Mondial 3.2 ported/big valve/cam/carb/compression - Ferrari Life
 
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post #1 of 7 Old 05-22-2008, 02:43 AM Thread Starter
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Mondial 3.2 ported/big valve/cam/carb/compression

http://media.putfile.com/Mondial-rebuild-1
video of first run before carb synch

After 5 years of running Weber 40 DCNFs very successfully on a Mondial 3.2 with a pretty good power pickup (290 hp, 240 ft-lb at flywheel) and increased reliability, we decided we coould freshen the heads. Well, one thing lead to another on the flow bench...

The car now has 44 DCNF carbs with 38mm venturis, ported head with larger intake valves, higher lift cam, 10.5:1 pistons and tubistyle european s/s headers and a new s/s exhaust system of my own design after pouring through exhaust textbooks and speaking with experts on the subject.

To get a bit more technical, the 44mm Webers will be tuned on the dyno, but the going in jetting which doesn't seem to far off is 145/F24/190 with 52 idles. It was intentionally jetted a bit rich, and we'll back down. Spark is supplied by the system it has had for 4 years, a Mallory electronic distributor triggered by an MSD 6AL. The cam kept near stock durations to keep a strong bottom end and match the math involving the venturi, but increased lift to .360 from a stock of .348. The flow bench shows ann increased flow velocity with and peak flow up over 10%, with flows up at all lifts giving a much greater area under the flow/time curve. the target was much more for a reliable daily car with a strong bottom end rather than for a high end screamer, which is more appropriate for the 3500 pound 2+2 GT.

Other attendant details included a Pierburg fuel pump, ceramic coating the headers, upgrading all of the water hoses to silicone, high torque starter, and freshening the original 85 amp alternator to 100+ Amps.

Amazingly, even with the grossly unsynchronized carbs, it runs with a minimum of spitting, but should smooth out substantially as initial barrel flows were all over from 2 to 10. Although too early to tell, the flow through muffler system sounds as expected with a low smooth quiet tone, and you can still roll a golf ball end to end. While a bit louder than stock, it is quieter and better sounding than a previous tubi muffler.

We'll see how she sorts out and check some dyno numbers later. Hope this is entertaining for some.
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post #2 of 7 Old 09-12-2008, 03:25 AM
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You are my hero!

I have just found a 4 valve engine out of a mondial cab for sell and just missed an opportunity on a set of webbers. I really like what you are doing and I am very impressed. Thanks again for all your detailed responses on my other thread.

Keep up the awesome progression!

Christian, Still searching and dreaming. It will happen as soon as I find the right mechanic. Utah is a strange place to be doing this.

I can't believe how amazing your mondial is. Probably this coolest one on the planet. The engine is beautiful!

Thanks for posting
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post #3 of 7 Old 10-07-2008, 02:53 PM Thread Starter
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On the road!

Well, we're on the road, still tweaking the carb jettings but she runs and pulls much stronger than ever. Before we started tweaking the mixtures, the dyno showed an over rich area where the main circuit comes in which we can jet out. even so, with initial jetting we are getting right at 259hp and 213 ftlbs at the rear wheels on a dyno-jet, up from a stock 214 rear wheel dyno hp for a stock 3.2/328 US spec motor. Using the standard approximate 17% drivetrain loss for these transverse V-8 cars suggests a flywheel hp of 312 SAE hp and 257 ft-lb of torque. We're hoping we can improve on that number to about 270 rwhp, or between 320 - 330 hp at the flywheel.

About 100 hp/liter. Not bad for a very streetable 3.2 liter carbureted car.

It looks like with the 38mm venturis, the smallest idle we can get away with is a 50, which is probably going to take a 150 main and an A/C around 230 using an F24.

Oh, and it pulls like an elephant and sounds magnificent!
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post #4 of 7 Old 10-31-2008, 04:11 PM Thread Starter
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Finally able to take a break from work to do an LM-2 run using the 150 mains and 255 air correctors. My best summary is that looking at 17 minutes of recording, it's not bad and very safe; it still is a wee bit rich in the 4-5.5K still but much better. Cruise averages out to a little over 13 which is great. I think with a 260 a/c it would be a bit better, I am going to try the 145/220 and choose between the two.

BONUS!
And now for the 4 of you who follow this incredibly boring thread, I made a crappy in-car video of part of todays test drive. I never could really "get on it" due to traffic, but you will get the idea. If you listen to a lot of these Ferrari V-8 exhausts (and I've must have heard a hundred different ones), the difference you will notice is that it is a much lower tone, and DOES NOT have that hard mechanical tinniness that most of the Ferrari V-8s have. I tried to get the tach in view so you could get a good feel as we tool down the highway. It's almost as quiet as I hoped for at cruise, and really sings when the throttles open. Not exactly like a 12, but pretty close:

www.youtube.com/watch?v=dknY5U122o4

LOTS of induction sound!! Hear those Webers sing!!!!!
Hope you enjoy!!
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post #5 of 7 Old 11-26-2008, 10:21 PM
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Come back and share more! I'm paying close attention to what you're doing with those Webers.
Ever thought of converting to EFI?
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post #6 of 7 Old 12-06-2008, 02:13 AM Thread Starter
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Well, not to much to tell -- I did decide on the 145/220s for now, and will probably dyno with that and the 150s in my pocket. It runs pretty well, starts instantly every time and seems quite reliable.

New to me at least, with the 145 main jets, was that accellerating from rest, the Michelin PS2 tires would squeel ("catch rubber") a bit in each of the first 3 gears as I accellerated from the torque. I didn't have room for 4th so don't know there. That was pretty different. I think the power is now at a good level that matches the rest of the car, but mainly it is also "how it does it" as well.

To move to EFI would probably gain me a few percent at a fairly high cost, and I am pretty happy now. This is just me, but the Webers are just so much more like mechanical works of art, classically elegant and simpler than wires running everywhere for EFI. I also like as few computers as possible between me and the mechanical components.

I'll readily conceed that there are a few more ponies going to EFI, but for my idea of what a classic Ferrari should be like, it's darn close to a perfect small GT.

The engine is reliable and comfortable in any rpm range; very smooth, steady and pulls quickly up to 8K with a dyno measured 310 - 320 hp. A lot of personality and a happy baritone voice.
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post #7 of 7 Old 01-26-2009, 01:33 PM Thread Starter
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Venturis

As I sit waiting out the winter here in Germany without my car, I have about talked myself into using 36mm venturis, as I think the flexibility and response will improve without a hit on top just based on looking at flow charts and the only dyno I have. Since I use it on the street, the increased response from the sl smaller venturis might be more useful (and fun) than any flow increase around 8000 rpm. It would also allow me to more easily use smaller mains to better control transition and accurateky dial in a leaner accross the board A/F.

So, when I get home I think we will dyno it with what we have, then swap to 36mm venturis and dyno again. if there is no loss, then the carbs are not the flow restriction anyway.
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