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 Free Flow Cross Box - How 2! 
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gym bunny
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Joined: December 8th, 2008, 4:08 pm
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Location: Burton-upon-Trent
Post Free Flow Cross Box - How 2!
As fitted to my Ami 8 when playing with air filters and exhausts:

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Also removed the silencer from the side pipe and made it exit half way along the rear door and fitted a high flow air filter! (All MOT Pass)

usual disclaimers... remember its your car, not mine, and play safe!

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November 11th, 2009, 7:24 pm
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Firing on two.
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Joined: July 27th, 2009, 10:43 am
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Post Re: Free Flow Cross Box - How 2!
grrrrrrrrrrreat. Thanx, Got something to do. I just need tot get my box off :? i think itl turn to rust dust first! :mrgreen: :mrgreen:

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November 14th, 2009, 9:30 pm
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Joined: December 20th, 2009, 10:00 pm
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Post Re: Free Flow Cross Box - How 2!
Hi all there!!

Does this cylindrical exhaust muffler have the same inner distribution as the one shown in those pics? I mean, those two chambers?

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Does anyone have a picture of this cylindrical 2 to 1 exhaust open wide?

Thanks in advance.

.


February 4th, 2010, 11:42 pm
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Agony Aunt - You have a car problem? Speak to Ken

Joined: March 6th, 2009, 1:40 am
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Post Re: Free Flow Cross Box - How 2!
Ummm,
don't forget that by getting rid of the baffles inside the crossbox, the primary pipe lengths will no longer be as close as possible to being the same length.

The result may well give more noise, but in all probability it will also give less power where you need it for use on the road.

Believe it or not, Citroen did know what they were doing when they designed these cars, including their individual parts... :roll:

ken

( p.s. @ chicago.
The Walker crossbox has a different arrangement for its baffles, but the general idea is the same, to equalise the paths from inlet to outlet for both cylinders. )

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February 5th, 2010, 12:24 am
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Firing on two.
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Joined: January 5th, 2009, 5:48 am
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Post Re: Free Flow Cross Box - How 2!
Is this what you're after?

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Ken's right as usual, but I didn't let that sort of thing stop me from cutting mine up.
viewtopic.php?f=5&t=137

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February 5th, 2010, 2:37 am
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Joined: December 20th, 2009, 10:00 pm
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Post Re: Free Flow Cross Box - How 2!
Thank you much for this pic,...But now I wonder what the exhaust gases paths are. It is easy to see in the previous sandwich-shape as in this pic.

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By chicago49, shot with N70-1 at 2010-02-03

Any schematic or drawing about what would the gases paths be in the cylindrical muffler?,

Thanks in advance.

Chicago.


February 5th, 2010, 4:18 pm
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Firing on two.
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Post Re: Free Flow Cross Box - How 2!
If I could do that clever thing with the arrows I would, but for me it would be quicker to take the box off the car, cut it open again, and draw the arrows with a marker pen. But I'll try to explain it.

Imagine the chambers are numbered 1 to 4, with 1 being the closest where you can just see the exit pipe.
The gas enter the box into chambers 2 & 4, and enters the perforated pipe through the holes,
It flows along the pipe and exits through the holes into chamber 3, where it enters the solid pipe through the few holes drilled in it.
It then flows up the solid pipe to chamber 1 and out the exit.
Note, the solid pipe is blocked at the far end, in camber 4, the perforated pipe is also blocked here, right at the very end.
the perforated pipe is also blocked where it enters chamber 1.

HTH!

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February 6th, 2010, 1:15 am
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Firing on two.

Joined: April 22nd, 2009, 11:06 pm
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Location: Ecosse
Post Re: Free Flow Cross Box - How 2!
chicago wrote:
Hi all there!!

Does this cylindrical exhaust muffler have the same inner distribution as the one shown in those pics? I mean, those two chambers?

Image

Does anyone have a picture of this cylindrical 2 to 1 exhaust open wide?

Thanks in advance.

.

Image

there is internal baffles at each outer 1/3 area the rh as seen from my pic is the exit
the middle section has an internal pipe from halfway to the outlet 1/3 for the RH cyl theLH goes in to the LH 1/3 where it has a seperate pipe running the full length of the box to the RH exit 1/3. the pipe tracks are of different lengths but are most definatley of "tuned" lengths

and as Ken states a gutted exhaust just means more noise and poorer driveability, the above dead box was a superb one that just seemed sweet mid to top range and had been put back on after replacing it with a new one which just didnt feel right.

As a "get it going while im waiting to get paid" an old gutted box from the pile of discarded race stuff was used, all it does is make more noise and lets the engine rev a bit higher but the 4k to 5.5k is gutless and thats where i do most of my driving.

I wouldnt recomend it to anyone, stick to the Walker crossbox and get a straight thru torpedo if you can.

the above catastrophy was caused by the 2nd boyer unit developing a fault the resulting misfire and ultimatley explosion was just too much for the old box that has been in service for about 15 years :cry:

Sean

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May 5th, 2010, 10:22 am
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Firing on two.
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Joined: January 12th, 2010, 10:33 am
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Location: Voorschoten, Netherlands
Post Re: Free Flow Cross Box - How 2!
:D

but it sure gives a nice sound!

other option with WALKER (and only Walker) is to make an extra exhaust on the other side, drill a hole weld in a short piece of pipe ( to connect the middle pipe) and cut and weld all other exhaust parts mirrored from the 'normal' side. had some good results with this in combination with my visa engine, don't know if there is any noticeable difference if you have a stock 2cv6 engine. like this: http://www.2cv-power.de/tuning/rennausp ... uspuff.htm (if your german isn't that good, try using google translate, or just take a look at the pics)

greetzzzzzzzzzzz

Rusty

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May 11th, 2010, 11:23 am
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