35 replies to this topic

[Fastorq]

Maybe I’m being stupid here, but what’s the advantages of shorter or longer ram pipes?

Fitting twin HS4s so looking for suggestions and options for filtration on a nicely built 1330 fast road engine

Ram pipes , velocity stacks , air horns , trumpets .............
Hmmm,
Don’t know much about SU carbs but Dellorto and Weber twin duals use 50mm as standard and its recommended that they are used inside proper air filters.
When fitting shorter stacks it’s generally to go under shorter filters , ie where space is an issue.
Alls they are doing is straightening the airflow into the carb throat and fitting the correct choke for airspeed in combination with the appropriate jetting for your application is what makes the carb work for you.

[nicklouse]

chapter 6 of the bible.

[Fastorq]

chapter 6 of the bible.

“The mathematical equations of Isaac Newton” one .?
Lol

[Ethel]

The gospel according to David Vizard

 

Rover thought this was a good idea when they had space to spare under a Maestro bonnet

[Fastorq]

Maybe I’m being stupid here, but what’s the advantages of shorter or longer ram pipes?

Fitting twin HS4s so looking for suggestions and options for filtration on a nicely built 1330 fast road engine

 
As you probably know the cone filter is a compromise on power, and a long way from period
 
Our stub stacks inside a round K&N
 
10% off for TMF members
 
http://www.retromini...roducts_id=1241
 

These are pretty much all you need.
The radiused edges will help to “funnel” the air entering the carb throat and IMHO make it look nicer (better than a sharp edge)
But .... that’s all it will do.

[AlexMozza]

In my 1330 with twin hs4s I have 40mm ram pipes and they work a treat. Tested before and after on the dyno. Cleaned up the curve and gain torque and power. Well worth it.

[Fastorq]

The gospel according to David Vizard

 
Rover thought this was a good idea when they had space to spare under a Maestro bonnet

Just ordered it

[Fastorq]

Now, these are what you call “Velocity stacks”

Attached Files

•  0894003D-E38B-4759-99F2-A79FA6157D72.jpeg   40.05K   0 downloads

[Turbo Phil]

Would I need bulkhead mods to fit these ? Lol

Phil.

[hhhh]

 

I flowbench tested this a couple of weeks ago, showed a decent gain in flow and is designed to fit under a K&N cone filter. Available for the 1-1/2" and 1-3/4" SU.

 

Different length ram pipes can be used to tune the inlet length and are used to alter the torque spread of the engine. Tuned lengths can have quite a dramatic effect when done correctly.

Phil.

 

 

Who's is that Phil?   There's a lot going on the face of it; there's gains to be made there!

 

It seems to me that the relatively sharp peak nearest the camera could be improved with a larger radius, but I doubt it would be a very significant improvement. Also the dashpot breather holes can be run out the back of the stack.

[Turbo Phil]

That's all been done on the latest development.

Phil.

 

[Fastorq]

Re the David Vizard “ bible”

Quite weirdly after buying a DV 1st edition by mistake I was having a rumble around in the garage and found a copy of David Vizard 3rd Edition, 1999, Haynes Mini workshop manual1969-1991 and Haynes Mini Performance Manual , by Tim Mundy 2003
I have no idea where they came from.... sure I gave away a red cover dealer workshop manual a few years ago when I wasn’t remotely interested in having a mini.

I’ve sent the DV 1st Edition back to be credited.
DavidR

[Retroman]

Going Back to The OP

 

Interesting developement in the pipeline

 

DV book top flow is a stub stack, but air demand on a running motor and bench flow are two different things and will vary on different engines

 

We ran a Ministox racer on the engine dyno and tried 3 different stubs and rampipes on the HS4 SU  1 1/2 

 

Optimized power with a 20mm stub stack then tried a 3D printed 30mm ram pipe...

 

Gained about 2 to 4 % torque right across the 3.5 to 6.4k rev range !! smoothing the curves out well and almost flattened a dip in the power curve over 5.9k

 

Then tried a 6in long flowerpot 3D ram pipe, similar to Longman split 45 type but with a smooth 'step' change 1/2 way down

 

Compared to the 20mm stub gained some below 4.4k and lost out above that, which is kind of what you would expect.

 

It was a surprise to all of us that the short 3D rampipe worked so much better especially over 4.5k...

[adarkmind]

I flowbench tested this a couple of weeks ago, showed a decent gain in flow and is designed to fit under a K&N cone filter. Available for the 1-1/2" and 1-3/4" SU.

 

Different length ram pipes can be used to tune the inlet length and are used to alter the torque spread of the engine. Tuned lengths can have quite a dramatic effect when done correctly.

Phil.

 

Hello,

 

sry for posting this in an old topic.

Are those still in production? Dave does not seem to be active any more?

 

Greetings from germany

[bpirie1000]

Interested to see the dimpled effect on that one. Most i have seen are chrome/ annodised and smoothed off to allow the flow..

I can see the benefits for both.

Also interested to see what everyone does for the air intake. Do you tube it from as low as possible to get dence air or just let the engine bay airflow au natural.