THIS COMING WEEK…Monday doing a 99 XCR800, Stock vs
DynoPort pipes, Vforce reeds, shim kit to raise cylinders, modified heads to compensate and then some…
Wednesday we have a SkiDoo600 with a 734 big bore…
Friday we’ll be tuning another D&D F8 top end with a Bikeman modded
stock pipe and maybe a new version of a D&D big bore single….
THIS IS BUGGING ME: some guy posted on the web, whining about not
wanting to pay $20 for DTR because he heard that all we say here is
aftermarket stuff doesn’t work?! So he has a stock F7 with 132 HP that
I can put on our dyno and tune with timing and fuel only to close to
150 HP. A bone stock 700 pump gas twin with 150 HP!! Did Arctic
Cat/ Suzuki leave anything on the table? Does a factory stock 700 twin
capable of 150 HP have bad reeds? Is the stock F7 single pipe low
on HP? Did Arctic Cat goof on the best possible airbox intake? Give us
all a break. The 03 snowPro intake was huge like the high $ billet
aftermarket intake horns, but 04 and later airboxes have the smaller
high velocity intakes like the F7s– could the smaller intake inlets
make more HP at peak revs due to airbox sound wave tuning? Or should
you poke a bunch of holes in your well-tuned airbox for “bullboys” and
let a bunch of HP robbing hot air into your intake??
Last Friday I had a guy from Maine tune his F7 dragracer w/ 500′
factory drag ECU. He came with a large diameter 03 snowpro intake,
switched to a stock F7 intake and he increased top end airflow CFM with
the smaller stock F7 air intake. With that stock airbox horn in place
he tuned to 151 HP.
So this whining guy with the 132 HP F7 can pay big bucks for big reeds,
big air horn, aftermarket pipe, big loud can and still may have
132 HP. Or he can read our stuff, figure out the facts, and have great
fun if he can find an instrumented dyno to tweak upon. The whining guy
has all the parts in his bone stock sled to make 150HP. All it takes is
tuning to get him there, or (wisely) partway there. My own tinking is
based upon the many sleds tuned here ONLY with fuel reduction and
timing increases, those 132 HP F7s are perfectly reliable for
intelligent people at 140-145 HP. And those 145 horse guys have stock
reeds, stock pipes, stock airboxes, and stock mufflers.