88 Supercharged Turbo
Car is finally beginning to run well - with the installation of 77 lb/hr injectors, a new best ET of email@example.com MPH (finally in the 10's) has been posted. A dyno day was being held by DV-SDAC and they gave out an open invitation for anyone who wanted to attend....I've been wanting to get a chance to put the car on a dyno for quite some time now - I HAD to go!
The SCTC on the dyno!
I made 4 pulls on the dyno, the first pull was with my big blower pulley in the same tune that the car was in when run at the track during the previous weekend. This combination with approximately 11.7 psi boost, ice water in the inter cooler tank, A/F ratio at about 11.5 produced:
463.4 RWHP and 596.4 ft-lbs Torque
While the engine cooled for a few minutes we swapped to the smaller blower pulleys and then ran 3 more pulls leaning the fuel slightly each pull. The final combination had approximately 13.7 psi boost, ice water in the cooler, and an A/F ratio at about 12.0 which produced:
474.7 RWHP and 654.1 ft-lbs Torque
I'll post the HP plot as soon as I get it scanned and hopefully we can get the car back to the track soon to see if the improved Torque and HP help ETs, or just cause increased traction problems...probably getting time to take a look at improving that stock rear suspension.
Finally got around to scanning that Dyno Plot, here it is!
As you can see from the plot, the smaller pulleys (~ 2 psi more boost) made the most difference at the lower end of the RPM range with the increased torque. Fellow forced induction fanatic, Bill Watson, (watch for his Twin Turbo 66 Mustang in a future issue of HOT ROD!) took the time to grind through the necessary calculations using dyno and quarter mile data, accounting for inertia loads, and converter inefficiencies to determine a crankshaft SAE NET HP and TORQUE. Here is a plot of his results, which is what we'd expect to see on an engine dyno from this combination.
That works out to be 670 ft-lb TORQUE at 4500 RPM and
612 NET HP at 5000 RPM. In case you're wondering what the increased HP due to
the smaller blower pulleys works out to in the quarter mile, you're not alone
- so were we. Seemed like a trip to the track was in order so we went back last
Sunday (4/29/01). The SCTC has now turned a new Best ET of 10.46
@ 129.6 and a new Best MPH with a pass of 10.52
@ 131.1 with a weight of 3470, 92 pump gas,
on DOT tires, and through the mufflers. I'll get the time slips posted
as soon as they are scanned. Could there be a single digit ET in this car's
future?......................I sure hope so ;).