test and tune day

stepside

stepside

Well-Known Member
hi
I drove 100 miles to the test and tune days
the track was slippery so I had to leave second gear
best time was 1.8 60ft 11.6 121mph
http://vid1106.photobucket.com/albu...10206048507708237_203054759_n_zps5diuzilm.mp4
so gearheads are there any tricks that I get this car to tens
my combo
all steel 69 cutlass
509 bbc
th400 4000stall
3,4:1 gears
engine specks
509 cid afr 305 heads dart tunnelram ms efi crane hyd roller 244/248 107 lsa
the car did not pull past 5600 so i shimmed valve springs 170 lbs to 200lbs and now it pulls to 7500 easy if i lost traction
 
whats the car weigh?
what is the engine rpm in the lights at the top speed?
what rpm are you shifting the trans at?
can you fit larger tires on the car?
whats the plenum vacuum read at peak rpms in the lights at the end of the track?
whats the header collector vacuum or back pressure read at peak rpms in the lights at the end of the track?
whats the fuel/air ratio every 1000rpm from 4K-5K-6K PEAK?
Are you getting a full width tire patch mark showing even full traction,on the pavement?
what was the air temperatures?
CAN you reduce the cars weight? (replace, bumpers, hood, fenders ,trunk ,lid ,lighter weight interior, like seats, carpet,etc.)
can you, or will you use NITROUS

http://garage.grumpysperformance.co...ng-to-drive-a-really-fast-car.906/#post-27083

http://garage.grumpysperformance.co...ir-shocks-and-helper-springs.7006/#post-23123
 
Last edited:
car weight 1800 kgs
rpm at the light 5600
shifting 5500
vacuum 100 kpa
fuel air ratio 11.8
tires 28 12.5 15 et street 14 psi
track was cold 14 c i think traction is the biggest problem
also converter is loose 15% slip
 
car weight 1800 kgs= 3968 lbs (you REALLY REALLY need to drop 200kgs-300 kgs in car weight)
rpm at the light 5600 (i would expect that to be closer to 6300rpm)
shifting 5500 (this seems like its at least 700 rpm to early in the power band)
vacuum 100 kpa
fuel air ratio 11.8 (closer to 12.5:1 should produce better power)
tires 28 12.5 15 et street 14 psi
track was cold 14 c i think traction is the biggest problem
also converter is loose 15% slip
 
rpms at the lights were down because the valves floated
i lifted spring pressure 170 lbs to 200lbs and now engine revs to 7500
now i can shift above 6000 rpm
 
You don't want to float the valves in any engine.
Big Blocks usually have heavy mass valves.
Lighter in Pontiac but still bad to float them.
I would not buzz any engine over 6,500-7,000 Rpms myself without Titanium retainers used . Ideally Titanium Valves used too.
Its a big torque engine the 509.
6,200-6,400-6,500 Shift Rpms is where you want to stay at to get the Car dialed in for best ET & MPH Trap speeds.
 
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