

[Crampy]

Make them look like this:



Sweet sweet TWM air horns. Very nice!

Also in carbon:

[spinster]

They look to be about the 7 degree taper used with dellortos etc. and that radius at the top is what im looking at doing too....cool im on the right track, cheers

[KinLoud]

Ideally 90 degree lip roll merging into a flat plate gives best flow, but tricky to make in some installations.

More than 90 degrees starts pulling air from behind lip creating extra turbulence and losses, but may be easier to make than above.

Lip radius - the bigger lip radius the better up to r/D=0.5 where r=lip radius and D=trumpet diameter from a flow point of view
HOWEVER
Bigger lip radius causes a loss of the reflected wave effect that helps force extra air into the cylinder.

CONCLUSION

Smaller radius lip rolled more than 90 will work fine and be easiest.

Ken
Ork
021 408 863

[matt dunn]

.

More than 90 degrees starts pulling air from behind lip creating extra turbulence and losses, but may be easier to make than above.

When Dad was in aus with the V8 supercar team,
they tested and found that the more air that comes from behind the lip the better, and found that the trumpet had to stick almost 1/2 way out into the airbox to get the best power.

The older set they used to use are now the ones on his GT40.