When I was hanging at a friends shop today we were all talking about our forced induction builds for over the winter. When we were discussing which cams we are running in our motors one of the old timers in the shop said that with our turbo setups, we should retard our cams 4 degrees at the cam sprocket on the timing chain. After this, everyone in the shop had a different opinion. Another turbo sbc guy said he wanted to advance his 4 dregrees. At this point I was going to leave mine at straight up at 0, but does anyone else have any opinions in this matter?

 

to vague

 

Comp told me , my cam had a 4º advance in it , so with a 113 lobe it goes in at 109 . I've never degreed a cam myself so I'm not exactly sure if I'm saying this right .

I let my engine builder do the short block stuff , like ring gaps , bearing clearences , cam degreeing ,ect .

I dont mind spending a little extra to have these things done right by someone with lots of experience.

 

it all depends on combo there is no way u can just say to advance with a turbo and retard with nitrous, dyno is the best way, or someone who has had experience building.

 

4* retard is probably way too retarded. I've found that turbo motors generally like a little less advance, but not retarded. I've found that N/A is in the 3-5* advance area, turbos like 2-3*, nitrous motors like 6-8*. I have yet to find any street engine run best with a retarded cam.

This is very vague and for street engines under 6500 rpm with a well matched cam. A poor cam choice can throw everything out of whack. Dyno is the only way to be 100% sure. I would not run it straight up. But don't confuse straight up with the notches on the cam sprocket. Most cams will have advance ground in. Check it and make sure it's where you want it.

 

turbowagon

These are more than likely the same guys that would tell you a blow thru won't work either.

 

Thanks for the infoeveryone. What the guy at the shop said didn't make much, I was just trying to get someone else's point of view

 

Advance 4* Retard 4* From what?

To answer your question.
You should always degree your cam in to know what you have to start with. There are differences in timing chains, differences in where the intake lobe is ground on the cam, etc.

There are a lot of things to consider. With out knowing all of the details I would say that if you set the intake in at 108-110 range you should be really close. If you advance the cam (smaller number) you will move the power band down slightly, retarding the cam (larger number) you will shift the power band up slightly.

 

Advancing or retarding the cam changes 4 valve events all at the same time. So, whether you need it retarded or advanced depends on which valve event is screwing you the most.

The most influential valve even is Intake Valve Close. On my car, my IVC was fairly late. Coupled with low static compression, my dynamic compression was very low and therefore, the low-end response and torque was poo. I advanced the cam 4 deg, and the car gained alot of pre-boost low-end. The car became much more driveable and the 60's and quarter mile times dropped also.

In my particular application, advancing 4 was the right thing to do.

Mike