SNAIL

silc · Posted: Tue Oct 07, 2008 10:44 pm Post subject: engine compression

Hi all,

I'm planning to do some modificaiton on the engine of my car. I don't want to do some racing with it... it is a 2 cv... made for crusing... but an addition of of few hbp would be nice. Therefore, I'm gonna fit 2 "Perfo" airfilter (one on the carbu and one on the crankcase breather) and replace the original frst muffler by a 2 to 1 pipe sytem. As I was sufing on the web I've seen a set of piston with a compression ration of 9:1. I know that more compression gives more power. It is much bigger than the original? And if I do the change, is there any other parts that I need to change?

Here are the links:
Air filter: http://www.ecas2cvparts.co.uk/sports-filter-fits-carburettor-2cv6-2635-p-951.html
2 to 1 pipe system: http://www.ecas2cvparts.co.uk/into-performance-manifold-extender-eendecent-p-1436.html
piston set: http://www.ecas2cvparts.co.uk/barrel-piston-barrels-pistons-rings-gudgeon-pins-circlips-quality-french-brand-perfect-p-512.html

What do you guys think of thoses things?
Thanks in advance for you help and comments...
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backfire · Posted: Wed Oct 08, 2008 12:32 am Post subject:

buy cylinders with piston set, keep original muffler and keep original airbox, rejet carbuartor and you should have about 32HP, fine tuning with powertube would get you up to 35HP.

PS I assume that you can find these cylinder sets easy in France.
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2CV, with Visa turbo charged

silc · Posted: Wed Oct 08, 2008 8:41 am Post subject:

Oh ok... so no need to change the muffler and the airbox... I thought it would have made a difference, but if it's not the case... I won't do it then... Better for my wallet Laughing

For the parts I can indeed get them in france, but as it is an english forum, I thought I was better to put english refecence Wink

By any chance, who knows the original compression ration of the 2cv engine (602cc)?
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Nothing else's better than a 2CV custom!!!
Yeah baby yeah!!!

backfire · Posted: Wed Oct 08, 2008 10:19 am Post subject:

compression 2cv 602cc depends on engine, old ones are 1:8,5 the last version is 1:7 if I am not mistaken. Last engine compression was lowered to better cope with octane 95. But according to an old instruction manual old engine should be able to run on octane94
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2CV, with Visa turbo charged

silc · Posted: Wed Oct 08, 2008 10:37 am Post subject:

7.1

As mine is from 1987 this is probably what I have... so going from compression ratio 7.1 to 9.1 should be a nice improvment Very Happy

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Nothing else's better than a 2CV custom!!!
Yeah baby yeah!!!

DrumVlado · Posted: Wed Oct 08, 2008 11:00 am Post subject:

Actually the engines are 1:8,5(m28/1) and 1:9,0(M28). You should have about 32 hp with the 1:9 pistons without anything else changed...

EirikJ · Snailer Joined: 23 Jan 2008 Posts: 36 Location: NOrWAY

Just look at you're engine plate for the engine type, and then have a look at this web-site:
http://www.cats-citroen.net/citroen_atypes/enginegearbox.html

The standard airfilter and exhaust system is what I understand, more than good enough for a standard or light tuned 2CV-engines.
A "sporting" airfilter only makes you belive you have more power because of more noise Rolling Eyes

The best way for a bit more power, is as you say, higher compression.
Most 2CV's from the 80's have 8,5:1 in compression. I think you can feel the differense buying a 9:1 kitt. And then you also have new piston and rings!

I also want to try this in combination with the 9:1 kitt:
http://www.pp-2cv.be/EN/News/Soufflante.htm
It's a copy of the setup on Dyane. Maybe that makes a differense too?
Anyone here tryed it?
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2CV x3
AMI 6 x1
DS x2
CX x1

backfire · Posted: Wed Oct 08, 2008 11:15 am Post subject:

Correction S6 engines are 7.9:1 and have 28HP
AM2 engine has 9:1 and have 32HP
Default 2cv have 8,5:1 with app. 29HP

check the site of Jeroen Cats.

http://www.cats-citroen.net/citroen_atypes/enginegearbox.html
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2CV, with Visa turbo charged

backfire · Posted: Wed Oct 08, 2008 11:18 am Post subject:

Thats what I called the powertube, this can give you extra 1 to 2 HP depending on correct setup of carb.

