Hello, I've recently scored a Fiat Coupé

Road-race engines and ancillaries - general discussion
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bassman71
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Hello, I've recently scored a Fiat Coupé

Post by bassman71 » Fri Apr 05, 2013 7:35 pm

Hi all,

as stated in the subject, I'm starting the restoration of a '95 Coupé equipped with the atmospheric 2.0 16V. The engine I swapped in (the original had serious problems to the crankshaft) is not bad, apparently no issues or suspect noises, therefore I was thinking to optimize the unit or - if you prefer - perform a so-called "soft tuning". I've been told by other owners a stock Coupé can be improved under several aspects:

- fuel pump
- fuel pression regulator
- airbox and filter
- ignition system
- exhaust
- remapped ECU

Some of the above mentioned tuning is clear enough to me and relatively easy to perform, therefore I'd like to concentrate my curiosity on the last points, starting from the exhaust.
It seems the exhaust manifold is made by pipes which are narrower than the ducts in the head and I suppose this fact endangers the outcome of the exhaust stroke in the cylinders. Infact, what I can see, googling around, is several manufacturers produce improved manifolds for the turbo-compound version of the same engine. Anyway, I cannot find the same improved manifolds for the atmospheric one, but only the middle and terminal silencers. Therefore I'd like to ask you if I am wrong in my remarks about the exhaust stroke.

Don't you think it is worth, for the atmospheric engine also, to start an efficient exhaust system by the manifold, even if keeping the same 4 in 2 in 1 layout in case?

Is it possible nobody ever thought to produce ready-to-install improved manifolds for the aspirated Lampredi?

The circumstance seems strange to me when I think improved exhaust manifolds are available for the Fiat 1.8 (Coupe, barchetta, etc.).

Thanks for your attention.
Regards
Concetto

Rich Ellingham
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Re: Hello, I've recently scored a Fiat Coupé

Post by Rich Ellingham » Tue Apr 09, 2013 12:22 am

Hi, and welcome.

I have a modified Tipo 16v built by Guy, so I can offer some insight.

Playing with the following items
- fuel pump
- fuel pression regulator
- airbox and filter
- ignition system
Is unnecessary if the engine is standard, the fuel pressure is matched to the calibration in the ECU, and you would only really change it if you significantly improved the breathing of the engine requiring more fuel to be injected then the injectors could supply at their base pressure. The air box and filter as standard take cold air and will flow well for greater power levels then standard. Single coil electronic ignition is capable for standard engine RPM.

- exhaust
- remapped ECU

Changes to the exhaust header in the standard car will move the peak torque and power figures around the rpm range, and in the standard engine this may not produce any benefit at all. The reason the aftermarket does not cater for this engine is due to numbers and the fact the original exhaust system was constructed by the 'super sprint' company. I do not believe the exhaust manifold primary pipes to the head are smaller than the exhaust ports.

To tune this engine you will need to change its cylinder filling either by inlet port work or by different cam shafts, together with a new ECU calibration these can yield notable gains. As for tuning the ECU alone without engine modifications this will provide modest changes which are probably not noticeable when driving.

The time to change the exhaust manifold would be in combination with cams and head work - but this becomes a very expensive venture and one where experience would count significantly towards the final design.
book 38

bassman71
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Joined: Fri Apr 05, 2013 12:11 pm
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Re: Hello, I've recently scored a Fiat Coupé

Post by bassman71 » Tue Apr 09, 2013 10:56 pm

Rich Ellingham wrote: I do not believe the exhaust manifold primary pipes to the head are smaller than the exhaust ports.
That is what a guy found while personally tuning his engine. It seems the ducts in the manifolds are not well jointed to the ducts in the head.
To tune this engine you will need to change its cylinder filling either by inlet port work or by different cam shafts, together with a new ECU calibration these can yield notable gains.
That is an option I was evaluating to tell the truth. Do you know the cam shafts made by Colombo & Bariani? They offer two different profiles for Tipo/Coupé: road medium and race medium. Here the data: http://www.cb-cams.com/catalogo_auto.ph ... 5&lang=eng
The time to change the exhaust manifold would be in combination with cams and head work - but this becomes a very expensive venture and one where experience would count significantly towards the final design.
Thanks for your suggestions!
Regards
Concetto

Rich Ellingham
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Location: Glasgow, UK
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Re: Hello, I've recently scored a Fiat Coupé

Post by Rich Ellingham » Fri Apr 12, 2013 4:14 pm

Hi, yes I have C and B race cams in my 16v (race medium), in my previous engine without throttle bodies I had a single C and B cam on the inlet (road medium), it made excellent torque.

