Ram pipes

[tdafforn]

I've been reading some books by Vizard on engine tuning and he has an
interesting flow analysis of ram pipes which demonstrates clearly that
the ones on the Lotus are not the best at flowing. Anyone tried any
others? I know that the performance increase is probably minimal and I
have enough fun with the +2 as it is, but I was just interested in other
peoples experiences,
Cheers
Tim

--
Dr Tim Dafforn
MRC Fellow
Biosciences
University of Birmingham
Edgbaston
Birmingham
B15 2TT
(0121) 414 5881

[lotuselan2]

Tim

What does Vizard propose? Would it fit in a +2 engine bay?

Ken



_____

From: ***@***.***lto:***@***.*** Behalf
Of Tim Dafforn
Sent: Tuesday, May 03, 2005 9:40 AM
To: lotus elan
Subject: [LotusElan.net] Ram pipes



I've been reading some books by Vizard on engine tuning and he has an
interesting flow analysis of ram pipes which demonstrates clearly that
the ones on the Lotus are not the best at flowing. Anyone tried any
others? I know that the performance increase is probably minimal and I
have enough fun with the +2 as it is, but I was just interested in other
peoples experiences,
Cheers
Tim

--
Dr Tim Dafforn
MRC Fellow
Biosciences
University of Birmingham
Edgbaston
Birmingham
B15 2TT
(0121) 414 5881
















_____

[tdafforn]

Actually what he proposes would fit much better than what is aready
there. He tests a load of pipes for flow in his book and concludes
that the best profile is an "eliptical flare" which is basically like
a ring donut split circumfrentially. Considering the limitations on
the flow in the airbox (it having to do a right angle bend) these may
even be better as they do not extend as far into the box..
Not sure what received wisdom is on the Twinc in an elan +2
Cheers
Tim
--- In ***@***.***, "Lotus" <lotuselan2@c...> wrote:

[lotuselan2]

Tim

"ring donut split circumferentially". Can you try another description; I
may be geometrically handicapped.

Ken



_____

From: ***@***.***lto:***@***.*** Behalf
Of tdafforn
Sent: Tuesday, May 03, 2005 4:43 PM
To: ***@***.***
Subject: Re: [LotusElan.net] Ram pipes



Actually what he proposes would fit much better than what is aready
there. He tests a load of pipes for flow in his book and concludes
that the best profile is an "eliptical flare" which is basically like
a ring donut split circumfrentially. Considering the limitations on
the flow in the airbox (it having to do a right angle bend) these may
even be better as they do not extend as far into the box..
Not sure what received wisdom is on the Twinc in an elan +2
Cheers
Tim
--- In ***@***.***, "Lotus" <lotuselan2@c...> wrote:

[john.p.clegg]

How about

" a speed hump all around the entrance to the carbs in the airbox?"

John

Lotus <***@***.***> wrote:
Tim

"ring donut split circumferentially". Can you try another description; I
may be geometrically handicapped.

Ken



_____

[tdafforn]

Exactly!

JOHN CLEGG wrote:


--
Dr Tim Dafforn
MRC Fellow
Biosciences
University of Birmingham
Edgbaston
Birmingham
B15 2TT
(0121) 414 5881


--
Dr Tim Dafforn
MRC Fellow
Biosciences
University of Birmingham
Edgbaston
Birmingham
B15 2TT
(0121) 414 5881

[lotuselan2]

John and Tim

I think I am getting it. Do you mean ONE ellipse around all FOUR carb
throats? How tall would the speed bump be? And do you throw away the
conventional trumpets? That would sure free up the traffic jam in the air
box! It would work for my BDR just as well as a TC.

Ken



_____

From: ***@***.***lto:***@***.*** Behalf
Of Tim Dafforn
Sent: Wednesday, May 04, 2005 6:29 AM
To: ***@***.***
Subject: Re: [LotusElan.net] Ram pipes



Exactly!

JOHN CLEGG wrote:

[tdafforn]

Hi Ken,
Speed bumps encircling each throat and no trumpets..
This increased flow by 1% over the best possible trumpet available and

Tim

Lotus wrote:


--
Dr Tim Dafforn
MRC Fellow
Biosciences
University of Birmingham
Edgbaston
Birmingham
B15 2TT
(0121) 414 5881


--
Dr Tim Dafforn
MRC Fellow
Biosciences
University of Birmingham
Edgbaston
Birmingham
B15 2TT
(0121) 414 5881

[john.p.clegg]

Without getting too technical (tuned lengths etc...) i think i did read that the best "trumpet" for general work was approx 1 1/2" deep?
John


Tim Dafforn <***@***.***> wrote:
Hi Ken,
Speed bumps encircling each throat and no trumpets..
This increased flow by 1% over the best possible trumpet available and

Tim

[lotuselan2]

Tim

Where can I buy such speed bumps or do I go out and pull them off the local
roads?



I have seen some quite short trumpets with heavily rolled inlets; they seem
closer to speed bumps than conventional trumpets.

Ken



_____

From: ***@***.***lto:***@***.*** Behalf
Of Tim Dafforn
Sent: Wednesday, May 04, 2005 10:24 AM
To: ***@***.***
Subject: Re: [LotusElan.net] Ram pipes



Hi Ken,
Speed bumps encircling each throat and no trumpets..
This increased flow by 1% over the best possible trumpet available and

Tim

Lotus wrote:

[lotuselan2]

John

Yes my trumpet is about 1 ?? (now let?s not start any personal
discussions!!). That is just long enough to cause congestion in the air box
for cylinder #3 and 4.

Ken



_____

From: ***@***.***lto:***@***.*** Behalf
Of JOHN CLEGG
Sent: Wednesday, May 04, 2005 10:50 AM
To: ***@***.***
Subject: Re: [LotusElan.net] Ram pipes



Without getting too technical (tuned lengths etc...) i think i did read that
the best "trumpet" for general work was approx 1 1/2" deep?
John


Tim Dafforn <***@***.***> wrote:
Hi Ken,
Speed bumps encircling each throat and no trumpets..
This increased flow by 1% over the best possible trumpet available and

Tim



















_____

[john.p.clegg]

Sorry

I tell a lie,having just measured my trumpets they are 1" long,and as a confirmation in theTwin-cam tuning book-D Vizard page 58 "the best all roundresults can be achieved with a ram-pipe having a flaring radius of approx1", This should continue through at least 75 degrees as in fig.20 "
John

Yes my trumpet is about 1 ?? (now let?s not start any personal
discussions!!). That is just long enough to cause congestion in the air box
for cylinder #3 and 4.

Ken

[steveww]

Pipercross the filter people also do fully radiused ram pipes for most
carbs http://www.pipercross.net/

[tdafforn]

These are all more pipe shaped that the ones Vizard suggests.
The profil he recomends I have seen molded in modeling clay, or resin as
it is adhered directly to the carburettor face..
Cheers
Tim

stevew_w wrote:


--
Dr Tim Dafforn
MRC Fellow
Biosciences
University of Birmingham
Edgbaston
Birmingham
B15 2TT
(0121) 414 5881


--
Dr Tim Dafforn
MRC Fellow
Biosciences
University of Birmingham
Edgbaston
Birmingham
B15 2TT
(0121) 414 5881

[pinsx3]

Actually, I mean velocity stacks. Does anyone know where I can get little
sock air flinters for these? Pete