Rolling Road Experience with Fulvia 1.3 S2

[drdafeller]

Good summer's day!

I recently added a 123 distributor and an Omicron grp. 4 exhaust to my 1.3 and found them both to be very good additions, so much so that I was interested to see how strong the engine actually is in measurable terms. After a little research I took the car over to Revivals garage in Thriplow, near Royston. They have quite a large shop and the owner has extensive experience tuning classic cars, mostly British. I wasn't so concerned about that as it was just supposed to be a couple of power runs, but in the initial testing (which they do to all cars to see if they are fit enough to make a full power run on the rollers) my car showed itself to be running quite lean.

After quite some fettling that day and this week, using gas analysis to tweak the f/a ratio to a tee, changing both the main jets (richer) and modifying the air control jets to balance the mixture. We now have a very good running 1.3 with strong power curves that run smoothly and steadily with peak hp of 91 flat bewteen 6000 rpm and redline (peak at 6575), and torque at 80 lbs/ft. There is probably more to be had as the intake tract is not a gleaming smooth path for air, but on the drive home it was an almost syrupy power delivery and easily moving with and past most traffic. It's just very, very driveable. And the sound is wonderful. I attach the dyno readout here.

I want to put in a good word for Revivals. Richard, the owner, is a proper old school mechanic with modern tools and knowledge. His concern about doing the job well, and not just fast and cheap or long and profitable, was inspiring and I will definitely be going back to them for dyno runs in the future. I think they're incredibly reasonable on price and I would highly recommend them to any club members interested in those sorts of services. As a byline, I should say that they are about to construct a Fulvia for another customer interested in rally work, so they are eager to help the Lancia community.

I think businesses like this should be rewarded and they will be getting my custom regularly.

[drdafeller]

Okay, I didn't post the curves.

[drdafeller]

And for the sake of comparison, the 'factory' curves from 1970.

[DavidLaver]

My rolling road experience was with an MG Midget that had had various tweaks by various owners.  It almost felt as if I took in a 4cyl and drove home a 6.

[drdafeller]

Actually the more interesting comparison is not with the factory curve but reading the 6 August curve against the first time we had it on the rollers, on 22 July. I attach that curve, but you can see on that one the very eratic Air-Fuel Ratio, but how the engine basically leans out at 5,000 rpm and power falls off from then on.  Peak power was only circa 79hp at 5955 rpm, and torque was 75 lbs./ft at 4800 rpm

After the tuning session on 6 August, we saw nothing but climb in the power figures to redline, with smoother curves and gains of 12 hp and about 4 lbs/ft of torque. The biggest gains come in from 4500 to 6500, so I am forced to explore these higher rev ranges to evaluate the end product. Poor me.  

[Charles Frodsham]

Very interesting and thanks for sharing.

Is the 123 module a programmable one, and if so, was the timing optimised throughout the rev range?

What carburettors/inlet manifold are you running?

[drdafeller]

The 123 is the basic model with micro-switched advance curves. We're using the no. 2 curve, which starts at 1000 rpm and reaches maximum advance of 15 degrees at 3200 rpm. We may tinker with the other curves, but it is a bit of a pain to open the switch with the dizzy in place.

The car has the stock manifold with a pair of Solex 35mm PHH.

[AusFulvia]

This is a very interesting thread. I did the same in April but went to Regency Autos here in Cambridge as I was given a recommendation that they had experience on some exotic italian stuff. They tuned out the flat spot at 3000 RPM. I attach my Graph as well for comparison.

Mine is a S1 Rallye 1.3S. Stock manifold but custom stainless exhaust. Standard engine but less than 5000 miles on a full rebuild.


Max power was 87.9 BHP at 5050RPM and 132.2 NM of torque which is 97.5Ft Lbs I think.


Mine seems to have less power at Lower Revs but more Torque? Does this make any sense?

BTW I think you are the guy I parked next to at Homebase Newmarket a few months ago?

[dhla40]

I agree, very interesting thread. I wonder if you could clarify a couple of figures on the first graph, it states main jets 144 this seems quite a jump from standard 120, also the air correctors, is 166 the size marked on the jets or physical measurement by gauge. Are you running airbox or open trumpets?

Sean

[drdafeller]

Yes, AusFulvia, we did meet in Newmarket! I've looked for you around the roads through the various horse farms on nice afternoons; we should get out more.

As to the jet issue, the stock main jets are 120, but when we pulled them out they had been drilled. We measured them at around 135 and as they were running very lean at over 5K, we drilled them out to the indicated 144. When the mixture was still somewhat lean at the upper end, we actually reduced the flow through the air correction jet until we had gas readings that showed we had the mixture right. This ended up being in line with the best power reading. I have read purported factory jet settings for the 1,.3 in various states of tune and 144 does seem large (same as used on the 1.3 HF Corso which made 114hp with cams, etc. 

There is more to be gained. I still have no idea if the valves or cams are stock, for example. I suspect that the Omicron grp. 4 exhaust moves air through the engine better, but on the intake side there is some obstruction. The trumpets on the engine are too large for the Solex 35s, for example, making a big step in the air way. I also think that matching the trumpet lengths to get consistent intake tract lengths for each cylinder would make a difference. When we first started tuning, the number four cylinder seemed to really not adding much to the party. I'm talking to a 3d printing company about making Solex 35-specific trumpets. I'll let you know what I find out.

But I'm replacing the engine this Fall and doubt that I'm going to spend much time getting more out of the 1.3 right now.

[AusFulvia]

I have been looking at your graph and my graph and have a couple of questions. We both have 808.303 engines. My redline is 6000RPM you have yours revving out to 7000rpm. This does not seem right.

My torque is very high compared to yours. My engine was built by an ex Fulvia racer in Australia and he did some things to the head. To me it was standard. So compared you yours I am down about 4hp from spec but up 16 ft ld of torque.  I wonder if he built it sacrificing HPnfor lbs ft?

Be interesting to get both cars on the same rolling road on the same day and temp.

Again a very interesting thread

[angelorange]

Alternative Dizzy:  http://www.lukafoto.com/racing/page17/page17.html

[Lightweight_911]

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I've look at that site before but the pages were all uploaded ~ 10 years ago with no 'recent' content added ...


.

[GG]

I have been looking at your graph and my graph and have a couple of questions. We both have 808.303 engines. My redline is 6000RPM you have yours revving out to 7000rpm. This does not seem right.

My torque is very high compared to yours. My engine was built by an ex Fulvia racer in Australia and he did some things to the head. To me it was standard. So compared you yours I am down about 4hp from spec but up 16 ft ld of torque.  I wonder if he built it sacrificing HPnfor lbs ft?

Be interesting to get both cars on the same rolling road on the same day and temp.

Again a very interesting thread

To answer your question, yes. There is a relationship between the torque curves nd where it peaks, and the horsepower curve. I remember fiddling with an Aurelia motor, and comparing stock curves to our higher-performance ones, and John Cundy took the curves and outlined how the max torque area had been shifted in the higher HP version. I don't recall the details, but the goal was always to increase both HP and torque, but keep as much of the torque down low if possible. Going for max HP necessitates a lessening of the lower (and Lancia-flat) torque curve. Pick what you want, can't have both... use of the dyne can sort out flat spots and tuning, and get the car dialed in right for max efficiency, regardless of which profile one chooses.