Looking to de-Mod my 1984 Camaro Z28. Here is a list of it's current state. I am going to de-mod it to return it as a daily driver. I live in California (no jokes please) so I have to pass a bi-yearly test. I had problems off and on with passing the Bi-Yearly test. Which is the reason now to de-mod.

Block is a 1989 350, bored 30 over. This is a later model roller block
10.5:1 compression
World S/R Torquer 67cc heads with 2.02/1.60 valves
GM ZZ4 camshaft (1st cam) 275*/280* 208*/221* .474”/.510” 112*
Edelbrock Intake,
Stock Electric Feed back Q-Jet with some chang T56 and my 71 Nova with a LS1/4L60e... and a few others..es in the secondary metering rods.
Stock ECM with Jet chip.
Stock Exhaust system with Cat.. and a Flowmaster muffler.

I changed the cam a while back to a Crane 2032/104224 270*/276*, 214*/220*, .452”/.465”, 112*
and was able to still pass the SMOG test with some problem (which I now want to avoid).

So.. looking for suggestion on another shot and getting something I will not have to worry about going forward for years to come and make it a good daily driver with good mileages. Not looking to replace the whole engine.. But to just change a CAM...

I know.. you ask why?... will have have other cars to mod and drive.. my 71 Chevelle with a LS1/T56 and my 71 Nova with a LS1/4L60e... and a few others..

So.. looking for good solid suggestion and no guessing. I have been around for a long time and have read countless Threads, Magazines and such.. but most all are for upgrades mods.. not de-mod...

I am even considering a stock TPI replacement cam (CS-808 Seal Power) 207*/214*, .410”/427”, 117*

The stock L69 cam is 294*/294*, 202*/206*, 403”/.415”, 115*

I have had this since new. I was a backup car to a two time SoloII champ in 85' and 85' for F-Stock... looking to keeping it stock (for the most part).

Thanks in advance.

BC

 

I have an 84 TA, but LG4 with the E4ME carb. I stroked the engine to 334 ci, because 20 years ago, CT was talking about adopting California emissions standards.
So I had similar mods as yours. I used the Crane CompuCam 2050 and passed emissions.
I think you will have detonation problems if you go any smaller with your camshaft because of your 10.5 to 1 compression ratio.

This tip might help though (I've been doing this for 30 years): when you lean out a carb, your HC goes down, but your CO goes up. If you add 1 quart of denatured alcohol to the gas tank, your CO goes to ZERO (or really close). So then you are able to lean the mixture screws and not worry about failing on CO. Your camshaft duration and compression ratio affect your NOX reading.

 

NoEmissions84TA.. thanks. but the 2050 cam is a flat tappet cam.. I have a Roller Cam in place and would like to keep the Roller setup.

Yeah.. the 10.5 compression is one of my concerns.. but will work with it as needed. thanks for the suggestion on the Alcohol..Might have to resort to that.

BC

 

Wouldn't be surprised if the problem is with the Jet chip.

You shouldn't have any problems passing with a ZZ4 cam, assuming all else is up to snuff and set to factory specs.

 

After installing the Chip.. the idle and low RPM seem to improve some. But it could also be a cause to some emission issue ??


Thanks..


BC

 

W/o providing your emissions test data we can only guess where the problem is. And replacing parts one at a time is very expensive unless you change the right part the first time.

Emissions data I mean HC, CO, NOx. High HC and CO meens your rich. But EGR and ignition timing can affect this. NOx increases with higher combustion temperature and compression and timing can affect this to. Shorter camshafts close the intake valve sooner and increase the effective compression ratio.

Well I can't list every situation here but if you search the internet you can find much better information than on this forum. Here's a link that has a great chart of the emissions products and how they interact:
http://www.endtuning.com/afr.html

What I'm saying is find out what the problems really are before spending any more $$$ on parts. Many times it's a burned out cat or the wrong EGR.

Hope this helps.

 

The biggest change that CHIPS make is a more aggressive timing curve.