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Angel and I dynoed my car with the SP74 at SpeedCraft Engineering in Jacksonville yesterday (264 cams, GReddy "3-row" FMIC, SP 72#/hr. injectors, SP fuel system, factory flywheel, stock head, intake, and bottom end). We didn't push it TOO hard boost wise. It made 710 RWHP SAE corrected (726 actual) at 29 PSI. 575 RWTQ. The HP curve didn't appear to have peaked at 6700 RPM and torque was flat from 5300 till we stopped at 6700. The turbo wants more RPM and more boost. (The engine wasn't commenting. ) It makes 500 rwhp about 250 RPM later than the T-64, which is entirely acceptable to me as a tradeoff.
It picked up the same amount of power-per-PSI when we increased from 27 PSI to 29 PSI as it did when we increased from 22 to 24 PSI. That indicates to me that it's not beginning to run out of steam at 29 PSI (and that's not surprising, as this turbo can reportedly blow 40 PSI on a 3.8 Grand National motor). Angel and I took it out on the road after we finished on the dyno and the car felt like it's in another league compared to when it was on the T-64. It just gets stronger the higher in the RPM range it goes. With the T-64 the car came on fully by about 5500 and held pretty much that force of acceleration to redline. With the 74 it's making the same exact amout of power at 5500 (600), but it piles on another 110 RW by 6700 and the curve is continuing upward at the same rate it was at 5500.
I'll try to get the graph posted in a day or so.
Steve - likes big turbos
It picked up the same amount of power-per-PSI when we increased from 27 PSI to 29 PSI as it did when we increased from 22 to 24 PSI. That indicates to me that it's not beginning to run out of steam at 29 PSI (and that's not surprising, as this turbo can reportedly blow 40 PSI on a 3.8 Grand National motor). Angel and I took it out on the road after we finished on the dyno and the car felt like it's in another league compared to when it was on the T-64. It just gets stronger the higher in the RPM range it goes. With the T-64 the car came on fully by about 5500 and held pretty much that force of acceleration to redline. With the 74 it's making the same exact amout of power at 5500 (600), but it piles on another 110 RW by 6700 and the curve is continuing upward at the same rate it was at 5500.
I'll try to get the graph posted in a day or so.
Steve - likes big turbos