You can go up to 39HP with diffeten camshaft en compression 1:10.
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2CV, with Visa turbo charged

silc · Posted: Wed Oct 08, 2008 6:44 pm Post subject:

Thanks for the web references... very usefull!!! I need to check the plate on the engine... will let you know Wink

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Nothing else's better than a 2CV custom!!!
Yeah baby yeah!!!

Bart · Posted: Thu Oct 09, 2008 10:27 am Post subject:

Hi silc,
I would say get off those pieces.
Higher compression pistons and barrels is definatly worth it, only try to get them from good quality manyfacturer... argentinan ones are no good, as one of my friends found out Sad

Also get that particular 2 in 1. I'm preaching for my own church as a couple of friends and I have developed this piece. However I can say it really works as rolling road testing (obviously with correct jets) gave about 10% torque increase from about 3000rpm to 5000rpm. You can also buy these exhausts from Pierre Focant from Belgium (he may be at Spa I'm not sure).
Finally a sports filter combined with a power tube will also give some more power, price you pay here is indeed noise...

Please remind that when changing exhaust and airfilter you should set the jets as well. Also don't forget that all times you start with a healthy and correctly adjusted engine. If that is not the case do that first, you'd be surprised what a full service can do.

Etienne · Hoodrider Joined: 25 May 2007 Posts: 2829

Hi!

I have Dyane engine in my 2cv, so an AM2 and 9:1
This works perfectly fine and it's really reliable. My engine is more than 200 000 km, never been opened, doesn't leak oil...
Only problem, I can't success to check the ignition well with the unleaded 95. So I use the 98 and then it's fine. But I'm not a all a mechanic specialist!
So that's my experience.
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www.super2cv.com

silc · Posted: Thu Oct 09, 2008 12:54 pm Post subject:

Hello Bartje,

The pistons and barrels set that I'm getting are french manufactured (from Perfect ci.) and it seams to be a good manufacture... for the air filter, I think I 'll go for it as they are not too expensive... But for the exaust, I'm actually thinking of building my own in order to obtain 2 exaust lines with 2 mufflers, etc... The only question is: is it gonna improve or decrease the performance compare to the original. At the end I know that it is a 2cv engine and I wont get much of it but I want to customise it to get a nice bubbly noise... In your note you're mensionning the tuning of the jets... what is it? The engine that I'm using is the orignal engine of my 2cv (120 000 kms) with a twin cam carburator... I'm changing the pistons and barrels, the rocker arms, the valves, all the seals and the other pieces mentioned earlier. So in my point of view the engine will be good as new... If you have more information about those jets, I whould highly appreciate it Wink

hi Etienne,

you're saying that the you have a 9.1 too on your engine and you use unleaded 98. Is it the same as "sans plomb 98"? do you know if those kits support "sans plomb 98" instead of "super"? Or you're mixing it with some dope? if not you're gonna spoil the valves don't you? Question

I need to check on my side if the new valves and the pistons and barrels set are compatible with the "sans plomb"... Idea

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Nothing else's better than a 2CV custom!!!
Yeah baby yeah!!!

Etienne · Hoodrider Joined: 25 May 2007 Posts: 2829

backfire · Posted: Thu Oct 09, 2008 5:45 pm Post subject:

two in two exhaust will give less torque at lower rpm but gives less restriction for higher rpm. To keep torque you should mount a good balance pipe (pipe between the left and right exhaust)

Instead of airfilter mount a good normal airbox with more capacity, a good airbox makes car run smoother.
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2CV, with Visa turbo charged