The Truth about the SR20VET Exhaust camshaft.
I have done tones of researching regarding OEM cam combos for turbo setups when the SR20VET exhaust camshaft got my attention with the 11.3mm lift on the low lobe.
We all should know that the SR20VET from factory only has VVL on intake side, and the exhaust rockers have VVL delete on them (no high lobe rocker pad). Everyone currently assumes that the LOW and HIGH lobe on the EXHAUST cam are identical (244º 11.3mm) WRONG
Take this image for example, this is a brand new SR20VET Exhaust cam. You can CLEARLY see that the high lobe has more duration (wider at the tip)
Also with a straight edge, you can see the high lobe has LESS lift than the low lobe. By about 0.1-0.2mm
A friend of mine who has physically measured the duration/lift/center line of all VVL Cams, and confirmed to me that my own research is correct.
What does this mean? The SR20VET high lobe has the same Duration and lift as the P12 '20v' camshaft, just with a different center line. So the SR20VET exhaust Cam is the ultimate OEM turbo cam with VVL enabled.
Low 244º 11.3mm
High 280º 11.15mm
The low lobe specs are awesome for turbo spool, then high lobe kicks in and allows more flow at high revs.
Why did nissan do this?
Maybe the SR20VET xtrail was one of many SR20VET powered cars but the xtrail was the only one that made it into production, The small exhaust housing on its turbo didn't need the larger duration on the high lobe so thats why they deleted the VVL on the Exhaust side. There was a S16 Silvia that was rumored to have the SR20VET. Maybe this cam would of been used in that with its full potential. Or maybe nissan used blanks for both 20V and VET and they machined the same high lobe on both to cut costs?
All i know that myself and a couple others have physically measured these cams and can confirm that the info i have posted is correct, I am sure this thread will rattle some peoples feathers, but if you have a VET Exhaust cam, simply look yourself. You can clearly see it by eye.
We all should know that the SR20VET from factory only has VVL on intake side, and the exhaust rockers have VVL delete on them (no high lobe rocker pad). Everyone currently assumes that the LOW and HIGH lobe on the EXHAUST cam are identical (244º 11.3mm) WRONG
Take this image for example, this is a brand new SR20VET Exhaust cam. You can CLEARLY see that the high lobe has more duration (wider at the tip)
Also with a straight edge, you can see the high lobe has LESS lift than the low lobe. By about 0.1-0.2mm
A friend of mine who has physically measured the duration/lift/center line of all VVL Cams, and confirmed to me that my own research is correct.
What does this mean? The SR20VET high lobe has the same Duration and lift as the P12 '20v' camshaft, just with a different center line. So the SR20VET exhaust Cam is the ultimate OEM turbo cam with VVL enabled.
Low 244º 11.3mm
High 280º 11.15mm
The low lobe specs are awesome for turbo spool, then high lobe kicks in and allows more flow at high revs.
Why did nissan do this?
Maybe the SR20VET xtrail was one of many SR20VET powered cars but the xtrail was the only one that made it into production, The small exhaust housing on its turbo didn't need the larger duration on the high lobe so thats why they deleted the VVL on the Exhaust side. There was a S16 Silvia that was rumored to have the SR20VET. Maybe this cam would of been used in that with its full potential. Or maybe nissan used blanks for both 20V and VET and they machined the same high lobe on both to cut costs?
All i know that myself and a couple others have physically measured these cams and can confirm that the info i have posted is correct, I am sure this thread will rattle some peoples feathers, but if you have a VET Exhaust cam, simply look yourself. You can clearly see it by eye.
Last edited by pTen
on 2014-10-03
at 02-21-19.
Originally Posted by Boostlee 
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