Join Date: Aug 2017
Location: North Georgia, USA
Racer-X is offline
Re: Current performance options
Underdrive pulley is a good way to recoup a bit of power.
The efan conversion doesn't give as much as most people think. If the fan clutch (standard duty on the tutus) is working properly, the fan is only turning 60%-70% of shaft speed when "fully engaged" and around 25% or less of shaft speed when disengaged. If you're moving over 30 mph, the fan is basically freewheeling and not using any hp at all. The only time it's going to be an issue is after sitting at a traffic light, heat soaking in hot weather. Then, for the first 5 to 10 seconds, it'll be pulling a few hp, and after you start moving, it disengages. BTW, with an underdrive pulley, the hp "used" by the fan is even less because of the underdrive.
I don't remember the size of the stock throttle body on the tutus. Some minor scratching on an index card here shows that for a 2.2L (135 cubic inch) engine, with a red line of 6500 RPMs, you'd need a 1.75" (45mm) throttle body. Up to a 50mm/2" would probably not really hurt drivability, but won't gain much performance either. Above that, unless you're going to spin the thing way over 6,500 RPMs, you don't need any more, and tip in issues will make a larger throttle body much less "street friendly" and "drivable" in day to day traffic. A 2 inch/50mm throttle body should flow enough for 8,000 RPMs on a tutu (achievable, but parts selection gets tricky), and a 65mm throttle body will flow up to 12,000 RPMs on a tutu (probably entirely theoretical), maybe even higher than that. That big might be useful in a boosted situation, but on any normally aspirated engine, I'd avoid that.
Every machine is a smoke machine if you operate it wrong enough.