I had the greddy initialy. Actualy beleive it or not but the greddy unit actually senses alternator speed if I recall. Thats how it counts up. There is also an extra wire on it that you can hook up to the speed sensor if you want to make full use of the greddy unit. THe problem is finding where this speed sensor signal is at.
The blitz unit senses pressure which is good, cause it senses a load on the engine so it starts counting up from there. It also senses alternator speed. There is a small AC signal in the 12v DC power in the car.
I did not install the brake wire on my srt because the center councel was a pain in the but to get too. Its more of a safty feature for the 5 speed cars. On the auto you really dont need it. On the stick shift, just make sure your wife of the vally guy does not park it in gear. Then again, its not like you need to here in FL, we have no hills.
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E.D. 3\" Turbo Back, , HKS SSBOV, GReddy-e01 Boost controller, Greddy E-manage fuel management, Blitz Turbo Timer, JE pistons, Ported Head, E.D. Large Frontmount Intercooler, E.D. Tubular manifold with t3/t4 (prototype), IPP coilovers, Limited Slip.