Aftermarket Cams For Ecr33 Rb25det .

[discopotato03]

Camshaft time for my late 96 R33 GTS25T so I need to explore options .

I suppose for simplicities sake most would just grab a pair of Tomei pon Cams because they drop in and work .

Now because I read posts about people using Tighe cam profiles I spent a bit of time and bashed out a few E mails to see just what they have . I got one reply from them saying that they are able to use Ford Sierra profiles on RB hydraulic type camshafts - lobes must be similar between YBB/BDA and RB hydraulic camshafts .

So from their site the first 3 Sierra profiles (708C/805C/845C) are like this .

708C 13 59-62 10 , 252/252 , 215 at 50 , 0.345" (8.763) lift .

805C 14 60-63 11 , 254/254 , 220 at 50 , 0.355" (9.017) lift .

845C 14 60-63 11 , 254/254 , 224 at 50 , 0.402" (10.21) lift .

From what I hear std camshafts (RB25 or RB26) need to be built up so that the lobes base circles say approximately the same to not screw up hydraulic buckets oil feed supply . STD RB26 cams must have greater lift so less to build up .

For road I like the idea of shortish duration and as much lift as mechanically possible because I think thats the way to make torque without turning high engine revs . The shortish duration is supposed to keep up the cylinders trapping efficiency up and any extra lift gets the largest flow restriction (valve heads) further out of the ports .

Extra lift while being good has limitations like the valves need to have a minimum distance clear of the piston crowns in the overlap phase (all valves open and piston moving over top dead center) . Also the buckets need to follow the lobes meaning the springs have to be up to the task . As the fella doing my head said "If the springs dom't close the valves the pistons sure will" ... Bent valves don't seal so big compression loss and exy repairs .

The 64 dollar question is do you stuff around with local cams or just go with the tried and apparently proven Tomei drop in ones ? At this point cost rears its ugly head and if there is a significant difference either way the cheaper one will probably get the nod .

I would really like to see what the R33 RB25 Pon Cams numbers look like but really its the result thats most important .

So unless Tighe can offer me something worthwhile at a competitive price the answer is right there .

Garys laughing at me again I can feel it , A .

[PM-R33]

Buy my HKS ones, simple

http://www.skylinesaustralia.com/forums/Rb...nc-t230152.html

Personally i wouldn't bother with reground cams unless they are a lot cheaper than the jap ones.