Hi, my understanding is that tb and TS have 300bhp, GTB and GTS 320bhp - is that correct please? Was the Spider always 320bhp or do I have that wrong? Cheers
Mmmm...... I seem to recall reading that when the TB's and TS' had cats fitted the power dropped down to 295bhp and so the gear ratio's were "tweaked" to counteract the drop in power - Fact or fiction?
I believe the 295 number comes from the Mondial 3.4T The 348 is always shown with 3 horsepower values: 300 for older models, 312 for US spiders and 320 for later Euro cars. What is unclear are these issues: 1. Is there a difference between early US and Euro cars? Non cat cars should be higher due to less exhaust restriction and they have slightly greater ignition advance. 2. There are other models such as the Series Speciale and Challenge cars that have single can exhaust and different chips. Some challenge cars have no cats. What are the different horsepower values for these? 3. The Euro Competizione GT had a slightly modified engine with more intake capacity and higher compression. What was it's output? The theory has always been that the non-cat single can exhaust cars had 320 HP and the catted versions were at 312HP. Personally I believe that the 320 number is only applicable to the Competizione without cats. This is why we dyno the cars. You cannot take any of this at face value. The factory has never been completely above board and open with these values. All I know is that my SS with all the work done to it, on factory chips and with custom exhaust shows a gross power equivalent of about 330HP.
There was not power difference on same year US mondials vs. TB/TS. The issue is the mondial carrying much more weight in a bigger chassis and 4 every growing American supersized people.
Do the cats not strangle the engine slightly by adding an additional restriction into the exhaust system?
Yes they do. I did comparison dyno pulls. One with the stock headers, cats, and single can muffler, then another with full custom exhaust. The stock pull was 293hp vs custom 305hp all power measured at the hubs. (both stock and custom numbers include ported throttle bodies and ported intake runners, on '93 Spider ECU mapping) Here is a link to the dyno sheets. http://www.ferrarichat.com/forum/143045830-post65.html
That looks to be a very useful increase in torque exactly where you want it in the mid-range. Years ago I owned an E30 BMW 325i Sport that had the cats delete option from the factory. One of BMW's service drivers delivered the car back to Me after having some work done and he said straight away: "That's a cat delete car isn't it? - I can tell because the throttle response is sharper than a car with cats on it. Cats are all well and good but they do tend to sap a bit of power!" When I bought My 348 TS I was happy to discover that it had no cats fitted.
