Fiat coupe 2.0 16v non turbo

[Honza]

After some time I would like to inform you about new improwement on my coupe. So I have left make brand new exhaust according to my requiremenst - this site, GC book and web site turbo124 was wery helpful when I search for dimension of headers and the rest of exhaust suitable for my engine. Of course owner of the garage gave me some suggestions.

I decide to substitute original 16v headers, because they have realy small pipes (38mm OD primaries, 41mm OD secondaries - with strange flatened shape before tailpipe, 52mm OD tailpipe, but the pipes has quite good lenght- ~60cm & 20cm) and I blamed them (and rest of exhaust system) for problems wich i had with poor idle and low and mid range performance.

For comparsion Lancia Thema VIS has headers with 42mm OD primaries and 52mm OD secondaries - but unfortunately primaries are wery short (~30cm).

So I decide to made enlarged copy of standart headers with 42mm OD primaries and 50mm OD secondaries and 60mm tailpipe and rest of exhaust. One problem occured during manufacturing - 42mm pipes were so large and they wouldn´t fit under the car (engine/gearbox), so i decide to modify standart headers - secondary pipes were enlarged to 50mm OD. Rest of the exhaust was made from 60mm OD pipe with two straigh-through-type silencers. One silencer has stainless steel body and internals and is fitted closer to the engine, inside it is one 60mm OD perforated pipe. Second silencer is constructed for better sound absorbtion - inside it are two ~40 mm perforated pipes wich has larger area than 60mm pipe.

When I collect car from garage (owner is ex-SkodaMotorsport employee) I was wery suprised - Idle is with this exhaust stable and hold 980-1000rpm, problems during ride in the city (lack of torque caused that I should drive at 2 gear)are away -now it isn´t problem to ride a car at 50kph with 3rd/4th gear and engine pulls happily from 2800rpm (with old exhaust it could pull from 3500 and more likely higher..). Of course the sound level is lower in comparsion with previous exhaust...

Now I have booked for instalation of fully programable ECU and mapping session in September - I hope that It will found last horspower from the engine, because actual maps in standart ECU are certainly far away from optimal setting...

[Honza]

Some problems with new ECU (especialy with new 34+2 trigger wheel) occurs, so it will be installed next year.

I also bought new slicks and 16VT wheels - the difference between slicks and road tires is incredible.
1/4 mile time with road tires before instalation of new exhaust was:
~14.9s, 148km/h

1/4 mile time with road tires after instalation of new exhaust was:
~14.9s, 153km/h - increase of trap speed simply indicates increased power ...

1/4 mile time with slicks after instalation of new exhaust was:
14.4s, 154km/h , first 1/4 ride with slicks with no experience with starting at slicks

1km time is 26.3s..wich is the same as 20VT coupe in good condition...

All times vere measured on same track, with same timing and almost same weather...

The last mechanical mod what I did on this engine was 60mm throttle body, wich I made from standart spare one.
(many 4 cyl. engines with ~160 BHP has 60mm throttle - for example PUG MI16, Honda 1.6 VTI, Citroen Xsara 2.0VTS, Clio sport, so I decide, that the 60mm TB will be OK, for good flow and throttle response)
The butterfly was made on CNC laser cut (according to my CAD model) from stainless steel. Throttle body was milled out on CNC maschine - before milling I should weld small amount ofmaterial to the bottom part, where isn´t enough material for milling.

Next I modified the throttle shaft - by reducing the thicknes of the shat by 4 mm I get next ~10% increase of throttle area. Total area increase of the area is equal to ~ 30%. Total cost of this mod is only 20 euro (1 euro CNC laser cut, 10 euro CNC milling, 9euro spare TB -so you can imagine the profit of companies wich do this mod for more than 100$..]

When I fitted it on the car, I noticed, that it will need some fine tuning of fuel/ingnition... The engine miss something, but is still powerful but with poorer throttle response caused by inadeqate (lean) accel. enrichment...

