Accessory Pulleys/Ignition Campaign

I was thinking about some tuner tips for the 348 and wondered about changing out the accessory pullies to smaller diameter versions. Has anyone done this or thought about it? It might makes us some HP by reducing parasitic drag. This is "found' HP without taxing the engine output more. I am not exactly sure which pullies this affects, but you really only get a single shot at it because I would not want to drop the engine more than once. Unless we can get to the pullies in the car. Minis get about 5% power gain from this mod. Hey that's like 15+ HP for us!

Also, tuners fit a hotter ignition system for some extra power. Can we do this? This generally means hotter coils, better spark plug set and maybe plugs? Are there upgrades to be done or did Ferrari already tap this vein?

My logic is this. If my car measures 245 RW HP stock (on my dyno - remember everything is relative) and the rating is 312 from the factory, that is 67 HP of parasitic drag - over 20%. If we can reduce the "overhead" we can make the drive train more efficient. I would think that a rear engined RWD car should be a lot better than what my measurements are showing. Heck, my Corvette lost less.

 

Yeah but I don't think you wanna go with smaller pulleys. From what I have read on the pulley swaps is that they go with an under drive pulley = larger diameter pulley, so that the a/c, alternator, and water pumps turn slower. If I'm not mistaken the pulleys are also made from 6061 aluminum so that they weigh less.

 

I seem to recall that the main benefit is if you can spin the water pump slower (which would be a major hassle with a 348 unless you removed the impeller and used an electric pump instead), and the alternator mainly produces drag as a result of its' charging and that's a constant, and the ac cuts off at full throttle anyway. I'm sure the hairdressers could get a benefit from spinning the power steering pump slower. All negativity aside tho, I'd love to see it done on the alt and ac, and see what result it gets.

 

Not a bad idea vince...... !

I think vince means a smaller crank pulley which would do what you said.... make the rest of them larger and hence slower ....

 

I was thinking of this too...on my STi I went with all VERY lightweight pulleys but kept same diameter. I'm not a big fan of underdriven pulleys, especially on the 355. I want all the amps and cooling capacity that's available...

 

I think you want to look at the back end. Smaller, lighter flywheel!

Water pump is internal and on the timing belt. Just unhook the a/c belt like the challenge cars did.

 

Here in Arizona, A/C is really important, even early in the mornings in summer (you can go 4-6 weeks without ever getting below 80degF!!). So I'd be concerned with slower compressor speed, but I suppose you could also put a smaller pulley on the compressor. Would be interested to see someone try this!