Fiat 128 B1 (zastava) 1979

[FiatGroup]

Hi to all

My neme its Zeljko (in english translation almost DESIRE ) ;) never end story

My home town its Rijeka (River) - Town ho is Flow :)

This is never end story...
I begen modifay first car(1964) about 1998 before I put him to retirement...
So now its fresh carosserie since 1979...

Its my litle project....
Yes its Fiat 128 B1( hatch back) , manufacture by ZASTAVA ex Yugoslavia - Serbia.

I hope complete engine and finally drive car after two year in the garage..


Engine modifications:

1.6L MPI with throttle body diameter 42mm (follows the angle of the inlet ports - as recommended by GC)
Ported head with 41mm intake 34mm exhaust, 7 mm stem valves from Ford Scorpio 2.0l (valve heads were turned down)
Camshaft and springs: 315‚° CATCAMS
Crankshaft lightened, polished, knife-edged, balanced with lightened fw.
OE standard rods balanced,

Electronic fuel injection is I.A.W. - sequential Alfa N- link: http://www.rplab.co.yu Nikola Radenkovic (my friend)

support for pencolis link: http://www.rplab.co.yu/

[FiatGroup]

question:

I need good exhaust manifold (pipes)

Can some tips, calculation? I have a 'knowledge gap' in this field..

I know a little about how dynamic CR, camshaft, ports and etc affect construction of the system..

system 4-1 or 4-2-1?

[Guy Croft]

OK, my advice is to use a 4-1 with matching 34" primary pipes, bore should be ex valve throat diameter plus 5mm. pipe lenght does not include collector.

Straight through pipe from collector to muffler, 1.75" bore, use the 'bunched' pipe layout below into the collector if you can:
00
00

not flat plane:
0000

Muffler should be a 2" bore oval, 18" x 8" x 4-5", perforated liner 3.1mm holes, glassfibre packed. Play safe, I am not going to advise on 4-2-1, too difficult to get right, just as easy to mess up the engine as make it better than a 4-1, and yes 4-2-1 has shown better torque compared with 4-1 on all the dyno and software results I have from the last 3 years.

GC

[fiatuno]

why not fnot flat plane: 0000

[Guy Croft]

Flat plane only if you have to because of the available space.

I seem to remember being told by my learned contact Dr McMullen at Cork Institute of Technology - who does a terrific amount of test and development (incl quite a lot of competition engines with GC prepped heads), that flat plane isn't as good. I am sorry but at present I don't know the technical reason, I will try to find out more.

GC

[FiatGroup]

Hi,

Is it better to make four-square (bunched) like this:

42
31

or

31
42

or

14
32

I mean about ignition sequence; Is there an effect on flow - turbulence?

I use the formula for calculation:

Length of 4-1 system primary pipes = (850xED)/RPM)-3

(RPM at best torque)

ED=180 + ‚°BTDC exhaust valve


Thanks!

[Guy Croft]

Hi,

I had to edit your post, it is forbidden to copy from books here, copyright, sorry. Please don't do it, authors and publishers do get very upset.

I don't know the best configurations yet, I hope to have more info soon. As far as formulas go, many are quite good but nothing is as good as advanced software analysis or dyno test.

Flat plane by the way is 1234.

GC