14 replies to this topic

[minilee94]

hi i have see ram pipes on webbers etc but now i have just seen a ram pipe on an su carb what the difference between having one and not having one on an su carb

[stickycreambun]

Hiya, do you have Vizards yellow bible? There is literally pages about this! Very briefly, it helps with the airflow into the carb, which can lead to an improvement in power. I had one with a sock filter, fitted on a HIF44 on my MG lump, it did seem to make some kind of difference but I also noticed it was waaay louder than the standard airbox, and it did lose some grunt at the bottom end of the range. Just in case you don't know, there are ram pipes as you get on Webbers, and also stub stacks are very short versions that can fit in cone filters.

Merry Christmas

[Frisco]

Sock filters are terrible for airflow

[mini93]

ram pipes do also move the engine torque slightly depending how long they are.... its do with the length of the full runners, thats from the valve centre to the very outter centre of the ram pipe, the longer it is the more it shifts the torque

[bourney]

i don't know a massive amount amount ram air but all i do know is it's just a pipe from the front of your car to the carb inlet. As you drive faster more air gets 'rammed' into it, so you're shoving more air into the cylinder (well denser, more compacted) so bigger bang more power. Just think of it as a poor mans forced induction.
I think they're a PITA to set-up properly though, rolling road set-up i believe is near impossible due to no flowing air, like you would get in real life

[mini93]

i don't know a massive amount amount ram air but all i do know is it's just a pipe from the front of your car to the carb inlet. As you drive faster more air gets 'rammed' into it, so you're shoving more air into the cylinder (well denser, more compacted) so bigger bang more power. Just think of it as a poor mans forced induction.
I think they're a PITA to set-up properly though, rolling road set-up i believe is near impossible due to no flowing air, like you would get in real life

thats not what a ram pipe is :S hes refering to whats also called a bellmouth

[Bungle]

you should of put Visards yellow bible on your christmas list

[minilee94]

iv had the book before but sold it on as to me dindt find it helpfull enough but thats just me i think as everyone else loves it lol and thats the thing im on about lol how does a cone filter fit to that ??

[Pigeonto]

Mini 93. You got 4 reverse and 1 forward gear in your Mini?!!! From the small amount of notice I have taken of these,and certainly not experience, I believe its the length thing. The longer the tube that the air is going along the better. Doesnt matter whether the tube is between the carb and head or between carb and the atmosphere(ram pipe needed).Minis present a big problem in this department due obviously to the space available. Just thinking logically I cant see how you can cram more air in at any time because the dashpot piston spends most of its time 1/4 maybe 1/2 way up if that. The length apparrantly helps speed up the air for torque production.

[Carlos W]

The advantage of a RAM air pipe is going to be intake temperature surely? You're going to be supplying cooler denser air, rather than hot air from the engine compartment

[mini93]

Thats a generic google picture... but ill repeat... thats not what a ram pipe is.
I think your on about a cold air feed which mounts an aweful conveluted tube to the front of the car in a vein attempt to gather a small amount of cold air and cirect it at the carb opening... thing is a convenluted tube provides alot of resistance internaly and wont flow enough air to be of any real benifit to the carb mouth, its going to gather air from the point of lease resistance which isnt going to be thru what is basicly a straw... this is a cold air feed

There is however propper cold air feeds which work well and are utilised by cars like the miglias but they utilised a huge airbox completly enclosing the carburettor mouth which means it HAS to draw air from within... air is gathered from the front due to its massive opening, much bigger than that of the cold air feed and its then fed up again by a conveluted tube but tis larger diam' so even with the resistance over the side walls your still feeding the caburetor's airbox with cool air.
Of course within the airbox the carburettor is still running rampipes (bellmouths) on the webber carburettors as the air entering the carburettor flows better... miglia bulkhead


just another quick photo so show the flow characteristics thru the bellmouth

without it air would be rathered from a surface perpendicular to the throat... this would mean air would have to turn round thru a greater degree meaning the normal straight flow into the throat would be resticted so you wont be recieving the best volumetric efficiency per stroke of the engine

[Bungle]

why would passing air through a shiny tube make the air colder ?

a minis engine bay has a big grill at the front and big hole at the bottom it's not that hot in there

[mini93]

That is the other point, ambiant temerature at the back of the engine is the same after such a low speed anyway...cars like the miglias go from long straights which produce alot of exhaust heat to slow corners and thats where the advantage will come from the propperly constructed airbox

[freshairmini]

to be honest there not really worth the hassle unless your racing your mini and need every ounce of power, as you need a range of lengths of these ram stacks to find the right power for what your using, as the differing lengths affect the way the power is delivered.

your best bet if you want a good flow air filter system is invest in one of the high flowing ITG air filters and a good stub stack. The stub stacks help like the rack stacks but they just remove the sharp corners around the carb throat by using a large radius curve.

MED engineering do one which I have on my own mini. works well, but is obviously reasonably loud because of the increased airflow.

see here

[Simont]

google bernoulli's principle... that will tell you all you need to know about ram pipes
other searches: convergent duct