C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
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Old Jan 16, 2015 | 11:26 AM
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Has anyone hopped up the 81 and kept the ccc system and was satisfied????????
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Old Jan 16, 2015 | 05:21 PM
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I think the question would be how much do you want to hop it up?
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Old Jan 16, 2015 | 06:54 PM
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Originally Posted by The13Bats
I think the question would be how much do you want to hop it up?


DUB
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Old Jan 16, 2015 | 07:44 PM
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The most and keep the ccc.
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Old Jan 16, 2015 | 08:11 PM
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There is nothing inherent in the CCC system that would limit your modification of the engine for performance. The Q-Jet carb (if it is performing adequately) is everything you would need, unless you put nitrous () or a blower on the engine, too. It has 750 cfm capacity and will 'self-regulate' to the needs of the engine. {This same basic carb was installed on most 454 engines too.}If operating properly, the fuel mixture solenoid [in the carb] should provide the fuel rate you need. There may be some need to alter the secondary rods, but this is something that you need to investigate, should you decide to do it.

You should be able to change cam, heads, and exhaust manifolds/pipes with no problem. If you want to retain the operating CCC system and upgrade the exhaust, you may need to run both exhaust manifolds (whatever brand you choose) into one large (3") outlet that contains the O2 sensor. Not sure how you would deal with it if you wanted dual exhausts all the way back.
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Old Jan 17, 2015 | 12:04 AM
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Originally Posted by 7T1vette
There is nothing inherent in the CCC system that would limit your modification of the engine for performance. The Q-Jet carb (if it is performing adequately) is everything you would need, unless you put nitrous () or a blower on the engine, too. It has 750 cfm capacity and will 'self-regulate' to the needs of the engine. {This same basic carb was installed on most 454 engines too.}If operating properly, the fuel mixture solenoid [in the carb] should provide the fuel rate you need. There may be some need to alter the secondary rods, but this is something that you need to investigate, should you decide to do it.

You should be able to change cam, heads, and exhaust manifolds/pipes with no problem. If you want to retain the operating CCC system and upgrade the exhaust, you may need to run both exhaust manifolds (whatever brand you choose) into one large (3") outlet that contains the O2 sensor. Not sure how you would deal with it if you wanted dual exhausts all the way back.
Thanks for your reply. Currently I have true duals and sensor in the left bank and it runs fine. All smog is gone, timing is set at 12, and larger secondary rods. Car runs good. Engine is stock with 120,000 and never touched. I want to go with different heads and cam and keep the ccc. Everyone says to get rid of the system but I want to try and keep it. I have been on here several times but just can't get an answer of which heads and cam will work. Any help from you would be appreciated.
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Old Jan 17, 2015 | 04:00 AM
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Rebuilt motor, head work on stock heads, Crower cam, high flow cat, roller rockers, Flowmasters, rebuilt/tuned stock carb-runs great with ccc. As said the ccc keeps the fuel mixture at the ideal fuel/air ratio.

Last edited by RC81; Jan 17, 2015 at 04:04 AM.
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Old Jan 17, 2015 | 02:55 PM
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The CCC has a "problem" with a cam that has a good amount of overlap as this reduces vacuum at idle and so the MAP sensor sends a low vacuum signal to the CCC which then "thinks" the engine is under load and thus needs more fuel. The engine will run okay, except it will be overly rich at idle and at crusing. Have an easy mod for the MAP sensor to fix this.

Heads....spend as much $$$ as you have. The stock heads are thin casting and have a 99.9% probability of being cracked, junk them and get a nice set of aluminum heads.
Put an O2 sensor in the header collector; although probably have to go with a heated O2 sensor due to the distance from the heads...anoher easy mod....just need switched +12V.

The stock intake is fine, not really worth replacing with anything unless you replace the stock hood with one that has a higher rise.

Pistons.....stock are dished low compression ones. Get a nice set of 2 valve relief flat top, 0.030 over and have the block zero decked. Going to spend a bit on a set of head gaskets that will yield the "perfect" quinch volume....but hey....its only money!

Do all of this and the engine will likely be well over 300hp. Now if you have a 4sp trans, the biggest change for the "seat dyno" would be to change-out the 2.73 rear gears and go to 3.07 or higher....as long as you do not expect to cruise down the highway at 80mph for any length of time. RPMs will be pretty high.

I have done all of this except change rear ratio on my '81.

Sure wish I had all that money & time back that I have spent on this '81!!!

Last edited by LannyL81; Jan 17, 2015 at 06:39 PM.
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Old Jan 17, 2015 | 03:46 PM
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This cam should work:

http://www.summitracing.com/parts/hrs-cl113215-10

If it's the stock lower end find heads with small chambers to bump up compression.

I'm going to be using ZZ4 heads with that cam. Trick flow 175s would be a good choice too.
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Old Jan 17, 2015 | 06:22 PM
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For your build, it would be useful to include a F/A gauge in the plan. That way, you could actually read how the F/A mixture is being handled at cold start-ups, warm idle, cruise, and at WOT and evaluate the performance of the CCC system with engine upgrades.

Unless to go to a very radical cam, I think you will be OK. But, it would be really interesting to collect some 'hard' data on how it all works.
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Old Jan 17, 2015 | 06:41 PM
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A F/A meter would be very helpful. Beg, borrow, steal, buy a wideband O2 meter with a narrow band output; connect narrow band output to the CCC and data log away.

If you get one....can I borrow it?????
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Old Jan 17, 2015 | 08:06 PM
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As a previous 81 owner who brought the CCC back to life and then Mod'd the motor..I was very happy! Lanny81, Qwank, and several others all helped me. I have since sold my c3 and got a c6 (2005 with 9000 miles) but I do miss the C3...I did add a new cam, heads, headers, MSD, etc and the CCC was just fine. Matter of fact the only mod i did was the MAP sensor trick of sending constant 4.2 volts to the map sensor so the CCC would play nice at ideal with the low vacuum from the new cam. if you get that far search the forum for my user name and you will see the threads I made on the build and mod of my map sensor for my 81.

The Q-jet and CCC are great - it doesnt care about HP
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