Outer Limits 4x4 Board

got a 304 efi with t700 in a gu running dual fuel, 285x16'' & 4.1 diff ratio
i need to know what is a good size cam i'm running the standed cam at the moment in which is a bit under power for the wagon
also whats a good brand

thanks

this is wat i use. crane 286. 511'' lift with 1.65 ratio rockers, you will also need to replace springs. get springs that match the cams lift. Good power from around 3000rpm to 6000rpm. You really need to up comp to 10.1 to get the best out of cam, you can do this by maching 40'' of the heads or change the piston. You got half the eng apart any way so doing the heads is the best way.I guess at the end of the day it depends wat you would to do with the car and how much your chasing. Maybe a smaller stick like a crane 276 if you do crawling, I think the comp can stay standard for that one

This is a pretty impossible question...
you could just get a std 30/70 grind cam for that motor, but it is unlikley to be exactly what you want..

In order to get a cam ground to exactly what you want, you will need to know:
Is the motor stock? (without at least some exhaust and computer work a new cam will be pretty useless)

if it has been modified:
Piston to deck height
Type of piston
has the head been shaved
Bigger valves?
rocker arm ratio
compression ratio
any porting work
inlet manifold type
extractor type (likley Tri-y) for a 4x4
primary exhaust runner ID
secondary exhaust runner ID
collector size
exhaust size and muffler type
Vehicle mass and gearing

Required RPM for max torque (the higher this is the narrower the powerband will likley be, but more HP)
what you are trying to achieve with the engine (towing, economy, all out performance ect.)
what % do you use gas/petrol
ect ect.

if your keen try to get as much of this info as possible and speak to a porfesional, ie crow cams. caminquiry@crowcams.com.au

remember that fitting the cam is a big job and will require a new timing chain. think about $1000 to fit.

if you mostly run on gas, consider gas only, as you can run a higher compression ratio, and get more out of that new cam.

also 4.1 ratio diffs sound a bit high for those tyres, your money may be better spent on 4.3 or 4.6 gears, you will notice a signifigant power increase from this.

Very true a difficult question. Start with where do you want the power in the rev range. I'll be general but a naturally aspirated engine makes good power in a 3000 rpm window. If you have a manual and standard gearing, big tyres you need torque down low, from 1500 rpm. On a stock 5.0l I would suggest a maximum of 210 degrees at 50 thou. The best perfofrming camshafts usually have the most lift for a given duration, but more lift over a short period of time means faster wear rates.
If you put in a cam like 220 @ 050 you would make more power and torque but higher in the rev range meaning that the sacrifice in low end power may make the vehicle unfreindly to drive, slow at low rpm and prone to stalling, forget about trying to winch and drive, kiss the clutc good bye.
An auto with a high stall can bypass the engines inefficiencies of a larger cam but with the loss of engine braking and other issues.

The size of the camshaft duration is relavent to the size of the cylinder volume, a larger cylinder takes longer to fill and requires larger cam shaft duration for the same rev range. As does the cam overlap relate to compression ratio, if too larger camshaft is used without suitable compression the power output will be low, too much compression on a small camshaft will cause the inability of optimum ignition timing due to pre ignition at low rpm from excessive cylinder pressure.
It takes some experience to choose an appropriate camshaft/compression selection that matches the vehicle mass and gearing.

Joel

DA DUDE wrote:got a 304 efi with t700 in a gu running dual fuel, 285x16'' & 4.1 diff ratio
i need to know what is a good size cam i'm running the standed cam at the moment in which is a bit under power for the wagon
also whats a good brand

thanks

the motor at 165 kw's probably is not underpowered ( even though the GU 4.8 is more powerful)

you need a cam that makes heaps and heaps of torque before 2000rpm. this can be easily obtained by asking a cam joint OR,
you can just go and get a cam designed for a boat ( make sure its not reverse rotation)

this will give you the torque where you need it.

Jes

well thanks for all the inform have been told to check out the computer while on the dyno then if not happy do the cam so thanks alot again

cheers