Box Stock

hh

Sounds as if some of the tolerances are tight and loosen as heat builds, or the carb is to fat on the bottom.
That's why we run data acquisition.
 
all jetting is in effect at WOT. I will bet that if you ran an EGT gauge you would see the heat output change the moment it picks up more speed.
 
flattop1 said:
All that , do you have a theory you want confirmation of ?
At 52 years old you should know better then tear off down a public highway at 50+ in a go kart .
U-tube might Be the answer.
You don't know if its down hill at the end , unless you used a transit or a new fangled gps/ theolite system .
Either the temp comes up enough to optimize the afr or it leans out gaining speed .
Possibly an unexplained phenomenon.
Click to expand...
Maybe , you didn't read my post. Either the temp comes up enough to optimize the afr or it leans out gaining speed .
lets face it 6 mph gain is big .
what rpm gain is that ?
 
we all Know gaining 945 rpm at full throttle is a feat not easily accomplished .
even it used to turn mid 85's now nearly 9k .
Without actual rpm data vs mph .
Possible the mph app is off ?
Long intake . the ram effect could be kicking in at the end .
 
Tires can't really grow that much plus rpm , should go down .
Clearances and bearings opening up or loosening . Doubtful , tenths of a sec at best .
Pipe , carb combo finally syncing up with the air flow / density , temperature.
On the pipe as they say .
Great when it happens .
 
My experience with long flatout runs . Typically ends with glowing exhaust pipes and holes in the pistons .
 
Only time I have had a big rpm jump in any racing engine I have owned which is not only limited to kart engines is when the engine decides to detonate. I wouldn't worry so much what speed I picked up but what did I damage doing this.
 
Swap that 390 to methanol and then feel good about a clean plug along with the added power. And if you want to run gas, buy you a nice stock appearing carb from Dover Power or someone. I dont like what I see with the sudden additional power up top, especially with no data
 
RPM's have now come into the debate, which was my point in mentioning GEARING earlier, I realized you didn't change it but it had gearing combo on it when you ran it, So I would now think tires and different conditions had some effect as well, Or am I missing the fact you didn't actually make multiple runs and once you got to and maintained full throttle for a certain length of time, then you saw the different results ?
or was those runs only on a dyno .
 
You must log in or register to reply here.
Back
Top