Does anyone offer a cam for a turbo 2.8? I was told Comp. Cams does, but I sit on hold for 20 minutes and end up hanging up. Their website is gone too.
I was using the Crane 2030 w/Comp. Cams 1.6 rockers with good results. Maybe I'll get another one if I can't find an actual turbo profile cam.
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06:32 PM
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Dennis LaGrua Member
Posts: 15146 From: Hillsborough, NJ U.S.A. Registered: May 2000
Turbo cams are usually cut on wide lobe centers of between 113* and 114* degrees in order to minimize the time that both valves are open simultaneously. These narrow overlap cams tend to trap the boost in the cylinder providing more horsepower. Use a cam with a shorter lobe center and more overlap and the boost just blows right out the exhaust. It is common to provide about .005" less lift on the exhaust valve on a turbo cam. My cam is .444 I .439 Ex. and 212* I /212* Ex @ .050"L. That translates to 260* adv duration cam at .006"L which could be up to a 284+* advertised lift at .000"L . Turbo cams for the V6 are unavailable as standard items. Comp Cams supplied a special turbo grind for me but many cam companies can also cut special cams. Crower offers a series of Turbo cams for the SBC. Perhaps they can help you if you can get through to Comp Cams.
Originally posted by Dennis LaGrua: Use a cam with a shorter lobe center and more overlap and the boost just blows right out the exhaust.
Not to pick nits; what you said is right for a supercharger, but with a turbo it's the other way around. Exhaust would blow through to the intake (unless you're operating in crossover all the time).
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08:41 AM
Dennis LaGrua Member
Posts: 15146 From: Hillsborough, NJ U.S.A. Registered: May 2000
Not to pick nits; what you said is right for a supercharger, but with a turbo it's the other way around. Exhaust would blow through to the intake (unless you're operating in crossover all the time).
I agree that with the wrong cam specs. reversion can be a problem in a turbocharged engine.
So any cam that has minimal overlap will work best with a turbo, right? And the Crane 2030 cam has very little overlap so the ECM will not go bonkers, right? And the Crane 2030 has more lift. I think I'll go with another 2030. After all, the guy in the supercharged Saleen saw my tail lights, and that guy in that 300ZX TT.
But I am wondering if the 1.6 rockers are hurting the airflow. Will they cause more overlap? Should I go back to 1.5 rockers?
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10:35 PM
Jun 1st, 2003
Dennis LaGrua Member
Posts: 15146 From: Hillsborough, NJ U.S.A. Registered: May 2000
Are you holding out on us Dennis? Have you found out how to operate in crossover all the time
Holding out on what??? If I had an idea of what you mean by operating in "crossover all of the time" I would be able to reply. I've checked two books on turbocharging that I own (HP and Maximum Boost) and there is no reference to a "crossover." The only "crossover" that I am aware of on a turbocharged engine is the pipe that feeds the turbo from the two manifolds. Perhaps I can state it in a simple and hopefully polite way; You can have boost losses with the wrong cam profile and a turbo. I've experienced it. BTW,if your motive is to perhaps proove to everyone that I'm not one of the worlds foremost authorities on Turbochargers let me save you some time. I've never claimed to be one.
Holding out on what??? If I had an idea of what you mean by operating in "crossover all of the time" I would be able to reply. I've checked two books on turbocharging that I own (HP and Maximum Boost) and there is no reference to a "crossover." The only "crossover" that I am aware of on a turbocharged engine is the pipe that feeds the turbo from the two manifolds. Perhaps I can state it in a simple and hopefully polite way; You can have boost losses with the wrong cam profile and a turbo. I've experienced it. BTW,if your motive is to perhaps proove to everyone that I'm not one of the worlds foremost authorities on Turbochargers let me save you some time. I've never claimed to be one.
Dude, I'm just messing with you (hence the ). Chill out!
Like Rogue said, you're operating in crossover if you have more boost than back pressure.
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02:29 PM
Jun 2nd, 2003
GTDude Member
Posts: 9056 From: Keysville, Virginia, USA Registered: Nov 2001
Yeah Dennis.......but you're the closest thing we've got.......LOL. Kick ass website btw.
Phil
------------------ 87 FIERO GT 2.8 5spd 0-60 in 6.8 seconds! 87 FIERO CPE 2.5 5spd 86 FIERO SE 2.5 AUTO 87 FIERO GT 2.8 4SPD If you found my advice helpful, please take the time to give me a positive rating. Thanks
