cam timing trick

[TXMazdaSpeeder]

my friend told me on his fs-de 626 he took the cams and moved them a little and gained hp...anyone know exactly what he did?

[viVid]

Probably slipped them a tooth. I was off a tooth on my intake cam after installing the j-spec one... absolutely no low end power and not much gains, if any, up top. There was a more abrupt change in power though, which I think most people mistake for "more power". FYI, I figured out that each tooth is about 6 or 8 degrees (can't remember, it has been a while). This is definitely not a fine enough adjustment for properly tuning the motor. To do it correctly, you need adjustable cam gears and some dyno time.

[akhilleus]

Actually there are a couple ways to change cam timing. First u can have the cam pin moved so that it either advances (low end) or retards(top end) the cam timing. or u can retard the cam gear timing(lowend) or advance it(top end) Vivd mistakenly advanced his cam gear timing. However I had my cam gear timing retarded and it totally brought back my low end that had been lost from other mods. I had it retarded by one tooth(i think it is 4deg) Its nice cause now i can dump top end power on it... But for fine adjustments, especially if your cams produce their usable power outside of the powerband or above the redline, then u kinda need cam gears... but power can be gained, however if u have your cam gear timing changed they may need to find TDC(top dead center) to align the valve events correctly in relation to the crank.

[Installshield 2]

Probably slipped them a tooth. I was off a tooth on my intake cam after installing the j-spec one... absolutely no low end power and not much gains, if any, up top. There was a more abrupt change in power though, which I think most people mistake for "more power". FYI, I figured out that each tooth is about 6 or 8 degrees (can't remember, it has been a while). This is definitely not a fine enough adjustment for properly tuning the motor. To do it correctly, you need adjustable cam gears and some dyno time.
This is an excellent post...When someone claims they gained power through little tricks, always take it with a grain of salt...The human body CANNOT recognize the extra accelerating force associated with a small bump in hp (takes usually more than 5hp on a physics level)...90% of the time comments like this are made more because of a change in the power and torque curves associated with these mods...a loss at lowend which then climbs back to slightly less than the original ouput quickly can be easily mistaken for a gain in power...when in reality they could be "peaking" lower than what they were before the mod...

Anyway...to do it correctly you need a dyno and a set of cam gears...Our ignition system will not allow any tooth slipping on the exhaust cam (it drives a triggering sensor...to make it really complicated any exhaust cam mods will be recieved as intake mods, simply because the ECU will treat one point on the exhaust cam gear as TDC...so moving that gear will just alter the intake cams postion at TDC relatively...that be confusing)...You could play around for days though even with the cam gears and still not get accurate gains without some dyno runs...so to do it correctly it takes a good bit of time...

[TXMazdaSpeeder]

i think im just gonna buy cams and forget it.

[wannabe]

probably a wise decision

[akhilleus]

actually depending on what cams u get u might need to get cam gears anyways, just to make the powerband available. Especially with cams u must realize that it will generally push your powerband higher, which may or not be good, but oftentimes it can make your low/mid weaker... cam gears can compensate for this. In my case the cam gear timing adjustment moved my powerband down at least 1k rpm. Now i have a good base for adding more top end gain mods. Cam gears/timing adjustments could even benefit a JDM/msp cam combo.

[Gen1GT]

On my car, 1 cam gear tooth is worth 12 degrees. That's HUGE. As in, piston slapping, valve breaking, no power whatsoever huge. .5 degree cam changes can yield a power difference.

Install is right, there's only one way to tune your cam timing, and that's on a dyno. Even what physics tells you is 'supposed' to happen when changing timing, doesn't always happen. It usually does, but with much more sacrafice than you'd think.....

[Gen1GT]

actually depending on what cams u get u might need to get cam gears anyways, just to make the powerband available. Especially with cams u must realize that it will generally push your powerband higher, which may or not be good, but oftentimes it can make your low/mid weaker... cam gears can compensate for this. In my case the cam gear timing adjustment moved my powerband down at least 1k rpm. Now i have a good base for adding more top end gain mods. Cam gears/timing adjustments could even benefit a JDM/msp cam combo.
He's right, you'd be foolish to get cams without being able to adjust their timing.

[akhilleus]

I think on our car the it is 8deg per cam gear tooth, however i have never run into any problems with valve interference, and also my powerband was not dramatically changed, but was changed just enough. I had thought, but i could be wrong, that the crank rotates at half the speed of the cam gear so it is more like 4degrees, also both intake and exhaust were retarded equally. Since i obviously dont have adjustable cam gears, i think twilight would be more suited to responding to this.