Q&A: Alky
versus Nitro
By Lyle Greenberg
Thanks to Bill Duke
Q: How much strain does an engine on alky face vs. a nitro mill? I
can only recall one alky car going kablowwy. That was Joe Amato's Firebird
in mid- late eighties. It seems that the alky mills were simpler to tune and
less volatile. Bill Duke
A: I think no one would argue that the nitro motors are under much
more strain to make 6,000+ HP. Since I've never run a nitro car, I can't
speak to some of the differences. I think they go kaboom far more often than
you think. The alky motors are making the kind of HP that the nitro cars did
say maybe 15 years ago. One big difference is the rpm that the alky motors
get turned. We make our 2-3 shift at 9,200 rpm with a 526 C.I. motor (4.50
stroke). Some of the smaller alky dragster motors get turned 10,500+
rpm.
About the only thing I can think of to gauge the
amount of stress is the number of alky funny car fires. There have been
several in the last year - Michael Simpson, John Lawson, Norm Hill, Jason
Rupert, Randy Fleming and a few others whose names don't come immediately to
mind. All of them were serious fires that resulted in badly damaged or
written off cars. I certainly don't keep track, but I wouldn't be surprised
if there has been more alky funny fires than nitro funny fires in the last
two or 3 years (although there are clearly more runs being made by alky
cars). NHRA thinks it’s serious enough to have mandated that we have to
have the on-board air systems. I can assure you that, having had a fire
myself a little over a year ago, I believe that we are leaning on the motors
way too hard.
I have been a vocal proponent of putting spec rev
limiters on the cars ala IRL. I believe that high RPM = broken parts = big
$. If they would limit us to about 8,000 - 8,500 RPM I believe that the
racing would be better and the costs would go down. Last year a proposal
surfaced to cut back the blower overdrive. This would have been a failure
because the guys would just spin the motor higher to try and make up for the
lost overdrive. More RPM, more broken parts, you get the picture. Sorry, I'm
up on a soapbox now. I'll step down & get back to your question ...
I think the "tuning window" to run respectably with an alky car is
much bigger than on a nitro car. Having said that, once you get a blown alky
car on the edge where it is making big power, the window gets pretty narrow,
pretty fast. The huge blower boost that we are running, coupled with big
volume pumps and fairly large static compression mean that the difference
(for me at least) between running a 5.80 and not having it hurt itself and
running a 5.90 _and_ hurting itself is a matter of .005 - .010 on the pill.
That means if the weather moves just a couple of degrees and you don't make
the right move, its gonna detonate and be a hurting pup. Some day I'll have
to tell you about how we tune the car off of how much the rod bearings get
mashed!
Lyle Greenberg
443 Federal Mogul Funny Car
http://www.lylegreenberg.com
