THe accused : 1977 Trans-AM
RACE: Pontiac
Crime Poor performance given Parts used
Evidence:
Engine
462cid #96heads, 274XE Cam 9.65 compression
72 intake ,1 inch spacer, TKO TRans and 3.42 rear gears, Drag radials, Caltracs.
Performance 13.31@102.75 8.5@82 1/8 with 1.84 60 ft
Best performance 13.14@105.4 in cool weather with 1.94 60 ft
Car seems unresponsive to jetting or timing changes.
This is the therorized cause of the crime.
Gas weighs about 6 lbs per gallon I think
water about 9 lbs a gallon,
1 foot of water exerts .433 psi of head pressure.
1 foot of Gas should exert about .3psi
ok theres about 15 feet of line from the pump to the tank.
pump operates at about 5 psi under no load
Launch G's are slightly above 1 G
1 g= 9.9 meters per sec I think
works out some where around 30 ft
1.84 sec to cover 60 ft would +> 1g correct ?
15 ft of head *.3 = 4.5 psi
5 psi -4.5 only leaves .5 psi
Ok the pump has a reserve due to the size of the canister this reserve carries the car through 1st gear maybe part of second but the level in the carb bowl is dropping fast.
middle of 2nd gear the fuel bowl is low the pump is straining to pull the fuel and is beginning to win the battle due to lessening g-loads. The pump and carb continue to play catch up thru most of 3td gear and probably regain control by forth. This might also explain why the car indicated 109 mph on the G-tech on the street before and after going to the track but only 106 at the track. It does not hook as hard on the street so the pump keeps up and it is running more normally. In this senereo the lag is in part of 2nd gear and third as the pump has not recovered the fuel level in the carb. This would lower the 1/8 and 1/4 mph figures.
Well does this make sence. I'm just trying to understand whats happening.
sorry if Ive beat this to death !
I am going to put a new pusher pump on it before it will see the track again.
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