[Honza]

new bits arrived:

- Walbro 255lph fuel pump
- bigger injectors, nice condition, from low mileage Vauxhal Astra 2.0 turbo (315ccm/3bar - with 80% duty cycle they are theoretically capable of 230BHP, instead of standard ones which safe limit is approx. 200bhp )

- new trigger rings (36teeth) - made acording to my CAD drawings on CNC laser cut.

All of these things are necessary for upgrade to new engine management system - Czech made, proved by many autocross/rallycross races with nice price/power ratio (still waiting because of lack of time.

Ive also found crankshaft in good condition with 8 counterweights and cambelt pulley which easily accept 1" cambelt (it came from Bravo 1.9 JTD - where it runs with 173teeth x 22mm belt ) the crank has same dimension of main and rod pins as the 2l engine one. So maybe I"ll try it in some engine in future, but firstly I have to found some information about it´s manufacturing process (forging/casting) and further heat treatment...

[Guy Croft]

Turbo diesel crank with wide nose pulley- very clever!

Interesting to see what you do for a belt. Make sure it's an 'automotive pitch' one of the right toothform..

GC

[Honza]

I checked timing belt catalogs for a long time to assure, that Tipo/Bravo JTD/TD has the same toothform of belt - and after receiving the crank I also tried to put the belt on the pulley.

Only thing wich makes me worry is that I cannot find suitable reinforced cambelt (for example Tipo 2l 16v use 173x18 GT 5279XS belt, where XS means reinforced - accordind to my knowledge, and tipo/bravo-all TD/JTD engines use 173x22 with marking GT 5180).

Fiat Bravo 1.8 16v, HGT or AR TS engines has belt with 168 teeth and it means that it´s about 35~40mm shorter, but it is reinforced (GT 5429XS).

Possible 173x25mm variant came from Citroen C25 1.9TD; MY 7/81-2/94 but it isn´t reinforced (GT 5299 ).

[Guy Croft]

I think XS just (!) means Kevlar weave inside the rubber - but I don't think you need that especially.

My 16v conversion belts aren't XS.

G

[Honza]

OK.. that change my situation and I´m next step nearer to proper 1" cambelt conversion ! :)

[1NRO]

Fiat Ducato belt. As always it snowballs and the cam pulleys need looked at as does the idler bearing.

Nik

[Honza]

new parts arrived today:) I´ve decided to buy complete set of 1" cambelt and other parts from Martin Crabtree instead of developing something already existing...


- steel billet flywheel ~4,2kg
- set of 1" camwheels, pulleys, tensioner, idler bearing etc...
- balance shaft elimination kit (I will use it in my Tipo 2l 8V)


I have to say - nice work !

sorry for the quality of the photos - taken via mobile phone

[Honza]

OMP clutch set arrived.

[Guy Croft]

I trust you will find your proper camera soon!

GC

[WhizzMan]

Are you planning any high compression pistons, flowed heads, fast cams and things like that?
How are the distances in the crank, will it just drop in, or do you need to machine the engine block?

[Honza]

Guy: I will take much better photos ASAP.

Once aganin Thank you for very informative book from wich I ´ve learned how to identify cast/Forged cranks!

- I´ve found, that ALL "new" cranks - JTD, AR TS, Fiat 1.8 16V (very similar to AR TS) are cast iron, not forget ...I have seen terribly cracked crankshaft from AR 156 1.8 TS . I haven´t seen 5 cylinder engines crank yet...

So I´ll keep only wide crank pulley from my "spare" JTD crank....

Whizzman:

Yes, I am plan forged pistons and rods for a long time... Together with engine rebore to 85 or 86 bore..I will try to keep CR around 11,5:1.

I also plan further modifications to my head with utilizations of new springs, I´ll keep the camshafts maybe I will use intake camshaft with larger lift, 10,3mm valve lift is qute small 11-11,5 should be fine.

Maybe this winter the time of "Big Bang" arrive..