Cam timing - to retard all advance

[Jono]

Hi all,

Dave Walker has written an article in Januarys PPC magazine covering cam time which makes intersting reading.
He sugests using the figures supllied with the cam as a starting point and then advancing the cam as this often picks up hp , check your results with a rolling road.

Unfortunatly I dont have a rolling road at home and with C1J being a total pain to adjust the cam timing on trial and error basis, can someone give me some figures of cam advance or retard that are know to work well on the C1J. Im using a Piper 285 with starndardish CR.

ta

Jono

[Sparkie]

depends on the turbo you are running....

[Jono]

t25

[Sparkie]

t25-t25 or t25-t2 ?
do you run the 0.35, the 0.49 or the 0.64 back end?

the bigger the number, the laggier the turbo, the later you want the cam to come in, the more you need to RETARD the cam...

[Jono]

Its a full T25 0.49AR.

How much would I retard? I dont know if 1 degree would be a huge or tiny step. If you get what i mean.

[rs250nut]

Would an egt gauge not come in handy here? Why not modify or get hold of an adjustable timing sensor?

[Jono]

RS I thnk you have mixed up ignition and cam timing!

[Sparkie]

someone once told me 4deg max. eitherway.
how true it is, other people will tell you on here! - who are have far more camtastic knowledge than me.

[Scoff]

some advance past the base number does not generally make for peak HP anyway, maybe more hp at lower rpm's, I'd re-read that article to be sure of what he means.

as sparkie says, some retard is what you might want if your interested in making big HP numbers and/or going quickly on the drag strip. I ran a lot of cam retard on my C1J, I think sparkie did too some moons ago

[Jono]

I was probably a bit unclear in my initial post, I think Dave Walker was refering to the fact , as a general rule their are gains to be had by advancing the timing. These gains could be outright horsepower or drivability. Though the article makes no reference to how this applies to Forced Induction over NA.

My 5 is for track work rather than on the drag strip.