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Ram Pipe Lengths


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#16 Fastorq

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Posted 14 December 2018 - 06:37 PM

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.

#17 nicklouse

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Posted 14 December 2018 - 08:05 PM

chapter 6 of the bible.



#18 Fastorq

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Posted 16 December 2018 - 09:40 AM

chapter 6 of the bible.


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

#19 Ethel

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Posted 17 December 2018 - 12:19 AM

The gospel according to David Vizard

9780854297320-uk-300.jpg

 

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



#20 Fastorq

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Posted 17 December 2018 - 07:16 PM

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
 
j6ZHuxA.jpg

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.

#21 AlexMozza

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Posted 24 December 2018 - 07:02 PM

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.

#22 Fastorq

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Posted 29 December 2018 - 11:10 PM

The gospel according to David Vizard
9780854297320-uk-300.jpg
 
Rover thought this was a good idea when they had space to spare under a Maestro bonnet


Just ordered it

#23 Fastorq

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Posted 19 January 2019 - 07:10 PM

Now, these are what you call “Velocity stacks”

Attached Files



#24 Turbo Phil

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Posted 19 January 2019 - 07:42 PM

Would I need bulkhead mods to fit these ? Lol

Phil.

#25 hhhh

hhhh

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Posted 19 January 2019 - 09:22 PM

 

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. ioCWq8s.jpg

 

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.



#26 Turbo Phil

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Posted 19 January 2019 - 11:48 PM

That's all been done on the latest development.

Phil.

 



#27 Fastorq

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Posted 25 February 2019 - 10:07 PM

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

#28 Retroman

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Posted 26 February 2019 - 12:14 PM

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...






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