final cam choice

[paultownsend]

basic spec-
2.0 agg 70k (ish)
bvh 40/35
newman 268
ported ex mani
milltek 2.25" exhaust
lightened fly

iv always been a little gutted that on midland vw's rotronics rr my engine only made 134 hp@ 5712rpm and 144.6lbft@ 4513rpm at the fly est. (torque im happy with) and im guessing if its over estimatind the T figure, hp would of been as well. so i think its a true enough reading

iv got my last wedge of cash which i want to finish the car with as i think the head can do more. iv already put a 2" jetex system on it which has improved things (a hell of a lot quieter too!) iv also a 4-2-1 supersprint manifold to put on to help breathing

so now its cam choice. looking at my newman 268, its very tame. with only 1.1 valve lift @tdc. i was looking at the newman 272, but this also only has the same valve lift of 1.1 @tdc.

so im looking at 2 other options

cat cams 266/266 with 1.7in/1,75 lift @tdc £180
schrick 272/272 with 1.6in/1.7ex lift @ tdc £260!

both cams have a noticeable greater lift @tdc over the newman

so which do we think is the better choice? im wanting a good idle, but keep the fantastic drivability that the car already has (that low torque) but also keep the way it revs clean to 6k
at the moment peak torque is 1.2k lower than peak hp. and at peak hp torque has decreased by 25lbf. so is moving the 2 peaks further away a good thing?

will the lower duration of the cat cam noticably hinder the way the engine revs higher? (hopfullly it will rev better with the new manifold)

will the slightly higher duration of the schrick notceably effect the low down drivability? (i love pottering around at 30 mph in 5th!)

cheers in advance chap (ps, im still new to all this  )

[DOA]

I think you need to look at those specs again as those valve lifts arent right, you are looking at the lifts at tdc (different to overall lift) and your also mixing your units up, they are in mm not inches (1.75 inches is a LOT of lift lol).

[paultownsend]

all are from the newman, cat, schrick catologues. yes at tdc

and they are in mm, 1.7in 1.75ex meaning 17mm inlet lobe and 17.5mm exhaust lobe.
i was told @tdc was the best way to compare lift?

[danny_p]

it cant be 1.7 inches  of lift,    normal high lift cam for vw is 11.xx mm.   11.75mm  makes sense to me.

chooseing cams is a tricky game  advertised duration is rarely true duration.  and there are other factors that are as inportant if not more inportant.

as far as lift goes  the question is how much do you actualy need there comes a point where once you have opend a valve so far it wont actualy flow anymore if it's opend further    but that vastly depends on the head.

can has a look at you rr graph.   but i'm thinking if you want power you need to be looking at the longer duration cams,    without looking up the ecact details   you wont notice any differance going from a 268 with 11.1 mm of lift to a 266 with 11.75mm of lift.      if the newman has better ramps it may even be opening faster and starting to close it later  hence allowing more air to flow.

cheep cams tend to have crap ramps.   very good ones have diffrent opening and closeing ( non semetrical ramps )   i tend to use kent or piper as have had them before and liked them

[paultownsend]

iv realised that now. iv gone for a newman 272. still runs on std markings, but has slightly longer duration and a little more lift

[danny_p]

should make it a bit more fruity