cam specs
cam specs Going to order a custom turbo cam what specs should I get? I live in Ca so it needs to pass the sniffer my smog guy does not care whether the kit or parts have a carb cert he just wants it to pass the sniffer. Goals of 650 rwhp using 91 oct and ability to up the boost when on 100 octane available at the pump here. Will have forged 348 motor with 9:1 compression with stage two ported heads and full bolt ons and the ptk single a to a intercooled kit with the base turbo 70mm. I am ultimately going to ask Jose over at forcedinductions what he would recommend, but thought I would ask here also to get a few more opinions. Thanks for any input. Using 1:75 pro mag rockers and 921 duals.
Turbo Cams Here's a list I've been compiling by searching all over this board. Many of the experienced turbo guys have said they didn't need that big of a cam to make good power with a turbo LS1. If you keep at or under a 224 intake duration you should pass emissions without a problem.
Those LPE cams are supposed to be designed for superchargers or turbos and idle well to boot.
Turbo Cams
LPE-GT2-3 207/220 .571/.578 118.5 CL
LPE-GT7 208/230 .554/.546 121CL
Lunati 218/218 .550/.550 115 LSA (-12)
Cam Motion 222/218 .57x/.56x 115 LSA (-10)
MTI Stealth II 224/220 .581/.581 116 LSA (-10)
Custom 226/220 115 LSA (-7)
Custom 226/222 .570/.570 114 LSA (-4)
Speed Inc 225-225 581-581 113 LSA (-1)
229/224 .590 116 LSA (-5.5)
230/224 (.544/.560) 116+4 LSA (-5)
230/228 .58X/.58X 116 LSA (-3)
231/228 .591/.574 116 LSA (-2.5)
From http://www.forcedinductions.com/help.htm
Add the intake and exhaust durations
Divide the results by 4
Subtract the LSA
Multiply the results by 2
Typically a overlap spread of -8 degrees to +2 is a safe bet. Of course this will differ with whatever combination header, turbo and exhaust is used, so those #'s could be higher or lower.
Those LPE cams are supposed to be designed for superchargers or turbos and idle well to boot.
Turbo Cams
LPE-GT2-3 207/220 .571/.578 118.5 CL
LPE-GT7 208/230 .554/.546 121CL
Lunati 218/218 .550/.550 115 LSA (-12)
Cam Motion 222/218 .57x/.56x 115 LSA (-10)
MTI Stealth II 224/220 .581/.581 116 LSA (-10)
Custom 226/220 115 LSA (-7)
Custom 226/222 .570/.570 114 LSA (-4)
Speed Inc 225-225 581-581 113 LSA (-1)
229/224 .590 116 LSA (-5.5)
230/224 (.544/.560) 116+4 LSA (-5)
230/228 .58X/.58X 116 LSA (-3)
231/228 .591/.574 116 LSA (-2.5)
From http://www.forcedinductions.com/help.htm
Add the intake and exhaust durations
Divide the results by 4
Subtract the LSA
Multiply the results by 2
Typically a overlap spread of -8 degrees to +2 is a safe bet. Of course this will differ with whatever combination header, turbo and exhaust is used, so those #'s could be higher or lower.
i run the Speed Inc cam w/ pretty good results on pump w/ a 76mm but i dunno if that cam will pass the smog test out there in Cali, Dunno how strict they are.
All the cams from cam motion and the ones above it should pass but dunno if u'll hit that power goal w/ those on pump w/o at least 12-13psi of boost from that turbo and a meth or alky kit....then again im no expert. Just my 2 cents
Either way best of luck!!!!!!!!!!!!!!!!!!!!!
All the cams from cam motion and the ones above it should pass but dunno if u'll hit that power goal w/ those on pump w/o at least 12-13psi of boost from that turbo and a meth or alky kit....then again im no expert. Just my 2 cents
Either way best of luck!!!!!!!!!!!!!!!!!!!!!
