3.2 carb, porting & compression update

[snj5]

Quick update on the Mondial 3.2's progress. This certainly will not be as spectacular as supercharging or V-12 into a 308, but it's a nice little engine targeted not at a max hp number, but at street use in the 3500# Mondial - so, we are focused on reliability, response and wide band power that requires no special servicing. To update and recap:

Head porting: Big news - the heads are done, and going back to Norwoods this week. These have been flow benched and ported using much larger intake valves with a combination multi-angle and radius seat. Peak flow is up about 15 - 17% with an increase in velocity measured on the entire induction system I am told.

Weber carbs have been uprated to 44 DCNF from 40 DCNF and port matched to the induction. Will have a choice of 36 or 38mm venturis. My current idea for initial jetting is 140/F24/170/55 on the 36mm venturis (smaller venturis are easier to jet for in initial stages - will work up to 38mm). We have two sizes of air horn available - the stock and a chromed custom set that are about .5" taller. The stock Ferrari airbox and side scoop have been opened up to accomodate the largest K&N cone filter available (see old threads).

Cams - turned out to be an interesting deal after the head was looked at by WEBcam. I chose a less aggressive grind focusing on max lift that would allow the use of the stock drive train and not promote premature valvetrain component wear. Shim-under was looked at, but not really where I wanted to go on this from a servicing standpoint. On WEBcams recommendation, for use with the stock buckets and keeping the maximum torque, the exisiting Speis racing cam profile was chosen increasing total lift @.360 with a rapid ramp, but only increasing duration slightly to keep lower end response. The "area under the curve" on the airflow graph is more than proportionately enlarged with respect to peak flow with large lower opening flows comparatively. She estimates a very wide power band from a bit above 3K to 7.5K rpm, and also well tolerated by the stock valve train components. Not a screamer, but as much torque that is possible.

New JE pistons are installed raising the static compression from the stock 9.2:1 to 10.5:1 - I am told this will make a very noticible difference. I have an adjustible ignition on mine with MSD, and will be interesting to see if we need to pull the advance back (34@3500) at all with the new compression.

Exhaust - The Tubi Euro stainless headers are being ceramic coated inside and out and will go to a dual/dual/dual exhaust system: each side will be separate and not communicate, the header collector will split into dual full length pipes on each side, and each side will have two small harmonically resonant absorptive s/s mufflers exiting through separate stainless resonated tips. The entire system will be ceramic coated.

Details: We'll be going to a Gustafson high torque starter, and am looking at upgrading to a 3 wire stronger alternator per the Consjero system.

Hope this will be together the end of the month. Extensive A/F and carb jetting tuning with dyno time in November I hope.