[oldman]

Originally Posted by KL01

I would like the motor to spin more but the shop that installed the cam and piston/ rods kept it to stock rpm. I'll have to call procharger to see what pulley setup they recommend.

the reason IMO to cam, rod and piston a centri setup is to get that extra RPM, it is torque that kills the drivetrain and on a street tire car can't be hooked to the ground. You really need to up the RPM to 7200 RPM, check or change your valve springs every 20K miles. In this way you are not increasing torque much but you are getting a huge increase in power, that "only 500 RPM" is about 25% of the power curve and all the peak power of a centri, it also puts you 500 RPM higher in the RPM in the next gear (about)... plus is is sheer music to listen to a 7200 RPM boosted engine and since my car is a street toy, the sound thru the gears is a far more meaningful to me, that some dyno number.

Nutshell, you put a cam, rods and pistons to spin the engine higher to make more power and use the D1X's boost curve, by keeping a 6500 RPM which is 700 RPM below what it should be, you need to build a WHOLE lot more torque, and a WHOLE lot more cylinder pressure for the same HP over the curve, probably better off with a ported stock blower.

I assume you are running a fuel system to support this, I have always been of the opinion that pure DI, sub 6ms is optimal for a street engine, as you go to cheaper routes, you need bigger margins of error, like lower CR, much more meth, spin the engine higher to keep the midlevel torque / cylinder pressure at bay. Of course now that I'm limited to 92 octane in Hawaii, I may start singing a different tune, I miss E85 pump!

I went back and read the OP, you should not pulley down on your fuel setup, E85 is completely out of the question. You don't run out of fuel, you run out of injector window. I'm even assuming you have a big fuel lobe on the cam, even then, no wonder the shop limited RPM to 6500 as the injector window was probably frighteningly long. From memory my p1c with cam lobe lt1 hpfp was really limited on gas to the 4” pulley or whatever came in the stock kit. Lt4 pump and injectors just gave me some safety. Don’t recall the boost but ported heads and headers actually lowered the boost let’s just say about 10 psi at 6800 rpm full breathing lt1 pump gas lt4 pump and injectors. Going from memory now but I needed the LPE HPFP and LPE injectors for the D1x and 3.85 to 3.65 pulley 7200 rpm on E85 on a full built setup.