Where do you want to make your power in the powerband? most of the high hp turbo motors run mild cams, don't really need to cam hard with a turbo. A stock cam has been proven to make 900 rear wheel.
Originally Posted by 52172
Going to order a custom turbo cam what specs should I get? I live in Ca so it needs to pass the sniffer my smog guy does not care whether the kit or parts have a carb cert he just wants it to pass the sniffer. Goals of 650 rwhp using 91 oct and ability to up the boost when on 100 octane available at the pump here. Will have forged 348 motor with 9:1 compression with stage two ported heads and full bolt ons and the ptk single a to a intercooled kit with the base turbo 70mm. I am ultimately going to ask Jose over at forcedinductions what he would recommend, but thought I would ask here also to get a few more opinions. Thanks for any input. Using 1:75 pro mag rockers and 921 duals.
When working with a supercharger cam, the duration should be about a 8-10 degree split. You do not need dramatic lift numbers, because you are forcing air in, .600-.615, Lower the number for lower CI and larger number for bigger CI. and for duration there are two schools of thought, thought 1, 115-117 LS. This school of thought will allow cylinder pressure to build, however the downside, is that getting the old air out and the fresh air in quick enough will be an effort as there will always be used air in the chamber which can equate to higher cylinder temps. Idle quality is very nice and well behaved.
School of thought #2, 108-112LS. This is a little hard for most people to swallow. This LS will allow some of your incoming boost to bleed out of the Cylinder. however, you are using a supercharger and are forcing air in. which means you will always be able to bleed off the used air and will always have nice clean cool air for the combustion cycle. The myth that you cannot get a cam with this lobe sep to idle correctly is just that, a myth. If you cant get it to idle right then you probably shouldnt be tuning in the first place. The key is to raise the timing. Raising the timing will make a 108-112ls car idle very close to the 115-117. You only need to change the timing in the idle section of the timing table. With this LS you also will get more power out of the engine itself.
Food for thought.
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Verdad Gallardo Passing Emissions Thanks Bryan. In your explanation, the #1 and #2 sticks are completely diffentent types of cams. Although you could get #2 to idle, that type of max effort cam would likely be impossible to pass an emissions test because of the overlap. Raw fuel is just pumping out the exhaust pipes and there's no way to stop it.
Cam perfection might come in the form of varible cam timing where you can idle and cruise with fuel and emissions efficiency, but get max power at WOT with optimal overlap for the boost level. Ahhh, some day.
If a stock cam can make power to 900 rwhp, then a little bigger cam should do it with less boost and have improved low end torque. Those LPE cams keep making more sense to me because of the longer exhaust duration to vacate the cylinder, but little overlap so emissions stay clean.
This might be a better emissions-friendly turbo cam list:
LPE-GT2-3 207/220 .571/.578 118.5 CL
LPE-GT7 208/230 .554/.546 121CL
Lunati 218/218 .550/.550 115 LSA (-12)
Cam Motion 222/218 .57x/.56x 115 LSA (-10)
MTI Stealth II 224/220 .581/.581 116 LSA (-10)
Cam perfection might come in the form of varible cam timing where you can idle and cruise with fuel and emissions efficiency, but get max power at WOT with optimal overlap for the boost level. Ahhh, some day.
If a stock cam can make power to 900 rwhp, then a little bigger cam should do it with less boost and have improved low end torque. Those LPE cams keep making more sense to me because of the longer exhaust duration to vacate the cylinder, but little overlap so emissions stay clean.
This might be a better emissions-friendly turbo cam list:
LPE-GT2-3 207/220 .571/.578 118.5 CL
LPE-GT7 208/230 .554/.546 121CL
Lunati 218/218 .550/.550 115 LSA (-12)
Cam Motion 222/218 .57x/.56x 115 LSA (-10)
MTI Stealth II 224/220 .581/.581 116 LSA (-10)
