blak92!

How is the idle of this cam properly tuned.
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'92 Z28 Black 5.7L 5 Speed
'95 Competition Yellow Corvette Coupe 6 Speed

[This message has been edited by blak92! (edited January 09, 2001).]

JakeJr

In a 350, idle is good with 1.5 rockers and vacuum remains high so there's no power brake problem. It's more noticable that a stock, but not in any way objectionable.

When you go to 1.6s on the intake and keep the 1.5s on the exhaust, the idle quality takes a small hit, but still very liveable.

It's when you put 1.6s on both the intake and the exhaust that the idle starts to give a little movement to the engine. It's still not unliveable, but You'll definitely know there's a cam in there. You also lose about 2 Hg of vacuum with 1.6s on the exhaust, but the brakes still work without a hitch.

A re-programmed PROM that raises the idle speed to 750/800 is really needed too. 650 is just too low IMHO.

I've tried running it in all the above configurations and had 10.8 CR at the time in my 355.

In my 415 you don't even know it's in there.

Hope this helps.

Jake


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1986 Corvette Coupe, 415 CID, Edelbrock 6073s, ZZ9


[This message has been edited by JakeJr (edited January 09, 2001).]

blak92!

Jake Thanx...
Of all the times this question was asked it was really never answered in detail like this. This was the answer I was hoping for...



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'92 Z28 Black 5.7L 5 Speed
'95 Competition Yellow Corvette Coupe 6 Speed

JakeJr

Here are a couple of other things I just thought of.

I had mine checked on a computerized camshaft checker at Dennis Wells' Racing and the duration numbers are not as advertised.

The intake checked 208.4 @ .050 with 1.5 rockers and 213.4 with 1.6s. So in order to get close to the 212 that is advertised I needed 1.6.s on the intake.

The exhaust checked closer to the advertised spec though. The exhaust lobe checked 224.1 with 1.5 rockers and 228.1 with 1.6s. (I'm going from memory on this; I may have the .1 and the .4 flip-flopped).

I don't know about the experience of others running the same cam but the lifters, (also TPIS'), needed one full turn of preload in order to keep the valve train quite. I tried the 1/4, 1/2 and 3/4 preload adjustments that I'd gotten away with on other profiles, but the ZZ9's ramps didn't like those preloads. So it took one full turn from zero lash to quiet them down.

I've got the computerized cam checking results saved to a file I can send you if you'd like to see it.

Hope this helps.

Jake

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1986 Corvette Coupe, 415 CID, Edelbrock 6073s, ZZ9

Ski89Z28

JakeJr, could you send me a copy too?
I would be real intereseted in this too since I run the ZZ9 cam too.
My idle is still a little rough but I had a bad ignition module and I haven't been able to reset the timing, IAC and TPS voltage sinc it is too cold. I also think the TPS level 5 chip isn't programmed too good so I hope to do some programming of my own soon.
Thanks,
Mike

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89 IROC 350 Auto
Custom DUAL Exhaust
Edelbrock Performer 6085 Aluminum Heads
ZZ9 Cam
TPIS Level 5 Chip
14.01 @ 97.0mph with 2.77's gears and a bad ignition control module!
And Free mods.

gta324

My idle is good when it's warm, but when its cold it seems a bit worried....

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GTA -89:Free flow muffler,dual 3" HF cats, Edelbrock headers, Vette heads, 1.52 RR 7/16, ZZ-9 cam, Big Mouth, AS&M LTR, !plenum, 52 TB, MSD 6AL, TPIS level V prom, Superior shift-kit and all the minor mods. and more to come!
http://www.itv.se/tacs/members_cars/m279/m279.html (Swedish Trans Am Club)

blak92!

I have an article in an old corvette magazine that stated the intake duration for that particular ZZ9 was 208 on the intake side. In their catalog they state the can "taylor" the cam to the customers needs. That would be great if you could send the computerized cam checking results.


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'92 Z28 Black 5.7L 5 Speed
'95 Competition Yellow Corvette Coupe 6 Speed

[This message has been edited by blak92! (edited January 10, 2001).]

JakeJr

Here's some more info TPIS and their famous ZZ9.

Before I had mine checked, I called TPIS to get the specs on the cam. I was told the cam has 212/224 @ .050 .484/.520 lift with 1.5 rockers. I was told I needed 120 lbs of spring seat pressure but when I pointed out their booklet said I needed a lot less, the guy recanted.

I then asked for the seat and .050 timing numbers (IO, IC, EO, EC) and was told they didn't have them!!!

Then I put up a post on another board and a guy scanned and sent me his timing card. It showed 212/224 @ .050.

Their website shows 212/226 (two twenty six) and .483/.520 lift with stock 1.5 rockers.

Mine checked 208 on the intake and my lobe centers checked 112.6 If the .050 duration specs are off a TOTAL of one degree, I don't feel it's a biggie, but to have the intake duration off by almost 4 degrees is really bad.

So it's apparent to me that they are playing a numbers game and/or their quality control suffers.

In all the years I've degreed in CompCams and Crane camshafts I've never found ONE that was off my more than 1 degree in duration and the LCA was always spot on. I've degreed both street and full race cams of hydraulic, mechanical and roller versions and those two companies know how to maintain tight quality control on their cams.

Bottom line: You really don't know what you've got unless you have the camshaft checked.

Hope this helps.

Jake

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1986 Corvette Coupe, 415 CID, Edelbrock 6073s, ZZ9

[This message has been edited by JakeJr (edited January 10, 2001).]