I would love to know how these killer large-displacement blower builds would stack up against a twin turbo build. I suppose for the mile-events a twin turbo would still reign supreme (all else being equal)
A properly sized and built turbo system will always produce more power and torque at the higher rpms, where we would run at the mile, over a screw system. Turbos are just more efficient compressors, generating less heat and less parasitic loss.
For example... Chris's GT in it's current configuration with turbos would have probably made somewhere right around 1050-1100 whp on race gas.
I'm a huge fan of turbos, but for a street car with a standard H pattern transmission.. the initial lag coupled with lag on each gear change kills the fun and performance of the GT on the street in my opinion. There are fixes for this boost lag with turbos... a sequential gear set for the stock transmission cases will fix the lag on gear changes keeping the boost up. Anti-lag or nitrous will fix the initial turbo lag, but you will never get rid of the anemic, light throttle tip in when playing in and out of traffic on the highway. The turbo engine is basically a NA motor when the Turbos aren't up.
Another "fix" is the compound system. Turbos blowing into the screw. This picks up the turbo lag but at the cost of less power up top than a straight turbo only system. It is more of a compromise between a turbo or a SC system but it probably fills the void for many.
for my purposes (just having fun on the street and the dragstrip), these latest blower builds seem pretty ideal!
I agree... I personally wouldn't want a turbo GT street car until I was trying to attain more than about 1600-1700whp. This is why we designed and built FUBAR's system with the big screw capable of about 2000hp. Even conventional big screw SC systems will make out to 1500whp on a mod motor. The only real downsides for a Screw vs Turbo at the same whp is more heat... but we already have components that combat that, like our larger 10gal intercooler water tanks that can take ice, intake hot water bypass kits that get the hot water out of the intake manifold, and external intercoolers that handle the increased heat much better... The upsides of the screw is 0 lag with almost instant throttle response and tons of torque with a huge powerband. Very difficult to beat the fun factor and will require a GT with far more power to outrun it because of the torque.
Cheers
