Adjustable Cam Gears

[MazdaTGTS]

I brought from eBay a set of Fidanza adjustable cam gears for my 323 with a GTX swap. I think is an excellent way to increase power. My objective for the car is to try increase top end power when I think is my weak spot . My question is if anyone has experience with adjustable cam gears on our cars and how many degrees advance/retard will give more power. I know in theory if I retard the timing will give me more top-end an advancing will give low-end power and better throttle response. Obviously I have to go to a Dyno to find it. But any ideas or experience will be appreciated.

[MazdaRacer]

Haven't heard any tuning done on a BPT, but both Gen1GT and naprotejay have done some good tuning on the BP. It may be a start atleast.

[Gen1GT]

I have adjustables, and I found best power with the intake retarded 4° and exhaust set at zero. It's hard to say just how much I was able to move the powerband up(and therefore trade low RPM power for high RPM power), but my intake cam and cam gears got me 8whp. If you change your exhaust cam timing, remember to reset your ignition timing, as the distributor is attached to the exhaust cam.

Like you said, the only way to know is on the dyno, as every combination with react somewhat differently. I'd try playing with the intake side first.....and oh, go out and get yourself another exhaust cam, and install it on the intake side. Do a search on 'exhintake cam' and research that....

[MazdaTGTS]

I have adjustables, and I found best power with the intake retarded 4° and exhaust set at zero. It's hard to say just how much I was able to move the powerband up(and therefore trade low RPM power for high RPM power), but my intake cam and cam gears got me 8whp. If you change your exhaust cam timing, remember to reset your ignition timing, as the distributor is attached to the exhaust cam.

Like you said, the only way to know is on the dyno, as every combination with react somewhat differently. I'd try playing with the intake side first.....and oh, go out and get yourself another exhaust cam, and install it on the intake side. Do a search on 'exhintake cam' and research that....

8 whp that is a lot for a NA application. I think for a turbo it will be more I guess. I will let you know. Thanks

[Gen1GT]

Ya, 8whp is a pretty good gain for one mod. With a turbo, the very same mod would net 15+ at the wheels. Check out my dyno chart. Red is before the cam and cam gear, green is after. As you can see, I got power right down from 3000RPM. So this would make an excellent FI mod also. My mid range comes on strong, and doesn't stop til fuel cut. There's is no downside to this mod, other than maybe MARGINALLY worse fuel milage. I must punctuate that I have the RX7 AFM, and tuned that on the dyno also. Anyone who's doing a semi-serious build with the stock, or piggyback computer is a fool to have not done the RX7 AFM anyways.....


Baseline, Before Cam, After Cam

[mike323]

I brought from eBay a set of Fidanza adjustable cam gears for my 323 with a GTX swap. I think is an excellent way to increase power. My objective for the car is to try increase top end power when I think is my weak spot . My question is if anyone has experience with adjustable cam gears on our cars and how many degrees advance/retard will give more power. I know in theory if I retard the timing will give me more top-end an advancing will give low-end power and better throttle response. Obviously I have to go to a Dyno to find it. But any ideas or experience will be appreciated.

I've done dyno tuning on a turbocharged BP and this is what works.

Retard the intake cam by 2-6degrees. Valve opens later.
Advance the exhaust cam by 2-6 degrees. Valve opens earlier.

Idealy you want more duration on the exhaust cam, than the stock BP exhaust came, especially if you're going to run more than 7psi.

If you want a modified exhaust cam I can provide you with one.

[MazdaTGTS]

[QUOTE=mike323]

Retard the intake cam by 2-6degrees. Valve opens later.
Advance the exhaust cam by 2-6 degrees. Valve opens earlier.

QUOTE]

How much whp you got with that setup?

[92_2_fast]

don't mean to thread whore. but what would you ask for the cam? Does anyone have a dyno chart with the gears and a bpt? And what are you setting your timing-distributer-to?

[mike323]

[QUOTE=MazdaTGTS]

Retard the intake cam by 2-6degrees. Valve opens later.
Advance the exhaust cam by 2-6 degrees. Valve opens earlier.

QUOTE]

How much whp you got with that setup?

We got 28whp with regrinded cams and the adjustable cam gears. I personally don't have data on the stock cams. But you should get around 10whp by playing with the cams gears and the stock cams.