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I would be interested in this too... The X-51 cams have a different part number, so they could be an upgrade. I think 3rd party ones may be cheaper though.
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Porsche 996 Carrera - '98, black, 3.4, induction kit, equal length headers, Intrax adjustable titanium dampers, UK M030 ARBs, SSK, carbon strut braces, LSD, Carbon buckets (black Alcantara/ red stitch), yellow (rebuilt) brakes, grey refurbed alloys, alcantara and red stitch GT3 gear stick, Toyo R888 track tyres.
3.4 & 3.6l cams are not interchangeable, just for information only. 3.6l X51 cams cost €2665,- at Porsche Germany, Schrick's similar ones are approx. 1750,- , also in Germany.
Autofarm charges £1600,- +VAT for that Schrick set.
Just the cams will not do miracles, you'll need a complete head job for maximum gain. A full X51 set ( cams, heads, intake & exhaust manifolds ) add 25 hp, according to the factory. My own guessimate is that there might be even more to gain with extensive head machining. We'll be back to that later...
BTW, if someone is interested, I have a full set of unused and NEW 3.6l X51 cams, which I'm willing to sell for half of that factory price...
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Pete
'87 951, RIP
'00 996 C2, L92U AQ / IXAA IXRB IX54 M030 M375 M376 M436 M476 M601 M983 ... + 997 turbo brakes, GT3 mkII sway bars and F & R adjustable control arms, Bilstein Cup Car coilovers revalved for GT3 RS springs, Techart SSK, PSE
What makes the cams not interchangeable? I was under the impression that the engines were virtually identical other than the longer stroke of the crank?
Cat cams (google them if you aren't familiar) would probably do you a set and they are well priced and gaining a real reputation for making good power with driveability, so may be worth a look.
I have seen flow curves for the heads and it does look like a set of cams would do *some* good as the full flow is not utilised with the factory cams. There is also little 'meat' to port the inlets from what I have seen and the standard inlet geometry would be hard to improve. At the risk of damaging your heads, I wouldn't actually touch them. Also, the metal *can* be soft on M96 heads and machining the face/ chambers can be risky.
If I was to drop my engine then I would look at higher CR pistons and cams if I was to stay with the standard capacity but 3.4 -> 3.7 would be best. These engines liek compression by all accounts and I like squish and torque.
I have also looked into the X51 aluminium inlet manifold as I wonder whether the standard, plastic one may be restrictive especially since you can't port match it?
Pete, what are your thoughts? Are you upgrading an engine?
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Porsche 996 Carrera - '98, black, 3.4, induction kit, equal length headers, Intrax adjustable titanium dampers, UK M030 ARBs, SSK, carbon strut braces, LSD, Carbon buckets (black Alcantara/ red stitch), yellow (rebuilt) brakes, grey refurbed alloys, alcantara and red stitch GT3 gear stick, Toyo R888 track tyres.
What makes the cams not interchangeable? I was under the impression that the engines were virtually identical other than the longer stroke of the crank?
3.6l has VariocamPlus, which includes a cam position wheel in the middle of the cam. EDIT: Of course in addition to this the cam lobes are totally different. It's hard to explain how, so see this animation: http://vids.myspace.com/index.cfm?fu...ideoID=7065336 Std Variocam lobes are "traditional" ones.
Quote:
Originally Posted by Dom9
Cat cams (google them if you aren't familiar) would probably do you a set and they are well priced and gaining a real reputation for making good power with driveability, so may be worth a look.
Googled, cams only for 996 GT3 Race and 911 2V heads, so nothing for M96.0x engines. German regrinder dbilas is another alternative though.
Quote:
Originally Posted by Dom9
I have seen flow curves for the heads and it does look like a set of cams would do *some* good as the full flow is not utilised with the factory cams. There is also little 'meat' to port the inlets from what I have seen and the standard inlet geometry would be hard to improve. At the risk of damaging your heads, I wouldn't actually touch them. Also, the metal *can* be soft on M96 heads and machining the face/ chambers can be risky.
I can comment after I've seen - and touched - a dismantled head. EDIT: Jake Raby claims just with his heads ( = cams/valves etc ) 1XX hp/l.
Quote:
Originally Posted by Dom9
If I was to drop my engine then I would look at higher CR pistons and cams if I was to stay with the standard capacity but 3.4 -> 3.7 would be best. These engines liek compression by all accounts and I like squish and torque.
I have also looked into the X51 aluminium inlet manifold as I wonder whether the standard, plastic one may be restrictive especially since you can't port match it?
At least plenum volumes and runner shapes are completely different. X51 parts ( plenum / runners / in & ex ports / exhaust ) are machined to match at the factory. EDIT: I think plenum/runners could be machined ( careful sanding & polishing ) to match manifolds, which can be matched to heads etc.
Quote:
Originally Posted by Dom9
Pete, what are your thoughts? Are you upgrading an engine?
I might be, I'm still weighing my options: a complete swap or a rebuild to 3.x l. In rebuild the cost effectiviness of X51 heads vs. machining of originals is still unclear. Also I still haven't decided whether to use LN Engineering or Autofarm services for displacement increase...
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Pete
'87 951, RIP
'00 996 C2, L92U AQ / IXAA IXRB IX54 M030 M375 M376 M436 M476 M601 M983 ... + 997 turbo brakes, GT3 mkII sway bars and F & R adjustable control arms, Bilstein Cup Car coilovers revalved for GT3 RS springs, Techart SSK, PSE
So, I would use them for any work. For the power increase you get though, the 3.7 (or even 3.9 with the 3.6 crank) is very, very expensive, especially if you are yet to blow your engine so don't 'need' one.
I have been toying with the idea of rebuilding an early Boxster S 3.2 engine as that is virtually identical and i could sell my good 3.4 for good money and buy the 3.2S for much less, effectively saving a couple of grand. Or, for the same money, running all steel internals.
Cams would be nice, but i don't see much point without high CR pistons as I have been told that I wouldn't want to skim the 3.4 head face much to get the CR up - at which point, i might as well rebuild the whole engine.
Cat Cams will do them if you ask, so that shouldn't be much problem and we have some good value regrinders over here, if that is possible, which it sounds like it is.
330bhp would be nice (10% increase) but that may be achievable, just, with bolt ons (full exhaust including headers, upgraded induction including maybe plenum) and a re-map/ stand alone ECU (with a rev limiter increase). I have been looking at the Emerald ECU over here as it is good value and very well respected in performance circles. I am still concerned about longevity though, so a rebuild including liners would see most sensible. I wouldn't want to spend a load of money only to have the engine pop after a few miles.
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Porsche 996 Carrera - '98, black, 3.4, induction kit, equal length headers, Intrax adjustable titanium dampers, UK M030 ARBs, SSK, carbon strut braces, LSD, Carbon buckets (black Alcantara/ red stitch), yellow (rebuilt) brakes, grey refurbed alloys, alcantara and red stitch GT3 gear stick, Toyo R888 track tyres.
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