Vs series 3 v8 ute

[The J'rod]

I'm actully looking at going 219/225 lobe sep @50 - .544/.533 lift - 112 LSA, thats a grind that howards cams has, wont be getting one off them as they want $1200, but will have one done to those specs, the rev range for that going by the cam manufacturer is from 1800-5600, which is perfect for what i'm after within the rev range, but then i ring or email another manufacturer and they say they it would bleed off way to much down low with stock compression, and then you have to decifer whether or not there just trying sell you there cam or whether it is true.

[vlad01]

I would highly recommend giving Clive cams a call. Their top quality billet cams are about $500-600 iirc. I paid $450 odd for my billet v6 custom one.

They really know their stuff too.

[lowace]

I'm actully looking at going 219/225 lobe sep @50 - .544/.533 lift - 112 LSA, thats a grind that howards cams has, wont be getting one off them as they want $1200, but will have one done to those specs, the rev range for that going by the cam manufacturer is from 1800-5600, which is perfect for what i'm after within the rev range, but then i ring or email another manufacturer and they say they it would bleed off way to much down low with stock compression, and then you have to decifer whether or not there just trying sell you there cam or whether it is true.

I think your meaning duration at 50th which buys the looks of it is a very close cam to mine save for a couple of degrees duration. I can vouch that it wont be coming on around 1800 unless you have a stroker with some good comp in there, i'd say it would be more like 2500rpm but thats only my opinion. I have attached my cam specs so take a look and see what you reckon, I would highly recommend giving Sam a call at c.o.m.e on 0395557308 and having a chat with him, I was just speaking with him about my staroker combo and he really knows his shit which I suppose 40 years of building holden v8's will give.

[MAGP]

but then i ring or email another manufacturer and they say they it would bleed off way to much down low with stock compression, and then you have to decifer whether or not there just trying sell you there cam or whether it is true.

It is probably true for a 5 litre, a 5.7 wouldn't be affected as much. The basic science is the larger the duration at 50 thou the higher compression you need to combat a longer exhaust evacuation (sorry the correct terminology eludes me at the moment) thus causing less cylinder filling. The higher the 50 thou duration the higher the usable rev range. for every 10 thou extra you can add 500 rpm to the rpm lower and upper limits for the same engine. For every half a litre engine capacity added you can lower the rpm range by approximately 500 rpm. Note I said approximately.

[immortality]

You can't look at the .050" numbers alone, to get a really good idea of how a cam will perform you also need the .006" numbers. You don't really get any genuine flow into the cylinder until about .050" lift but the piston will push air back out of the cylinder until the valve is fully closed.

To use a classic cam as an example, the Crane 286 is advertised at 294° (.006") and 230° @ .050 and .490" valve lift now you can get a similar cam from Kelfords in NZ which is also listed as 230° @ .050 but it only has 280° advertised duration and as a bonus has about .518" valve lift. The Kelfords cam will run better than the Crane with less compression because the inlet valve closes much earlier and therefor bleeding off less cylinder pressure but has a more lift and aggressive ramp rate so will make more power to boot.

That COME CSBR 416 is a really mild cam for a roller.

Edit: that cam listed above from Howards is a much more decent roller cam grind.

[vlad01]

The term is called dynamic compression ratio, a relationship between valve timing events and static CR. You hit the nail on the head on what you said.

[MAGP]

Thanks for the correction Vlad but the term I couldn't think of in my old age was valve overlap. Silly me forgetting Cam 101 .

[The J'rod]

Immortality in your opinion would say that Howard's cam is to aggressive for stock compression and will bleed off to much down low with 8:8:1 stock compression, I have an extrude honed banana manifold going on which I'm hoping because of the long runners will maybe hang on to the torque a bit more down low, but obviously still get the airlow going, as most people who put in an agressive cam change inlet manifold to an aftermarket with short runners, could all be a bit of mith and hope on my side with that, but love getting feedback from guys on here with genuine knowledge.

[vlad01]

Well it will likely help some, but really depends on induction wave timing interacting with valve timing.

There is actually a good calc here to work out runner length. If the cam happens to demand a length the same or close to the actual ones then you are laughing, if its way off then you're at a loss.

Note that induction wave amplitude is inverse of the harmonic number and so is the length. Normally 3rd is the preferred practical but you can check other numbers and see what they land on, as well as other parameters.

I recall doing a sim and calcs on a 5.7 with a moderate clive cam and stock bananas and the runners were bang on for size and length for the combo and rpm range, actually up to a max of 6k so limiting factor was not the length but rather the stock elbow and bored out stock TB would choke it before reaching the manifolds true potential.

http://www.wallaceracing.com/intake-runner-length.php

[immortality]

Immortality in your opinion would say that Howard's cam is to aggressive for stock compression and will bleed off to much down low with 8:8:1 stock compression, I have an extrude honed banana manifold going on which I'm hoping because of the long runners will maybe hang on to the torque a bit more down low, but obviously still get the airlow going, as most people who put in an agressive cam change inlet manifold to an aftermarket with short runners, could all be a bit of mith and hope on my side with that, but love getting feedback from guys on here with genuine knowledge.

It's hard to say because there are no advertised timing numbers. It's definitely a more performance orientated cam simply by looking at the lift numbers.

edit: If I'm reading this right you are intending to build a stroker, if that is the case spec the cam to suit the stroker rather than the 304.