17 replies to this topic

[creakyjaws5533]

Couldn't find a previous post
Just want to know the benefits of ram pipes
Thanks Jack

[Big_Adam]

David Vizard - How to tune the A-series engine , page 57 to 72 / The chapter called RAM CHARGING.

[OfMini&Men]

The big yellow book will tell you everything you need to know :)

[MRA]

The bottom line is, if they are done correctly you can gain performance increases over the other option which is is, without them.

There are various different types.

The principle is that the ram pipe decreases the affects that air trying to go round a sharp edge will create, namely the Vena Contracta, the ill effects of poor flow are reduced power, torque and response...

Take a look at the following link you may find it interesting

http://en.wikipedia..../Vena_contracta

[creakyjaws5533]

Thanks so would it be worth it on a 998? If I can get it low price
Jack

[MRA]

It would be worth it on any fluid application, so yes, however it depends on the ram pipe, some work, some are excellent, some are rubbish and others are simply a total waste of time and money. have you a photo of it ?

Some if they have a good radius, but a sharp edge can create an even lower air flow, due to them amplifying the Vena Contracta

And even if you get a really good item if its up against the filter housing or bulkhead etc.... then forget it unless you are going to modify these parts.

[creakyjaws5533]

Okay I think would need to modify the engine bay thanks for the help though any other tips on get a few more bhp out of a 998?

[KernowCooper]

if everything like plugs/points and a full engine tune, then the next step is a stage 1 kit but depends what your budget is? one thing I have learnned over the years BHP is not cheap

[creakyjaws5533]

Ha it's got a weber 28/36 Kent 731 cam 12g295 head it's an updated exhaust not sure what already on it

[MRA]

Not familier with that Weber, I've used DCOE 40's, 45's and IDA's on Mini's, if yours is a downdraft then be careful how you get the air in to the engine, as the IDA was pretty good until the air going over it stopped going into it, above that speed and there was little acceleration until I "boxed" it in.

[mini93]

The chokes on the Weber 28/36 are quite close together. getting a bellmouth to fit both chokes in there and still have a useful radius will be diffuclt.
That said, i also believe the 28/36 is a progressive choke system, so part throttle only 1 choke will be operated till you floor it... i dont think the ram pipes will lend them particualy well to this application (would you require 2 different length of ram pipes??)

[MRA]

There are way to deal with chokes that are very close and that is to bend the ram pipes, not an easy job, or have acombined twin pam pipe machined to fit the specific carb.

Different lengths on various carbs, ie tuned lengths do work on some engines, not sure about the A series, could be worth a try...

Thanks Dilligaf for the info above, how much room above the carb to bonnet is also important, its all very well having the best flow potential into the carbs ...but if the bonnet gets in the way, youve just wasted loads of cash and time.

[mini93]

Iv always thought a tuned runner length was more over ITB's etc... would be little point tuning a runner length for 1 of the choke when post carburettor, the air joins up from the other choke to then be split off down the line.
This kind of set up would cause alot of dirtied air anyway (with the joining up and then splitting away of air to different paths), hardly ideal for a performance set up but good for the eco drive as will also allow for greater mix and swirl

Edited by mini93, 10 February 2013 - 11:02 AM.

[MRA]

The ram pipes in this exercise are to increase air flow into the carburattor, once it is in the carburettor, it doesn't matter if the characteristics are the same as before, because more air means more torque, if further increases in efficiency within the rest of the system are available then in theory more power will also be available.

The Vena Contracta in this case (without the ram pipes) will cause reduced torque, even if the engine is trying to "pull" the air in, ie higher vacuum.

For anyone confused, dirty air is turbulant air, it is not unfiltered air.

[MRA]

Thanks Dilligaf for the info above, how much room above the carb to bonnet is also important, its all very well having the best flow potential into the carbs ...but if the bonnet gets in the way, youve just wasted loads of cash and time.

You can get the thinnest KN (1.25" iirc) on under the bonnet, if you remove the domed nuts on the filter and replace with normal ones. This does depend a lot on which manifold you use, the best for power (supposedly, I didn't notice a difference) is as the above link. i.e.. with the carb at right angles to the engine. But this type wont fit without serious modes to the bonnet. The manifold to use with a mini is the type that sits the carb parallel, ie. with the float chamber pointing forwards.

In that case you are going to be hard pressed to get a decent ram pipe to work, there are stubby types but they are more for show. The longer they are the higher the torque increase to an extent, not forgetting the laws of diminishing returns.