Hey guys,

In the middle of Australia and the middle of the day @ 3500 ft my car ran 135mph, back on the west coast at night and 500 ft it ran 131mph, both passes 10.2.
Does this tell you anything ? Needs more fuel in better air ? valve springs going bad ?

Cheers

I would add more fuel.. thats the easiest thing
to do.. see what happen

Any chance the Aussie's are still running the old school timing system with another timing trap 66 feet after the finish line?

I wouldnt care.. he has already picked up 4mph
with no jet change.. to be safe go fatter.. he
can always go leaner if needed

I was just questioning whether or not he actually lost any mph or not. I lost 3 mph when our track switched in 94. (from 101 to 98)

No clue.. but I doubt it

Don't do that in the altitude where you are at. Do that when you get back to the mineshaft...

Dave , he lives on the coast
Yes i think it needs a bit more fuel

Tex

If it was mid temps. 60 to 75 F with low humidity and 29.+ barometric pressures in the middle of Australia and low temps(40 to 60 F with high humidity, low B.P. the density altitude at the coast could have been worst than in the mid part with cool dry air and higher B.P.
Been there done that, moist damp air doesn't burn worth a hoot, no matter where your at
Do you know the density or actual weather readings in both locations? If so post them on here so we can see it, that will help us help you
Cold dry air with high B.P. readings at low altitude flat rock for drag racing

you can't base your tune-up off of an actual altitude.. always have to use the correction.. because like cab said being at a low elevation doesn't always mean the air is good.. typically going from bad air too good air you you would pick up a little.. even without making an adequate jet change.. you could be dangerously lean.. and probably wouldn't hurt to take a look at the valve springs

you know i am not smart enough to determine if it's a ignition (detonation) or fuel issue from a single data point (car slows down in better air).
since you didn't give us any O2 data, I will assume you don''t have a sensor, can you tell me what size carb and jetting along with type of cylinder heads and your ignition total timing.

Joe

Way to little info. First question you need to ask: is the data even believable?

1) Post all of the time slips, or all of the time slip data from both outings.
2) Collect and post the atmospheric data from the track or from local airports for the two days.

Then we can get a little more intelligent in the responses.

Sorry guys the 3500ft (135mph) and 500ft (131mph) are the (rounded off) air density altitude figures.
Yeah I was expecting to run like 136++ but sh1t happens....
I will be pulling the heads I think and going over them, it's been a while.

When going up in altitude and higher Da numbers I always thought you had to remove fuel compared to what it is at sea level, so you may be a little lean at sea level.
Adding fuel at sea level can't hurt to try.