IIRC (again) the 14-71 eats nearly 10% at 12,000 rpm.
that equates to around 750-800 bhp.
Yeah thats a lot of power. I would be happy if I had 50% of what that supercharger is taking.
How are these cars tuned?
with a screwdriver… and jets.
Actually AEM/FAST type stuff…
they still get digital readings from the motor… they just aren’t allowed to control it w/ electronics like
here’s my relative’s page from IHRA. he was pro-mod champ in 2000, although I believe he retired.
http://www.ihra.com/profile/promod/fred_hahn.html
the c5 vette was nice, but he had a '54 vette that was so sick. here’s his bds car when he drove with them:
so far as tuning the TF’s, not sure, although they are fuel-injected, not carbed. most of the technology is pretty standard stuff, still using a pushrod V-8 and a belt driven power-adder.
nice facts…shit is just ridiculous
Lets say you were in a Z06 and had a long enough straight in which to get up to 200mph. Lets say that once you reach 200mph there is a top fuel dragster waiting at a standstill at the starting line of a 1/4 mile. If the dragster leaves the exact time you cross the starting line of the 1/4 mile (your still going 200mph), by the time you pass the finish line of the 1/4 mile the top fuel dragster will have past you. In short, you could have a 200mph head start in the 1/4 mile and still lose to a top fuel dragster.
I heard that the reason the turbos arent used is because they would spool out of control… With the rate the engines turn, and the volume of air they pump out, the turbos would boost until the engine exploded.
Since S/C depends on the engine RPM, boost is much more easily regulated, while turbos spin freely at their own will.
The truth to this I am unsure… this is what I heard, and it makes sense to me.
What?? “turbos spin freely at their own will”??
They spin as a result of exahust gas. The flow of exhaust gas is heightened by RPM. Its not a mechanical tie to RPM the way a supercharger is but I don’t believe the theory that they would overboost and blow the engine.
isnt that what a boost controller does? :shrug: it would seem to me the lag would be the main issue. just think how big of a turbo or turbos you would need to flow all that air and then once you did spool up to your 8000 or so hp wouldnt you just instantaneously spin the tires? im sure you can control the boost rate but thats just wasting e.t the supercharger is always on but i could be way off just my opinion
Another interesting fact is that in the rule book, they are allowed to run multiple engines (or at least they used to be able to-I have the rule book from '95). Tuning nightmares stopped all teams from doing this back in the mid-70’s. 500 cubic inches is the max for the motor, the tire size is limited, and the clutches must be manually controlled (no electronics). This is what holds them back, the tires and clutch set-ups. Getting more power out of the motors right now is rather irrelevant. They have enough power to propel 2200lbs much faster, they just dont have the chassis to be able to do so. Someone with good physics knowledge should be able to figure out a hypothetical E.T. that 8000 HP in a 2200 lb car could do. 3’s anyone?
I was referring… as you said… to the lack of a mechanical tie to rpm and the rpm of the turbo… changing something in the turbo, like say, the bearings, would alter the power delivery of the turbo… therefore the mechanical tie of the turbo to the engine is less cut and dry then that of the S/C … you know exactly how fast that S/c is spinning at every instance through the RPM range. Im sure there are equations relating to air volume and the speed of the turbo, but as I mentioned before, bearings, oiling, and such can effect the characteristics of the turbo, therefore it power delivery… Why do you think people have tried to make turbo speed sensors? It’s not to add another gauge to their dashboard I’ll tell you that much… It is my belief that the turbo power is less controlable…
Consider water flowing over a generator. Condsider the water is flowing at a rediculous rate… even after diverting the water away from the generator I am willing to bet money that generator will continue to accelerate, in other words… continue to spin faster, even tho the water has been diverted… even if for a breif period of time.
same theory on the turbo… just because the air is re routed… the pure energy of the air that has already passed through may cause the turbo to continue to spool after the wastegate has opened. This would cause crazy boost spikes… boost spike = kaboom in such a tight tolerance engine. 
there is obviously a reason why you don’t see it too often… it works on a similar principle as nitrous drag cars… it can be done… its just a larger margin of error.
thats another good point that I would consider as well… the turbo power comes on so fast I think traction would be a larger issue.
one reason i know for sc over turbo is that the sc is much more consistent then the turbo set up would be since there are say 20 cars usually all within a tenth of a second i wouldnt want something being slightly unconsistent
I think the main thing is they’re still using carbs up on the highest levels, and using a cab + roots blower is just easier to tune and more consistent as mentioned.
On some of the lower levels (funny car, etc) I believe there’s starting to be more widespread use of turbos and fuel injection, I think they’ve been altering the rules in recent years to make turbo’s more appealing in those classes, and you may see some real advancements over the next few years.
good read :tup:
- Even with nearly 3000 CFM of air being rammed in by the supercharger on overdrive, the fuel mixture is compressed into nearly-solid form before ignition. Cylinders run on the verge of hydraulic lock.
- Dual magnetos apply 44 amps to each spark plug. This is the output of an arc welder in each cylinder.
- At stoichiometric (exact) 1.7:1 air/fuel mixture (for nitro), the flame front of nitromethane measures 7050 degrees F.
- Nitromethane burns yellow. The spectacular white flame seen above the stacks at night is raw burning hydrogen, dissociated from atmospheric water vapor by the searing exhaust gases.
- Spark plug electrodes are totally consumed during a pass. After 1/2 way, the engine is dieseling from compression-plus the glow of exhaust valves at 1400 degrees F. The engine can only be shut down by cutting off its fuel flow.
:eek: :tup:
That’s borderline unbelievable, though, I know it’s true.