Adjusting Cams

[volymmannen]

Hello
Is there any experience of adjusting cam timing on F7 engines? has some one gained anything by setting the cams in a different timing other than specified lift at TDC?
seams silly money on pulleys, if you set them as standard pulleys.

[Vandella]

was wondering the same thing just yesterday.. I presume you could remap for more fuel/air and disregard the mpg, make it abit more aggressive.. if that's what you wanted to do.. as I presume Renault went in the middle for best fuel efficiency setup.. only a presumption though!!

[Wobba]

Well, you can take the cam pulley locating lug out to adjust on standard cams, but tbh I have no idea about possible gains in advancing the timing on standard inlet cams. I guess it might be beneficial at higher rpm maybe, but would need a remap and higher RPM limit to take advantage....

[volymmannen]

So pulleys are useless assuming you get the cams in the specified lift at TDC on standard pulley regardless of cams you use ?

[kj16v]

Depends on the situation and the setup. Turbocharged engines are extremely sensitive to cam timing. While experimenting with timing on turbocharged engines I've seen gains of 40 bhp and 40 lbsft. Invariably you lose one while gaining the other, so it's a balancing act of torque and power to make the engine as fast as possible on the tarmac.

Natually Aspirated and supercharged engines tend to be less sensitive to small changes in cam timing. Often adjusting cam timing is more about moving the power band to suit the driving style and also to retain the engine's idle/low-end driveability as much as possible without losing power.

[tutuur]

@Kj16v

Do you have experience with retarding the intake cam on a turbocharged F engine?
Been playing with the idea for a while but don't have the car mapped correct enough and lambda feedback to the ecu isn't stable so won't be able to log any differences atm.

[kj16v]

Done a lot on Lancia Integrale engines but not F7 engine, though the results will be much the same; Retarding the inlet will tend to gain horsepower and lose torque, having the effect of "flattening2 out the torque - up to the point where power drops off again.

On an F7 I'd probably want to try advancing the exhaust can maybe 2 degrees to gain torque - providing the car can put the torque to the road and the chocolate gearbox can handle it!

[tutuur]

That isn't the problem as i have a 02m gearbox, i was wondering because i have a gt3071 in a t25 housing so it'll probably choke on the top end. I'd rather lose some in the mid range to gain some at the top.

i was thinking to retard the intake cam by 5 degrees...