Chuck84TA

Here are some cam specs -- is this too much cam?


I've got a CCC quadrajet - rebuilt with larger idle tubes and larger fuel inlet.

Vortec heads on a L98 350 bored over to a 355.

Cam specs -
112 Lobe separation
Duration intake 226
Duration exhaust 234


Will this work out?

Chuck84TA

Originally was thinking this was ok, then I've been hearing differing opinions --

Damon

You're definitely on the bubble. I've gotten them to work with 224* cams, but up in the 230+* range it was definitely not happy. They're more "self tuning" than EFI systems are, but they have their limits. Mostly once you get into big lumpy cams, the mere fact that the ECM shoots for 14.7:1 mix at idle and part throttle is a problem. You can NOT make a big cammed motor run acceptably that lean (not with a carb and wet-flow manifold, anyway). It will surge and hesitate and buck and basically give you the middle finger.

sofakingdom

iTrader: (1)

Roller or flat?

Chuck84TA

Roller cam

Chuck84TA

Would burning a chip help?

sofakingdom

iTrader: (1)

An aftermarket roller with any given "specs" tends to act like about 10° more cam than a flat that "appears" to have about the same "specs".

I'm thinking it'll test your tunning skilllllz TO THE MAX and then some.

Prolly too much. I'd suggest backing it off a notch. High 2teens, low 220s. Be VERY aggressive except smaller.

Chuck84TA

So burning a chip to make the ECM happy is not adviseable?

If I kept the cam, I would be looking at moving to a non CCC Qjet, Holley or an EFI setup?

sofakingdom

iTrader: (1)

I'm not aware of it being practical to "burn a chip" for that old system. It's even more Stone Age than TPI or TBI. If memory serves it's a MC6809. To my knowledge it was never sufficiently reverse-engineered for hobbyists to be able to modify it.

Pretty much, you're at a crossroads; that cam, or everything else. Not both. It might "work" well enough to at least drive, but having BTDT, I don't think it'll really be completely satisfactory.

naf

iTrader: (7)

The biggest problem with the ccc-qjet system, in this regard and IMO, is that it is so SLOW. A larger cam will require the system to 'hunt' for that optimum ratio and the resulting idle can fluctuate whereas a more efficient system may be able to compensate faster.

AFAIK the ccc has never been hacked and I'm not sure what could be done to it anyway, other than perhaps disabling O2 input under certain conditions.

Another issue with it is that reading it disables the timing advance functions (with later KS equipped models). This makes real-time work with it difficult.

Chuck84TA

So, if I move to a more suitable cam alternative ..... Some alternatives would be

1- LT4 Hot cam

Lift (In/Exh) Duration (In/Exh)
.525 / .525 218 / 228

2- ZZ4 cam --- (seems like a bit too weenie though )

.474 / .510 208 / 221

3- Lunati Voodoo--

http://www.lunatipower.com/Product.aspx?id=1988&gid=289

Advertised Duration (Int/Exh): 270/278
Duration @ .050 (Int/Exh): 219/227
Gross Valve Lift (Int/Exh): .515/.530

4-jegs Chinesium special

http://www.jegs.com/i/JEGS+Performan...00500/10002/-1

I assume any of these cams would work with my Vortec heads.... 1.5 roller rockers, though ..

But as long as that qjet is a happy camper, that's really all that matters... The cam spec drop probably won't decrease hp/tq all that much from the original cam specs, running a smooth motor with some respectable kick is all I care about anyway.

Chuck84TA

Having said all of that....perhaps I should have mentioned in the beginning that this is not your "stock" CCC Qjet.


I rebuilt it with Cliff Ruggles' HP rebuild kit with the .135 fuel inlet

The Idle air tubes were enlarged by Cliff

The Primary shaft has had the bushing treatment

The Throttle plate was checked for warpage, sanded down as necessary.

New TPS/MCS have been installed.


Then --- get a 1228079 computer with a custom chip from GMCOPO--(Seems pricey, but if anybody can hack a CCC ECM youd think they can..

http://www.gmcopo.com/gmcopo%20zz4%2...r%20tuning.htm

http://www.gmcopo.com/Forms/CLCC%20C...0Worksheet.pdf


So with these modifications in mind, do I have a snowballs chance in hades to have a descent running motor?

86LG4Bird

iTrader: (1)

maaaybe not so weenie ?
It depends what hp level you're shooting for.
Not trying to say you should use the ZZ4 (personally, the Lunati option sounds the best to me), but just for reference:
From trap speed and car weight, my daughter's car in the sig with the ZZ4 cam is doing about 325 hp through factory TPI exhaust and manifolds. The Vortec heads are not ported, just bowls and valveguides cleaned up. 1.6 RR's on the intakes, 1.5's on the exhausts.
I think with headers and good exhaust, you could push 340-350 hp with it.

Chuck84TA

Well 350hp is certainly a goal. Was hoping the 226/234 cam could/would work, that would push it into the 400hp range...

But good idle (Vacuum) performance is also important to me...


I'm trying to find that "sweet spot" cam for the CCC that provides very adequate vacuum and very respectable horsepower for what I've got so far. So yes... I want my cake and eat it too...

Chuck84TA

How about 218/226 --112?

naf

iTrader: (7)

For your requirements, the LT4 cam is a proven performer. I installed one last Summer with 1.5 rockers and my idle fluctuates some at around 800-850. Bit more lope than a mech carb could provide but livable.

You also have the option to run it with 1.5 rockers then maybe step up to 1.6s later.

Fast355

iTrader: (2)

I am not sure if these are still on closeout, but I picked up one of these from Lunati for under $100.00 shipped. Basically a Hotcam with quicker ramps and more lift.

http://www.lunatipower.com/Product.aspx?id=2607

http://www.lunatipower.com/CamSpecCa...rtNumber=10030

w41duvernay

I'm in the same boat here. Does anyone still do a custom chip tuning for a 86 Quadrajet LG4 305 Firebird? I contacted TBI chips and got a no! I can supply OEM chip. Yes I have a 212 @.050s (Comp Cams 260H) cam in it now, and an Edelbrock 3701 manifold. And I'm dropping in a set of headers in it, w/ a 3" single exhaust system.

Chuck84TA

I had GMCOPO supply a new computer and PROM based on my 355 build. Why do you want a new chip for your LG4?

http://www.gmcopo.com/GMCOPO%20ZZ4%2...r%20Tuning.htm

Chuck84TA

Oh, sorry...ok new cam headers... Just read it again

Chuck84TA

It's not cheap. But my engine build runs well with the CCC Qjet

w41duvernay

Define Not cheap, please! And I can supply the OEM chip to be redone. The OEM peanut cam is 41 degrees smaller than the Comp Cam 260 H profile.

Chuck84TA

I sent my engine/trans/rear end specs and It cost me around $500 to have GMCOPO supply a prom, computer and ZZ4 knock sensor. Also figure in a modified E4ME with larger idle tubes to feed more gas at idle, that could easily run $400/$500 for a quality rebuild to suit the increase in cam and other mods.

Then way I see it, it's my (your) car and its value is only important to you. Others may say, waste of money ... That's fine, it's not their car anyway. My car runs great with the GMCOPO mods than before it was done. Plus the aggressive cam I've got is very street able with the computer mods.

Chuck84TA

Not sure if supplying your own OEM chip will help defray costs, but it's worth looking into. Good luck!! Any other questions you have just shoot me a message

Chuck