For you I would budget aprrox €4000, have head work done correctly (many people say they can do it and ruin cylinder heads), re-profiled valves and seats - again needs to be done correctly and leak tested. C&B road medium + Guy Croft Pulleys, programmable ECU, new piston rings (you will probably need forged pistons as I am not sure you can by original oversize Fiat pistons any more), re-bore of block & Flexhone finishing; even with standard exhaust and inlet this will produce 180BHP.

Regards

Rich

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bassman71
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Re: Hello, I've recently scored a Fiat Coupé

Post by bassman71 » Fri Apr 12, 2013 8:42 pm

Rich Ellingham wrote:Hi, yes I have C and B race cams in my 16v (race medium), in my previous engine without throttle bodies I had a single C and B cam on the inlet (road medium), it made excellent torque.
Here is an interesting (for me) aspect of the tuning. I'm impressed but it is not my intention to have more power more than the stock engine. I'm interested more in a prompt engine with excellent torque. Do you think that C&B (road medium both inlet and exhaust) and some tuning to the ECU could give a significant improvement too? Thanks.


(edited - correctly I hope - by GC. Merely some differences of language...)
Regards
Concetto

Uros Piperski
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Re: Hello, I've recently scored a Fiat Coupé

Post by Uros Piperski » Mon Apr 15, 2013 11:48 am

If memory serves me well, NickRP told me the stock Tipo 16v ECU has less than ideal ignition maps (exhaust emission, I guess) and with a light remap he achieved noticeable gain. Maybe this is the case with the Coupe, too. Try contacting him about this remap if you don't want much more power.

Uros

bassman71
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Re: Hello, I've recently scored a Fiat Coupé

Post by bassman71 » Mon Apr 15, 2013 6:00 pm

Done. Thanks for your suggestion.
Regards
Concetto

Honza
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Re: Hello, I've recently scored a Fiat Coupé

Post by Honza » Fri Apr 19, 2013 4:07 pm

what is worth and what is not on stock 2l 16V

- modify the throtle body.
Stock has in the upper side restriction-which restrict the area to almost 50% of full 56mm bore... by removing this you will get better throttle response and bigger area - you can see some info in my Fiat coupe NA project and Fiat tipo 8v on this page...

- headers are good, but...

Primaries are dimensionally OK - the area of the tube exactly correspond to area of the valve seats
Secondaries are too small, and I found them very restrctive...(primaries are 38mm OD, secondaries only 42mm... the optimal size is 50mm OD). SO enlarge the secondaries up to 50mm OD, and you can lenghten them up to 30cm.. it WILL transform the car to the different dimension!

Rest of the exhaust - you can keep the standart diameter, but I would prefer after my personal test enlarging to 54(almost stock)-60mm (heavily modified engine) piping , 2 straighttrought silencers and No cat (depens on the way of use of car/regulations..)

- remove the balance shaft timing belt - you will get more reliability, because snapped balance shaft timing belt occurs very often and it ends in camshaft timing belt, which result in several bent valves...smal bonus is that you will not turn with two almost 6kg heavy shafts in the block..which result in better throttle response...

- Remap from reputable company.. I will send you PM...

EDIT: I also forgot for my favourite mod -drilled airbox... find bottom part of the 16VT airbox and make to it e.g. 6 holes with diameter ~32mm... this will reduce pressure dop before air filter and improve engine breathing.


this is basic list of very cost effective and simpliest mods which are worthy... easily can produce over 160BHP...if its in excelent condition

I can prove, that after only airbox and exhaust mod (however not on the exhaust manifold), I pushed 1/4 times under 16s (15,74s was record)-and its territory of standart 16VT coupe..
with serial car without any other modification...

with mods mentioned above you can be even faster....-low 15s is very realistic...
#100

bassman71
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Joined: Fri Apr 05, 2013 12:11 pm
Location: Italy

Re: Hello, I've recently scored a Fiat Coupé

Post by bassman71 » Sat Apr 20, 2013 1:12 pm

Honza wrote:what is worth and what is not on stock 2l 16V

- modify the throtle body.
Stock has in the upper side restriction-which restrict the area to almost 50% of full 56mm bore... by removing this you will get better throttle response and bigger area - you can see some info in my Fiat coupe NA project and Fiat tipo 8v on this page...
Ok, clear...
- headers are good, but...

