For a non wild best for daily driver that wants to most power, i'd agree.stage 2 hitechs
Id go with stage 2 Hi techs, one of the best things with these is u dont have to change the valve springs like other cams!
For everyone else, he's talking about Intake Lobe Center line and not the LSA you see advertised often. A lot of companies dont even release thier ILC.Nick @ Modular Head Shop( MHS ) has done a lot of research lately and a lot of different cams. He has found some very scary info regarding many of the aftermarket cams. Any cam with more than 230 intake duration installed at 110 intake centerline in PI Heads will have PTV contact. These cams need to be installed at 114. When installed at 114, they make less power than the smaller available aftermarket cams.
Popular Cams that are known with PTV contact are:
Comp 270
CMS/VT Stage 2 N/A
HiTech Stage 2 N/A
Personally, I would talk to Nick at MHS and find a cam from him that will work for you.
For everyone else, he's talking about Intake Lobe Center line and not the LSA you see advertised often. A lot of companies dont even release thier ILC.
Could you go into this more, TGJ? Even if in pm. I find this intriguing. I've seen VT stg 2's timed correctly w/out problems, and 270's degreed correctly without problems - but still wanna get all the info I can if there's something I'm missing.
Just as a critique:
Installing a 230 duration cam at 110 means the intake valve will close at the latest 45 degrees; and opens at 5 degrees (shouldn't be interfering on opening range). You said you'll consequently need to install at 114. This doesn't make sense, 114 would cause the seat timing to be 1 and 49 degrees open/close which means the intake actually seats later causing interference to be more likely not less, right? With the theory that 45 degree seating is the limit against interference, that means at a 114 ILC you'd need to be as low as 222 intake to meet that limit while VT stg 2.5 blower cams have intake at a huge 228 (48 degrees seating) and I've never seen or heard of VT blower cams PTV'ing.
For everyone else, he's talking about Intake Lobe Center line and not the LSA you see advertised often. A lot of companies dont even release thier ILC.
Could you go into this more, TGJ? Even if in pm. I find this intriguing. I've seen VT stg 2's timed correctly w/out problems, and 270's degreed correctly without problems - but still wanna get all the info I can if there's something I'm missing.
Just as a critique:
Installing a 230 duration cam at 110 means the intake valve will close at the latest 45 degrees; and opens at 5 degrees (shouldn't be interfering on opening range). You said you'll consequently need to install at 114. This doesn't make sense, 114 would cause the seat timing to be 1 and 49 degrees open/close which means the intake actually seats later causing interference to be more likely not less, right? With the theory that 45 degree seating is the limit against interference, that means at a 114 ILC you'd need to be as low as 222 intake to meet that limit while VT stg 2.5 blower cams have intake at a huge 228 (48 degrees seating) and I've never seen or heard of VT blower cams PTV'ing.
It just doesn't make sense to me, maybe i'm missing something? It appears to be talking about LSA in relation to duration and ICL for exhuast valves, not just ICL - but he only mentions ICL. A higher ILC means the valve opens later and seats later, so how would a higher ICL be safer?
Granted cam timing can be confusing as all hell. Once you start looking at it becomes easier to figure out.
Retarding the cam moves the intake valve opening event closer to TDC. Which gives less of a chance of the valve kissing the piston. Piston is closer to TDC and then heading back down as valve is opening. If your intake is advanced like me trying to get my cams installed at 110. Now they are opening the intake valve earlier as piston is coming up. Which in a mod motor there just isn't enough clearance with stock valves and pistons for the valve to open that early without some contact with piston. Especially with the higher duration alot of cams use.
Hitech stg 2(my set Comp ground one at 110 left cam and other at 112 right cam leaving me to figure out where to install)
234 dur @ .050 Intake
At 110 ICL opening is 7* BTDC, closes at 47* ABDC - PTV at this install point
At 112 ICL opening is 5* BTDC, closes at 49* ABDC - No PTV but too close for comfort
At 113 ICL opening is 4* BTDC, closes at 50* ABDC - No PTV and been safe enough for my liking and making good power still.
Again this is with my particuler engine.
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