Turbocharged, Supercharged or N/A?

[John Milmont]

B-I-N-G-O ! ! ! !

Also - if Turbochargers were more efficient than superchargers, John Force would have them on his Top-Fuel Funny Car...

There are alot of turbos on drag cars and I remember back in the 80's and early 90s when they experimented with them on Top Fuel cars.. They worked well but at the end of the day it was the Wheezer that won..

Jim - At one point I was thinking of combining something along the line of a CVT with a supercharger to actually vary the percentage of overdrive depending on the signal from the ECU.. Are you guys playing with that yet?

??? turbos are more efficient then supercharges... The reason why they are not used in top-fuel is because turbos of that size need to spool up some how, and, they have a potential to create some pretty serious drama. Where a belt driven supercharger simply does not. I think it takes something like 2000hp just to DRIVE the supercharger on those cars as well... I think superchargers are more stable when the driver peddles the gas, too; since turbos don't produce a linear power ban by nature, i can only think of the manifold pressures with someone jumping on and off the gas with 6000hp on tap.
Have you ever seen those truck pulls where they have a semi-tractor pulling a weight transfer sled? Those things may have 6 HUGE turbos and they have to sit at the line and spool them up... sounds like an F-16 before take-off.

 

[Bobski]

One way to look at it is back in 1987 when the F1 cars were using turbos, they were producing 1500hp out of 90cid motors. Thats over 15 hp per cubic inch.
Now days a top fuel drag car produces between 6000 and 7000 hp out of 600+cid supercahrged nitro fed motor. Thats about 10 to 11 hp per cubic inch with 20 years more technology.
By the way, turbos use thermal energy to spool up which is otherwise wasted out of the exhoust, and they do produce some backpressure, but so do mufflers.

 

[Jim S.]

Bobski,

The thermal energy that a Turbo actually uses to spool itself up only equates to around 10 to 15% of the energy needed to spin the turbine wheel up to operating speed the other 85% is from back pressure.

 

[Jim Cowden]

For my 40 it could only be N/A.
I have played with a lot of turbo projects and if done correctly they can be excellent but if mismatched or poor set up they can be very average(lag).

I always look at how good it is a 4.500rpm as well as peak power.
And generally on a 4 cylinder you should be able to make it by 6.500rpm.
This rule off thumb makes for a good driving car.

I like turbos they can be fun.
Have not had much to do with blowers

Jim

 

[Pat Buckley]

I prefer a N/A engine in a GT40 -

The turbo in my Subaru STi is seamless however, and sure makes me smile.

Regarding the "cheating" comments - the way I read the comment is that it was made in an affectionate/kidding manner -

 

[marc]

With all the choices the question becomes application, intent and cost.
Application demands regarding show piece, street use, track use, dragging, or mixed use. We did not even ask about Nitrous Oxide. My "filosophy" is N/A and maybe some N2O (small shot), or if money is available then TT. Twin turbos would give me the softer bottom of the rev band and give me all the kick I need near redline. HP down low just means the tires break loose earlier (right foot controlled). The supercharger method is a concern for me with a GT40 eventhough that is the way Ford went with the GT. They could have put more effort into building the engine better to get the numbers w/o a SC.

My other concern for the quest for HP/Torque is weight. These "lumps" are 1/3 to 1/2 the weight of the whole car. BBs are over half a ton. I am researching a lexus maybe with twin turbos, but we'll see.