If you upgrade your exhaust manifold to some extractors and a proper intake, any mild cam (a regrind even) will give you significant power increases, and make you car rev more freely. While it can be argued that the extractors and intake will do this by itself, it really depends on the restriction imposed by you gas system how your car will perform and what sort of power and torque gains you will get from the cam specifically.
I have a friend which was able to obtain 120 rwkw on a stock (300+ k) motor with a crap gas system, a 2.5inch exhaust with a hi flow cat and extractors and a cam. Point is it was pulling hard, and very happy revving. And it got real happy revving once the cam was in...
What I mean when I say gas will decide:
If you have an old-style gas system which is a mixer stuck inside of the plastic stuff between the airbox and the throttle body, you will have larger gains due to the cam (but you can't use a pod) consider a bmc hi flow air filter in the standard air box (and remove the snorkle. they prefer warmer air)
If you have a larger mixer which forms an integral part of your intake system, you may be able to use a pod, and this will in itself increase performance. A cam will help here also. (depends if it's closed loop or not)
If you have a gas-research type throttle body which mixes the air and gas there, you can definately use a pod type filter, and you will pull serious power. I am not sure how much of it will be due to the cam though.
pulling upt to and including 140 rwkw is very easy with a stock I6
my engine was fresh but stock stock pistons and all that i cleaned up the ports "did not port them" put some crane valve springs in her and a crow 2529 camshaft i think from memory and bolted some extractors and an exhaust and pod and it pulled 148rwkw and a massive 504nm of torque at the treds!
might not sound like much power but thats truck loads of torque thats more torque than any turbo diesel 4x4 on the market and they are flywheel readings!
the first thing you want to do is decide what rpm range the engine will spend about 80% of its time in. for the street that is the 1000-5000 rpm range. now select a few cams from different grinders that work in that rpm range. you can push the range up or down a bit as needed. once you have the cams you want to look at, check the specs on each cam, and look at the lobe separation angle. for the street you want a lobe separation angle in the 108-112 degree range. if you are running a low compression engine, then the wider the better. with a high compression engine you can go narrower. next look at the lift the cam will generate. for best low speed and mid range power, higher is better. then look at duration, where the intake valve closes, and valve overlap. longer duration, higher rpm power. later intake valve closing higher rpm power. longer valve overlap, high rpm power. some of these choices can be mitigated though with the proper selection. for example, 112 degree lobe separation angle with longer duration will trick the engine into thinking the engine has a higher compression ratio at low rpm, while maintaining higher rpm power.
hi. use crow 2222519 cam, pacemaker 4480 extractors and good 2.5" cat and straight thru glass pack muffler( walker / lukey ) Gas likes cold air more more so than petrol so keep the snorkel on but you must have a balance line of at least 16mm id going to your convertor. fixed gas mixer in air intake is ok if sized right but best for power is impco 425 modded to run inline. run a pod filter but modded to use inside stock air box so its away from heat, after market snorkel with more flow is a must. (s&s inductions or equiv). you will be impressed. cheers.
hi loud. around $600 for supply and installation of crow cam. i sell a mandrel bent stainless steel intake pipe for $325. it goes in to stock air box, best results when used with K&N air filter and big cold air snorkel. stay away from the pod filters unless you are going to fit it inside the stock air box. cheers
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