OK, I've asked about the "sluggishness" of my ZHP throttle in another thread. To recap, what I'm referring to is sitting in the car at idle, stabbing the throttle throttle, and the response is slow to non-existant... I stab the throttle, and I can hear air in the throttle body, it sounds and feels like the ECU is tilling the engine to rev, and there's fuel and air, and the RPM's go up some - just not much. The best metaphor I can think of is that the engine is connected to a big, heavy flywheel... It's like mass/inertia is keeping the engine from revving.
In that old thread, pretty much everybody unanimously agreed it was the crappy fly-by-wire throttle map/response, and that a Shark Injector, SprintBooster, or other tune with throttle remapping would correct the issue. I stored it away in my data bank and wrote it off for after I have my wheels and tires redone this spring. Important stuff first, then on to the really fun stuff.
Fast forward to a couple of nights ago. I had to restart my wife's E83 X3 in the garage and shut it down, so I revved it up a little for fun. Wow! Not only is it night and day, but the X3 revs like a frickin' F1 car compared to my ZHP! I mean, the difference is incredible. Now, the X3 is an '07 LCI with the N52B30, so a totally different engine, and no doubt BMW improved the throttle response between '04 and '07. Still, should they be THAT different?
So, I started thinking... The X3 is an automatic, so then I started wondering about flywheels. Because that's what it seems like... Like my ZHP has a 100-pound flywheel and the X3 has like a 50-pound flywheel. I know there's a big difference between stock and performance flywheels, and that one of the main benefits of a light-weight flywheel is throttle response and faster acceleration. I looked it up, and our stock dual-miss flywheel is 25 pounds, while a lightweight aluminum flywheel is only 10 pounds.
So... Then I started wondering... Is there a big difference between flywheels on autos and sticks on our cars? Does anybody have significant seat time in both auto and 6MT ZHP to know if the throttle response is different between the two?
Cheers,
SC