STUB25

I have a 89 305 TBI, i have converted it over to TPI and it has WP S/R Toruqer 305 Heads. I was wondering if I should use a hydrualic roller cam or just a roller cam. Any help is wonderful.

93ND500

Go with the hydraulic setup. The solid(lash) might play tricks with your knock sensor.

HiTech5

iTrader: (4)

A hydraulic roller cam is worth roughly 20 HP over a similar flat tappet hydraulic cam. Both Crane and Comp Cams have something for your application. Just be conservative on duration and keep the lift under .500. Then enjoy your new found power!

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D&Z Performance
"Putting Power to the Pavement"

[This message has been edited by HiTech5 (edited July 18, 2001).]

STUB25

So Crane has a hydrualic with .509/.528 lift. Why is it important to stay under .500? I thin I am going to go with a SLP cam insted though there lift is .487/.509. Which would be better? SlP also offers a .480/.487 cam as well if that would work better???

HiTech5

iTrader: (4)

Even though you have SR Torquer heads, they will not flow over .500 lift without port work. Also anything over .500 lift, you must check the piston to valve clearance. Comp Cam has an Extreme Energy Hyd Roller line that should have a good cam for your application. Something like 212/218 .480 lift
.490 lift with a 112 lsa.


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D&Z Performance
"Putting Power to the Pavement"

88IROCs

The published tests for the 305 Torquers indicate port stall occurs after 0.500" lift. But even if you install a cam with >0.500" lift: the valve will be open, at that amount of lift, for an almost inconsequential amount of time. What's more meaningfull is the flow at lift heights below the maximum. At 0.400" to 0.450", the ports on the 305 Torquers do just fine(nowhere near stall).

Valve to piston interference is more a function of duration than max lift. Keep in mind that: the max lift points occur well before(exhaust valve) and well after(intake valve) the piston reaches TDC. A longer duration cam though will delay the closing point(exhaust valve ATDC) and advance the opening point(intake valve BTDC), and this is what may cause interference.
A 305, by virtue of it's lesser displacement, requires less camshaft duration to reach to reach a cylinder filling efficiency target number.

The cam mentioned(212/218° ) is about as large as I'd go for a mild 305(where idle, drivability and mileage are concerns). You might even want to go one step smaller(206/212° ) if mileage and low-end torque weigh heavily.

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"The reasonable man adapts himself to the world.
The unreasonable one persists in trying to adapt the world to himself.
Therefore all progress depends on the unreasonable man"
--George Bernard Shaw.

[This message has been edited by 88IROCs (edited July 21, 2001).]

STUB25

The guy at jegs told me I could not go with the extreme energy seris because it was not computer compatable?? What is he talking about

88IROCs

The Xtreme HR series have limited lobe seperation angle(LSA) which increases overlap, which in turn decreases idle stability. The stock ECM and prom may have trouble establishing the desired idle speed.

CompCams has a series of computer compatible cams(LSA = 112 - 114° ). Unfortunately, the greater LSA comes at price of reduced max lifts. Still, there are two that might be of some interest: CS-262HR-12(206/210 dur@0.050" .450/.480" lift 112° LSA) for a completely stock 305/TPI and, CS-264HR-12(210/220 dur@0.050" .480/.480" lift 112° LSA) for a modified 305/TPI(prolly would help to use 1.6:1 rockers on the exhaust valves).