Northstar Engines and System Technical Discussion Discussion, Cam Question in Cadillac Engine Technical Discussion; This question does not really apply to the N*, but I was wondering what kind of improvements a performance camshaft ...
This question does not really apply to the N*, but I was wondering what kind of improvements a performance camshaft makes to an engine? I've heard its not really a power upgrade but an acceleration upgrade. Wanted to know how much power and acceleration it would imporve a car by, and if it is a good upgrade.
If you're talking about engines in general, think of the camshaft as the brains of the engine. Whatever you want the engine to ultimately do lies in the camshaft. Depending on lift, duration, and separation, you can take two originally identical engines and with a cam swap, make them do very different things. Depending on what you want to do, you can find a camshaft for it. If you want to tow, buy an RV cam. If you want a high-revving screamer with no low-end power, then you buy a huge cam with lots of overlap. If you want good fuel economy......well, you get the idea.
You can make a hell of a difference just by changing cam timing. Advancing cam timing improves bottom end torque. Retarding cam timing enhances top end horsepower. Mercedes was doing this on-the-fly in the 1930's. This is the reasoning behind Cadillac VVT engines. I've still got a drawer in my tool box with a handful of various offset woodruff keys.
Changing cams and choosing a grind is practically an art form.
Terms like lift, duration, degrees of separation, and profile all come into play and each little difference can change the performance of the engine itself.
Changing a cam requires more than just sticking a new cam in, often it requires re-tuning of the induction system, the fuel system and many other little nuances to make sure the engine runs properly.
The variable valve timing on most modern Cadillac Engines really enhances performance and adds to the complexity of the design of the cams themselves.
You can make or break an engine by swapping cams.
Back in the day I bought a fan to flywheel Z28 302 to put in my '66 El Camino. Chevrolet came out with a cam and spring kit for the Trans Am Z28's. I put that thing in it along with a carburetor off an L88 427 and AFR heads and it was like adding 2 more cylinders. That engine turned over 8000 RPM and when I held muster every horse answered up.
Take an engine, any engine, and stick a wild grind cam in it. Without extensive tuning and intimate knowledge of what power ranges you're tuning for, and why, you will undoubtedly create a pig. No idle, no fuel economy, no power, no reliability. "Stick a cam in it" isn't close to the answer........
The short answer should be yes.
Most of the sensors can make up for differences but to truly work properly with the grind of the cam you would need to change a few things in the calibration.
Technically it would run, but it might not "perform" the way you might expect.
About the only mods you can do to an engine that will improve the power throughout the range of operation is to raise compression and increase displacement, otherwise you are going to raise the output at higher RPM's at the expense of the lower and mid range. You are also going to narrow the power band and require more gears in the transmission.The rule of thumb is that the higher RPM you get the engine to peak at the higher the horsepower but the narrower the power band.
Computer control systems are truly wonderful, but they cannot compensate for cam grinds unsuited for a particular engine, nor can they replace the MECHANICAL advance and retard installation options in a non-VVT engine. And just how good are we at degreeing DOHC heads? Is there any way to degree the cams in a N*? Who makes the parts? Do you stab them in advanced or retarded? What valve degree centerline/overlaps do you use with a DOHC setup? Will Comp or Engle or Edelbrock go to their cam suppliers and order you a special grind? Have you ever seen aftermarket chains or sprockets? What piston/valve clearance do you need at TDC for valve interference in a 32-valve N*? If you go from stock SLS to stock STS cams, you still have to reflash the PCM. As stated in the above replies, an advanced cam starts its power/torque band at an earlier RPM than a retarded setup, which is better for long-term pulling or midrange power. A retarded setup favors power at the top of the RPM curve at the sacrifice of low-RPM streetability. Rotsa ruck.......
^^ Yeah I had in mind computer controlled cars. When upgrading a cam do you need to tweek the computer at all?
Depends on the grind... Something close to stock won't need any intervention. Something like the 288 degree's from CHRF will require a lot of modifications (that can't currently be done with the stock computer)
The 3800 guys swap cams all the time, but they have power tuners that allow them to adjust their MAF tables at idle, raise rev limiters, change shift points, etc...
Computer control systems are truly wonderful, but they cannot compensate for cam grinds unsuited for a particular engine, nor can they replace the MECHANICAL advance and retard installation options in a non-VVT engine. And just how good are we at degreeing DOHC heads? Is there any way to degree the cams in a N*? Who makes the parts? Do you stab them in advanced or retarded? What valve degree centerline/overlaps do you use with a DOHC setup? Will Comp or Engle or Edelbrock go to their cam suppliers and order you a special grind? Have you ever seen aftermarket chains or sprockets? What piston/valve clearance do you need at TDC for valve interference in a 32-valve N*?
I'm not sure what the point of this post was...
Do you want us all to get VVT heads?
You ask a lot of questions that can best be answered by Alan Johnson at www.chrfab.com
You can have the cam sprockets drilled to any combination of advance/retard you want.
Well, since this question applies to all engines, it's not fair to say swapping a cam close to stock won't require a computer re-program. Engines with MAF sensors take to modifications easily, but other engines such as the L05 in my Brougham with a TBI engine won't run well at all if I was to change the cam. Even if you swap in a cam that's close to stock, a computer re-program is in order, to truly get the engine running as best it can. But then again, if you're swapping the cam, you're probably not gonna swap to another cam that's close to stock, a cam swap is usually to gain some decent power.