heavyduty

I was wondering would if its possible to run a 2*-4* degree advance on a cam in a computer controlled car... would do any good in a computer controlled car? or would it make the computer go crazy?

UnderCover89TBI

iTrader: (25)

from my experience, if you have to advance your cam. your cam is too big. id just install it straight up and adjust the base timing yourself and let the computer handle the advancement.

eflores

he's talking about advancing the cam timing not giving it viagra! cam too big? its a stock cam! it isn't gonna grow any bigger if you advance it. sounds like your talking out your hind side to me, apparently you never heard of advancing or retarding the cam to crank correlation to pickup torque or HP down low to the OP IDK lets try it and see its not changing duration or lift so you shouldn't have any issues out of the comp and it should in theory pull the same amount of vacuum so the ECM should have map sensor issues, i dont believe the TBI motors check cam / crank correlation so IMO it should be fine

BronYrAur

iTrader: (1)

If it's the stock cam, I don't know why you would ever want to advance it. It's tiny and makes gobs of torque down low, but lacks any top end power. If anything I would think retarding it would do you better, but I wouldn't do either. The heads are limited on the upper level. Your best bet is just to buy a well suited cam for whatever setup you choose to run.

Change cam timing all you want, it's still a garbage cam.

Nub383

I think most Comp cams come advanced 4*. Isn't that what the -4 on the end of the part number means? Do they just assume that the customer is over-camming the engine so they go ahead and advance it for you?

BronYrAur

iTrader: (1)

You're right they do grind in advance, usually 4*. It's my understanding that they grind the advance in, so that when you install it at zero (dots aligned) the cam is completely unloaded. Then when you set your valvetrain up it applies load on the cam, returning it to about 0*, not sure how accurate that actually is. The built in advance is good though because you have to figure the timing chain is going to stretch pretty quickly and the ground in advance may account for that.

UnderCover89TBI

iTrader: (25)

his post doesnt say anything abouta stock cam, you assumed stock I assumed if he was there he was putting in a bigger aftermarket cam so excuse me.

heavyduty

WOW...yah i am going back with a stock vortec cam...back in the day we would take an RV type of cam and throw a 4* advance on it for low end since it was for our trucks and such...i am working on my surburban right now and with me and the family loaded with all the gear we take with us i would say between the 4800lb burban and all the kids etc....its an easy 6000 lbs...so i am just looking for anyway to get better mpg...

there used to be a good advantage of moving the cam around along time ago..before the computer age...so i really had not clue what would happen if applied to a computer controled car..anyways thanks guys

Fast355

iTrader: (2)

With the L31 vortec cam you are running, I honestly do not see any point to advancing it. The valve timing events are nearly optimum for getting good fuel economy. I suspect you will see a solid 1-2 mpg improvement from the decreased friction of the roller lifters and the more aggressive roller profile.

IMO, the only cam that would get better fuel mileage is the roller from the TBI cars. The peanut cam, stamped 155. It would do better on mileage because the duration and overlap are MUCH less. It was designed to pull around 4,000+ lbs cars with 2.56 gears and OD.

eflores

btw it got thrown in weekend b4 last and it runs good for being in a heavy **** suburban

heavyduty

Yes we got the BIG GOLD BRICK going with the new motor...I put in a vortec cam, edlebrock performer RPM intake with adapter plate, and roller tip rockers...really alot more torque..kinda grumpy in the mornings when first started for about 30 seconds..but runs good on the stock chip. It just makes me wonder how good it would run with a tune...