How do guys... Can anyone spot any obvious issues with the below G60 cam spec? Any thoughts on it? Are those valve lifts achievable/able to be gotten along with the other spec? And are those timings looking alright? Also, 40deg of overlap if im not mistaken, thats fine as far as im aware. 268/276 Valve lift inlet - 11.75mm Valve lift exha - 11.75mm Timing inlet - 20-68 Timing exha - 76-20 Full lift 114 deg Cheers, Neil.
Yes 40 deg of overlap but most of that will be at very low lift. do you have the duration or timing @1mm ?
Cheers mate...I don't have those bits of info as its basically a spec ive pulled out of thin air Im trying to come up with a cam thats a little more adventurous than the newman VOLGS/264/463 and the piper G60BP285H...Best of both really but id also like split duration. Im not really sure how to go about coming up with the figures/spec? Can i basically just come up with figures (as above) and it will work? The newmans is as follows but has too much overlap for my liking, the figures dont seem to make sense either somehow. The standard G60 cam has 40deg of overlap btw 264/278 Valve lift inlet - 11.75mm Valve lift exha - 10.99mm Timing inlet - 20-64 Timing exha - 76-32 Full lift 112 deg And the piper: 268/268 Valve lift inlet - 11.13mm Valve lift exha - 11.13mm Timing inlet - 20-68 Timing exha - 68-20 Full lift 114 deg How can i make the best from the those two specs? The car is currently 206bhp with minimal mods and standard head, but id like a cam to work in this head and also to work well in a possible ported head in the future...There is 15psi of boost backing up in the inlet side of things so a real good cam spec could see a good little gain...obviously the standard head ports/valv sizes will limit that potential gain for now. Neil.
Serious cams give the full duration and the duration at 1mm or 50thou if it's a yank cam. depending on the ramp length the first 20-30 degrees of opening the valve lift is less than 1mm or 50 thou, Which is not enough lift to flow. Again depending on the ramp length the last 20-30 degrees the valve is also below 1mm or 50 thou so not enough to flow. it is possible for a cam with a shorter overall duration using short ramps to have a greater duration at 1mm than a cam with longer overall duration but longer ramps. I have seen very few aftermarket vw cams which mention duration at 1mm. Shorter ramps are very hard on valve spring on lift and hard on the valve because instead of seating in gently it basically drops the valve back onto the seat. At sustained high rpm this wears out the valve train quicker. the first cam probably has no overlap at 1mm. The second probably has a tiny bit. Find out the duration @ 1mm to be sure. You could go with some stiffer valve springs and have a cam made with very short ramps which would allow longer duration without overlap. A graham Bell has a good chapter in his 4 stroke performance tuning book that goes further into this.
Cheers mate, just to clarify...The 'ramp' is the lobe/severity of the lobe? Im not really sure how to go about 'speccing' a cam for what i want? I could just go for the newmans, the piper or the schrick 268/276 but im sure they can give a little more in one way or another. Neil.
Cheers lads, much appreciated thus far Im trying to find the spec of the Schrick 268/276 to work from, its a pretty expensive cam, but if i can find the spec i can have it ground by newmans...possibly tweak it too. Don't suppose anyone knows the details? Neil.
Camshaft Data: - Number of degrees = 268 / 276 - Spread = 112 - Valve lift = 11.2 / 11.5 mm - Stroke in OT = 1.3 / 1.8 mm - Asymmetrical profile
another camshaft worth considering: http://www.bahnbrenner.com/vw_audi/products/454/8V_Hydraulic_Camshaft_268_260
Depends what you want out of the car i guess , i have a mk3 8v schrick 276/276 in my g60 works well for top end power , but suspect it looses some torque low down Steve at PSD mapped so was fine once mapped , but it does pulse rather a lot I reckon your better off spending the money on a better head and using a schrick spilt duration cam
Cheers lads. Ill be playing with the head meself at some stage Duff and i agree that the schrick 268/276 looks like a good all rounder, but id like to incorporate the exhaust duration of the newmans. Im just looking into the lift on overlap of the newmans though as it may be too much for what i want... G60, cheers mate. Looked at that bahn brenner cam, but id like more duration on the exhaust side to help with scavenging, pulling the boost through and getting rid quickly. Neil.