Primaries are dimensionally OK - the area of the tube exactly correspond to area of the valve seats
Secondaries are too small, and I found them very restrctive...(primaries are 38mm OD, secondaries only 42mm... the optimal size is 50mm OD). SO enlarge the secondaries up to 50mm OD, and you can lenghten them up to 30cm.. it WILL transform the car to the different dimension!

Rest of the exhaust - you can keep the standart diameter, but I would prefer after my personal test enlarging to 54(almost stock)-60mm (heavily modified engine) piping , 2 straighttrought silencers and No cat (depens on the way of use of car/regulations..)
Let's see if I've understood: the manifold should be made letting the stock 4 primaries (38mm.), while the secondaries (where the 4 primaries turn into 2 pipes, correct?) should be 50mm (inner diameter?) and 30cm. longer than the stock ones. The rest of the exhaust (where the secondaries turn into a single pipe) should be 54mm.. Cat should be removed letting a 54mm. pipe run to the central silencer and from there to the terminal silencer. Correct?
- remove the balance shaft timing belt - you will get more reliability, because snapped balance shaft timing belt occurs very often and it ends in camshaft timing belt, which result in several bent valves...smal bonus is that you will not turn with two almost 6kg heavy shafts in the block..which result in better throttle response...
Clear...
- Remap from reputable company... I will send you PM...
Suggestions are well accepted. PM me...
EDIT: I also forgot for my favourite mod -drilled airbox... find bottom part of the 16VT airbox and make to it e.g. 6 holes with diameter ~32mm... this will reduce pressure dop before air filter and improve engine breathing.
uhmmm...is the 16VT airbox bottom compatible with the one in the atmospheric 16V? In other words, do I have to assemble the top of the 16V airbox with the bottom of the 16VT one once I've drilled six 32mm. holes? And where do I have to drill the holes? Bottom, sides? Any particular scheme for the holes (3 per side, etc.)? Do you have some picture to better understand? Thanks.
Regards
Concetto

Honza
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Re: Hello, I've recently scored a Fiat Coupé

Post by Honza » Sat Apr 20, 2013 5:06 pm

as for manifold - you let the primaries, and replace the secondaries with 50m OD diameter pipes 30cm long..I don´t have any nice photo of my modification

remap -I sent you PM yesterday...I don´t know wheter you receive it, but its very cost effective and reliable solution
in comparison to other offers in the market..


the airbox... usually the bottom part of 16v or 16VT are interchangeable, but I modified mine airbox from original 16v NA as visible on photos...

I also added cold air feed directly from the front fender, because I removed pre-heating of the throtlle body and found that the intake manifold was still quite hot..after coul air feed theintake manifold gets hot only in long standing in traffic jam... but once you again run, its getting colder...
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Last edited by Honza on Sun Apr 21, 2013 6:29 am, edited 1 time in total.
#100

bassman71
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Re: Hello, I've recently scored a Fiat Coupé

Post by bassman71 » Sat Apr 20, 2013 5:34 pm

Honza wrote:as for manifold - you let the primaries, and replace the secondaries with 50m OD diameter pipes 30cm long..I don´t have any nice photo of my modification
Ok, clear now.
remap -I sent you PM yesterday...I don´t know wheter you receive it, but its very cost effective and reliable solution
in comparison to other offers in the market...
No, sorry. I can't see any message from you in my inbox. Try again, thanks.

As for the airbox, I can see in the pics of your Coupé an airbox with a trumpet shaped inlet. It seems the T20 airbox...
Regards
Concetto

Honza
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Re: Hello, I've recently scored a Fiat Coupé

Post by Honza » Sun Apr 21, 2013 6:32 am

PM already sent...

airbox is realy original 16V NA... but I used "Bassreflex" from hifi to create front intake with trumpet shape..
#100

bassman71
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Joined: Fri Apr 05, 2013 12:11 pm
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Re: Hello, I've recently scored a Fiat Coupé

Post by bassman71 » Sun Apr 21, 2013 7:43 am

Honza wrote:PM already sent...

airbox is realy original 16V NA... but I used "Bassreflex" from hifi to create front intake with trumpet shape..
Oh ok. I've asked because several people use to replace the stock airbox with the one from the 20v. Differently you've built the Venturi port taking advantage of the port from a bass reflex loudspeaker. But why using a pipe from the bumper to the airbox then? I guess you are not taking advantage of the Venturi effect this way...
Regards
Concetto

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