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Author Topic: Cant get it in, if you cant get it out ...  (Read 10593 times)
cooter131
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« on: December 07, 2009, 11:56:00 AM »

"Cant get it in, if you cant get it out ..."

Generally, that is true, I guess!

But what happens when talking about intake and exhaust configurations?
It is common to improve how a motor "breathes" by upgrading the intake (ie installing bigger carbs).
This is obvious as we get easier air flow especially on motors that are very restricted by the manufacturer. Also, as the induction works on vacum, the overall task requires less effort.

But what do you think about my 1600 TC motor with twin 40 IDFs?
Would it make any great difference installing any other exhaust than the 131 original?
I really enjoy the carbs sound and dont realy want to add a noisy exhaust unless it is really worth the pain Cool
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George K.
Athens, Greece

131 Special '77 (1300cc) 1977-1999
131 Special '76 (1600cc) 2007- . . .
Thotos
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Theo Kyriacou


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« Reply #1 on: December 07, 2009, 12:20:11 PM »

A good breathing exhaust is not necessarily a noisy exhaust. I would think the most restrictive part of a standard 131 exhaust is its cast iron manifold. Replacing that with a free flowing 4-2-1 manifold/downpipes should improve matters without increasing the noise (assuming you keep the rest of the exhaust as standard). Next step would be to go for a bigger bore exhaust but you don't have to go for a 'drain pipe' sized exhaust. A slightly bigger bore exhaust with sufficient (but free flowing) silencing should let the gasses escape easier without adding too much to the noise.
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Theo Kyriacou
Enfield, UK
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« Reply #2 on: December 07, 2009, 11:43:01 PM »

I think the 124CC/CS exhaust manifold is the "best" factory one. although the difference is not huge to the 2 litre 131/132 ones. If you run decent secondary pipes from the factory cast manifold its not a bad setup really. if your not going to max HP, just a reasonable increase you can probably get away with the factory manifold setup as long as the rest of the exhaust is free flowing
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djape1977
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« Reply #3 on: December 09, 2009, 01:15:30 AM »

there's an cast iron exaust manifold from lancia, don't remember which model, fits 131/132 head with bigger bore. makes the engine bread a lot easyer
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get a bigger hammer!
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« Reply #4 on: December 09, 2009, 02:22:44 AM »

I've got a set of 4-2-1 headers on mine that were blowing in to a 1 & 3/4" system all the way to the back. I replaced it with a 2" system all the way through and the result was phenomenal, it was a bit louder but not too annoying, (I think it sounds great under load between 2 & 4k/rpm). It now holds 4th gear pulling up hills where it previously had to go back to 3rd, low end torque is improved and there was a small improvement in fuel consumption. At around OZ$200 it's the best bang for buck solution I've tried for a while.
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Mick.
Tasmania. Australia.
Red/grey series 2 (Daily driver)
Dark blue series 1 (Dismantled)
Light blue series 2 (Crashed then dismantled)
Metallic blue series 2 (Dismantled)
miro-1980
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« Reply #5 on: December 12, 2009, 05:35:56 PM »

Mick,

Got a picture of the headers ?

Miro
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Fiat Abarth 131 Rally Gr4 1976 (replica)
Fiat 124 Abarth Rally Gr4 1973 (replica)
MF 131
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« Reply #6 on: December 13, 2009, 07:44:50 AM »

Hi I am running the standard Fiat 4-2-1 and  took off the  standard pipes and  put 2inch with 2  mufflers ,Big change in power ,still has the same Fiat cackle but a bit louder. hard to hear inside as the inductiion noise from the twin 40s is loud.Cost me $200 NZ.Son took it for a  drive trhe other day and sound was Great Not to loud but definitely FIAT
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Gary Want.Mid life crisis to restore 131R.Also YamahaXS 650 Not to many 131Rs down under but plenty of rust
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« Reply #7 on: December 13, 2009, 07:42:27 PM »

Hi Gary i think we need some video footage of your orange beaut Cheesy Cheesy Wink Wink
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Tas131
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« Reply #8 on: December 20, 2009, 04:35:47 AM »

Mick,

Got a picture of the headers ?

Miro

As requested! The rusty set came off the blue car I wrote off when I cleaned up a Hyundai excel.


* Headers_fitted.JPG (166.57 KB, 461x346 - viewed 541 times.)

* Headers_rusty.JPG (166.28 KB, 461x346 - viewed 594 times.)
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Mick.
Tasmania. Australia.
Red/grey series 2 (Daily driver)
Dark blue series 1 (Dismantled)
Light blue series 2 (Crashed then dismantled)
Metallic blue series 2 (Dismantled)
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« Reply #9 on: December 22, 2009, 01:12:27 AM »

Tas,

How can I get hold of a 4-2-1like this?

Miro 
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Fiat Abarth 131 Rally Gr4 1976 (replica)
Fiat 124 Abarth Rally Gr4 1973 (replica)
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« Reply #10 on: December 22, 2009, 01:14:42 AM »

there's an cast iron exhaust manifold from Lancia, don't remember which model, fits 131/132 head with bigger bore. makes the engine bread a lot easier

Try finding which Lancia please

Miro

PS: will get you the documents I promised before Xmas.

M  
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Fiat Abarth 131 Rally Gr4 1976 (replica)
Fiat 124 Abarth Rally Gr4 1973 (replica)
Thotos
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« Reply #11 on: December 22, 2009, 01:16:35 AM »

Tas,

How can I get hold of a 4-2-1like this?

Miro 

Looks very similar to a Janspeed and I know where there's a new (or nearly new) one hanging on a wall  Wink Grin Contact Mark at www.ItalianRaceServices.co.uk and see if you can make him an offer he can't refuse.  Wink Cheesy
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Theo Kyriacou
Enfield, UK
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« Reply #12 on: December 22, 2009, 01:36:39 AM »

Hey thanks a lot  Thotos ! Grin Grin

I just did , let us see what his reaction going to be.

Will let you know!

Miro
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Fiat Abarth 131 Rally Gr4 1976 (replica)
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« Reply #13 on: December 22, 2009, 01:44:19 AM »

Mark is not always very quick with emails so don't worry if you don't hear back tomorrow. If I remember I'll give him a call tomorrow and put in a good word for you  Wink Grin
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Theo Kyriacou
Enfield, UK
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« Reply #14 on: December 22, 2009, 01:56:25 AM »

Thanks, I really appreciate your help.


Miro
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Fiat Abarth 131 Rally Gr4 1976 (replica)
Fiat 124 Abarth Rally Gr4 1973 (replica)
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