Rocker Arms Or Underdrive Pulley
Posted in Performance Chips | Asked on Mar 17, 2011
I have a 2005 chevy silverardo with the 4.8. Right now i have my muffler cut of but left the cats on, and i have a spectre CAI. I plan to buy a hypertech power programmer iii soon because i can get it for pretty cheap. I am looking to either get rocker arms at 1.8 and replacing the springs with it(only if its highly recomended), or doing a new pulley set-up. Which is more worth the money and work, and where can i find a pulley set-up with an alt and belt included?
There are 3 Answers for "Rocker Arms Or Underdrive Pulley"
I can tell you this…underdrive pulleys are NOT a good idea for anything other than a race car. You gain almost nothing, and you give up a LOT when it comes to idle performance of the water pump, power steering, and the alternator if you drop their RPM.
Like Monekey said, the underdrive pulley really aint good for a stock, driver.
I have a daily drive “race car” as people call it. I’m running about 45% underdrive on all my acc.
At a norm idle speed (800 rpm), I only have 11.3 volts. But my engine can’t run on that low of idle speed anyway. I have to idle it at 1,000-1,100 and at that rpm I have 12.1 volts.
I don’t see 12.8 volts or more till 2,000 rpm
This is also on an older carb’ed engine, using a 105 amp CS130 alt. So I don’t have alot of elec items draining my voltage like newer ones do.
I’m also running a high volume water pump to make up the flow diff in water pump vs driven speed
Yeah as stated and rocker arms/springs are only maybe going to help with valve float at really high rpms. It’s what’s the rockers are between that’s going to matter, like changing the cam and/or valves.
Won’t even look pretty as you can’t see em.
Source(s):
GM/ASE Master Tech 30+ years
Collision Center Manager 10+
Family owned Insurance Agency 50+