Well, time slips don't lie ;) I went racing friday with the intake set to - 3 degrees retard, and the results are - slower car :(

All runs but one were 15.67 to 15.74, with one 15.59 run where I got a really good launch. The best trap speed of the night was 88.60 mph. Now the weather did not really cool off until after racing was over (no cill in the air) but on other days rather recently when it was hotter I was getting higher mph with the intake cam advanced.

And, compared to the last day I was racing when I hit my best 1/4 mile time (in the sig below, of course ;) ) I am 1.7 mph slower than before. The temperature was cooler when I ran my fastest run, but not 1.7 mph cooler :) if you get what I mean. So I think advancing the intake cam is the way to go from the 1/4 mile results.

Also, I went over this again and again to be sure (comparing what different camshaft indexes would do to shifting the valve lift profiles of the exhaust and intake valves in comparison to each other), and advancing the intake cam is what we'd want to do for more overlap and top end, retarding the intake would help bottom end. You guys had it right, and I had it right the first time before I second guessed myself. Oh well, nothing like a little tuning to figure things out.

So, I re-adjusted the intake to +4 degrees advanced. I let the car idle until it warmed up (didn't have a chance to drive it and push the car to redline since it's raining) and it seems to idle fine with the car just starting to kind-of sort-of lump/lope/stumble but not really. Can't really describe it but is seems fine to me, not really noticeable. Next time up to the drag strip I'll see what happens.

Thanks for the help before everyone.

Turbo Magazine did a review with AEM cam gears not to long back. Anyone know what there settings were cause they weren't listed.

Its hard to tell these kind of things, you are decreasing overlap but possibly letting more air in which isnt overcoming the decreased overlap so maybe the overlap should be shifted a little with a retard in both cams, like E-5 I-2(0) or so, maybe even bigger moves would help like breezio said(can we move the cam gears to the full limit without piston strike?). Only problem here is you risk leaving the exhaust open too long and have the gases coming back into the chamber and it opening too late and slowing the piston, but in my mind high engine speeds should negate both of these. I looked at the stock duration, pretty much 220*, so I figure the intake opens 20* BeforeTDC and closes 20* AfterBDC(if you look at it simply) and the exhaust opens 10-20*BeforeBDC and closes 20-30*AfterTDC. But maybe the intake and exhaust are switched, who knows! Anyway you look at it this is more evidence that stock we dont get a good overlap so thats something that must be addressed, but whether or not our exhaust and intake are tuned for the upper rpm in my mind is still not fully answered!
Brent

todd
What is your exhaust gear set at with your intake set at +4? I want to reset my gears and was wondering.

thanks

When I was naturally aspirated, I had my car dyno-tuned with the AEM cam gears. The best setting was: adv intake 2 degrees, retard exhaust 2 degrees. This setup netted 7 whp.

They didn't list thos settings in their mag article. I e-mail the tech guy and he e-mailed me back... and this is what he said

"Normally we don't give out this kind of information because it gives readers
the impression (or hope) that they can tune their cars with other people's
specs. This is entirely not true. The point of tuning a car is to extract
the most power out of your particular motor; this cannot be done without
some type of horsepower measuring device (a dyno.) And, if you have access
to a dyno, you should be able to adequately tune your specific engine.

Now, with all of that said...

The intake was advanced 7 degrees. The exhaust was left at 0 because any
change (advance or retard) lost power.

I hope this points you in the right direction." now they had a ca back exhaust, a header, aem cold air aem cam gears and 50 shot NOS. this article said they resulted in a 7 WHP increase

I have the exhaust cam set to 0 as well.

With my best run and the 90.3-90.5 runs I had, my intake was at +3 the exhaust was 0.

Hey, it's not a bad place to start, and yes different cars would need different settings but in general certain things would apply and can give you a place to start from. It's like tuning the SAFC. You would start off by leaning out a bit (say -5%) becuse all our cars run too rich at WOT, but to know how far to lean it out you need to log some O2 readings at least, if not using EGT, wideband O2 readings, AND dyno time to help REALLY fine tune it.

I just adjusted my cam gears. I had them set at Intake R2 and Exhaust R5. I'm now running Intake A5 and Exhaust 0. My idle is alot better as well. Thanks for the advice.

Glad I could help. It seems if you leave the exhaust cam alone you can bump the intake cam a little more in the advanced direction. (well that makes sense since the overlap between the gears should be the same with a +2 intake/-2 exhaust versus a +4 intake /0 exhaust setting)

I drove the car around a bit at +4 last night in 55 deg. weather, it sure felt like it had more power than with the intake cam set at -3! And it seemed to idle fine. Hopefully I can get to the track friday.

One question, why were you set at intake -2 retard and the exhaust at -5 retard? Just trying something different?

Actually those were my settings I guessed at earlier, either he tried them or was using them before. Just out of wondering is there a good power difference between the I+5 and the E-5 I-2? Any quirks while running this setup?
Brent

The reason I was set at -2, -5 was because this site said to. I have my head milled and it says if you have your head milled then go with the -2, -5 setup.

you got some good numbers. I just want to know what your shift points were in the 1/4? and do you 2-step? if not what do you think I should? right now i'm 2-steping at 3250 rpm.