I am considering modifying or replacing the exhaust system upon my beloved. Has anybody fitted a "Tubi" (or similar) to a carb model 308 ? Has anybody opened up an "Ansa" exhaust system and carried out internal 'surgery' ?.....If so, were carburation adjustments required ? many thanks in anticipation.....david
My '78 is a US spec car that came with a thermal reactor muffler. When it was changed to an ANSA sport exhaust I am pretty sure the carburetors were rejetted to compensate for the reduced back pressure. It still runs a bit lean and I get some popping and light backfiring during deacceleration. More than likely you will have to do the same if you go with a Tubi or ANSA
The jetting specs for Euro/US and various MY 308s have been posted before on this site and this should get you close. Search the archives. FYI, my 77 was run with an Ansa and a Tubi without cats using 135/55/F36/220 jets (stock) with no problems. Without looking back at the data, I'd guess a 78 with a comparable exhaust would be similar, maybe one step smaller mains (130) to compensate for the lower lift/shorter duration cams. Philip
Yup, went from the 800lb thermoreactors to the ANSA exhaust and had to increase the mains one size up. You won't regret the decision, best choice you'll ever make. I have a slightly used ANSA exhaust for a 308 I am selling cheap.
Ansa , K&N , 135 mains, 55 idle, 200 air . no cats , no air pump. freshly redone carbs and all new top end gaskets. MY FERRARI SCREAMS NOW! stock jetting for a 78 is 125 mains, 55 idle. i have a set of # 60 jets i may put in later.oh yea and the BACKFIRE AT SHUTOFF IS GONE!
78/79 North American 308's had completely different jetting....I don't have all the numbers handy, but I do remember that the main jets were only 125's. I think the AC's were 200.....
The stock exhaust on the 78/79 cars included twin cats (one for each bank). The thermo reactors where particular to the earlier cars.
ok im confused now. i thought ansa was the OEM supplier to ferrari for the past 40 years. i must be missing something. dont they come stock on all ferrari's?
Yeah what a deal, sell the car manufacturer the lesser (but smog legal!!) model and then market the better model to the owners. Gotta love it, Capitalism at it's best. Dave I think your'e right about the thermal reactor's. From what I've read they stopped using them in '76 or '77. Mine looks to be bone stock though I'm not sure how to tell if the cats are actually cats or test pipes?? Anyone have any hints without actually taking them apart? Replacing the exhaust is, by the way, on my "to do to the Ferrari" list. If I ever get it back on the road that is!! Edit: There was also a thread a while back about a Magnaflow? exhaust swap. Supposedly sounded great and was dirt cheap! May be an alternative!?
