Whats the driveability difference between a big inch 420+ and a SC or turbo car? Any preferences? I am till trying to decide on a new motor for next year and the thought of a 42x nitrous recently motor came across my desk. If I could build a 42x inch motor that made 600-625 at the wheels I would probably be in. The idea of forced induction is really my first choice.
Sam

 

TT's is the answer for driveability and *big* hp. Big CI just doesn't have the cool factor. JMHO.

Mark

 

I don't think that there's a right answer--just different ones for different people. My specific choice was to use an ATI unit. Drives like stock, sounds louder though but is smooth and definitely has the power.

 

There is nothing like driving big cubic inches on the street. These motors live at the rpm you drive, stop light to stop light. The horse power of both is very close and a blower car has a great sounding whine, so I guess you need a big cubic inch vette with a blower.

 

If you want a 427cid NA motor is superb stock-like drivability (meaning a cam that would give the motor 19" Hg or higher vacuum at 850 rpm idle). I think LPE's mildest 427cid (see C&D's latest 427 Caddy CTS) that approximately fits this bill makes 510 ***flywheel*** hp. Of course there are 427s that make more than that at the rear wheels, but I'm betting idle vacuum would be less to far less than 15" Hg even with an elevated idle speed.

An intercooled Magnuson with a 3.3/3.4" upper pulley on an otherwise bone stock LSx motor (granny-friendly 20-22+ Hg idle vacuum), you're looking at 450 rwhp on a manual or 520+ flywheel hp, which is just enough advantage to make up for the blower pkg's add'l weight. Even with a very mild GT2-3 cam, drivability will be virtually stock-like and probably 18+" Hg at idle. We're talking also probably 540+ flywheel horsepower on an IC Mag with GT2-3. Torque and throttle response below 2500 rpms is truly 427NA-like with an IC'd Mag. Torque from 2500 to 4500 rpms is similar to a mild 427 or moderately aggressive 38xcid NA. And top-end power is like a mild 427 or highly aggressive 346cid H&C NA.

So your topic is focused on drivability, and the answer is once drivability/refinement enters the picture and if it is a very stringent criteria, F.I. is heads and shoulders above NA ***FOR equivalent power vs. refinement.***

Going turbos vs. positive displacement blower is a bit of give and take. Take away a bit of throttle response when going from SC to turbos. but the large C5 displacement makes turbo spool-up still very fast, although not eyeblink fast like a Mag. You gain some with quietness for given muffler arrangement when going turbos because the turbines attentuate/harness acoustic pressure energy. Finally, once turbos are spooled, it's way ahead of 427 NA or positive displacement blowers in torque; just put the gear in 4th (if you have a manual) and squeeze 1/2 way into the gas from 35 mph and feel that magnetic silent surge forward to 100+ mph that is the most distinguishing characteristic of well-designed turbos.

 

I wanna hear more about this... anyone else?

 

ttt...