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greg bohohos
12-26-2001, 09:31 PM
I HAVE A 95 GMC JIMMY 2 WHEEL DRIVE WITH A CPI MOTOR WHAT IS THE BEST CHIP?IGNITION?ALREADY HAVE AN INTAKE AND A FLOWMASTER MUFFLER.

drewdaddyblazin
01-06-2002, 07:13 PM
ok i got some stuff for ya... i have a 96 blazer with:
MSD ignition 6a, this ran 131 bucks, and enabled me to burn out on any cement... i used to not to be able to burn out on white cement, but any black stuff? shit, there goes my tires...
New 8mm wires
i just ordered a hypertech power programmer 3, but i dont think you can reprogram a 95...thats only 96 and up for trucks, but some sports cars from 94 can be reprogrammed...
So for your 95, i would get either a JET chip or module, or the hypertech ones... they run about 190-240 for the modules about about 150 for a chip... the jet and hypertech modules are about the samem, both give about 15 to 20 hp...
and i got flows, and a K&n
OH!!! GET A HELIX THROTTLE BODY SPACER!!! THEY HELP WITH ACCERATION!!! ONLY 100 BUCKS! and they whistle, so it sounds like you got a tubro... lol its great shit...

blueskyjack
01-08-2002, 03:59 PM
from my sig.:D

drewdaddyblazin
01-08-2002, 07:04 PM
what do your rollers do, and are they hard to put in?

blueskyjack
01-09-2002, 12:54 PM
for either 4.3 or 350 engines with center bolt valve covers. They replace the OEM 1.5 ratio stamped steel rocker arms which open the valves when activated by the cam, lifters and pushrods. The 1.52 or 1.6 ratio roller rocker arms have a roller on the end that contacts the valve stem. They free up HP by reducing friction. They are a tiny bit larger ratio and the steel is stiff and resist flexing giving you a higher more accurate lift. To use them you need to change your non-adjustable 10mm rocker studs to an adjustable type, preferably the standard 3/8" type. You can use GM (p/n 476530) adjustable 10mm studs if you are going to use rockers like the Comp Cam "Magnum" series. If you want to use full blown roller rockers with needle bearing fulcrum like the "Pro Magnum" series you will need to drill and tap for standard 3/8" rocker studs or pay about $140 for a set of Crane Cams 10mm-3/8" conversion studs. I drilled and tapped for standard ARP 3/8" studs for an additional $50, since my heads were already out and being modified.

As for "is it hard"? No not really, as long as you closely follow the proper procedure to adjust valve lash after installation.

He can't use a throttle body spacer because he said he had the CPI engine.

drewdaddyblazin
01-09-2002, 04:14 PM
He can use the TBS, i got the CPI engine on my 96 blazer and it works just fine, adds about 10 or 12 horses... mid to high end torque...

blueskyjack
01-09-2002, 04:36 PM
that is unusual since the L35/CPI/W series engine was only used '92-95 according to GM. The L35/CSFI/W series engine with six sequentially fired injectors replaced the one injector batch fired CPI system in '96. Did you install an old engine? What is the eighth character in you VIN? If you have a W, then I think you may be confusing the '96 up CSFI with the '92-95 CPI since they are both designated as the L35/W engine.

Forgive me if I'm unclear about what you mean by a throttle body spacer. Are you saying that you added a spacer between the upper and lower intake manifold plenums or what? I am unaware of any aftermarket TBS for the CPI. Who makes it?

drewdaddyblazin
01-09-2002, 04:53 PM
Yeah the 8th number is a W, in my blazer repair mannual it says if the 8th number is a W its a CPI engine and i looked on my vin number, and its a W... i was like, wtf... The spacer fits between the throttle body and the exhuast manifold... its made by street performance products, and other is made by a company called powerid i think...

blueskyjack
01-10-2002, 09:59 AM
Originally posted by drewdaddyblazin
Yeah the 8th number is a W, in my blazer repair mannual it says if the 8th number is a W its a CPI engine and i looked on my vin number, and its a W... i was like, wtf... The spacer fits between the throttle body and the exhuast manifold... its made by street performance products, and other is made by a company called powerid i think...
If you have a '96 and a "W" in the VIN and you haven't changed the engine you don't have a L35/CPI you have the newer L35/CSFI with Central Sequential Fuel Injection. I am really confused when you say it fits between the throttle body and "EXHAUST" Manifold. I think you must mean "INTAKE" manifold.:confused:

drewdaddyblazin
01-10-2002, 08:24 PM
oops yes, its intake manifold, sorry about dat... here is a link to the TBS manufactures...
http://www.streetandperformanceelectronics.com/helix.htm

blueskyjack
01-11-2002, 08:27 AM
none of those are for or will fit a CPI engine. The CPI has split intake manifold. Air enters at the front center of the upper intake manifold. The intake opening is angled towards the front driver's side corner. Once the air enters it is split to six individual tunnels that match up to six individual tunnels in the lower intake manifold. There is a poppet valve mounted at the very end of each air tunnel where it sprays fuel directly into the intake runner of the heads to join the incoming air. I suppose you could make two large spacer plates that ran the entire length between the lower intake and each head or sandwich one large plate between the upper and lower intake manifolds. I doubt if either of those would be very beneficial.

Short of forced induction the proven way to improve airflow in the CPI or any engine is head work. A big start is to port gasket match the lower intake and heads and have a non-restrictive intake like the K&N FIPK system to allow more air to be pulled in. You can further increase air movement by doing an extensive polishing of the upper and lower air tunnels to the point where the fuel is introduced. You don't want to polish the head intake ports after fuel is introduced, just remove casting flaws and smooth with 80 grit stone. It is also beneficial to profile and polish the combustion chamber, polish the exhaust ports, install larger valves and do a multi-angle valve job to further improve air flow. Yes all that is much more expensive than a throttle body spacer, but it produces real horsepower. The CPI already has a fairly decent cam to make use of the added air and fuel with:
Valve Lift - Intake.433/Exhaust.441
Duration@.050 - Intake 206 deg/Exhaust 207 deg
Lobe centers - Intake 121 ATDC/Intake 115 BTDC
Lobe separation angle 118 degrees
The biggest problems I have encounted are the added compression, combustion heat and smoothing out fuel delivery at partial throttle applications.