OEM
intake: 200@ 1.0mm
exhaust: 200 @ 1.0mm
intake valve lift: 8.50mm
exhaust valve lift: 8.50mm
Schrick
intake: 222 @ 1.0mm
intake open @ 1.0mm: -1 deg
intake valve lift: 10.00mm
exhaust: 221 @ 1.0mm
exhaust open at 1.0mm: +2 deg:
exhaust valve lift: 10.01mm
Catcam
intake: 223 @ 1.0mm
intake open @ 1.0mm: -1 deg
intake valve lift: 10.10mm
exhaust: 215 @ 1.0mm
exhaust open at 1.0mm: +1 deg: (i believe this is overlap)
exhaust valve lift: 9.50mm
Which one of the above would give the better performance please?
Car is:
1.4 Polo 16v AFH
CRB600
front fed cold induction
4-2-1, decat, sports exhaust
Megajolt ecu
Which would be better please?
O would Go for schrick one.
For no other reason that it has same lift on both profiles.
But it is based in nothing else
Why would catcams have gone for smaller duration on exhaust? Anything to do with 16 valve setup.
Exhaust flow is 2/3 of intake ( unless turbo)
Valve head sizes dictate max flow i.e. ¼ valve head diameter is max usable lift
Although to caveat if you lift past ¼ rule your valve open duration at max flow is longer
Does exhuast duration effect cat?
I'm running de-cat. Would higher exhaust lift and high exhaust duration be better with decat?
With appropriate overlap longer exhaust duration will help scavenge spent gases and with this it will help fill the cylinders better at higher revs at the expense of lumpier idle.
None of those cams will give you a worth while power increase, all are mild.
sometimes, cam manufactures opt to produce cams that drop into an otherwise stock engine, to avoid the customer having to modify the head or pocket
pistons.
It would be worth speaking to piper or Kent or Catacams to see if they will do you a custom profile.
You need long duration and as much lift as physically practical, something like 240-250@1mm (285-290@0mm)
Its alot of money to spend for 10-15BHP on those cams you listed, a good profile will give 20+BHP gain (guesswork, but you see my point)
You will probably also need to get the CR up abit to make use of a long duration wild cam.
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quote:
Originally posted by bikecarbfred
Does exhuast duration effect cat?
I'm running de-cat. Would higher exhaust lift and high exhaust duration be better with decat?