Degree of advance for big cams?
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TECH Fanatic
Joined: Apr 2002
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From: kuwait
Degree of advance for big cams? I have MMS229 cam and I am woundering if I do a degree of advance, would that make any difference in adding more power to my car??
I feel my car is not as fast as it should be and how much of a difference would be expected ?
Thanks
Adnan
I feel my car is not as fast as it should be and how much of a difference would be expected ?
Thanks
Adnan
Re: Degree of advance for big cams? You need to have your engine dynoed like it is first. If the peak hp is about 200-400 below your shift points then it is degreed about right. And if you launch at peak torque you are degreed about right.
Most cams make max peak hp/torque with zero advance. This does not give best et in many cases. For the average street racer 4-6 degrees advance will give best results depending on how big a cam and how well your engine flows.
Need to know more before recommending advancing or retarding your cam.
Most cams make max peak hp/torque with zero advance. This does not give best et in many cases. For the average street racer 4-6 degrees advance will give best results depending on how big a cam and how well your engine flows.
Need to know more before recommending advancing or retarding your cam.
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Teching In
Joined: Mar 2003
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From: Fresno CA (home) Davis CA (school)
Re: Degree of advance for big cams?
What I mean is what do advanced mean? Why does a cam have advanced ground into it?
Re: Degree of advance for big cams? I think originally tuners were grinding 2 degrees advance to make up for the chain slop so the cam would be really installed straight up or equivalent to 0 degrees.
You can change cam timing or the power curve by advancing or retarding the cam. If you advance a cam, you'll lower your powerband and increase low-mid torque at the expense of a few rpm's on top, while retarding the cam you'll push the powerband higher. If you retard a cam and GAIN power mid-top, generally your motor wants MORE or a BIGGER cam. If you advance and you gain all the way to the top, you're over cammed.
Advancing/retarding is a tuning tool really. There is no reason to order a cam with advance/retard ground into it. If you order the right size cam to begin with that makes peak torque and peak HP where you want it, you don't want/need degrees of advance or retard. However, if you install the cam straight up without advance or retard and find out on the dyno you're making power below or above what you wanted, you can make some fine tuning adjustments with an adjustable timing chain to move your power curve to suit you.
But remember that advancing the cam will generally result in less Piston-2-valve clearance so beware. And this is just general, I'm sure there are instances where an over-cammed motor (or too high of a powerband for your needs) will run well with lots of advance. That's my take on the G5X2.
You can change cam timing or the power curve by advancing or retarding the cam. If you advance a cam, you'll lower your powerband and increase low-mid torque at the expense of a few rpm's on top, while retarding the cam you'll push the powerband higher. If you retard a cam and GAIN power mid-top, generally your motor wants MORE or a BIGGER cam. If you advance and you gain all the way to the top, you're over cammed.
Advancing/retarding is a tuning tool really. There is no reason to order a cam with advance/retard ground into it. If you order the right size cam to begin with that makes peak torque and peak HP where you want it, you don't want/need degrees of advance or retard. However, if you install the cam straight up without advance or retard and find out on the dyno you're making power below or above what you wanted, you can make some fine tuning adjustments with an adjustable timing chain to move your power curve to suit you.
But remember that advancing the cam will generally result in less Piston-2-valve clearance so beware. And this is just general, I'm sure there are instances where an over-cammed motor (or too high of a powerband for your needs) will run well with lots of advance. That's my take on the G5X2.
Re: Degree of advance for big cams?
Need to know more before recommending advancing or retarding your cam.
TECH Apprentice
Joined: Nov 2001
Posts: 309
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From: Tallahassee,Florida/ now Kuwait for good...
Re: Degree of advance for big cams?
What are the complete specs on your cam and take a look at your dyno sheet. I'm just not familar with an MMS229 cam.
Re: Degree of advance for big cams? [/quote]
229/229 .578/.578 114
[/quote]
If that cam is ground on a zero ICL it's going to take quite a lot of rpm to launch and shift to get optimum et. If you are limited to about 6400-6500 rpm shifts then I would advance it about 4 degrees and give it a try. Of course as I have mentioned if it's already in the engine then we need to look at the dyno sheet and see where peak hp occurs.
Did you port match your Mac headers? Are you running through a cutout? The Flowmaster muffler is pretty restrictive and may not allow for very high optimum rpm. For the cam to work best it has to have good intake and exhaust. Peak hp will be lower if the intake and exhaust will not allow good breathing.
TECH Apprentice
Joined: Nov 2001
Posts: 309
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From: Tallahassee,Florida/ now Kuwait for good...
Re: Degree of advance for big cams?
According to the cam card the specs are 230 578 114 with a 111 ICL. The advance works out to be 3 degrees if Im correct.